JP7500903B2 - Joint integrated product including different structural materials and manufacturing method thereof - Google Patents

Description

The present invention relates to an integrated joint containing dissimilar structural materials, in which dissimilar materials, such as various metal materials, FRP materials, FRTP materials, and other high-strength materials, are bonded together with high strength, and to a method for manufacturing the same. More specifically, the present invention relates to an integrated joint containing dissimilar structural materials, in which dissimilar materials, such as various metal materials, fiber-reinforced plastics such as GFRP materials, CFRTP materials, and other materials with significantly different linear expansion coefficients, are bonded together with high strength and laminated, and to a method for manufacturing the same.

The inventors of the present invention have proposed adhesive structures and methods for bonding various metal materials, such as aluminum alloy members, magnesium alloy members, stainless steel materials, copper alloy materials, titanium alloy materials, steel materials, and aluminum-plated steel sheets, to various FRP materials using adhesives (Patent Documents 1 to 9). They have also proposed a one-component epoxy adhesive and an adhesive method for use therein (Patent Documents 10 and 11). These adhesive bonding techniques basically involve chemical conversion treatments that differ depending on the type of metal material, and are an assembly (laminate) of adhesive bonding techniques between the various chemically treated metal materials and FRP or FRTP.

(Advanced Adhesion Technology: NAT)
The present inventors have developed and proposed an advanced adhesion technology for increasing adhesive strength, called NAT (short for nano adhesion technology). This is not a technology for improving the performance of adhesives, but a technology related to the surface treatment method of the metal pieces to be bonded, i.e., the metal pieces that are the adherends. In other words, NAT is an adhesive bonding technology for all metal types, and NAT specifies the following five points as necessary conditions for its establishment. Of these, the following three points ((1) to (3)) are necessary conditions for the metal pieces to be used, and the surface treatment method for chemically treating the metal pieces to satisfy these three points is called "NAT treatment".

The requirements for NAT are:
(1) Roughening the metal surface with irregularities of 0.8 to 10 μm period;
(2) Having ultrafine projections and recesses with a period of 5 to 300 nm on the rough surface;
(3) The surface forming the double uneven surface of (1) and (2) above is made of a thin layer of a hard ceramic material such as a metal oxide, a metal phosphate, etc.
In addition, the following two conditions are required regarding the type of adhesive used in the NAT and the adhesive operation:
(4) As adhesives, give priority to the use of one-component adhesives, and if one-component adhesives are not available, select and use the slowest acting hardener;
(5) The bonding operation includes a step of "soaking treatment."
The two conditions are:

The above condition (4) requires that the adhesive be attached to the metal surface as uncured low molecular weight molecules, and condition (5) is a process for directing the low molecular weight molecules to penetrate deep into the ultrafine recesses on the ultrafine uneven surface described in condition (2). In other words, to put it simply, what NAT aims for is that the preferred surface shape of the metal to be adhered is an ultrafine uneven surface with a period of 5 to 300 nm, and that having a rough surface with a period on the order of microns means that the density of the ultrafine uneven surface described in (2) above is high, and that applying the adhesive in a low molecular weight state (with low viscosity), penetrating to the bottom of the recesses on the ultrafine uneven surface, and then accelerating polymerization to harden it, produces the strongest adhesive strength.

This NAT theory has been verified with various metal materials (Patent Documents 1 to 7). In addition, although one-component adhesives are preferred for condition (4), the inventors have determined that, from the viewpoint of adhesive strength, the most effective adhesive for NAT is, at the current technological level, an epoxy adhesive, and most of the verification tests were conducted with one-component epoxy adhesives. In fact, the strong adhesive strength shown by NAT has shocked many skilled engineers. For example, when using the general-purpose one-component epoxy adhesive "EP106NL (manufactured by Cemedine Co., Ltd. (headquarters: Tokyo, Japan))," the shear adhesive strength of the above-mentioned NAT-treated bonded pairs of the same metal pieces was approximately 70 MPa at 23°C for almost all metal types, which is nearly twice the shear adhesive strength of the conventional adhesive method.

(One-component epoxy adhesive and its heat resistance)
In the test described in Patent Document 1, the NAT-treated JIS A7075 aluminum alloy (hereinafter, referred to only as "JIS" and "aluminum alloy" is also written as "Al") pieces were joined together, and the shear bond strength obtained by tensile breaking the bonded pair (test piece shown in FIG. 1) using the above-mentioned "EP106NL" was high and stable at 70 MPa. From this, it was thought that it would be possible to evaluate the adhesive strength of the adhesive by obtaining a one-component epoxy adhesive that is widely available on the market and measuring the shear bond strength of the bonded pair of the same A7075Al pieces mentioned above. Therefore, a dozen types of one-component epoxy adhesives that are commercially available in Japan and overseas were purchased and the shear bond strength of each was measured. Furthermore, the shear bond strength of the test pairs of A7075Al using these adhesives was measured in an environment of 150°C to obtain the heat resistance performance of each adhesive. As a result, it was determined that, among the currently commercially available one-component epoxy adhesives, "EW2040 (manufactured by 3M Japan Co., Ltd. (headquarters: Tokyo, Japan))" was the most suitable for the above-mentioned NAT. This is because, in the above test, the shear bond strength was approximately 60 MPa at 23°C and 30 MPa at 150°C. However, the present inventor subsequently made efforts to develop a heat-resistant one-component epoxy adhesive, and developed and proposed a one-component epoxy adhesive with a shear bond strength of 35 MPa or more at 150°C for the same bonded pair (test piece) using A7075Al (Patent Document 9).

(Method of measuring adhesive strength)
Patent documents 1 to 7 disclose the shear bond strength and tensile bond strength of one-liquid epoxy adhesives that have been subjected to NAT treatment and NAT operation for various metal materials. However, the adhesive used in the experiments of the present invention was changed from the above-mentioned "EP106NL" to the above-mentioned "EW2040". The reason for this is that it was determined that the heat resistance of the adhesive is essential to perfect the bonding technology with metal materials for CFRP materials, which have already begun to be mass-produced as ultra-lightweight, high-strength structural materials, and to use them as the main component of mobile machines such as aircraft and automobiles. Patent document 8 discloses the results of improving the NAT treatment method after making the above-mentioned "EW2040", which has excellent heat resistance, the standard adhesive used for the above-mentioned NAT, and discloses that the shear bond strength of the bonded pairs of various metal materials at 23°C has become more stable and the tensile bond strength has increased.

The adhesive strength measurement methods used in Patent Documents 1 to 9 and in the present invention described below are different from general adhesive strength measurement methods. That is, the shear adhesive strength and tensile adhesive strength described in these patent documents were not measured using the measurement methods specified in JIS (Japanese Industrial Standards) K6849, K6850, etc. It was determined that these standardized measurement methods were too strong to accurately measure the tensile lap-shear strength. With regard to the measurement of tensile adhesive strength, it is difficult to obtain metal pieces of the shape determined by the standardized method, and in particular, for many commercially available metal materials as plate materials with a thickness of 0.5 to 3.0 mm, the shape is not such that accurate values can be measured. That is, in each of the patents related to NAT disclosed by the present inventors and in the present invention, the shear adhesive strength was measured using the test piece shown in Figure 1 described below. Furthermore, when the invention described in Patent Document 1 was invented, the shape of the bonded pair used to measure the tensile adhesive strength was measured using a bonded pair in which the 4 mm x 3 mm end faces of two 18 mm x 4 mm x 3 mm thick metal pieces were bonded together. After that, there were changes, and in the present invention, the shape was changed to two 45 mm x 18 mm x 1.5 mm thick metal pieces, which will be described later, with the 18 mm x 1.5 mm thick end faces bonded together, that is, the shape shown in Figure 2 of the present invention.

(Shear adhesive strength of CFRP pieces)
The final goal of the inventors of the present invention regarding the adhesive technology was to completely bond CFRP material and A7075Al, and to utilize it for the production of the basic structure of aircraft and the like, which require ultimate weight reduction. On the other hand, NMT (short for Nano Molding Technology) proposed by the inventors of the present invention is a bonding technology that bonds metal and resin with high strength by injection molding of metal material and highly crystalline thermoplastic resin. The inventors of the present invention judged that if the metal surface treatment technology used in this NMT is diverted, it will lead to a high-strength bonding technology between metal materials, even in bonding dissimilar materials with adhesives, and completed the above-mentioned NAT. And, they thought that if they could use part of this NAT to successfully bond CFRP materials to each other and CFRP materials to A7075Al, they would be quite close to the above-mentioned goal. However, the shear bond strength of the bonded pairs of CFRP pieces, which are test pieces of the above-mentioned "EW2040" with the shape shown in Figure 1, was an unexpected value.

As a result of joint research with a carbon fiber (hereafter referred to as "CF") manufacturer, the latest type of CF used in CFRP materials for aircraft is a high-strength fiber with a tensile strength of about 6 GPa. Its electron microscope photograph shows that the cross section is almost a perfect circle, with no vertical streaks and a smooth side. A CFRP piece is cut out from a CFRP thick plate obtained by laminating prepregs using this CF, and the surface edge is roughened and other surface treatment is performed. The above-mentioned "EW2040" is then used to form an adhesive pair with the shape shown in Figure 1, and the shear bond strength is measured to be about 40 MPa. On the other hand, CF manufacturers have been producing CF since before the industrialization of this latest type of CF,
If this is the old-type CF, it is a high-strength fiber with a tensile strength of about 3 GPa, and its electron microscope photographs show various cross-sectional shapes, such as elliptical or gourd-shaped. The side of this CF always has one or two vertical stripes, and small convexities and concaves can be seen here and there. Similarly, the above-mentioned "EW2040" was used to make an adhesive pair of the shape shown in Figure 1 from a CFRP thick plate using this CF, and the shear bond strength was measured to be about 60 MPa. In other words, when a bonded pair of CFRP pieces bonded with a one-liquid epoxy adhesive is forcibly broken by shear, the breakage begins not in the surface layer where the adhesive and CF are bonded, but in the matrix resin layer separated from this.

The true adhesive strength between the CF and the matrix resin cured product is estimated to be about 40 MPa, and for the CFRP piece using the new CF, this value is the shear adhesive strength, but for the CFRP piece using the old CF, the surface area is large. That is, the new CF is a fiber with a cross section close to a perfect circle, but the old CF is not a perfect circle, so the actual surface area is larger than the nominal apparent surface area, resulting in a shear adhesive strength of about 60 MPa (Patent Document 9). In short, the question is how to bring the strong adhesive structure between the CFRP material and A7075Al that the inventor aimed for close to the ultimate strength of the material. Since the present invention is premised on the use of high-strength CFRP material for aircraft, etc., this means that even when using the above-mentioned "EW2040", a high-strength heat-resistant one-liquid epoxy adhesive, the maximum adhesive strength between the adhesive and the CFRP material is premised on an adhesive strength of about 40 MPa, which is slightly lower than expected, which is less than the strength of the adhesive.

WO2008/114669 WO2008/133096 WO2008/133296 WO2008/126812 WO2008/133030 WO2008/146833 WO2009/084648 Patent Publication 2016-210942 Patent Publication 2011-073191 Patent Publication 2011-006544 Patent Publication 2011-026457 Patent Publication 2016-60051

More than ten years have passed since CFRP, an ultra-lightweight, high-strength material, began to be widely used as the main structural material for passenger aircraft. It is well known how aircraft manufacturers struggled to build assembled structures (bonded structures) between multiple CFRP components, and assembled structures (connected structures) between CFRP components and extra-super duralumin (A7075Al, Japan Industrial Standard). CFRP has mechanical strength equal to or greater than that of high-strength metals, but it is essentially plastic, and various problems arise when it is used in fastening structures. For example, when drilling a through hole in CFRP material and fastening a bolt inserted into the through hole to another structural material, the CFRP material will be destroyed if the nut is tightened too much.

Even if CFRP and metal materials such as A7075Al can be strongly bonded, the use of such bonded structures in moving machinery such as automobiles and aircraft will be affected by temperature changes in the usage environment and temperature shock cycles caused by engine heat when moving or stopped. In addition, there are temperature changes due to seasons and climates, and in the case of aircraft, they must be able to withstand temperature changes between extremely low temperatures of -50 to -60°C in the stratosphere, high temperatures of +50°C at tropical desert airports, and high temperatures of over +80°C on the aircraft surface. In addition, automobiles used in extremely cold places such as Alaska and Siberia must be able to withstand the current test method of 3,000 temperature shock cycles of -50°C/+80°C, and in the engine room and near light emitters, they must be able to withstand 3,000 temperature shock cycles of -50°C/+150°C.

When the inventors first developed the chemical conversion treatment for the above-mentioned adhesive technology, they thought that the problem could be easily solved by significantly improving the adhesive strength against such temperature changes. However, when they started the durability test for practical use after that, it was not necessarily solved. The linear expansion coefficient of CFRP material is (0.1 to 0.2) x 10 ^-5 K ^-1 , and that of A7075Al, which is called super duralumin, is 2.3 x 10 ^-5 K ^-1 , so the difference in linear expansion coefficient between the two is 2.2 x 10 ^-5 K ^-1 . If the temperature drops (or rises) by 200°C during the temperature shock 3,000 cycle test of -50°C/+150°C, the length between the two materials will change by the product of 4.4 x 10 ^-3 , or 0.44%.

In short, if the adhesive strength is weak, it will not be able to withstand the deformation caused by such temperature shock and will break immediately, while if the adhesive strength is strong, it will not break even when the temperature changes, but the shape of the two materials will change slightly, and the deformation cycle due to temperature changes will be repeated. If this temperature change cycle is repeated several thousand times, it is estimated that at low temperatures it will suddenly break with a breaking sound such as a "crack". And even if the adhesive strength is very strong, the hardened adhesive has durability such as resistance to moist heat, and the metal material is a type that does not rust easily, the deformation due to temperature changes will continue semi-permanently. However, if the thickness of both materials is, for example, 10 mm or more, and they are joined together, both of which are highly rigid and difficult to bend and deform, large internal stress will be generated inside the material, and even if the adhesive strength is strong, the adhesive will break if there is a large change in temperature.

The inventors have proposed ways to increase the strength of adhesion between various metals and CFRP materials. However, when test pieces with the maximum adhesive strength proposed were subjected to severe temperature shock tests of several thousand cycles, it was confirmed that the larger the test piece, the greater the adhesive area, the more likely it was to be destroyed. In other words, there are limits to the development of improved adhesive methods to overcome differences in linear expansion coefficients, depending on the usage environment. In particular, there are limits to the adhesion between various metals and non-metallic materials such as CFRP, which have large differences in linear expansion coefficients.

The present invention is intended to solve the above problems and achieve the following objects.
An object of the present invention is to provide a bonded and integrated product containing dissimilar structural materials, in which two types of high-strength materials having a large difference in linear expansion coefficient selected from various structural metal materials, CFRP materials, and CFRTP materials are bonded and laminated with an adhesive, and a method for manufacturing the same.
Another object of the present invention is to provide an integrated product containing dissimilar structural materials, which is resistant to temperature changes and is obtained by laminating two or more high-strength structural materials having a large difference in linear expansion coefficient selected from various structural metal materials, CFRP materials, and CFRTP materials using an adhesive bonding method, and which includes the integrated product.
Yet another object of the present invention is to provide an integrated product including dissimilar structural materials, which includes bonding and clad bonding of two or more high-strength structural materials having a large difference in linear expansion coefficient selected from various structural metal materials, FRP materials, and FRTP materials, and a method for manufacturing the same, and which can be bonded and laminated using a commercially available one-component epoxy adhesive and two-component epoxy adhesive.

In order to achieve the above object, the present invention takes the following measures.
The joined and integrated product (e.g., the three-layer, three-material product in FIG. 4) containing the odor-causing structural material of the present invention 1 is as follows:
The two ends of the structure are made of two different materials, namely, material "A" and material "B", which are selected from a group of FRP and structural metal materials, respectively.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material of 0.3×10 ⁻⁵ K ⁻¹ or more are bonded with an adhesive,
The integrated product is
A plate-like material made of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm, which is material "D", or a structure of the pure aluminum-based aluminum is laminated between material "A" and material "B",
It is characterized in that it is made up of three materials, the "A" material, the "D" material, and the "B" material, which are laminated in that order with their joining surfaces fixed together.

The jointed and integrated product containing the odorous structural material of the present invention 2 (for example, the four layers and four materials in Figure 6) is as follows:
The two ends of the structure are made of two different materials, namely, material "A" and material "B", which are selected from a group of FRP and structural metal materials, respectively.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material of 0.3×10 ⁻⁵ K ⁻¹ or more are bonded with an adhesive,
The integrated product is
Between the "A" material and the "B" material, a thin plate of 1.0 mm or less made of a metal material having a yield strength of more than 150 MPa, which is a "C" material, and a plate-like object or structure of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm, which is a "D" material, are laminated;
It is characterized in that it is made up of four materials, the joining surfaces of which are fixedly laminated in the order of "A", "C", "D" and "B".

The jointed and integrated product containing the odorous structural material of the present invention 3 (for example, the five layers and five materials in FIG. 5) is as follows:
The two ends of the structure are made of two different materials, namely, material "A" and material "B", which are selected from a group of FRP and structural metal materials, respectively.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material of 0.3×10 ⁻⁵ K ⁻¹ or more are bonded with an adhesive,
The integrated product is
Between the "A" material and the "B" material, there is a "C" material, which is a thin plate of a metal material having a yield strength of more than 150 MPa and a thickness of 1.0 mm or less, and a "D" material, which is a plate-like object of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm;
It is characterized in that it is made up of five materials, the joining surfaces of which are fixedly laminated in the order of "A", "C", "D", "C" and "B".

The jointed and integrated product containing the odor-causing structural material of the present invention 4 (for example, the four-layer, four-material variant of FIG. 6) is as follows:
The two ends are made of two different materials, FRTP material (material A) and material B (material B) selected from a group of structural metal materials.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material is 0.3×10 ⁻⁵ K ⁻¹ or more are joined together,
The integrated product is
Between the "A" material and the "B" material, a thin plate of 1.0 mm or less made of a metal material having a yield strength of more than 150 MPa, which is the "C" material, and a plate-like object of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm, which is the "D" material, are laminated;
The joint surface is fixed and laminated in the order of "A", "C", "D" and "B", and the joint surface is laminated in the order of "A", "C", "D" and "B".
The joining method of the FRTP material and the "C" material is to join the "C" material with the same type of resin as the matrix resin of the FRTP material by an injection joining method, and then join the FRTP material and the resin by thermal fusion.
The bonding surfaces of the bonding other than the thermal fusion bonding are bonded by an adhesive.

The joined and integrated product containing the odorless structural material of the present invention 5 is
The two ends are made of two different materials, FRTP material (material A) and material B (material B) selected from a group of structural metal materials.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material is ^0.3 × 10-5 K ^-1 or more are joined together,
The integrated product is
A thin plate of 1.0 mm or less made of a metal material having a yield strength of more than 150 MPa, which is a material "C", and a plate-like object or structure made of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm, which is a material "D", are stacked between the material "A" and the material "B",
The joint surface is fixed and laminated in the order of "A", "C", "D", "C" and "B", and the joint surface is laminated in the order of "A", "C", "D", "C" and "B".
The FRTP material and the "C" material are joined by insert molding a resin similar to the matrix resin of the FRTP material into the "C" material, and then the FRTP material and the resin are joined by thermal fusion.
The joint surface of the joint portion other than the heat fusion joint is characterized in that it is joined by an adhesive.

The bonded and integrated product containing odorous structural materials of invention 6 is a bonded and integrated product containing dissimilar structural materials of inventions 1 to 5, characterized in that the "D" material is pure aluminum-based aluminum and is one type selected from Japanese Industrial Standards A1080, A1085, and A1050.

The bonded and integrated product containing the peculiar odor structural material of invention 7 is a bonded and integrated product containing the peculiar odor structural material of inventions 2 to 5, characterized in that the "C" material is one selected from the group consisting of A5052 aluminum alloy, A5083 aluminum alloy, A6061 aluminum alloy, and SUS304 stainless steel, as specified by the Japanese Industrial Standards.

The bonded and integrated product containing odorous structural materials of invention 8 is a bonded and integrated product containing dissimilar structural materials of inventions 1 to 5, characterized in that the bonded surface includes one or more surfaces selected from flat surfaces, curved surfaces, and cylindrical surfaces.

The bonded and integrated product containing an odorous structural material of Invention 9 is a bonded and integrated product containing dissimilar structural materials of Inventions 1 to 8, characterized in that the "D" material is a plate-like body having one surface which is flat or curved and the other surface which is formed with a large number of circular or angular pillars having a cross-sectional area of 0.05 to 0.25 ^cm2 standing in parallel with each other.

The bonded and integrated product containing an odorous structural material of Invention 10 is a bonded and integrated product containing dissimilar structural materials of Inventions 1 to 7, characterized in that the "D" material is a plate-like body having one side which is flat or curved and on the other side which has a large number of wall-like protrusions each having a thickness of 3 to 5 mm spaced apart by 2 to 3 mm, or a plate-like body having concentric wall-like protrusions each having a thickness of 3 to 5 mm spaced apart by 2 to 3 mm.

The joined and integrated product containing the odorous structural material of the present invention 11 is a joined and integrated product containing dissimilar structural materials of the present invention 10,
The center of the concentric wall-like projection is characterized in that the portion of 1 to ⁵ cm2 is a circular thick plate having a thickness of 1 to 5 mm.

The bonded and integrated product containing an odorous structural material of Invention 12 is a bonded and integrated product containing dissimilar structural materials of Invention 3 or 5, characterized in that in the bonding between the five materials "A" material, "B" material, "C" material, and "D" material, the adhesive cured layers present at the joints bonded with an adhesive all contain a cured layer of a one-component epoxy adhesive or a cured layer of a two-component epoxy adhesive.

The bonded and integrated product containing odorous structural materials of invention 13 is a bonded and integrated product containing dissimilar structural materials of inventions 2 to 5, characterized in that in the bonded product containing four or more materials, namely, material "A", material "B", material "C", and material "D", a part of the bonded part is a clad joint instead of a joint joined with an adhesive.

The bonded and integrated product containing odorous structural materials of invention 14 is a bonded and integrated product containing dissimilar structural materials of invention 12, characterized in that the one-component epoxy adhesive is a heat-resistant one-component epoxy adhesive that exhibits a shear bond strength of 50 MPa or more at 23°C and 25 MPa or more at 150°C in a tensile breaking test.

The joined and integrated product containing the odorous structural material of the present invention 15 is a joined and integrated product containing the different structural materials of the present inventions 1 to 14,
The "A" material and the "B" material are characterized in that they are one type selected from a CFRP material and a titanium alloy material, a CFRP material and a general steel material, a CFRP material and a stainless steel material, a CFRP material and a high-strength aluminum alloy material, a GFRP material and a high-strength aluminum alloy material, a CFRTP material and a titanium alloy material, a CFRTP material and a general steel material, a CFRTP material and a stainless steel material, a CFRTP material and a high-strength aluminum alloy material, a titanium material and a general steel material, a titanium material and a stainless steel material, a titanium material and a high-strength aluminum alloy material, a general steel material and a stainless steel material, a general steel material and a high-strength aluminum alloy material, a ferritic stainless steel material and an austenitic stainless steel material, and a stainless steel material and a high-strength aluminum alloy material.

The joined and integrated product containing the odorous structural material of the present invention 16 is a joined and integrated product containing different structural materials of the present invention 4 or 5 ,
The FRTP of the "A" material is CFRTP,
The resin is a highly crystalline thermoplastic synthetic resin composition having a thickness of 0.5 mm or more, and the total thickness of the "C" material and the resin is a composite plate having a thickness of 2 mm or less;
The "A" material and the "C" material are bonded together by thermally fusing the matrix resin of the CFRTP and the highly crystalline thermoplastic synthetic resin composition,
The "B" material is characterized in that it is one selected from a titanium alloy material, a general steel material, a stainless steel material, and a high-strength aluminum alloy material.

The joined and integrated product containing the odorous structural material of the present invention 17 is a joined and integrated product containing different structural materials of the present invention 15 ,
The high-strength aluminum alloy material is characterized in that it is a duralumin selected from A2014, A2017, A2024, and A7075 of the Japanese Industrial Standards, or one type of aluminum alloy selected from A5052, A5083, A6061, and A6063 of the Japanese Industrial Standards.

The method for producing a bonded and integrated product containing the odor-causing structural material of the present invention 1 is as follows:
The two ends are made of two different materials, FRTP material (material A) and material B (material B) selected from a group of structural metal materials.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material of 0.3 x 10-5K-1 or more are joined together,
The integrated product is
Between the "A" material and the "B" material, there are laminated a "C" material, which is a thin plate of a metal material having a yield strength of more than 150 MPa and a thickness of 1.0 mm or less, and a "D" material, which is a plate-like object or structure of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm,
A method for manufacturing a jointed and integrated product including dissimilar structural materials consisting of four materials in which the joining surfaces are fixedly laminated in the order of the "A" material, the "C" material, the "D" material, and the "B" material,
an injection joining process in which the "C" material is inserted into a mold and then the resin is injected to join the FRTP material and the "C" material in order to join the same type of resin as the matrix resin of the FRTP material to the "C"material;
a heat fusion step of joining the FRTP material and the resin by heat fusion after the injection joining;
Another bonding method is characterized by an adhesive bonding process.

The method for producing a joined and integrated product containing the odor-causing structural material of the present invention 2 is as follows:
The two ends are made of two different materials, FRTP material (material A) and material B (material B) selected from a group of structural metal materials.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material is 0.3×10 ⁻⁵ K ⁻¹ or more are joined together,
The integrated product is
Between the "A" material and the "B" material, there are laminated a "C" material, which is a thin plate of 1.0 mm or less made of a metal material having a yield strength of more than 150 MPa, and a "D" material, which is a pure aluminum-based aluminum plate or structure having a thickness of 1.5 to 5.0 mm,
A method for manufacturing a bonded and integrated product including dissimilar structural materials consisting of five materials in which the bonding surfaces are fixedly laminated in the order of the "A" material, the "C" material, the "D" material, the "C" material, and the "B" material,
an injection joining process in which the "C" material is inserted into a mold and then the resin is injected to join the FRTP material and the "C" material in order to join the same type of resin as the matrix resin of the FRTP material to the "C"material;
a heat fusion step of joining the FRTP material and the resin by heat fusion after the injection joining;
Another joining method is characterized in that it comprises a joining process using an adhesive.

Each element constituting the present invention will now be described.
[Summary of Materials "A", "B", "C", and "D" of the Present Invention]
In the present invention, "A" material and "B" material refer to the members at both ends of the bonded and integrated product containing dissimilar structural materials of the present invention, which is a laminate. "C" material and "D" material refer to the members fixed and laminated between "A" material and "B" material. "A" material, "B" material, and "C" material of the present invention refer to one type selected from "(1) FRP material, FRTP material" and "(2) structural metal material" below. "D" material of the present invention refers to "(3) "D"material" described below.

(1) FRP material, FRTP material The FRP material in the present invention is a general fiber reinforced plastic (FRP), which is a molding material or a molded product in which glass fiber, carbon fiber, or other fibers are compounded with epoxy resin, which is a thermosetting resin, as a matrix resin, to improve its strength. FRP using carbon fiber is CFRP, and FRP using glass fiber is GFRP. On the other hand, FRTP material (Fiber Reinforced Thermo-plastics) is a molding material or a molded product or a general-purpose material such as a pipe material or plate material, which is reinforced and improved by adding fibers such as glass fiber, carbon fiber, or other fibers to a matrix resin such as polyamide resin, polyphenylene sulfide resin (hereinafter referred to as PPS), polyether ether ketone resin (hereinafter referred to as PEEK), which is a thermoplastic resin having crystallinity, etc. FRTP using carbon fiber is called CFRTP, and FRTP using glass fiber is called GFRTP. These molded products of FRP and FRTP materials include standardized general-purpose materials such as plates, tubes, rods, and sheets, as well as individually designed molded products.

(2) Structural metal materials In the present invention, the structural metal materials refer to structural metal materials such as Ti alloy materials, various structural steel materials, various stainless steel materials, and various aluminum alloys, which are standardized or specially specified by the Japanese Industrial Standards, etc. Aluminum alloys include Al-Cu-based (Japanese Industrial Standards 2000 series), Al-Mn-based (Japanese Industrial Standards 3000 series), Al-Si-based (Japanese Industrial Standards 4000 series), Al-Mg-based (Japanese Industrial Standards 5000 series), Al-Mg-Si-based (Japanese Industrial Standards 6000 series), Al-Zn-Mg-based (Japanese Industrial Standards 7000 series), and pure aluminum-based aluminum (Japanese Industrial Standards 1000 series). The aluminum used in the present invention includes the 1000 to 8000 series of stretched aluminum alloys specified by the Japanese Industrial Standards, and further includes cast aluminum alloys such as ADC12. Therefore, the structural aluminum alloy materials of the present invention include both stretched aluminum alloys and cast aluminum alloys.

(3) "D" material of the present invention The "D" material of the present invention has an important function and action among the components constituting the present invention. That is, the "D" material of the present invention is a soft metal having ductility as a mechanical property, and has a high bonding property, for example, a sufficiently strong adhesive force (shear adhesive strength) against the one-liquid epoxy adhesive "EW2040" mentioned above. In addition to this, the basic property is that it is sandwiched between the "A" material and the "B" material mentioned above, and bonded with a sufficiently high adhesive force to form an integrated product of three or four materials, "A", "D", "B" and "C". The integrated product is required to have a property of not breaking even when subjected to a temperature shock test of 3,000 cycles at -50°C/+150°C. In the present invention, there is a large difference in the linear expansion coefficient between the "A" material and the "B" material. For this reason, the length of the "A" material and the "B" material changes with a strong temperature change. As a result, in the case of three layers and three materials, the "D" material, which is strongly bonded to the "A" and "B" materials on the top and bottom surfaces, has different length expansions and contractions on both sides, so stress to deform occurs in the "D" material. However, since the "D" material is a malleable and soft member, it deforms on its own, absorbing and suppressing the stress caused by the thermal contraction, and can maintain its bonded state even after being subjected to a temperature shock test of several thousand cycles. The most suitable metal material for this "D" material is pure aluminum-based aluminum, and it is preferable to use pure aluminum-based aluminum such as A1085, A1080, and A1050 as specified by the Japanese Industrial Standards.

(4) "C" material of the present invention The "C" material in the present invention has a special role different from that of the "D" material. That is, the jointed and integrated product including dissimilar high-strength structural materials of the present invention is required to be high-strength and lightweight, and the most suitable material for achieving this is CFRP material, CFRTP material, etc. However, when CFRP pieces are bonded together, for example, with the one-liquid epoxy adhesive "EW2040" and tested with the bonded pair of test pieces shown in FIG. 1, the shear bond strength is about 40 MPa. The reason is as described above, and therefore, for example, when a CFRP piece is used as the "A" material, it is recommended to use the above-mentioned "D" material, which utilizes its extensibility as described above. If the "D" material has a surface chemical conversion treatment that is optimal for adhesion, the adhesive strength between the metal "D" material and the adhesive cured product is about 60 MPa. However, when a CFRP piece is used for material "A", even if the strongest adhesive strength is obtained in the direct bond between material "A" and material "D", the true adhesive strength between the CF and the cured matrix resin is estimated to be about 40 MPa for the reasons mentioned above, and the adhesive strength, which is the shear bond strength of the laminate, which is the bonded and integrated product, will be pulled down by the lower adhesive strength, and will be approximately 40 MPa or less.

In addition, when CFRTP material is used for the "A" material, adhesive methods cannot be used to bond the CFRTP and "D" material. This is because the surface of the CFRTP material is its matrix resin, a thermoplastic resin, and there is no general technology to directly and strongly bond a thermoplastic resin to a metal material. Therefore, in the bonding method proposed by the inventor of the present invention, the matrix resin used in the CFRTP material, for example, PEEK (polyether ether ketone) resin, is bonded in the following process. That is, after surface treatment for injection bonding (the above-mentioned NMT treatment, new NMT treatment, etc.) is applied to the thin metal plate material, it is inserted into an injection molding die, and PEEK-based resin adjusted for injection bonding is injected and bonded to the inserted thin metal plate to create a composite plate-like object in which a thin plate-like object of PEEK-based resin is surface-bonded to the inserted thin metal plate. Then, this composite plate and a thick CFRTP plate made of PEEK resin are heat-press fused to create a thick CFRTP plate with a thin metal plate (see Patent Document 12).

In short, as a method for creating an integrated product of CFRTP material and metal material, for example, there is the joining method proposed in Patent Document 12. In the case of this joining method, when CFRTP material is used, the joining strength (shear joining strength) between the CFRTP material and the metal sheet material of the integrated product of the present invention is the same as the injection joining strength between the surface-treated metal material and the PEEK-based resin used for injection joining. At present, when a soft material "D" material, for example A1050Al, is used as the metal material, the shear breaking strength of the product injection-joined with the PEEK-based resin for injection joining is around 45 MPa. This value of 45 MPa is lower than the expected value of 60 MPa when the "A" material and the "D" material are directly bonded with an adhesive in an integrated product using a metal material as the "A" material. Furthermore, if the matrix resin of the CFRTP material is a PPS-based resin, the above value is approximately 40 MPa, and if the matrix resin of the CFRTP material is a semi-aromatic polyamide resin, the above value is 45 to 50 MPa, which is also lower than 60 MPa.

In short, when CFRP, CFRTP, etc. are used as materials "A" and "B", the adhesive strength remains at about 40-50 MPa. Also, when a new alloy appears, if the chemical conversion treatment of its surface is not optimal, the adhesive strength with the metal material may remain at about 40-50 MPa. Therefore, if the basic adhesive strength of the joint surface of materials "A" and "B" is about 40 MPa or lower, the joint part is weak, and the mechanical strength of this jointed integrated product will be weak. For this reason, it is necessary to construct a total adhesive structure so that the adhesive strength between materials "A" and "D", "B" and "D", etc. of this jointed integrated product is at the same level as the other joint parts, resulting in a strength of about 60 MPa. This is the reason why thin metal plate material "C" is further sandwiched between materials "A" and "D", and between materials "B" and "D".

(Role and function of "C" material)
As can be understood from the above explanation, in conclusion, it is preferable that the "C" material of the present invention is a malleable thin metal plate with different characteristics from "D". Even if the structural materials have significantly different linear expansion coefficients, if the adhesive strength of both materials to the epoxy adhesive is sufficiently high, if one of the materials is a thin plate, it will follow the other and adhere strongly as it is, and can withstand severe environmental temperature changes. In short, if a thin plate "C" material that is more rigid than "D" material is sandwiched between "A" material and "D" material and adhesively bonded, even if the integrated product in which these three are integrated is subjected to a large temperature change or temperature shock, the thin plate "C" material that is more rigid than "D" material will first follow the expansion and contraction of the more rigid "A" material, and the expansion and contraction of "C" material following the expansion and contraction of "A" material will be transmitted directly to the soft material "D" material.

Similarly, if a thin plate "C" is sandwiched between "B" and "D" and bonded with adhesive, even if the bonded product in which these three are integrated undergoes temperature changes or thermal shocks, this "C" will first follow the expansion and contraction of "B", and the expansion and contraction of this "C" material following the expansion and contraction of "B" will be transmitted directly to "D". With this thought pattern, if we imagine a fully bonded structure in which a five-layered structure consisting of "A", "C", "D", "C" and "B" materials is bonded together (for example, the laminate in Figure 5), the expansion and contraction of both "A" and "B" materials will be transmitted to the top and bottom surfaces of "D" material in the center. At this time, since "D" is a soft metal that is pure aluminum-based aluminum, all forces absorb deformation without drawing breaks into the bonded surface. In other words, "C" has a function of absorbing deformation between "A" and "D" materials, and between "B" and "D" materials. However, material "C" does not only have a cushioning function to absorb the expansion and contraction of material "A" and material "B".

To explain more specifically, in the bonded integrated product of the present invention, if the adhesive strength between the "A" material, such as CFRP or CFRTP, and the adhesive cured product is only about 30 MPa, and the adhesive strength between the other "B", "C", and "D" materials and the adhesive cured product has a shear breaking strength of about 60 MPa, the adhesive area between the "A" and "C" materials must be twice the adhesive area between the "C" and "D" materials in terms of structural design in order to maintain the same shear breaking strength. In short, the actual adhesive strength is the product of the shear adhesive strength and the adhesive area, and thus the adhesive strength can be amplified, which is why the "C" material was used. And for this amplification effect to actually occur, the "C" material must also have a high strength (or allowable design stress), and even if it is a thin plate, it must be able to follow the expansion and contraction of the "A" and "B" materials within the range of its elastic deformation. Moreover, since this acts as an amplifier to increase the joint strength, the conditions under which the tearing phenomenon (fracture failure) does not occur are related to the strength. In this invention, material "C" is used when four or more layers of four materials are used and strength is required. Material "D", which is made of malleable soft metal, has weak mechanical strength, and even if it is directly bonded to material "A" or "B", the adhesive strength does not reach the desired level.

As mentioned above, in order for the "C" material to function as an adhesive strength amplifier, it must not tear itself off even when it is made into a thin plate, and it must be a material with a strength (allowable stress) that can withstand a general adhesive strength, and at the same time, it must have tensile strength. This is based on the results of the test experiment (see Table 6) described in the experimental example (test piece shown in Figure 1) described later, but it is desirable for the strength to be about 150 MPa or more (in the experiment described later, it was found that for the "C" material, a metal material with a higher strength than A5052 Al alloy is desirable for practical purposes), and since a thin plate with a thickness of 0.28 mm could be used for SUS304, the product of the Young's modulus ≒ 190 GPa and the thickness of 0.28 mm, 53 GPa・mm, can be set as the tentative standard. In short, the upper limit standard for the "C" material is set to "Young's modulus x thickness = 53 GPa・mm".

According to the above formula, all aluminum alloys have a modulus of elasticity of around 70 GPa, so the preferred thickness of "C" material is 0.75 mm or less (see Table 6 below). Aluminum alloys and stainless steels have been well developed in the NAT processing method, and they have high adhesive strength, are practical, and are resistant to rust. Based on this formula, the thickness of "C" material is a thin plate of 1 mm or less. There are examples of "C" material that have been verified in the examples below, and the verified examples are A5052, A6061 aluminum alloys, and SUS304 stainless steel. Therefore, the metals that can be preferably used are A5052, A5083, and A6061 aluminum alloys, and SUS304 and SUS316 austenitic stainless steels.

[Means and members for bonding and laminating the joining surfaces of the present invention]
The methods of bonding and laminating the faying surfaces of the present invention are adhesive and clad bonding.
(1) Adhesive The adhesive for fixing and laminating the joint surfaces of the present invention may be of any type as long as it can bond the various FRP materials and FRTP materials used in the present invention to the various structural metal materials used in the present invention with the strength of the design value under the required environment. However, one of the important high-strength structural materials in the present invention is CFRP material, and the matrix resin of this CFRP material is generally an epoxy resin, so an epoxy adhesive is preferable as the adhesive. Moreover, epoxy adhesives are also optimal for bonding various metal materials, so they are also preferable in this respect. This epoxy adhesive can be used as either a one-part or two-part epoxy adhesive. Two-part epoxy adhesives are adhesives that are copolymerized and hardened by chemically reacting two parts, a liquid epoxy resin as the main agent and a curing agent called polyamines, at room temperature. One-part epoxy adhesives contain a curing agent and are polymerized by reaction when heated. Some have excellent heat resistance and strength, so they are used for jointed and integrated objects that require heat resistance.

(2) Clad bonding In the present invention, the term "clad bonding" refers to bonding various dissimilar alloys by overlapping them with each other and using a method that relies on the explosive force of gunpowder (explosive bonding), hot rolling, hot rolling, etc. The members used for clad bonding are treated by the above-mentioned hot pressing method, which is strongly bonded like welding and generally has a higher bonding strength than bonding by adhesives. However, some surface treatment is often performed in advance, and is particularly necessary when using aluminum alloys such as hot rolling. In short, when two materials are to be clad bonded, which method should be selected? If the simplest hot rolling method is selected, it is necessary to first develop an optimal surface treatment method for each of the two materials to ensure successful bonding.

[Difference in linear expansion coefficient according to the present invention (0.3×10 ⁻⁵ K ⁻¹ or more)]
The difference in linear expansion coefficient between the "A" material and the "B" material used in the "jointed integrated product containing dissimilar structural materials" of the present invention is a maximum of 0.3×10 ^-5 K ^-1 or more. The reason is as follows. The linear expansion coefficient of the FRP material constituting the present invention, for example, the CFRP material, is (0.1 to 0.2)×10 ^-5 K ^-1 . On the other hand, the linear expansion coefficient of the various structural metal materials constituting the present invention is about 2.3×10 ^-5 K ^-1 for the A7075 aluminum alloy called extra super duralumin. Among the various structural metal materials widely used, the Ti alloy material has the lowest linear expansion coefficient, about 0.8×10 ^-5 K ^-1 . Ordinary steel and ferritic stainless steel have a resistance of about 1.1 x 10 ^-5 K ^-1 , austenitic stainless steel has a resistance of about 1.7 x 10 ^-5 K ^-1 , and duralumin and aluminum alloys have a resistance of about 2.3 x 10 ^-5 K ^-1 . Furthermore, although they are hardly structural materials, other metal materials include copper at about 1.8 x 10 ^-5 K ^-1 , silver at about 1.9 x 10 ^-5 K ^-1 , tin at about 2.3 x 10 ^-5 K ^-1 , magnesium at about 2.5 x 10 ^-5 K ^-1 , and lead at about 2.9 x 10 ^-5 K ^-1 (note that these values differ by about 0.1 x 10 ^-5 K ^-1 depending on the literature).

Among these various structural metal materials, the linear expansion coefficient is closest between Ti alloy material, general steel material, and ferritic stainless steel, and these metal members may be used in combination as a laminate, which is the jointed and integrated product of the present invention. The linear expansion coefficient difference between these various structural metal materials is about 0.3×10 ⁻⁵ K ⁻¹ , and if the linear expansion coefficient difference is less than this, the load on the bonding surface is substantially small and does not need to be considered. Therefore, the jointed and integrated product including dissimilar structural materials of the present invention has a linear expansion coefficient of about 0.3×10 ⁻⁵ K ⁻¹ or more when the closest dissimilar structural materials are combined. In addition, in the temperature shock test (3,000 cycles) in the experiment of the present invention, the test was performed in a low temperature room at -50°C and a high temperature room at 150°C. That is, in a temperature change of about 200°C (-50°C to 150°C), which is the environmental temperature required for automobile parts and the like, CFRP material and A2017 aluminum alloy (duralumin), which have the greatest difference in linear expansion coefficient, were designated as material "A" and material "B," and a temperature shock test of 3,000 cycles was carried out on a four-layer bonded integrated product of material "A," material "C," material "D," and material "B" of the present invention. As a result, the shear adhesive strength between material "C" and material "D," which was most likely to cause the adhesive structure to be destroyed, was found to be within the allowable value without any problems. Incidentally, the temperature shock cycle test involved repeatedly applying a temperature change of approximately 200°C (from -50°C to 150°C) between materials "A" and "B". There is a linear thermal expansion coefficient difference of 2.1 x ^{10-5K -1} between materials "A" and "B", and this temperature change of 200°C resulted in a length difference of 0.42%, so if materials "A" and "B" had been directly bonded, this would have certainly caused the material to break.

As described above in detail, the manufacturing method of the bonded integrated product containing dissimilar structural materials of the present invention has the effect of maintaining the bonded laminated structure even when subjected to a large temperature shock by indirectly bonding two or more types of high-strength materials with a large difference in linear expansion coefficient, rather than directly. Therefore, even if the product is installed in a place where the environmental temperature changes drastically, or in a place where not only the environmental temperature changes drastically but also the temperature changes occur several thousand times, the basic structure will not change. Therefore, it is very suitable for use as a component material for outdoor machines and equipment, and for automobiles, aircraft, and other mobile machines. In particular, the product of the present invention, which uses CFRP material and duralumin material as material "A" and material "B", is ultra-lightweight and is extremely suitable as a component material for mobile machines.

FIG. 1 is a perspective view showing a test piece for measuring the shear adhesive strength between metal pieces, in which FIG. 1(a) shows a single test piece, and FIG. 1(b) shows a laminated test piece in the case of a thin test piece. FIG. 2 is a perspective view showing a test piece for measuring the tensile adhesive strength between metal end faces, which is a test piece for metal pieces. FIG. 3 is a photograph of the edge of a nine-layer integrated structure made by bonding five 0.3 mm-thick A5052 aluminum alloy thin plates and 0.3 mm-thick CFRP prepregs together using a one-component epoxy adhesive with excellent heat resistance. FIG. 4 shows an example of a laminate with a three-material, three-layer adhesive structure, in which high-strength structural materials "A" and "B" with different linear expansion coefficients are used at both ends, and a pure aluminum-based aluminum A1050 plate, "D", is sandwiched between the two. FIG. 5 shows an example of a five-material, five-layer laminate with adhesive structure made of "A", "C", "D", "C" and "B" materials, in which high-strength structural materials with different linear expansion coefficients "A" and "B" are used at both ends, and "C" material is an A5052Al thin plate, and "D" material is an A1050 aluminum plate, which is a pure aluminum-based aluminum, is sandwiched between the two. FIG. 6 shows an example of a laminate with a four-material, four-layer adhesive structure made of materials "A", "C", "D", and "B", in which high-strength structural materials with different linear expansion coefficients are used at both ends, material "A" being a thin plate of A5052 aluminum alloy (material "C"), and material "D" being a pure aluminum-based aluminum A1050 aluminum plate (material "D"). FIG. 7 shows an example of a five-layer laminate similar to that shown in FIG. 5, which is used to measure the shear adhesive strength at the location where stress is concentrated (shear surface). FIG. 8 shows an example of a four-layer laminate similar to that shown in FIG. 6, which is used to measure the shear adhesive strength at a location (shear surface) where strong stress is concentrated.

FIG. 9 shows an example of a five-layer laminate similar to that shown in FIG. 5, which is laminated and bonded in a form close to that of a practical product, and was created for use in a temperature shock test of several thousand cycles. FIG. 10 shows an example of a four-layer laminate similar to that shown in FIG. 6, but in this example, a thick CFRP plate is used as material "A" and duralumin is used as material "B", and this was created in order to undergo severe temperature shock tests of several thousand cycles. FIG. 11 shows the manufacturing process when the "A" material is a composite material using CFRTP material. FIG. 12 shows the manufacturing process when the "A" material is a composite material using CFRTP material. FIG. 13 shows an example of a "D" material, which is a pure aluminum-based aluminum, that is not in the form of a flat plate material but has a large number of thin pillars on its surface. FIG. 14 shows an example of a "D" material, which is a pure aluminum-based aluminum, that is not in a plate shape but has a concentric wall. FIG. 15 is a process diagram showing a method for measuring the shear strength when a thick plate of 64Ti alloy is used as a high-strength structural material and a thin plate of aluminum alloy or SUS304 stainless steel is bonded to this thick plate with a one-liquid epoxy adhesive. FIG. 16 is a process diagram showing the procedure for measuring the "tensile adhesive strength" of the plate surface of a metal piece. FIG. 17 is a process diagram following FIG. 16, showing the procedure for measuring the "tensile adhesive strength" of the plate surface of the metal piece.

FIG. 18 is a process diagram following FIG. 17, showing the procedure for measuring the "tensile adhesive strength" of the plate surface of the metal piece. FIG. 19 shows an example of a four-layer structure in which an A7075 aluminum alloy thick plate is bonded to the end of a CFRP material, and shows a structural example in which the CFRP material can be fastened to other materials with bolts and nuts via the A7075 aluminum alloy thick plate. FIG. 20 shows an example of a four-layer structure in which an A7075 aluminum alloy thick plate is bonded to the end of a CFRP material, and shows a structural example in which the CFRP material can be fastened to other materials with bolts and nuts via the A7075 aluminum alloy thick plate. FIG. 21 shows an example of a four-layer structure in which an A7075 aluminum alloy thick plate is bonded to the end of a CFRP material, and shows a structural example in which the CFRP material can be fastened to other materials with bolts and nuts via the A7075 aluminum alloy thick plate. FIG. 22 shows an example of a three-layer structure in which an aluminum alloy machined product is bonded to the end of a CFRP material, and shows a structural example in which the CFRP material can be fastened to other materials with bolts and nuts via an A7075 aluminum alloy thick plate. Figure 23 shows an example of a three-layer structure in which a thick aluminum alloy plate with bolt fastening holes is bonded to the end of a CFRP tube material, demonstrating that the CFRP tube material can be fastened to other materials with bolts and nuts via an A7075 aluminum alloy processed product.

The following explanations and examples will specifically explain the surface treatment method for various materials according to the present invention, the bonding method after the treatment, the method for measuring the physical properties of the bonded product, and the shear adhesive strength and shear adhesive tack of the bonded integrated product containing the dissimilar structural materials of the present invention.

The present invention will be described in detail below with reference to Experimental Examples instead of Examples.
(a) Electron Microscope Observation An electron microscope was used to observe the surface of the substrate used in this example. The electron microscope used was a scanning electron microscope (SEM) "SSM-7000F (product name)" (manufactured by JEOL Ltd. (headquarters: Tokyo, Japan)) and observation was performed at 1 to 2 kV.

(b) Measurement of adhesive strength A tensile tester "AG-500N/1kN" (Shimadzu Corporation, head office: Tokyo, Japan) was used to measure the breaking strength of an adhesive bonded product (e.g., the test piece in Fig. 1) when it broke under tension, which was taken as the "shear adhesive strength" (x-y plane). A test piece bonded at its end faces (see Fig. 2) was pulled by the tensile tester, and the breaking strength when it broke under this tension was taken as the "tensile adhesive strength" (y-z plane). The tensile tester used was used at a tensile speed of 10 mm/min.

(c) Measurement of shear adhesive tenacity In this experimental example, the term "shear adhesive tenacity" refers to the results obtained by the following experimental method. When measuring shear adhesive tenacity, the "shear adhesive strength" is measured in advance using a tensile tester with a test piece (FIG. 1). Then, a test is started in which a tensile force of about 75% of the "shear adhesive strength" is repeatedly applied to the test piece 300 times. The load method using the tensile tester in this test method is set by the operating software of the control device of the tester. This operating software sets the maximum tensile force to about 75% of the above, the minimum tensile force to about 2/3 of the maximum tensile force, and the tensile speed to ±10 mm/min for one cycle. If there is no shear rupture with this repeated load, the maximum tensile load is increased by about 2 MPa and the minimum tensile force is corrected, and the same test is performed with 300 repeated loads. If the specimen still does not break, a further pressure of about 2 MPa is applied and the same procedure is repeated until the specimen shown in Figure 1 breaks. When the specimen breaks, the maximum tensile force before the break is indicated in MPa, and in this experiment this is taken as the "shear adhesion tenacity" value.

(d) Non-destructive inspection of adhesive surface The judgment and observation of whether peeling occurred on the adhesive surface was performed by the following method. A simple test method is to apply a colored aqueous penetrant to the external part of the adhesive layer, wipe it off, and check whether the colored part can be wiped off. When it is necessary to check in detail to what extent peeling has spread in the adhesive area, a non-destructive inspection machine "MS Line (Hitachi Power Solutions Company (Head Office: Ibaraki Prefecture, Japan))" that can observe by irradiating ultrasonic waves on the adhesive surface was used.

(e) Temperature shock cycle test For the temperature shock cycle test, a temperature shock cycle tester "Small-sized thermal shock device TSE-12-A" (Espec Corporation (Head office: Osaka, Japan)) was used. The standard conditions for the temperature shock cycle test were a low-temperature room temperature of -50°C, a high-temperature room temperature of +150°C, a residence time in each room of 25 minutes, and a movement time of about 5 minutes. The room in which this tester was installed was a room that was constantly regulated to 27°C, and the temperature of the low-temperature room was periodically raised to room temperature, and automatic operation was set to naturally melt the frozen parts of the tester.

[Experimental Example A] Surface treatment of each material Below, experimental examples of chemical conversion treatment for treating the surface of the structural metal material constituting the present invention will be described. That is, the chemical conversion treatment in the experiment described below is intended to find the optimal chemical conversion treatment method for each type of structural metal material.

[Experimental Example A1-1] Surface treatment (NAT treatment) of A1050 aluminum (hereinafter referred to as "A1050Al")
A plate material of A1050Al, which is a pure aluminum-based aluminum , having a thickness of 0.5 to 3.0 mm was obtained, machined into a rectangular piece, and a hole was opened at the end of the piece to prepare an alloy piece as a test piece. A gardening wire with a PVC cover was passed through the hole of the alloy piece, and the piece was hung so that it could be immersed in each liquid treatment. A water tank with an ultrasonic oscillation end was filled with an aqueous solution containing 10% aluminum degreaser "NA-6" (Meltex Inc. (head office: Tokyo, Japan)) at 60°C, and the alloy piece was immersed for 5 minutes and then washed with water. Next, a 1% aqueous hydrochloric acid solution at 40°C was prepared in another tank, and the piece was immersed for 1 minute and then washed with water. Next, a 1.5% aqueous caustic soda solution at 40°C was prepared in another tank, and the Al piece was immersed in this aqueous sodium hydroxide solution for 4 minutes and then washed with water. Next, a 3% concentration aqueous nitric acid solution at 40° C. was prepared in another tank, and the Al pieces were immersed in this aqueous nitric acid solution for 3 minutes, and then washed with water.

Next, in another tank, a 3.5% hydrazine hydrate aqueous solution at 60°C was prepared, and the A1050Al pieces were immersed for 2 minutes. Next, in another tank, the pieces were immersed for 0.5 minutes in a 0.5% hydrazine hydrate aqueous solution at 33°C, and then rinsed with water. Then, in another tank, a 5% hydrogen peroxide solution was prepared, and the A1050Al pieces were immersed for 5 minutes, and then thoroughly rinsed with water. After these treatments, the pieces were placed in a hot air dryer set at 67°C for 15 minutes to dry.

[Experimental Example A1-2] Surface treatment of A1050Al (NAT7 treatment: Reference Example)
As in Experimental Example A1-1, A1050Al pieces were prepared so that they could be immersed. A water tank with an ultrasonic oscillation end was filled with an aqueous solution containing 10% aluminum degreaser "NA-6" at 60°C, and the A1050Al pieces were immersed for 5 minutes and then washed with water. Next, a 10% aqueous solution of caustic soda at 40°C was prepared in another tank, and the pieces were immersed for 1 minute and then washed with water. Next, a 1% aqueous solution of aluminum chloride hydrate and 5% aqueous solution of hydrochloric acid at 40°C was prepared in another tank, and the Al pieces were immersed for 10 minutes and then washed with water. Next, a 2% aqueous solution of ammonium difluoride and 10% aqueous solution of sulfuric acid at 40°C was prepared in another tank, and the A1050Al pieces were immersed for 1 minute and then washed with water. Next, in another tank, a 1.5% caustic soda solution at 40° C. was prepared, and the A1050Al pieces were immersed in this for 2 minutes, and then rinsed with water. Next, in another tank, a 3% nitric acid solution at 40° C. was prepared, and the A1050Al pieces were immersed in this for 2 minutes, and then rinsed with water.

Next, in another tank, a 3.5% hydrazine hydrate aqueous solution at 60°C was prepared, and the A1050 pieces were immersed for 2 minutes. Next, in another tank, the pieces were immersed for 0.5 minutes in a 0.5% hydrazine hydrate aqueous solution at 33°C, and then rinsed with water. Then, in another tank, a 5% hydrogen peroxide solution was prepared, and the A1050Al pieces were immersed for 5 minutes, and then thoroughly rinsed with water. The pieces were then placed in a hot air dryer set at 67°C for 15 minutes to dry.

[Experimental Example A1-3] Surface treatment of A1050Al (NAT5 treatment)
As in Experimental Example A1-1, A1050Al pieces were prepared so that they could be immersed. A water tank with an ultrasonic oscillation end was filled with an aqueous solution containing 10% of aluminum degreaser "NA-6" at 60°C, and the A1050Al pieces were immersed for 5 minutes and then washed with water. Next, a 10% aqueous solution of caustic soda at 40°C was prepared in another tank, and the A1050 pieces were immersed for 1 minute and then washed with water. Next, a 1% aqueous solution of hydrated aluminum chloride and 5% aqueous solution of hydrochloric acid at 40°C was prepared in another tank, and the A1050 pieces were immersed for 3 minutes and then washed with water. Next, a 1.5% aqueous solution of caustic soda at 40°C was prepared in another tank, and the A1050 alloy pieces were immersed for 4 minutes and then washed with water. Next, a 3% aqueous solution of nitric acid at 40°C was prepared in another tank, and the A1050Al pieces were immersed for 1.5 minutes and then washed with water.

Next, in another tank, a 3.5% hydrazine hydrate aqueous solution at 60°C was prepared, and the A1050 pieces were immersed for 2 minutes. Next, in another tank, the pieces were immersed for 0.5 minutes in a 0.5% hydrazine hydrate aqueous solution at 33°C, and then rinsed with water. Then, in another tank, a 5% hydrogen peroxide solution was prepared, and the A1050 pieces were immersed for 5 minutes, and then thoroughly rinsed with water. The pieces were then placed in a hot air dryer set at 67°C for 15 minutes to dry.

[Experimental Example A1-4] Surface treatment of A1050Al (NAT (20 min) treatment)
The same treatment as in Experimental Example A1-1 was carried out for all the treatment steps, with the only difference being the final reaction step, in which a 5% concentration hydrogen peroxide solution was prepared and the A1050Al pieces were immersed in the hydrogen peroxide solution for 5 minutes, which was extended to 20 minutes.

[Experimental Example A1-5] Surface treatment of A1050Al (NAT5 (20 min))
The same treatment as in Experimental Example A1-3 was carried out for all steps, with the only difference being the final reaction step, in which a 5% concentration hydrogen peroxide solution was prepared and the A1050Al piece was immersed for 5 minutes, changing the time to 20 minutes.

[Experimental Example A1-6] Surface treatment of A1050Al (NAT-Ano (anodic oxidation) treatment)
The same treatment process as in [Experimental Example A1-1] was carried out, and a 3% concentration aqueous nitric acid solution at 40 ° C was prepared, and the Al pieces were immersed in this for 3 minutes, and then washed with water. Next, a 10% concentration aqueous phosphoric acid solution at 25 ° C was prepared in another tank, and the Al pieces were connected to a Ti anode, a carbon rod cathode was inserted into the end of the immersion tank, and anodized for 15 minutes with a direct current of 20 V. The anodized Al pieces were washed with water for 30 minutes, dried in a hot air dryer set at 67 ° C for 15 minutes, and further dried in a hot air dryer set at 100 ° C for 30 minutes.

[Experimental Example A1-7] Surface treatment of A1050Al (NAT5-Ano (anodic oxidation) treatment)
The process was carried out in the same manner as in [Experimental Example A1-3], and a 3% concentration aqueous nitric acid solution at 40 ° C was prepared, and the A1050Al pieces were immersed in this for 1.5 minutes, and then the same treatment was performed up to the point where they were washed with water. After this treatment, the treatment method of NAT5 was changed, and then a 10% concentration aqueous phosphoric acid solution at 25 ° C was prepared in another tank, the A1050Al pieces were connected to a Ti anode, a carbon rod cathode was inserted into the end of the immersion tank, and anodized for 15 minutes with a direct current of 20 V. The anodized A1050Al pieces were washed with water for 30 minutes, dried in a hot air dryer set at 67 ° C for 15 minutes, and further dried in a hot air dryer set at 100 ° C for 30 minutes.

[Experimental Example A2-1] Surface treatment of A5052 Al alloy (NAT7 treatment method)
A5052Al alloy plate material with a thickness of 0.5 to 3.0 mm was obtained, machined into rectangular pieces of various sizes, and holes were drilled at the ends. The A5052Al alloy pieces were hung through the holes in a PVC-covered gardening wire so that they could be immersed in each solution. In an immersion tank, an aqueous solution containing 10% aluminum degreaser "NA-6" was heated to 60°C, and the A5052Al alloy pieces were immersed for 5 minutes and then washed with water. Next, in another tank, a 10% aqueous solution of caustic soda at 40°C was prepared, and the A5052Al alloy pieces were immersed for 1 minute and then washed with water. Next, in another tank, an aqueous solution containing 1% aluminum chloride hydrate and 5% hydrochloric acid at 40°C was prepared, and the A5052Al alloy pieces were immersed for 6 minutes and then washed with water. Next, in another tank, an aqueous solution containing 2% ammonium difluoride and 10% sulfuric acid at 40°C was prepared, and the A5052Al alloy pieces were immersed in this for 4 minutes, and then washed with water. Next, in another tank, an aqueous solution of caustic soda at 1.5% concentration at 40°C was prepared, and the A5052Al alloy pieces were immersed in this for 1 minute, and then washed with water. Next, in another tank, an aqueous solution of nitric acid at 3% concentration at 40°C was prepared, and the A5052Al alloy pieces were immersed in this for 1.5 minutes, and then washed with water. Next, in another tank, an aqueous solution of hydrazine hydrate at 3.5% concentration at 60°C was prepared, and the A5052Al alloy pieces were immersed in this for 2 minutes, and then in another tank, an aqueous solution of hydrazine hydrate at 0.5% concentration at 33°C was immersed for 0.5 minutes, and then washed with water. Then, the pieces were immersed in hydrogen peroxide at 5% concentration for 5 minutes, and then thoroughly washed with water, and then placed in a hot air dryer set at 67°C for 15 minutes to dry.

[Experimental Example A2-2] Surface treatment of A5052 Al alloy (NAT treatment: Reference Example)
As in Experimental Example A2-1, A5052Al alloy pieces were prepared so that they could be immersed. In an immersion tank, an aqueous solution containing 10% aluminum degreaser "NA-6" was set to 60°C, and the A5052Al alloy pieces were immersed for 5 minutes, and then rinsed with water. Next, in another tank, a 1% concentration hydrochloric acid aqueous solution set to 40°C was prepared, and the A5052Al alloy pieces were immersed for 1 minute, and then rinsed with water. Next, in another tank, a 1.5% concentration caustic soda aqueous solution set to 40°C was prepared, and the A5052Al alloy pieces were immersed for 4 minutes, and then rinsed with water. Next, in another tank, a 3% concentration nitric acid aqueous solution set to 40°C was prepared, and the A5052Al alloy pieces were immersed for 3 minutes, and then rinsed with water. Next, in another tank, a 3.5% hydrazine hydrate aqueous solution at 60° C. was prepared, and the pieces were immersed in this for 2 minutes, and then in another tank, a 0.5% hydrazine hydrate aqueous solution at 33° C. was immersed for 0.5 minutes, and then washed with water. Then, the pieces were immersed in a 5% hydrogen peroxide solution for 5 minutes, and then thoroughly washed with water. After that, the pieces were placed in a hot air dryer set at 67° C. for 15 minutes to dry the A5052Al alloy pieces that had undergone the above treatment, and were then wrapped in clean aluminum foil and stored.

[Experimental Example A3] Surface treatment of A6061Al alloy (NAT treatment)
A6061Al alloy plate material with a thickness of 0.5 to 3.0 mm was obtained, machined into rectangular pieces of various sizes, and holes were drilled at the ends. The holes in the A6061Al alloy pieces were hung with gardening PVC-covered wire so that they could be immersed in each solution. The subsequent surface treatment method was exactly the same as the NAT treatment method shown in Experimental Example A1-1.

[Experimental Example A4-1] Surface treatment of A2017Al alloy (NAT7 treatment method)
A2017Al alloy plate material with a thickness of 0.5 to 3.0 mm was obtained, machined into rectangular pieces of various sizes, and holes were drilled at the ends. A gardening wire with a PVC cover was passed through the holes in the A2017Al alloy pieces and hung so that they could be immersed in each liquid. In an immersion tank, an aqueous solution containing 10% aluminum degreaser "NA-6" was set at 60°C, and the A2017Al alloy pieces were immersed for 5 minutes and washed with water. Next, in another tank, a 10% aqueous caustic soda solution at 40°C was prepared, and the A2017Al alloy pieces were immersed in this for 1 minute and then washed with water. Next, in another tank, an aqueous solution containing 1% aluminum chloride hydrate and 5% hydrochloric acid at 40°C was prepared, and the A2017 alloy pieces were immersed for 1 minute and washed with water. Next, in another tank, an aqueous solution containing 2% ammonium difluoride and 10% sulfuric acid at 40° C. was prepared, and the A2017Al alloy pieces were immersed in this for 3 minutes and then rinsed with water.

Next, in another tank, a 1.5% caustic soda solution at 40°C was prepared, and the A2017 alloy pieces were immersed in this for 2 minutes and then rinsed with water. Next, in another tank, a 3% nitric acid solution at 40°C was prepared, and the A2017Al alloy pieces were immersed in this for 2.5 minutes and then rinsed with water. Next, in another tank, a 3.5% hydrazine hydrate solution at 60°C was prepared, and the A2017Al alloy pieces were immersed in this for 2 minutes, and then in another tank, a 0.5% hydrazine hydrate solution at 33°C was immersed for 0.5 minutes and then rinsed with water. Then, after immersing in a 5% hydrogen peroxide solution for 5 minutes and rinsing with water, the pieces were placed in a hot air dryer set at 67°C for 15 minutes and dried.

[Experimental Example A4-2] Surface treatment of A2017Al alloy (NAT treatment: Reference Example)
A2017Al alloy sheets with thicknesses of 0.5 to 3.0 mm were obtained and machined into rectangular pieces of various sizes, with holes drilled at the ends. Gardening wires with PVC covers were passed through the holes in the A2017Al metal pieces and hung so that they could be immersed in each solution. The subsequent surface treatment method was exactly the same as the NAT treatment method shown in Experimental Example A1-1.

[Experimental Example A5] Surface treatment of A7075Al alloy (NAT treatment)
A7075Al alloy sheets with thicknesses of 1.5 to 3.0 mm were obtained and machined into rectangular pieces of various sizes, with holes drilled at the ends. The A7075Al alloy pieces were hung through the holes with PVC-covered garden wires so that they could be immersed in each solution. The subsequent surface treatment method was exactly the same as the NAT treatment method shown in Experimental Example A1.

[Experimental Example A6] Surface treatment of ADC12Al alloy (NAT7 treatment)
The ADC12Al alloy pieces, which were cast using the ADC12Al alloy of the Japanese Industrial Standards, and had a small shape of 45 mm x 18 mm x 1.5 mm thick and had holes at the ends, were obtained and subjected to the following liquid treatments. In an immersion tank, an aqueous solution containing 10% aluminum degreaser "NA-6" was set to 60°C, and the ADC12Al alloy pieces were immersed for 5 minutes, and then washed with water. Next, in another tank, a 10% concentration aqueous caustic soda solution at 40°C was prepared, and the ADC12Al alloy pieces were immersed in this for 1 minute, and then washed with water. Next, in another tank, an aqueous solution containing 1% concentration aluminum chloride hydrate and 5% concentration hydrochloric acid at 40°C was prepared, and the ADC12Al alloy pieces were immersed in this for 4 minutes, and then washed with water. Next, in another tank, an aqueous solution containing 2% concentration ammonium difluoride and 10% concentration sulfuric acid at 40°C was prepared, and the ADC12Al alloy pieces were immersed in this for 1 minute, and then washed with water. Next, in another tank, an aqueous solution of caustic soda at 1.5% concentration at 40°C was prepared, and the ADC12Al alloy pieces were immersed in this for 4 minutes, and then washed with water. Next, in another tank, an aqueous solution of nitric acid at 3% concentration at 40°C was prepared, and the ADC12Al alloy pieces were immersed in this for 2 minutes, and then immersed in a water tank equipped with an ultrasonic transmission end for 5 minutes. Next, the ADC12Al alloy pieces were returned to the immersion tank containing the aqueous solution of nitric acid at 3% concentration at 40°C, and the ADC12Al alloy pieces were immersed for 0.5 minutes, and then washed with water.

Next, in another tank, a 3.5% hydrazine hydrate aqueous solution at 60°C was prepared, and the ADC12Al alloy pieces were immersed in this for 2 minutes, then in another tank, a 0.5% hydrazine hydrate aqueous solution at 33°C for 0.5 minutes, and then rinsed with water. Then, after immersing in a 5% hydrogen peroxide solution for 5 minutes, this was rinsed with water. This was placed in a hot air dryer set at 67°C for 15 minutes, then dried in a hot air dryer set at 100°C for 15 minutes, and then immersed again in a water tank equipped with an ultrasonic transmitter for 5 minutes, and then dried in a hot air dryer set at 67°C for 15 minutes.

[Experimental Example A7] Surface treatment of SUS304 stainless steel (latest NAT treatment)
SUS304-2B steel plates with a thickness of 0.3 to 3.0 mm were procured, machined into rectangular pieces of various sizes, and holes were drilled at the ends. The metal pieces were hung through the holes with PVC-covered gardening wires so that they could be immersed in each solution. In an immersion tank, an aqueous solution containing 10% aluminum degreaser "NA-6" was heated to 60°C, and the steel pieces were immersed in this for 5 minutes and then washed with water. Next, in another tank, an aqueous solution containing 10% sulfuric acid and 1% ammonium difluoride at 65°C was prepared, and the SUS304 stainless steel pieces were immersed in this for 10 minutes and then washed with water. Next, the pieces were immersed in a water tank equipped with an ultrasonic oscillator for 5 minutes to separate the smut adhering to the SUS304 stainless steel pieces. Next, in another immersion tank, an aqueous solution containing 5% sulfuric acid and 0.5% ammonium difluoride at 60°C was prepared, and the SUS304 stainless steel pieces were immersed in this for 20 minutes, and then washed with water. Next, the pieces were immersed in a water tank equipped with an ultrasonic oscillator for 5 minutes to separate the smut attached to the SUS304 stainless steel pieces. Next, an aqueous solution of 3% nitric acid at 40°C was prepared, and the SUS304 stainless steel pieces were immersed in this for 3 minutes and washed with water. Next, in another immersion tank, the pieces were immersed in an aqueous solution containing 10% caustic soda and 5% sodium chlorite at 55°C for 6 minutes, and then washed with water. Then, the pieces were placed in a hot air dryer set at 80°C for 15 minutes to dry.

[Experimental Example A8-1] Surface treatment of SPCC (New NAT treatment: Reference Example)
Commercially available SPCC (cold rolled steel plate) with a thickness of 1.6 mm and 3.2 mm was purchased, and the steel pieces were cut into various desired shapes to be used as test pieces. The SPCC test pieces were blasted with white alumina powder (WAF100) using a shot blasting machine to roughen the areas to be bonded. The SPCC test pieces were placed in an immersion tank equipped with an ultrasonic transmitter, and an aqueous solution containing 10% aluminum degreaser "NA-6" was prepared at 60°C. The SPCC test pieces were immersed for 5 minutes and then washed with water. Next, an aqueous solution containing 1% ammonium difluoride and 10% sulfuric acid at 65°C was prepared in another immersion tank, and the SPCC test pieces were immersed for 1 minute and then washed with water. Next, 1% ammonia water was prepared in another immersion tank, and the SPCC test pieces were immersed for 1 minute and then washed with water. Next, in another immersion tank, an aqueous solution containing 2% potassium permanganate, 1% acetic acid, and 0.5% sodium acetate hydrate was prepared at 45°C, and the SPCC test piece was immersed in this for 5 minutes and then rinsed with water.Then, the SPCC test piece was immersed for 7 minutes in a water tank equipped with an ultrasonic oscillator to remove smut and rinsed with water.The washed SPCC test piece was placed in a hot air dryer set at 80°C for 15 minutes to dry it.

[Experimental Example A8-2] Surface treatment of SPCC (latest NAT treatment)
SPCC steel pieces of 1.6 mm and 3.2 mm were purchased on the market and cut into various desired shapes by machining to prepare test pieces. In an immersion tank, an aqueous solution containing 10% aluminum degreaser "NA-6" was set at 60°C, and the SPCC test pieces were immersed for 5 minutes, and then washed with water. Next, in another tank, an aqueous solution of 5% ammonium difluoride at 65°C was prepared, and the SPCC test pieces were immersed for 25 minutes, and then washed with water. Next, in another tank, an aqueous solution of 1% ammonia was prepared, and the test pieces were immersed for 1 minute, and then washed with water. Next, in another tank, an aqueous solution containing 2% potassium permanganate, 1% acetic acid, and 0.5% sodium acetate hydrate at 45°C was prepared, and the SPCC test pieces were immersed for 5 minutes, and then washed with water. Then, the SPCC test pieces were immersed for 7 minutes in a water tank equipped with an ultrasonic oscillator to remove smut and wash with water. Next, in another tank, an aqueous solution containing 0.2% triethanolamine at 40° C. was prepared, and the SPCC test piece was immersed in this for 30 minutes, and then washed with water. Then, the SPCC test piece was placed in a hot air dryer set at 80° C. for 15 minutes to dry it.

[Experimental Example A9-1] Surface treatment of 64Ti alloy (New NAT treatment)
We prepared 64Ti alloy pieces (original material: "KS6-4" (manufactured by Kobe Steel, Ltd. (head office: Hyogo Prefecture, Japan))) of 150 mm x 50 mm x 3 mm, 45 mm x 18 mm x 3 mm, 45 mm x 18 mm x 1.5 mm, etc., made by a metal processing manufacturer. The surface treatment method was a direct application of the treatment method and surface properties called New NAT described in Patent Document 8, etc., and since this is a publicly known technology, the treatment method will be omitted. After this surface treatment, the pieces were wrapped in clean aluminum foil and stored.

[Experimental Example A9-2] Surface treatment of 64Ti alloy (latest NAT treatment)
As in the above experimental example, 64Ti alloy pieces were obtained and used as test pieces. In an immersion tank, an aqueous solution containing 10% aluminum degreaser "NA-6" was set to 60°C, and the 64Ti alloy pieces were immersed for 5 minutes, and then washed with water. Next, in another tank, a 5% concentration aqueous solution of ammonium monohydrogen difluoride was prepared at 65°C, and the 64Ti alloy pieces were immersed for 5 minutes, and then washed with water. Next, in another tank, a 3% concentration aqueous solution of nitric acid was prepared, and the test pieces, which are the 64Ti alloy pieces, were immersed for 3 minutes, and then washed with water. Next, in another tank, an aqueous solution containing 2% concentration of potassium permanganate and 3% concentration of caustic potassium was prepared at 70°C, and the 64Ti alloy pieces were immersed for 30 minutes, and then washed with water. Then, the pieces were immersed for 20 minutes in an aqueous solution containing 15% of a newly developed adjuster at 55°C, and then washed with water. Then, the pieces were placed in a hot air dryer set at 80°C for 15 minutes to dry.

[Experimental Example A10] Surface treatment of Ti alloy "KSTi-9" (New NAT treatment)
A 1 mm thick heat-resistant titanium alloy plate material "KSTi-9" (manufactured by Kobe Steel, Ltd. (head office: Hyogo Prefecture, Japan)) was procured and cut to the required size. The surface treatment was exactly the same as that of the above-mentioned Experimental Example A9. The above is the surface treatment method for the various metal pieces used in this Experimental Example. Next, the surface treatment method for the CFRP material when bonding with these metal pieces will be described.

[Experimental Example A11] Surface treatment of CFRP material Two types of CFRP material were used in this experiment. One was a CF (commercially available) with a tensile strength of approximately 3 GPa, which was made by stacking unidirectional prepregs in the same direction and curing them, and was 45 mm x 15 mm x 3 mm thick.

For the other type, 0.2 mm thick CFRP unidirectional prepreg "P225S-25" (manufactured by Toray Industries, Inc. (headquarters: Tokyo, Japan)) was obtained and outsourced to a specialized processing company to create a 500 mm x 500 mm CFRP thick plate with the CF direction aligned and 3 mm thick, to create the plate. Part of this plate was cut into a CFRP piece with the CF parallel to the long side of 45 mm x 15 mm. The CF used was "T800SC" (manufactured by Toray Industries, Inc. (headquarters: Tokyo, Japan)), and the tensile strength of the CF yarn was approximately 6 GPa. Both used a heat-resistant matrix resin.

The surface of the CFRP material for adhesive bonding is pretreated by strongly grinding it with #600 sandpaper until some of the CF is exposed. After grinding, the CFRP pieces are immersed in an ultrasonic degreasing tank (a water tank containing a degreasing agent for aluminum material at 60°C) to separate any adhering dirt, and then thoroughly rinsed with water. They are then dried in a hot air dryer at 100°C for around 15 minutes, and then wrapped in clean aluminum foil and stored.

[Experimental Example A12] Preparation of an Adhesive Integrated Product of CFRP Material and Al Alloy Thin Plate A method of preparing an adhesive integrated product of a CFRP piece and an Al alloy thin plate from a CFRP prepreg in one go was also carried out. That is, a 0.75 mm thick A5052 Al alloy thin plate was cut in advance to 98 mm x 98 mm, and the same treatment as in Experimental Example A3 was carried out. One side of the plate was thinly coated with a one-liquid epoxy adhesive "EW2040 (manufactured by 3M Japan Co., Ltd. (headquarters: Tokyo, Japan)) and a Teflon sheet was pressed on top of it to prepare an adhesive and store it. Using both this adhesive preparation and a CFRP prepreg "P225S-25" (manufactured by Toray Industries, Inc. (headquarters: Tokyo, Japan)), a 3.5 mm thick CFRP thick plate shape with a 100 mm x 100 mm A5052 Al alloy thin plate was prepared. This preparation was performed by heating and bonding in a reduced pressure autoclave, with the maximum heating conditions being 150°C x 40 minutes. The obtained CFRP thick plate with the A5052Al alloy thin plate was cut to a size of 45 mm x 15 mm so that the CF was parallel to the long sides.

[Experimental Example B] Test to confirm adhesive strength [Experimental Example B1] Measurement of adhesive strength (shear adhesive strength, tensile adhesive strength) Various test pieces of 45 mm x 18 mm x (3-6) mm thickness, which were treated in the same manner as the above-mentioned [Experimental Examples A1-A12] group, were used to form adhesive pairs in the shapes shown in Figures 1 and 2. More specifically, the shape of the test piece shown in Figure 1(a) is 45 mm x 18 mm x (4.5-6.0) mm thickness in order to apply a tensile load. However, when the Al alloy material is soft, especially when thin pure aluminum -based aluminum Al is used, it is used with a thickness of 6.0 mm, and otherwise with a thickness of 4.5 mm. For this reason, 1.5 mm thick products were often bonded in three or four layers to form a thickness of 4.5 mm or 6.0 mm, and this is shown as the shape shown in Figure 1(b). In addition, for the CFRP pieces described in Experimental Examples A11 and onwards, the CFRP piece shape was 45 mm x 15 mm x 3 mm thickness. These were directly formed into the laminated structure shown in FIG.

[Test piece preparation procedure]
The specific bonding method for preparing the test pieces shown in Figures 1 and 2 will be described below. The basic shape of the various metal pieces used by the inventors was mostly 45 mm x 18 mm x 1.5 mm thick, and the CFRP and CFRTP pieces were 45 mm x 15 mm x 3 mm thick. In addition, when the base material of the metal pieces is a rolled plate, the rolling direction is the 45 mm direction of the long side of the rectangle, the perpendicular direction is the width direction of 18 mm, and the thickness is the thickness direction of the rolled plate of the base material. Therefore, only the SPCC pieces have a thickness of 1.6 mm or 3.2 mm, which is an integer multiple of 1.6 mm. This is because only products with this thickness are produced. For A6063 aluminum alloy and 64 titanium alloy, which are supplied as base materials in thick plates or ingots, such a rule cannot be made and depends on the processing accuracy of the metal processing. In addition, for CFRP materials that use prepregs containing bundled CF and in which the CF bundles are all aligned in the same direction, the bundle alignment line is set to a length of 45 mm. In the case of the shape shown in Figure 1(b), many metal pieces are laminated, so all of the individual metal pieces described above are surface-treated by a specified treatment method before being bonded.

As a pretreatment before gluing, a very small amount of one-part epoxy adhesive "EW2040" is placed in an adhesive container, to which a solvent, MIBK (methyl isobutyl ketone), is added to make a very thin solution, and the adhesive from the container is attached to the tip of a wooden bar, which is then smeared onto the area to be glued of the chemically treated test piece, the metal piece. The test piece is then placed in a hot air dryer set at 50°C for 20 minutes to evaporate the solvent. The adhesive "EW2040" is then smeared onto the primed area. For laminated adhesive surfaces that are not related to the shear fracture test, no primer application is required, and the adhesive is applied directly to the entire surface of the test piece, which is then laminated as shown in Figure 1(b), and the laminate is then pressed and fixed with a jig (stationery clip) to form a laminate.

During the above-mentioned bonding operation, a large desiccator is placed in a hot air dryer set at 50°C to preheat it. The desiccator is removed, and the laminated body with the jig fixed in place is placed in the desiccator as is. The desiccator is then evacuated with a vacuum pump, and after about 5 minutes, air is refilled. This decompression/pressurization operation is repeated at least twice, and the desiccator is removed from the desiccator. Next, the desiccator is placed in a hot air dryer and heated at 170°C for 20 minutes. After the curing process is complete, the fixed jig is removed. After the curing process is complete, the test piece has many hardened areas where the adhesive has overflowed from the adhesive surface, and these are removed with a router. This machining process is performed the day after the curing process to reduce the effects of the machining process, and the values of "shear adhesive strength" and "shear adhesive tackiness" are measured using a tensile tester. The method of preparing the test piece shown in Figure 2 for measuring "tensile strength" is the same as the above method.

Table 1 shows the main data of the shear bond strength measured for the same kind of test pieces bonded by the above chemical conversion treatment and bonding method. As can be seen from Table 1, the shear bond strength between the same kind of metal pieces is generally about 60 MPa, and the only one with a low value was about 54 MPa for A1050Al alloy, which is a pure aluminum-based aluminum, which is a soft metal. On the other hand, in the test pieces between CFRP pieces prepared in Experimental Example A11, the test pieces between CFRP pieces prepared using a CF with a tensile strength of about 3 GPa obtained about 60 MPa. However, even in the test pieces between the same CFRP pieces, the test pieces between CFRP pieces prepared using a CF with a tensile strength of about 6 GPa obtained about 40 MPa. The data in Table 1 show that the treatment of the bonding surface is not a mechanical surface treatment such as polishing, but the bonding method using various chemical conversion treatments proposed by the present inventors is effective for the bond strength. It was also found that the tensile adhesive strength (test piece in FIG. 2 described later) was stronger than the shear adhesive strength. The reason for this is understood to be that the rolling direction of the metal, i.e., the direction of the metal fibers described later, affects the adhesive strength.

[Experimental Example B2] Measurement of tensile bond strength of various surface-treated metal materials Various metal pieces of 45 mm x 18 mm x 1.5 mm that had been treated in the same manner as in Experimental Examples A1 to A9 were used to prepare test pieces in the shape shown in Figure 2. That is, in the shape of the test piece shown in Figure 2, the end shape of the metal piece is 18 mm x 1.5 mm, so various metal pieces for measuring shear bond strength according to ISO19095 are manufactured by test piece manufacturing companies and are commercially available. Therefore, these test pieces were used as they were.

The results of the measurement of the tensile bond strength using the test piece shown in Figure 2 are also shown in Table 1. As mentioned above, the tensile bond strength is measured on the y-z plane of the supplied metal plate. According to the experimental results of this tensile bond strength, only the pure aluminum-based aluminum A1050Al stands out, recording about 95 MPa. In actual measurements, some test pairs showed about 100 MPa, and about 95 MPa is the average value of several pieces, and is not an abnormal value due to experimental variation. It is speculated that the metal crystal form of the Al alloy formed by the stretching process such as rolling when forming metal is related to this. The crystal form is elongated and fibrous, which gives it high tensile strength in the x direction, and this is thought to be related to the tensile bond strength. If this inference is correct, then even if a processing method that produces high tensile bond strength values is developed using the test piece shown in Figure 2 for rolled products, a bonding method that does not take into account the direction of the metal fibers will not increase the shear bond strength of the processed product. Conversely, if a metal block is forged and then machined into small plate-shaped pieces, it is estimated that there is a proportional relationship between the tensile adhesive strength value and the shear adhesive strength value.

[Experimental Example B3] Measurement experiment of "tensile bond strength" of metal plate surfaces (x-y surfaces) As shown in Table 1, for example, the "tensile bond strength" of the y-z surface of experimental example Al is abnormally high at about 95 MPa. The reason is presumed to be that the direction of the metal fibers is different from that of the adhesive surface of the x-y surface, as described above. By analyzing the values of Al050, which is a pure aluminum-based aluminum recorded in Table 1, it is predicted that the "tensile bond strength" on this plate surface (plate surface: x-y surface) is different from the "tensile bond strength" based on the plate cross section (y-z surface) measured with the test piece shown in Figure 2. Since there is no standardized test method for measuring the "tensile bond strength" based on the plate cross section (x-y surface) in the rolling direction, a test piece was prepared and measured by the method described below.

(1) Method for measuring "tensile adhesive strength" on plate surface (plate surface: x-y plane) Figures 16 to 18 are schematic diagrams showing an outline of the procedure for preparing test pieces for measuring "tensile adhesive strength" on plate surface (x-y plane (Figure 2)). First, six sheets of A5052Al alloy, 45 mm long x 18 mm wide x 1.5 mm thick, were bonded and laminated with a one-liquid epoxy adhesive. After heating and curing, the sheets were cut in the plate thickness direction with a saw blade as shown in Figure 16 (lower), and further machined to 18 mm wide x 9 mm long x 1.5 mm thick by end mill processing. As shown in Figure 17, the machined pieces were bonded to the end faces of two sheets of the A5052Al alloy (45 mm long x 18 mm wide x 1.5 mm thick) of the same material in thickness and width with the same adhesive as above, and the excess parts were cut off after curing (lower part of Figure 17).

In this bonded state, even if a tensile load is applied, it is not possible to determine which bonded surface will break, so this is not a preferable test method. Therefore, as shown in the lower part of Figure 18, the central part was cut into an arc shape using an end mill. Then, in the laminated test pieces, the width direction of this bonded surface was narrowest (9 mm wide x 1.5 mm thick) so that the bonded surface at the center would break. The load at which this bonded surface broke was taken as the tensile bond strength of the x-y surface. As a result, the tensile bond strength of the x-y surface was 46.0 MPa for the same pure aluminum -based aluminum A1050Al, which is the same material, and is the same chemical conversion treatment (NAT) product with the same adhesive, and is lower than 95.0 MPa for the y-z surface (see Table 1). Similarly, it was 51.3 MPa for A5052Al, which is lower than 76.4 MPa for the y-z surface, and 47.0 MPa for 64Ti alloy, which is lower than 75.2 MPa for the y-z surface.

In the present invention, the physical properties of the plate surface of the metal piece produced by rolling are important for the bonding operation. In the NAT treatment, the specific research on improving the NAT treatment method was how to improve the shear bond strength using the shape of the test piece shown in Figure 1, and the present invention was also based on the securing of a strong adhesive strength of 60 MPa at room temperature and 30 MPa at 150 ° C., and was successfully developed. However, research on improving the surface treatment method of various metal alloys reaches its limit and stagnates when the shear bond strength approaches about 60 MPa. This is because it is undoubtedly approaching the upper limit value. Therefore, there is no clear indicator to use after approaching this maximum value. Theoretically speaking, since the shear bond strength is measured on the plate surface of many metal pieces, if the tensile bond strength on the plate surface can be measured, it can be said that "the higher the value, the better the structure of the adhesive surface." Therefore, if the shear bond strength reaches 60 MPa, it was decided that the next step would be to measure the tensile bond strength of this part and try and error the surface treatment method. This is the reason for carrying out the above-mentioned "Experimental Example B3." However, because the test method is too difficult and experimental errors are likely to occur, it was determined that this method is not suitable for use in the present invention as an improvement evaluation method for advancing improvements through trial and error in surface treatment.

[Experimental Example B4] Measurement of adhesive strength (shear adhesive tackiness value) of various metal materials From the above-mentioned circumstances, furthermore, a method for evaluating adhesive strength that can easily measure adhesive strength and is close to the load when used in actual equipment, rather than a simple tensile load, was searched for. This is the conclusion reached by the present inventor and the measurement of "shear adhesive tackiness" proposed. Table 2 shows the measurement results of the "shear adhesive tackiness" described above for the test piece shown in Figure 1 when metal materials of the same material are bonded together. That is, as already mentioned, referring to the previously measured shear adhesive strength value, about 75% of the force is applied 300 times, and if there is no breakage, the force is increased by about 2 MPa and applied as it is 300 times, and if there is still no breakage, this is repeated. As can be seen from the results shown in Table 2, all target metals were measured with NAT treated products, and the "shear adhesive tackiness" value was also measured for NAT5 and NAT7 treated products. In addition, from a practical point of view, the "shear adhesive tackiness" is preferably 50 MPa or more.

[Experimental Example B5] Measurement of adhesive strength (shear adhesive strength) of one-component epoxy adhesive between dissimilar metal materials. Using the same chemical conversion treatment as shown in Experimental Example A, 45 mm x 18 mm x (4.5-6.0) mm metal pieces, test pieces (shape shown in FIG. 1) between dissimilar metal pieces were prepared under the curing conditions of 170°C x 20 minutes using the one-component epoxy adhesive "EW2040". The results are shown in Table 3. As mentioned above, one-component epoxy adhesives usually cure at 150-180°C for 15-30 minutes. In the experiments of the present invention, when "EW2040" was used, the curing conditions were all 170°C x 20 minutes. Therefore, when the curing is completed and the pieces are taken out of the hot air dryer, they are immediately cooled and completely return to room temperature after being left for 1 hour. In other words, the adhesive surface is fixed at 170°C, and after returning to room temperature, the environmental temperature is lowered by about 150°C. If the test piece shown in Figure 1 is a bonded pair of dissimilar metal materials and there is a large difference in linear expansion coefficient between the dissimilar materials, the adhesive cured layer will either be partially or completely damaged, or the adhesive condition will not change, but it will deform slightly, even if it is not clear to the naked eye. Internal stress corresponding to the deformation of the test piece will be generated, and the adhesive strength will decrease accordingly. In either case, if the shear adhesive strength is measured with a tensile tester, the value will definitely decrease. It was estimated that if the bonded pair after curing were subjected to a temperature shock test of -50°C/+150°C, the deterioration would be more clearly evident.

Four pairs were prepared for this test, two of which were tested for adhesive strength the day after the bonding operation, and the remaining two were tested after 100 cycles of temperature shock at -50°C/+150°C. However, since there was no clear difference between the first two pairs and the latter two pairs, the average value of the four pairs is shown in Table 3. As a result, the shear adhesive strength of the dissimilar materials, one of which was A1050Al and the other was A7075Al, was 55-57MPa, and since there was almost no difference in the linear expansion coefficient, all of the adhesive strengths were naturally high. In addition, when A1050 aluminum, which is pure aluminum, was bonded to a dissimilar material with a linear expansion coefficient that differs greatly from that of A1050 aluminum, it was strange that a strong adhesive strength was obtained both before and after the temperature shock test, with a value of about 55 MPa or more. This data is important for the present invention and is the origin of the present invention.

On the other hand, as shown in the lower column of Table 3, the shear bond strength of the one-part epoxy adhesive bonded between high-strength materials with clearly and significantly different linear expansion coefficients is greatly reduced. It is presumed that part of the adhesive cured layer was damaged by cooling after curing. The adhesive area of the test piece with the shape shown in Figure 1 is about 0.7 cm2. It can be seen that even such a small area can be greatly affected by the difference in linear expansion coefficient. In short, the clear fact that no decrease in shear bond strength is observed in the data of Table 3 is a phenomenon caused by the physical properties of the soft metal of A1050 and A1085 aluminum, which are pure aluminum-based aluminum.

[Experimental Example B6] Measurement of adhesive strength (shear adhesive strength) between test pieces in multi-layer metal adhesive The laminated bonded integrated product including the dissimilar material structural material of the present invention is a bonded integrated product laminated with adhesive in four or five layers, with the "A" and "B" materials as both end members, and the above-mentioned "C" and "D" materials sandwiched between the "A" and "B" materials. This bonded integrated product has three or four adhesive surfaces. Therefore, we tried to measure the actual adhesive strength (shear adhesive strength) at each of these adhesive surfaces. Examples of the laminated product of four or five layers are shown in Figure 5 (five layers) and Figure 6 (four layers). However, the shear adhesive strength and temperature impact strength cannot be measured with the laminate shown in Figure 5 (five layers) and Figure 6 (four layers). The measurement results obtained with the test piece shown in Figure 7 as a five-layer laminate and the test piece shown in Figure 8 as a four-layer laminate are shown in Table 4.

Table 4 shows nine measurement examples, where 64Ti alloy, A2017Al alloy (duralumin), A7075Al alloy (super duralumin), SUS304 steel, CFRP pieces, etc. were used as "A" and "B" materials. A5052Al alloy 0.75mm thin plate, A6061Al alloy 0.5mm thick thin plate, SUS304 0.28mm thin plate were used as "C" materials, and A1050Al 1.5mm plate was used as "D" material. The shear bond strength of each bonded joint (part of // in Table 4) was high at 55-58MPa, and there was little difference in shear bond strength after the same test pieces were subjected to a temperature shock test of -50℃/+150℃, and there was no problem with the bond strength of the bonded joint even after the temperature shock test. As can be seen from the adhesion examples in Figures 7 and 8, the adhesion area of the bonded portion to A1050Al, which is a pure aluminum-based aluminum, is the smallest and the weakest. Therefore, this test provided data on the shear adhesive strength and temperature impact strength of at least the bonded portion to the A1050Al member.

[Experimental Example B7] Experiment on moisture and heat resistance test of test piece of one-liquid epoxy adhesive in the shape shown in Figure 1 The data in Table 4 above is not test data in a high temperature and high humidity environment. The present invention is a laminated adhesive of three, four, or five layers, with "C" and "D" materials sandwiched between "A" and "B" materials. The first thing required for this adhesive is whether the adhesive strength of the adhesive surface of both "C" and "D" materials can withstand the severe environment when used as structural materials for automobiles, etc. Specifically, even if there is no problem in the above-mentioned temperature shock test, a test in a high humidity environment is also necessary. A general high humidity test is a humidity test at a temperature of 50°C and a humidity of 95%, but in this experiment, this was accelerated and a test was performed in which the test piece was exposed to a high temperature and high humidity tester at a temperature of 85°C and a humidity of 85% for 1,000 hours. However, aluminum alloys have a thin hydroxide (rust) generated on their surface, which changes the color tone, and rust occurs when water droplets adhere to them when the door of the tester is opened and closed during the test. Therefore, before placing the test pieces in the test machine, they were coated with engine oil (10W-30) that is generally available on the market, and then placed in the test machine. As shown in Table 5, the samples were A1085Al, A1050Al, A6061Al alloys, and SUS304, which are used in the "C" and "D" materials, but for reference, 64 titanium alloy, which is likely to be used in the "A" and "B" materials, was also tested. The adhesive was the aforementioned "EW2040". The results are shown in Table 5. The data shown in Table 5 shows that the shear adhesive strength of pure aluminum-based aluminum did not decrease even after the moist heat test, but the other materials did.

That is, looking at the results in Table 5, after being exposed to high temperature and humidity at 85°C and 85% humidity for 1,000 hours, the adhesive strength decreased to about 45 MPa in shear adhesive strength, except for pure aluminum-based aluminum (Japan Industrial Standard 1000 series). From the results, it was determined that the reason for this was that the adhesive cured product (epoxy resin cured product) absorbed water molecules under long-term high temperature and humidity, causing it to soften slightly. It was understood that the reason why the adhesive strength decrease in the pure aluminum-based aluminum was slightly reduced was because the hardness of the adhesive cured product, which had absorbed moisture and softened, became closer to that of the pure aluminum-based aluminum, dispersing stress. That is, in the case of A6061Al alloy, SUS304, etc., which have a large hardness difference between the adhesive and the metal, the hardness difference between the metal and the adhesive became large, making it easier to break due to stress concentration.

Therefore, it was determined that the moisture-absorbed adhesive pair was heated at 80°C for 92 hours, and then dried with hot air at 170°C for 1 hour, and that this had expelled the water molecules that had settled within the narrow cured layer of adhesive. This 1,000-hour high-temperature, high-humidity test at 85°C and 85% humidity was an accelerated test that placed the pair under harsh conditions that would not exist in an actual environment, and the problem was to determine how much irreversible problems would remain after removing the moisture from the adhesive pair. Therefore, the drying process described above was carried out. The reason for first heating at 80°C for a long time was that if it was placed at a high temperature of 150°C or higher from the beginning, steam would be released from the cured adhesive that had absorbed sufficient moisture, preventing the structure of the cured adhesive from being destroyed. Then, after removing the majority of the water molecules, it was heated at 150°C or higher, and it was determined that the moisture-absorbed material was almost completely expelled.

From the results in Table 5, it can be seen that the adhesive strength of the same metal pieces bonded together using the hardened one-part epoxy adhesive "EW2040" after strict moisture absorption conditions was 53-55 MPa for all of them, except for the NAT-treated 64Ti, which the inventors judged to be good results. In short, the environmental humidity conditions on Earth to which mobile machines such as automobiles that move on the ground are exposed are a maximum of approximately 40°C and 100% humidity, and even in northeastern India, which has the most rainfall in the world, the temperature is 25-30°C. Therefore, the decrease in shear bond strength is somewhat large, at 43 MPa, for the 64 titanium alloy shown in Table 5. However, since titanium materials are used as the "A" and "B" materials in this invention, when the adhesive strength of the thin plate material used as the "C" material to the titanium material is weak, this can be compensated for by increasing the adhesive area. Conversely, if the adhesive performance of the "C" and "D" materials does not show an irreversible decrease in adhesive strength in the accelerated test in this high humidity environment, this invention will not have to face major problems that are troublesome in practical use. In that sense, it was found that for A6061 aluminum alloy and SUS304 stainless steel, which can be used as "C" materials, and A1050 and A1085 aluminum, which can be used as "D" materials, strong adhesive strength can be obtained under high temperature and high humidity conditions, even though the bonding is between the same metal types.

[Experimental Example B8] 64Ti/pure aluminum-based aluminum Al surface bonded material (preliminary test 1)
From the above experimental considerations, in order to confirm the effectiveness of pure aluminum -based aluminum as a laminate as the "D" material, the adhesive strength between Ti alloy and pure aluminum-based aluminum was measured using a one-part epoxy heat-curing adhesive. A 45mm x 18mm x 3mm thick 64Ti alloy with the new NAT treatment described in [Experimental Example A9-1] and a 45mm x 18mm x 1.5mm thick A1080Al plate with the NAT treatment described in [Experimental Example A1-1] were surface-bonded using the NAT bonding method with the one-part epoxy heat-curing adhesive "EW2040". Next, a 45mm x 18mm x 3mm thick 64Ti alloy with the same surface treatment as above and a 45mm x 18mm x 1.5mm thick A1050Al plate with the NAT treatment were surface-bonded using the aforementioned "EW2040" using the NMT bonding method.

Furthermore, the same surface-treated 64Ti alloy 45mm x 18mm x 3mm thick product and the NAT-treated A1100Al plate 45mm x 18mm x 1.5mm thick product were surface-bonded by the NMT bonding method using the aforementioned "EW2040". In short, A1080, A1050, and A1100 Al plates were surface-bonded to the 64Ti thick plate with a bonding area of 45mm x 18mm, or ^8.1cm2 , using the same method. A total of nine pieces were made, each in units of three, and these bonded products were placed in a temperature shock cycle tester at -50°C/+150°C and subjected to a load of 1,000 cycles. In this load test, all three of the 64Ti/A1100Al bonded products had surface fractures, and no abnormalities were found in the other six. Therefore, the thermal shock test was continued, and when the specimens were removed at 2,000 cycles, small peeling-like features were observed in one or two places on the four corners of both 64Ti/A1050Al specimens using a non-destructive testing machine, while no peeling was observed in any of the three 64Ti/A1080Al specimens.

This experiment showed that, even with soft Al, A1080, the softest, did not cause any problems, but A1050Al did cause slight but clear problems with the adhesive surface with Ti material. According to Table 2 mentioned above, the "shear adhesive tackiness" value of the test piece of A1050 Al (NAT treated product) of experimental example Al was 50.5 MPa, which was the very limit of the allowable shear tackiness value assumed in this experiment, while the "shear adhesive tackiness" value of 64Ti (new NAT treated product) of [Experimental example A9-1] was 45.8 MPa, which was clearly low. At the start of this experiment, the 64Ti alloy (latest NAT treated product) of [Experimental example A9-1] had not yet been found. Therefore, based on this result, we created a new type of NAT-treated product of the aforementioned "KSTi-9", which is the Ti alloy of [Experimental Example A10], and used this to create a new type of NAT-treated product of the Ti alloy "KSTi-9" made by bonding three 45mm x 18mm x 1mm thick plates together, and two NAT-treated products of 45mm x 18mm x 1.5mm thick A1050Al plates, bonded together with the aforementioned "EW2040". The "KSTi-9" used has a very high "shear adhesive tackiness" value of 56.5MPa, as recorded in Table 2, and if edge peeling occurred around 2,000 cycles of temperature shock due to insufficient adhesive strength between 64Ti and Al050Al, we thought that it would be sufficient to replace the Ti material with the weaker adhesive strength. As a result of subjecting it to a temperature shock test of 3,000 cycles, there was no problem at all and no edge peeling occurred.

[Experimental Example B9] Pure aluminum-based aluminum Al and Ti alloy test pieces sandwiched between A1050 plates (Preliminary Test 2)
A three-layered adhesive was created as shown in Figure 4. A new NAT-treated 64Ti alloy measuring 45mm x 18mm x 3mm thick, a NAT-treated A1050Al measuring 45mm x 18mm x 1.5mm thick, and a NAT-treated A7075Al alloy measuring 45mm x 18mm x 3mm thick were surface-bonded using the NAT bonding method with "EW2040". Although it is called a three-layered adhesive, to be precise, in this experiment, all metal pieces were 1.5mm thick, and the 64Ti alloy was laminated with two layers, and the A7075Al alloy was also laminated with two layers, resulting in a surface-bonded product with five layers in total. Two identical pieces were created and subjected to a temperature shock test of -50℃/+150℃ for 3,000 cycles.

Visual inspection of the bonded material removed from the test machine revealed no defects. Based on the results of the above experiment, there was a good chance that peeling had occurred at the four corners between the 64Ti alloy part and the A1050Al plate, and this was checked using a non-destructive testing machine. As a result, a peeling signal was obtained at one of the four corners. However, no peeling signals could be detected at all in other areas. Ultimately, the test results were the same as those of experiment B8.

[Experimental Example B10] Test piece in which A5052 Al alloy thin plate and A1050 Al plate are sandwiched between Al alloy and Ti alloy (Main Test 1)
The bonded integrated product shown in Fig. 5 is a laminate consisting of five materials and five layers. The bonded integrated product shown in Fig. 6 is a laminate consisting of four materials and four layers. The bonded integrated product shown in Fig. 5 is a 5-layer bonded product in which the latest NAT-treated product of 64Ti alloy (material A) having a thickness of 45 mm x 18 mm x 3 mm, the NAT7-treated product of A5052Al alloy thin plate (material C) having a thickness of 45 mm x 18 mm x 0.75 mm, the NAT-treated product of A1050Al (material D) having a thickness of 45 mm x 18 mm x 1.5 mm, the NAT7-treated product of A5052Al alloy thin plate (material C) having a thickness of 45 mm x 18 mm x 0.75 mm, and the NAT7-treated product of A2017Al alloy (material B) having a thickness of 45 mm x 18 mm x 3 mm are laminated with the above-mentioned adhesive "EW2040".

The bonded integrated product shown in Figure 6 is a simplified version of the laminate shown in Figure 5, and is a laminate consisting of four materials and four layers. This laminate is a laminate of the latest NAT-treated 64Ti alloy (material A) measuring 45mm x 18mm x 3mm thick, a surface-treated A5052Al (material C) alloy thin plate measuring 45mm x 18mm x 0.75mm thick, a surface-treated A1050Al (material D) measuring 45mm x 18mm x 1.5mm thick, and a surface-treated A2017Al alloy (material B) measuring 45mm x 18mm x 3mm thick, and is a four-layer bonded product using the adhesive "EW2040" mentioned above.

By examining the results of the thermal shock test in the preliminary experimental example, it was confirmed that there was no problem in this experimental example with these laminated composites, even if an A5052Al alloy thin plate was inserted (interposed) between the 64Ti alloy and the A1050Al. When the 64Ti alloy and the A5052Al alloy thin plate are bonded, the A5052Al alloy thin plate of the "C" material expands and contracts in response to the heating or cooling from the thermal shock test, because the 64Ti alloy thick plate is thick and has high rigidity. Therefore, the shear fracture internal stress occurs between the A1050Al of the "D" material, which follows the expansion and contraction of the A5052Al alloy thin plate of the "C" material due to its low rigidity and softness. If the internal stress here exceeds the adhesive strength between A5052 and A1050, fracture will occur, but theoretically both have strong shear adhesive tenacity in their own test pieces, and the internal stress is reduced by both elastic deformation and plastic deformation (figurative) in A1050Al. At the time of this experiment, A1050 is NAT-treated, and A5052Al alloy thin plate is NAT7-treated, so the adhesive strength between the two should be sufficiently high.

[Experimental Example B11] Measuring the adhesive strength between high-strength thick plate and thin plate Next, the shear adhesive strength between structural metal thin plate and titanium alloy material was measured. This is because the linear expansion coefficient of titanium alloy material is 0.8×10 ⁻⁵ K ⁻¹ , which is the smallest among metals, and other structural metal materials such as SUS304 are about 1.7×10 ⁻⁵ K ⁻¹ , and aluminum alloys including duralumin are all about 2.3×10 ⁻⁵ K ⁻¹ . Therefore, when these metal pieces and titanium material pieces are bonded with one-liquid epoxy adhesive, high shear adhesive strength is not usually obtained. This is because the hardening condition of one-liquid epoxy adhesive is high at 150 to 180°C. When it is cooled to room temperature after hardening, part of the adhesive hardened layer breaks. The only way to obtain and maintain a strong adhesive state without destroying the adhesive hardened product is to make the metal material bonded to the titanium material thin and reduce its rigidity. However, to know how much thin plate can be used, and what level of yield strength and modulus of longitudinal elasticity of metal material can be used, it is necessary to actually make an adhesive pair and measure its shear adhesive strength. Figure 15 is an explanatory diagram showing how to make a test piece for this test. Since thin plate material has no rigidity, it will bend even when subjected to a shear test, so a thick plate material is bonded to reinforce it (lower part of Figure 15). Generally, if the thickness of the metal piece is not 4 to 6 mm, the thin plate side will deform before shear fracture, and peeling will occur due to stress concentration caused by deformation, causing early fracture. Or, tearing fracture will occur in the thin plate. Table 6 shows the measurement results of shear adhesive strength and shear adhesive tackiness when titanium alloy material is bonded to SUS or aluminum alloy.

From the shear bond strength and shear bond tackiness values shown in Table 6, it is judged that the SUS304 steel thin plate with a thickness of 0.28 mm can be used as the "C" material. Also, the A5052 aluminum alloy can be used if it is 0.75 mm thick or less, but if it is thinner, 0.5 mm thick, it may break when a strong external force in the shear direction is applied, and it may not be able to play the role of a structural material or an amplifying material. Next, it is judged that the 0.5 mm thick A6061 aluminum alloy has no problem at all as the "C" material. What can be further said from this experiment is that when CFRP or CFRTP material is used as the "A" material, the difference in linear expansion coefficient between the "A" material and the "C" material becomes even larger than in this experiment series. When material "C" is an aluminum alloy and material "A" is titanium, the difference in linear expansion coefficient is 1.5×10 ^-5 K ^-1 , whereas when material "A" is, for example, CFRP, the difference is 2.2×10 ^-5 K ^-1 , which is 50% greater. The data shown in Table 6 reveals that in bonding material "A" titanium alloy and material "B" high-strength Al alloy, a 0.75 mm thick Al alloy is preferred as material "C" that can conform most obediently to material "A".

However, in a bonded integrated structure in which CFRP is used as material "A" and a high-strength Al alloy is used as material "B", it is questionable whether a 0.75 mm thick Al alloy can be used as material "C". In other words, if the difference in linear expansion coefficient increases by 50%, the thickness of material "C" should be 1/1.5, or 0.5 mm. According to this idea, the material that can be used as material "C" is an aluminum alloy that has a strength that does not cause the shearing phenomenon even at a thickness of 0.5 mm, and this is not A5052, but at least A5083, or an aluminum alloy with a high strength equal to or higher than A6061 Al alloy. In other words, according to the data shown in Table 6, it is judged that a 0.5 mm thick A6061 Al alloy can withstand this performance requirement. Following a similar approach, when considering SUS304 steel thin plates, a 0.28mm thick plate can be used for bonding to Ti alloys, but when bonding to CFRP materials, the thickness should be 1/1.5, or 1.8-1.9mm. However, it is somewhat difficult to obtain SUS304 thin plates of this thickness on the market, and since the thickness is reduced by about 0.02mm on both sides during NAT-type conversion treatment of SUS304 steel, the chemical stability of the steel itself must be particularly reliable. Based on these experimental results, the inventor believes that a 0.5mm thick A6061Al alloy should be selected as the standard material for "C" materials.

[Experimental Example B12] Preparation of a fully bonded structure including an A6061 thin plate and an A1050 soft metal material between a CFRP piece and a duralumin material and a temperature impact test (Main Test 2)
As can be seen from the data in Table 6, it was found that the A6061 aluminum alloy with a thickness of 0.5 mm is most suitable as the "C" material. It is considered that A1050 aluminum with a thickness of at least 1.5 mm can be used as the "D" material to be bonded to this "C" material. In order to confirm this consideration with an actual bonded integrated product, a bonded integrated product was created by laminating four materials, namely, CFRP (material A), aluminum alloy (material C), pure aluminum-based aluminum (material D), and aluminum alloy (material B), as shown in FIG. 10. A fully bonded structure was created using a CFRP thick plate as the "A" material and an A2017 aluminum alloy thick plate as the "B" material, and this laminated bonded integrated product was tested in a temperature shock test of 3,000 cycles at -50°C/+150°C.

However, to prevent any bonding errors in the bonding between the CFRP material (material "A") and the material "C", the entire bonded structure was created as follows. That is, a 45mm x 18mm x 0.5mm thick A6061Al alloy thin plate (material "C") was bonded to a 90mm x 18mm x 3mm thick CFRP piece (material "A") with epoxy adhesive to create a composite plate material, a bonded and integrated product of the CFRP material and the A6061Al alloy thin plate. The manufacturing method was to cut a 0.5mm thick A6061 alloy thin plate into the above rectangular shape, subject it to NAT7 treatment, and then thinly coat one side of the plate with the one-liquid epoxy adhesive "EW2040" mentioned above. A Teflon sheet was pressed onto the coated surface, which was then placed in a polyethylene bag, sealed, and stored in a refrigerator at 5°C as a bonding preparation. Using both this adhesive preparation and the CFRP prepreg "P225S-25" (manufactured by Toray Industries, Inc. (headquarters: Tokyo, Japan)), we commissioned a processing specialist company to create a 90mm x 18mm x 3mm thick CFRP plate shape with a 45mm x 18mm A5052 Al alloy thin plate. This was done using the autoclave method, with the heating conditions specified as 150°C x 40 minutes.

The CFRP thick plate with the A6061 aluminum alloy thin plate obtained in this way was polished with #600 sandpaper to obtain a metallic luster, since the exposed part of the A6061 alloy thin plate may have been dirty during these operations, and then, with the CFRP plate attached, the surface to which the CFRP was not attached was subjected to NAT treatment. After this liquid treatment, the CFRP thick plate material with the A6061 alloy thin plate was prepared for the next process. In addition, NAT-treated A1050Al alloy of 45mm x 15mm x 1.5mm thick and NAT7-treated A2017Al alloy of 45mm x 18mm x 3mm thick were prepared, and these and the one-liquid epoxy adhesive "EW2040" were used to surface-bond the three materials using the NAT bonding method (the bonding operation with the soaking treatment is called this method) to finally obtain the shape shown in Figure 10. The jointed and integrated product shown in Figure 10 was subjected to a temperature shock test of -50℃/+150℃ for 3,000 cycles. As a result, no abnormalities were found on any of the adhesive surfaces.

[Experimental Example B13] Creation of a Large Fully Bonded Structure The pure aluminum-based aluminum, which is the "D" material in the present invention, described above, was a flat plate material. However, this "D" material may be a plate-like body with a flat or curved lower surface and a large number of circular or angular columns standing side by side on the upper surface, as shown in FIG. 13, instead of a flat plate. In the plate-like body of this example, the cross-sectional area of the circular or angular columns is 0.05 to 0.25 ^cm2 . The manufacturing method of this plate-like body was to machine a thick plate of A1050Al, which is pure aluminum-based aluminum, with a tool such as a cutting saw to the dimensions and shape shown in FIG. 13. This plate-like body was subjected to NAT treatment according to the above-mentioned Experimental Example A1.

Furthermore, a 200mm x 100mm x 0.75mm A5052Al alloy thin plate piece was subjected to NAT7 treatment using the method described in [Experimental Example A2-1]. In addition, the above-mentioned CFRP prepreg "P225S-25" and one of the above-mentioned surface-treated A5052Al alloy pieces were combined with a one-part epoxy adhesive "EW2040" to create a CFRP plate with a metal plate, with one end face of the 200mm x 100mm x 0.75mm Al alloy thin plate coinciding with the CFRP thick plate piece, 300mm x 100mm x 5mm thick, using the autoclave method. The A5052Al alloy plate on the CFRP was dirty, so its entire surface was polished with #1000 sandpaper, and then the surface treatment of Experimental Example A2 was performed again while it was still attached to the CFRP plate.

In addition, a 300mm x 100mm x 3mm thick 64Ti alloy plate was obtained and surface-treated as described in Experimental Example A9. After that, everything was fully bonded using the adhesive "EW2040". That is, an A5052Al alloy thin plate was bonded onto the 64Ti alloy plate, the A1050Al three-dimensional object obtained first was bonded onto the A5052Al alloy thin plate, and a CFRP plate with an A5052Al alloy thin plate was further bonded onto that with the metal part facing down. This created a large fully bonded structure with an area covered by the A1050Al piece, i.e. an apparent bonded area of 200mm x 100mm = 200cm2.

This bonded material is similar to that shown in Figure 5, but is significantly different in that the A1050Al portion is not a simple plate material, but a three-dimensional object with voids. The area ratio of these voids is 64%, since the actual bonded area is 200mm x 100mm x (9/25) = 72cm2, whereas the bonded surface is 200mm x 100mm = 200cm2. This was subjected to 3,000 cycles in a temperature shock tester at -50°C/+150°C, and the surface where the upper part of the column is bonded was observed with a non-destructive testing machine, but no peeling was observed.

[Experimental Example B14] Creation of a large fully bonded structure A 3 mm thick A1050Al thick plate was procured and machined to obtain the shape shown in Figure 14. That is, a 200 mm x 100 mm thick plate was created by cutting a circular groove 2 mm wide and 2 mm deep, leaving the center of the plate 10 mm in diameter, and having many overlapping 3 mm wide circular walls spaced 2 mm apart. The A1050Al pieces with many linear walls were then surface-treated according to the same chemical conversion treatment as in [Experimental Example A1] described above.

On the other hand, instead of the CFRP material and A5052Al alloy thin plate used in Experimental Example B12, a surface-treated SUS304 stainless steel material measuring 300 mm x 100 mm x 3 mm (treated by the same method as in Experimental Example A7) and a surface-treated A5052Al alloy thin plate measuring 0.75 mm were prepared. Using these, a large 200 cm2 fully bonded structure using the shape shown in Figure 10 shown in Experimental Example ^B11 was created with the same appearance as the three-dimensional shape of the A1050Al part and the shape in which SUS304 steel was used instead of CFRP material. This was subjected to a 3,000-cycle test in a temperature shock tester at -50°C/+150°C, and the surface where the upper part of the column was bonded was observed with a non-destructive inspection machine, but no peeling was observed.

[Experimental Example C] Experiments and tests for further improving adhesive strength [Experimental Example C1] Implementing a new idea for improving adhesive strength of A1050Al From the results of Table 5 obtained in the above-mentioned [Experimental Example B7] and Table 6 obtained in [Experimental Example B11], it was found that the adhesive performance of the "A" material or "B" material and the "C" material is the most important for the actual bonded integrated product of the present invention. The bonded integrated product of the present invention has been evaluated not only by the shear adhesive strength, but by changing the evaluation method to the "shear adhesive tackiness" value, and durability performance such as resistance to moisture and heat has also been confirmed. However, from the viewpoint of a bonded integrated product, the adhesive performance of the "A" material or "B" material and the "C" material alone is not sufficient, and we thought that we should reconsider the basic performance required for the "D" material, that is, its softness and the adhesive performance of its skin.

In short, the data on the shear adhesive strength of the pure aluminum alloys A1085 and A1050 shown in Table 5 did not change significantly before and after the high temperature and humidity test. For A1085, there was no change at 55 MPa, and for A1050, the strength was 54 MPa before the test and dropped to 50 MPa after the test, but returned to 54 MPa when dried. The biggest change caused by the application of high temperature and humidity heat is not the absorption of moisture in the cured adhesive material, but rather in the metal material, which indicates that the cured adhesive material softened slightly. Therefore, the fact that the adhesive strength did not change much in A1085 and A1050 is presumed to be due to the fact that the hardness change of the cured adhesive material is close to the hardness level of A1085 and A1050, so when a tensile breaking force is applied, for example, because the hardness of the ground (metal side) and the nail (cured adhesive material) are close, both the metal side and the cured adhesive material deform, which has the effect of delaying the breakage. In the case of hard metals, such as SUS304 and titanium alloy 64 in Table 5, the initial shear bond strength was around 60 MPa, but it dropped sharply to 43-45 MPa due to softening caused by moisture absorption in the resin part. In the case of SUS304, it recovered to 53 MPa when the resin part dried. The inventors understood that if the metal side was hard and the surface shape of the metal side did not change due to high humidity, the shear bond strength would have fluctuated in the same way as SUS304. In short, A1085 and A1050, which are pure aluminum-based aluminums, followed a different course from SUS304 and the like because they are soft.

Therefore, we predicted what would happen if we slightly changed the final process of the surface treatment method for A1050 and A1085 to make only the surface harder. Pure aluminum-based aluminum, which is a soft metal, has a hard outer skin and a soft inner structure. The idea is to make the skin harder and slightly thicker, leaving the outer skin hard and the inner soft. We estimated that we could at least perform the same test as in Table 6 to get out of the state where the shear bond strength was clearly lower than other materials, at 54 to 55 MPa. As a result, we started testing experiments on a new surface treatment method for A1050 aluminum. The five items in [Experimental Example A1-3] to [Experimental Example A1-7] in [Experimental Example A] were performed after all items in [Experimental Example A] and [Experimental Example B] were completed, and the data in Tables 5 and 6 were analyzed as described above, and then experiments different from the surface treatment method described above were performed. The results of the experiment are shown in Table 7. In other words, the data shown in Table 7 is a chemical conversion treatment that hardens only the surface of pure aluminum-based aluminum.

Looking at the top of the data in Table 7, the final immersion time in 5% hydrogen peroxide for the NAT and NAT5 treated products was 5 minutes, but when it was increased to 20 minutes, the shear bond strength of the NAT treated product increased from 57.5 MPa to 60 MPa, while the shear bond viscosity remained at around 50.5 MPa. On the other hand, when the immersion time in hydrogen peroxide for the NMT5 treated product was changed from 5 minutes to 20 minutes, the shear bond strength increased from 55.5 MPa to 57 MPa, and the shear bond viscosity increased from 51 MPa to 53.4 MPa. The anodized product showed the greatest change, with the NAT-Ano treated product achieving a high shear bond strength of 68 MPa and a high shear bond viscosity of 57.5 MPa, while the NAT5-Ano treated product achieved a shear bond strength of 63 MPa and a shear bond viscosity of 54 MPa.

It was confirmed that the thin aluminum oxide layer on the surface was undoubtedly strengthened by the long hydrogen peroxide treatment, and that it was effective to make the outer skin of the "D" material hard and the inside soft. It was also confirmed that the surface layer of the A1050 became an unsealed anodized aluminum through anodization, resulting in a structure with an even harder surface layer, and that it demonstrated surprisingly high shear bond strength and shear bond tackiness. In the case of other aluminum alloys such as A6061 and A2024, which are not pure aluminum-based aluminum, there were more cases where there was no difference in shear bond tackiness between the reinforced product treated with hydrogen peroxide water and the anodized product, and this is presumably a characteristic of soft aluminum alloys. In short, it was confirmed that with soft metals such as A1050 aluminum alloy, the adhesive strength can definitely be improved by increasing the hardness of the surface layer, and that this can be achieved more reliably by anodization methods, etc.

Bonded and integrated products containing different structural materials can be used in structures such as mobile machines such as aircraft and automobiles, and industrial machines such as machine tools.

Claims (19)

The two ends of the structure are made of two different materials, namely, material "A" and material "B" selected from a group of FRP and structural metal materials,
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material of 0.3×10 ⁻⁵ K ⁻¹ or more are bonded with an adhesive,
The integrated product is
A pure aluminum-based aluminum plate or structure having a thickness of 1.5 to 5.0 mm, which is material "D", is laminated between material "A" and material "B",
A jointed and integrated product including dissimilar structural materials, characterized in that it is made up of three materials, the "A" material, the "D" material, and the "B" material, which are laminated in this order with their joint surfaces fixed together. The two ends of the structure are made of two different materials, namely, material "A" and material "B", which are selected from a group of FRP and structural metal materials, respectively.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material of 0.3×10 ⁻⁵ K ⁻¹ or more are bonded with an adhesive,
The integrated product is
Between the "A" material and the "B" material, there are laminated a "C" material, which is a thin plate of a metal material having a yield strength of more than 150 MPa and a thickness of 1.0 mm or less, and a "D" material, which is a plate-like object or structure of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm,
A jointed and integrated product including dissimilar structural materials, characterized in that it is made of four materials, the joint surfaces of which are fixedly laminated in the order of "A", "C", "D", and "B". The two ends of the structure are made of two different materials, namely, material "A" and material "B" selected from a group of FRP and structural metal materials,
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material of 0.3×10 ⁻⁵ K ⁻¹ or more are bonded with an adhesive,
The integrated product is
Between the "A" material and the "B" material, there is a "C" material, which is a thin plate of a metal material having a yield strength of more than 150 MPa and a thickness of 1.0 mm or less, and a "D" material, which is a plate-like object of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm;
A jointed and integrated product including dissimilar structural materials, characterized in that it is made of five materials whose joint surfaces are fixedly laminated in the order of "A", "C", "D", "C", and "B". The two ends are made of two different materials, FRTP material (material A) and material B (material B) selected from a group of structural metal materials.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material is 0.3×10 ⁻⁵ K ⁻¹ or more are joined together,
The integrated product is
Between the "A" material and the "B" material, there are laminated a "C" material, which is a thin plate of a metal material having a yield strength of more than 150 MPa and a thickness of 1.0 mm or less, and a "D" material, which is a plate-like object or structure of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm,
The joint surface is fixed and laminated in the order of "A", "C", "D" and "B", and the joint surface is laminated in the order of "A", "C", "D" and "B".
The joining method of the FRTP material and the "C" material is to join the "C" material with the same type of resin as the matrix resin of the FRTP material by an injection joining method, and then join the FRTP material and the resin by thermal fusion.
11. A jointed and integrated product including different structural materials, wherein the joint surfaces of the joint other than the thermal fusion are joined by an adhesive. The two ends are made of two different materials, FRTP material (material A) and material B (material B) selected from a group of structural metal materials.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material is ^0.3 × 10-5 K ^-1 or more are joined together,
The integrated product is
A thin plate of 1.0 mm or less made of a metal material having a yield strength of more than 150 MPa, which is a material "C", and a plate-like object or structure made of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm, which is a material "D", are stacked between the material "A" and the material "B",
The joint surface is fixed and laminated in the order of "A", "C", "D", "C" and "B", and the joint surface is laminated in the order of "A", "C", "D", "C" and "B".
The FRTP material and the "C" material are joined by insert molding a resin similar to the matrix resin of the FRTP material into the "C" material, and then the FRTP material and the resin are joined by thermal fusion.
11. A jointed and integrated product including dissimilar structural materials, wherein the joint surfaces of the joint portions other than the heat fusion joint are joined by an adhesive. In the jointed and integrated product including dissimilar structural materials according to any one of claims 1 to 5,
The "D" material is a pure aluminum-based aluminum and is one type selected from Japanese Industrial Standards A1080, A1085, and A1050. In the jointed and integrated product including dissimilar structural materials according to any one of claims 2 to 5,
The "C" material is one selected from the group consisting of A5052 aluminum alloy, A5083 aluminum alloy, A6061 aluminum alloy, and SUS304 stainless steel, all of which are specified by the Japanese Industrial Standards. In the jointed and integrated product including dissimilar structural materials according to any one of claims 1 to 5,
A bonded and integrated product comprising dissimilar structural materials, characterized in that the bonding surface includes one or more surfaces selected from a flat surface, a curved surface, and a cylindrical surface. In the jointed and integrated product including dissimilar structural materials according to any one of claims 1 to 8,
The "D" material is a plate-like body having one flat or curved surface and a large number of parallel-arranged circular or angular pillars with a cross-sectional area of 0.05 to 0.25 ^cm2 on the other surface. In the jointed and integrated product including dissimilar structural materials according to any one of claims 1 to 8,
The "D" material is a joined and integrated product including dissimilar structural materials, characterized in that one surface is flat or curved, and the other surface is a plate-like body having numerous wall-like projections, each having a thickness of 3 to 5 mm, spaced 2 to 3 mm apart, or having concentric wall-like projections, each having a thickness of 3 to 5 mm, spaced 2 to 3 mm apart. The jointed and integrated product according to claim 10,
A jointed and integrated product including dissimilar structural materials, characterized in that the center of the concentric wall-like projection is a circular thick plate having a thickness of 1 to 5 mm and an area of 1 to ⁵ cm2. In the jointed and integrated product including dissimilar structural materials according to claim 3 or 5,
A bonded and integrated product including dissimilar structural materials, characterized in that in bonding between five materials, namely, material "A", material "B", material "C", and material "D", all of the adhesive cured layers present at the bonded portions bonded with an adhesive include a cured layer of a one-component epoxy adhesive or a cured layer of a two-component epoxy adhesive. In the jointed and integrated product including dissimilar structural materials according to any one of claims 2 to 5,
A jointed and integrated product including dissimilar structural materials, characterized in that in the joints formed by joining four or more materials, namely, material "A", material "B", material "C", and material "D", a portion of the joints is a clad joint instead of an adhesive joint. The bonded and integrated product comprising different structural materials according to claim 12,
The one-component epoxy adhesive is a heat-resistant one-component epoxy adhesive that exhibits a shear bond strength of 50 MPa or more at 23°C and 25 MPa or more at 150°C in a tensile breaking test. A jointed and integrated product comprising dissimilar structural materials according to any one of claims 1 to 14,
The "A" material and the "B" material are one type selected from a CFRP material and a titanium alloy material, a CFRP material and a general steel material, a CFRP material and a stainless steel material, a CFRP material and a high-strength aluminum alloy material, a GFRP material and a high-strength aluminum alloy material, a CFRTP material and a titanium alloy material, a CFRTP material and a general steel material, a CFRTP material and a stainless steel material, a CFRTP material and a high-strength aluminum alloy material, a titanium material and a general steel material, a titanium material and a stainless steel material, a titanium material and a high-strength aluminum alloy material, a general steel material and a stainless steel material, a general steel material and a high-strength aluminum alloy material, a ferritic stainless steel material and an austenitic stainless steel material, and a stainless steel material and a high-strength aluminum alloy material. The jointed and integrated product including dissimilar structural materials according to claim 4 or 5,
The FRTP of the "A" material is CFRTP,
The resin is a highly crystalline thermoplastic synthetic resin composition having a thickness of 0.5 mm or more, and the total thickness of the "C" material and the resin is a composite plate having a thickness of 2 mm or less;
The bonding between the "A" material and the "C" material is performed by bonding the matrix resin of the CFRTP and the highly crystalline thermoplastic synthetic resin composition by thermal fusion,
The "B" material is one selected from the group consisting of titanium alloy material, general steel material, stainless steel material, and high-strength aluminum alloy material. The jointed and integrated product including different structural materials according to claim 15,
The high-strength aluminum alloy material is a duralumin selected from A2014, A2017, A2024, and A7075 of the Japanese Industrial Standards, or one type of aluminum alloy selected from A5052, A5083, A6061, and A6063 of the Japanese Industrial Standards. The two ends are made of two different materials, FRTP material (material A) and material B (material B) selected from a group of structural metal materials.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material is 0.3×10 ⁻⁵ K ⁻¹ or more are joined together,
The integrated product is
Between the "A" material and the "B" material, there are laminated a "C" material, which is a thin plate of a metal material having a yield strength of more than 150 MPa and a thickness of 1.0 mm or less, and a "D" material, which is a plate-like object or structure of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm,
A method for manufacturing a jointed and integrated product including dissimilar structural materials consisting of four materials in which the joining surfaces are fixedly laminated in the order of the "A" material, the "C" material, the "D" material, and the "B" material,
an injection joining process in which the "C" material is inserted into a mold and then the resin is injected to join the FRTP material and the "C" material in order to join the same type of resin as the matrix resin of the FRTP material to the "C"material;
a heat fusion step of joining the FRTP material and the resin by heat fusion after the injection joining;
and a bonding process for bonding the other joint using an adhesive. The two ends are made of two different materials, FRTP material (material A) and material B (material B) selected from a group of structural metal materials.
An integrated product in which members having a difference in linear expansion coefficient between the "A" material and the "B" material is 0.3×10 ⁻⁵ K ⁻¹ or more are joined together,
The integrated product is
A thin plate of 1.0 mm or less made of a metal material having a yield strength of more than 150 MPa, which is a material "C", and a plate-like object or structure made of pure aluminum-based aluminum having a thickness of 1.5 to 5.0 mm, which is a material "D", are stacked between the material "A" and the material "B",
A method for manufacturing a bonded and integrated product including dissimilar structural materials consisting of five materials in which the bonding surfaces are fixedly laminated in the order of the "A" material, the "C" material, the "D" material, the "C" material, and the "B" material,
an injection joining process in which the "C" material is inserted into a mold and then the resin is injected to join the FRTP material and the "C" material in order to join the same type of resin as the matrix resin of the FRTP material to the "C"material;
a heat fusion step of joining the FRTP material and the resin by heat fusion after the injection joining;
and a bonding process for bonding the other joint using an adhesive.

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