JPH0210211B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides vibration damping that is ideal for preventing pollution caused by vibration and noise from various transportation systems and large machinery, performance deterioration caused by vibration from various precision machines and electronic equipment, and the harmful effects of various vibrations and noises that exist in the living environment. The present invention relates to an Al-Co-based vibration absorbing alloy with high performance and a manufacturing method. Attenuation capacity generally used to compare attenuation capacity
Q ^-1 has a relationship with the vibrational energy ΔE lost during one cycle of vibration and the total vibrational energy E as shown in the following equation. Q ^-1 = 1/2π·ΔE/E In other words, the larger the value of Q ^-1 , the smaller the amplitude becomes in a shorter time and the greater the damping effect. Conventionally known vibration absorbing alloys include Fe-based alloys such as dientalloy, Mn-Cu alloys, and Al-Cu alloys.
-Ni-based alloys and Ni-Ti-based alloys. Fe-based vibration-absorbing alloys such as dientalloy and Mn-Cu-based alloys have a large damping capacity, but their specific gravity is around 8 g/ ^cm3 , making them unsuitable when reducing the weight of equipment. Ni-based alloys and Ni-Ti-based alloys have a drawback in that they have poor cold workability and are completely impossible to cold work. In order to obtain a vibration-absorbing alloy that is lighter than conventional vibration-absorbing alloys, the present invention uses aluminum as its base, which has a very small specific gravity of 2.7 g/ ^cm3 , and has a weight ratio of 0.1 to 20.
% of cobalt is heated to a temperature below the melting point of 250°C or higher to undergo homogeneous solution treatment, and then subjected to cold working at a rate of 5% or more to increase dislocations.
The object of the present invention is to provide a vibration absorbing alloy that has a large damping ability due to the hysteresis phenomenon and at the same time has high strength. Next, a method for manufacturing the alloy of the present invention will be explained. First, an alloy with the above composition range is melted in an ordinary melting furnace in air, an inert gas, or a vacuum, and then thoroughly stirred to make a uniform molten metal, which is then cast into a sand mold or metal mold. Make ingots. Next, this ingot is subjected to the following heat treatment. (A) After heating for solution treatment at a temperature as high as possible, for example, at a temperature of 250°C or higher below the melting point of the alloy for 5 minutes or more (preferably 30 minutes or more and 100 hours or less), rapidly cool it or at a rate of 1°C per second or less. Cool slowly. (B) Subsequently, cold working is performed at room temperature by forging, rolling, extrusion, swaging, or drawing at a cold working rate of 5% or more in order to obtain the large damping capacity that is the objective of the present invention. (C) The material that has been cold worked with a cold working ratio of 5% or more in (B) is heated at a temperature of 250°C or less for 1 minute or more (preferably 30 minutes or more and 500 hours or less) and then rapidly cooled or 1 second per second. Cool slowly at a rate below ℃. When melting, add flux such as MgCl ₂ , borax, CaF ₂ , KCl, etc. in a total amount of 5% or less as a blocking agent, and add metals such as Mg, Be, etc. in a total amount of 0.5% or less as a deoxidizing agent. Good too. The reason why the homogenization treatment is carried out in step (A) is to make the components homogeneous since non-uniformity of components may occur in the ingot. If the heating temperature is high, the heating time can be shortened, and if the heating temperature is low, the heating time must be lengthened. On the other hand, if the weight of the molded object is large, it is necessary to raise the heating temperature and increase the heating time, but if the weight of the molded object is small, it may be heated at a relatively low temperature for a short time. The reason for this is that if homogeneous solution treatment is not performed sufficiently,
This is because product performance such as damping capacity cannot be made uniform. The cold working in step (B) after the homogenization treatment in step (A) is an essential step in order to increase the dislocation density due to processing strain and to obtain a large damping capacity due to the dislocation hysteresis phenomenon. It is also necessary to increase the tensile strength of the molded article. In addition, in order to increase the damping capacity, cold working of 5% or more is enough to achieve the purpose, but if the cold working rate is large or depending on the composition of the alloy, bending,
Some products are difficult to form by deep drawing, punching, etc. Therefore, after cold working in step (B), 250
When heated to a temperature below ℃, it will bend at room temperature,
Forming such as deep drawing and punching becomes easier.
The reason why the annealing temperature was set to 250°C or lower is that heating to 250°C or higher causes a rapid increase in elongation but a decrease in damping ability. Example A total of 100 g of metal having the composition shown in Table 1 was melted in an alumina crucible using a high-frequency induction electric furnace while passing Ar gas to the surface, and cast into an iron mold with a diameter of 10 mm.
An ingot was obtained. Next, this was heated at 500° C. for 5 hours and slowly cooled, then cold swaged and drawn into a 1.1 mm wire, and a 150 mm long wire was cut from this to serve as a sample. The damping capacity Q ^-1 was measured by the inverted torsion pendulum method at a frequency of approximately 1 Hz and a maximum strain amplitude γ _n =10×10 ^-6 . The damping capacity Q ^-1 and tensile strength of Al-based alloys depend on the cold working rate. As an example, Figures 1 and 2 show the damping capacity Q ^-1 and tensile strength when an Al-5%Co alloy was heated at 500°C for 5 hours, slowly cooled, and processed by cold swaging and drawing. The relationship between strength σ _t and cold working rate is shown. Both the damping capacity Q ^-1 and the tensile strength σ _t increase with increasing cold working rate, which is a result of the dislocation density increasing with increasing working strain.
As a result, the objective of the present invention is the damping capacity Q ^-1 = 6
It can be seen that in order to obtain a value of ×10 ^-3 or more (γ _n =10×10 ^-6 ), it is necessary to perform cold working of 5% or more. Next, Table 1 shows the relationship between cold working rate and damping capacity Q ^-1 for Al-Co binary alloys.

[Table] As is clear from Table 1, aluminum subjected to 95% cold working has a damping capacity Q ^-1 of 4 x 10 ^-3 , making it unsuitable as a vibration absorbing material for the purpose of the present invention.
It can be seen that when 0.1% or more of cobalt is added to aluminum, a large value of Q ^-1 of 6 x 10 ^-3 or more, which is the object of the present invention, can be obtained. In short, the value of the damping capacity Q ^-1 of the alloy of the present invention is the damping capacity Q ^-1 of general metals =
This is several tens of times larger than the value of about 1×10 ^-3 . As described above, in the present invention, as the cold working rate increases from 5% to 95%, the damping capacity increases, but the elongation decreases, the brittleness decreases, and the workability decreases.
It is necessary to anneal at a temperature below 250℃. Annealing at a temperature below 250°C increases elongation, making it easier to process, and the damping ability decreases slightly, but this is not a problem. This is because the number of dislocations increased by processing is annealed by annealing, resulting in fewer dislocations. In addition,
When the annealing temperature is raised to 250° C. or higher, the elongation increases rapidly to 25% or higher, but the damping capacity Q ⁻¹ becomes 4×10 ⁻³ or lower, and the object of the present invention cannot be obtained. Furthermore, the specific gravity ρ of the alloy of the present invention is considerably smaller than that of ordinary metals, and the tensile strength σ _t is considerably larger than that of cold-worked aluminum, which is 10 Kg/mm ² . For example, sample No. 1 of the example has σ _t =14Kg/mm ² and ρ=
It shows 2.9g/ ^cm3 . Finally, the reason for limiting the composition of the alloy of the present invention will be described. First, in binary and multi-component alloys
Co not only contributes to improving the damping capacity Q ^-1 , but also
Strengthen the alloy. The reason why the Co content is limited to 0.1 to 20% by weight is that if the lower limit of the composition is not reached, sufficient damping ability, which is the objective of the present invention, cannot be obtained, and if the upper limit of the composition is exceeded, cold working is impossible. This is because. In addition, for homogeneous solution treatment, heating at a temperature of 250℃ or higher and lower than the melting point for a long time (100 hours or less) and sufficient solution treatment will increase the required attenuation capacity.
Absolutely necessary to obtain strength and workability. Note that performing cold working at a cold working rate of 5% or more is an absolutely necessary condition because it increases the damping capacity by increasing the working strain and dislocation density. The alloy molded body is heated to 250℃ below the melting point of aluminum.
When the homogeneous solid solution treatment is performed by heating at the above high temperature for a long time, the state of dispersion of Co particles in the aluminum matrix becomes homogeneous. If cold working is performed at a cold working ratio of 5% or more, the Co particles will be finely dispersed and the dislocation density will increase. When this dislocation density increases, when vibration is applied from the outside, the applied external force (vibration, impact, torsion, compression, tension, etc.) disappears as thermal energy etc., causing vibration damping. be. Therefore, in order to increase the attenuation capacity, it is necessary to
Long-term heating at higher temperatures and cold working of 5% or higher are enough to achieve the purpose, but if the cold working rate is large or depending on the composition of the alloy, bending, deep drawing, punching, etc. There are some items that are difficult to mold, such as For this reason, when annealing is performed by reheating at a low temperature of 250°C or lower for a long period of time, the damping capacity and strength do not deteriorate significantly, and forming processes such as bending, deep drawing, and punching become extremely easy. In this case, if the reheating treatment is carried out at a temperature of 250° C. or higher, the attenuation ability will decrease, which is not preferable. As mentioned above, the alloy of the present invention is characterized by having a large damping capacity, being lightweight, having good cold workability, high strength, and being non-ferromagnetic. Therefore, the alloy of the present invention can be applied to various transportation systems, internal combustion engines for automobiles, large machinery, moving parts of electronic devices, parts operated by magnetic fields, various household goods, and structural materials for buildings, etc., and can be used to prevent vibration and noise, Very suitable for weight reduction.

[Brief explanation of drawings]

Figure 1 is a characteristic curve diagram showing the relationship between damping capacity Q ^-1 and cold working rate when an Al-5%Co alloy is heated at 500°C for 5 hours, slowly cooled, and then cold worked. 1 is a characteristic curve diagram showing the relationship between the tensile strength σ _t and the cold working rate of the same alloy as in FIG. 1. FIG.

Claims (1)

[Claims] 1. Al comprising 0.1 to 20% cobalt and the balance aluminum in terms of weight ratio, and characterized in that the damping capacity Q ^-1 with increased dislocation density is 6 x 10 ^-3 or more.
-Co-based vibration absorbing alloy. 2. An alloy consisting of 0.1 to 20% cobalt and the balance aluminum (by weight) is heated at a temperature of (A) below the melting point of the alloy or above 250°C for 5 minutes to 100 hours or less, or rapidly cooled at a temperature of 1°C per second or below. (B) Production of an Al-Co-based vibration absorbing alloy characterized in that the damping capacity Q ^-1 is set to 6 × 10 ^-3 or more by performing slow cooling at a speed of 5% or more. Method. 3. An alloy consisting of 0.1 to 20% cobalt and the balance aluminum by weight, (A) at a temperature of 250°C or higher below the melting point of the alloy for 5 minutes or more.
After heating for 100 hours or less and rapidly cooling or slowly cooling at a rate of 1°C per second or less, (B) cold working with a cold working rate of 5% or more (C) (B) with a cold working rate of 5% or more Damping capacity Q ^-1 can be achieved by heating the processed material at a temperature of 250°C or less for 1 minute or more and 500 hours or less, and then rapidly cooling it, or slowly cooling it at a rate of 1°C or less per second. 6×
A method for producing an Al-Co-based vibration-absorbing alloy, characterized in that it has a vibration absorbing alloy of 10 ^-3 or more.