JP6787752B2 - Aluminum alloy member - Google Patents

Description

The present invention relates to an aluminum alloy member, and more particularly to an aluminum alloy (hereinafter, also referred to as "aluminum alloy" or "Al alloy") member having excellent heat resistance and a relatively high coefficient of thermal expansion.

Aluminum alloys have a lighter specific gravity than iron alloys, and have become widely used because they can improve efficiency during operation and followability during operation, for example, in rotating and reciprocating members such as compressor members. It was. As an example, a vane-type rotary compressor has a rotor (1) that rotates inside a cylinder (2) with a non-circular inner circumference, as shown in FIG. 1, and the vane (3) has a rotor (1). ) Is inserted into the groove formed on the outer circumference, and is urged from the back toward the cylinder (2) by a spring and oil pressure (not shown) and centrifugal force of rotational movement, so that the tip of the vane (3) And the inner peripheral surface of the cylinder (2) come into contact with each other, and a vane (3), a rotor (1), a cylinder (2), and a side plate (not shown) form a plurality of working spaces (6) in the cylinder (2). .. A shaft (7) is fastened to the rotor (1), and the rotor (1) rotates in the cylinder by rotating the shaft (7) with a power source (not shown). When the rotor (1) rotates, the volume of the working space (6) changes. Therefore, the refrigerant gas is sucked from the suction port (4), the refrigerant gas in the working space (6) is compressed, and the discharge port (5) is used. The compressed refrigerant gas is discharged from the air to act as a compressor. In addition to the vane type rotary compressors shown in Fig. 1, the vane type rotary compressor has a circular inner peripheral cross section of the cylinder (2) and the center of the cylinder (2) and the center of the rotor (1) are eccentric. In some cases, 3) is placed on the cylinder (2) side instead of the outer circumference of the rotor (1).

The vane (3) used in such a mechanism is that the vane itself is lightweight due to the centrifugal force of the vane when the rotor rotates, and the member temperature rises from room temperature to about 150 ° C. It has high strength and high wear resistance at temperature, and the clearance between members (especially vanes and side plates) is kept small in order to avoid a decrease in compressor capacity at the beginning of operation, that is, the difference in the coefficient of thermal expansion between members. Is required to be small.

Patent Document 1 proposes an aluminum alloy powder molded product to which a large amount of Si and transition metal elements are added by using a quenching solidification method. This molded product contains, for example, Si: 20 to 25%, Ni: 2 to 9%, Cu: 1 to 5%, Mg: 0.2 to 3% by weight, and the balance is aluminum composed of Al and impurities. It is produced by compacting a rapidly cooled solidified powder made of an alloy, solidifying it by hot extrusion, and then adjusting it to an appropriate hardness by solution treatment or aging treatment. By adding a large amount of Si and Ni, an aluminum alloy having high strength and resistance to heat load has been obtained.

Further, Patent Document 2 describes Si: 12 to 35%, Cu: 10% or less, Mg: 3% or less, and the balance substantially Al, in a matrix in which extremely fine primary crystal Si is distributed. We disclose a wear-resistant aluminum-silicon extruded body having a structure in which particles having an average particle size of 3 to 60 μm are dispersed by 3 to 25% in a hard material that is harder than a matrix and has a small coefficient of thermal expansion. This extruded body is a fine hypersymbolic Al-Si atomized alloy powder and coarser grains, has better wear resistance than the hypersymbolic Al-Si alloy, and has a small coefficient of thermal expansion. By hot extrusion processing using powder, particularly preferably one or both of metallic Si and silicon nitride (Si ₃ N ₄ ) as raw materials, it has even better wear resistance than conventional hypersymcyclic Al-Si alloys. Moreover, since the Al-Si molded body has a small coefficient of thermal expansion, the difference in coefficient of thermal expansion from the vane can be suppressed to a small size even with an Fe-based (for example, cast iron) side plate, so that the compressor at the initial stage of operation It is possible to avoid a decline in the ability of.

However, in order to meet the recent needs for further weight reduction of various members, many of the compressor members have been changed from Fe-based materials to general-purpose aluminum alloys, and along with this, Patent Document 1 and In the aluminum alloy of Patent Document 2, the difference in the coefficient of thermal expansion from that of the sliding partner material becomes large, so that it is required not to decrease the coefficient of thermal expansion. The coefficient of thermal expansion can be increased by reducing the Si content or the content of hard particles such as Si ₃ N _{4 in} the opposite direction of the technical idea of the above patent documents. In that case, there is a concern that the strength will decrease.

In addition, in order to meet the needs for weight reduction, there is a tendency to reduce the size of the compressor itself even if the compressor member is made of an aluminum alloy material. While the scale is reduced, the same output as the current aluminum member compressor is required, so the load stress in the usage environment tends to increase, and it is necessary to improve the strength even for compressor members such as rotors. There is.

JP-A-11-302807 Special Publication No. 61-50132

In view of the above circumstances, the present invention provides an aluminum alloy member having a high temperature strength equal to or higher than that of an aluminum alloy to which a large amount of Si or the like is added by a conventional quenching and solidifying method, and having a relatively high coefficient of thermal expansion. Is the subject.

As a result of diligent research to solve the above problems, the present inventors reduced the amount of Si added and set the amount of Cu added in the situation where Fe is contained as an additive element to the solid solubility limit or more to make Al- An aluminum alloy that improves high-temperature strength and has a relatively high thermal expansion coefficient by finely crystallizing or precipitating Al-Cu-Fe-based intermetallic compounds in addition to Fe-Si-based intermetallic compounds. Succeeded in obtaining, and completed the present invention.

That is, the aluminum alloy member of the present invention is made of Si: 10.0 to 16.0%, Cu: 4.5 to 9.5%, Mg: 0.2 to 3.0%, Fe: 3.0 to 9.0%, and the balance is Al and unavoidable impurities in mass%. becomes, the average particle size of 2μm or less of the intermetallic particles and an aluminum alloy member following Si particles having an average particle diameter of 5μm are dispersed, the intermetallic compound particles Al-Fe-Si system during Al alloy matrix compounds comprising particles and Al-Cu-Fe-based compound particles, wherein the Al-FeSi compound particles comprise Al ₃ FeSi ₂ compound particles and Al ₉ Fe ₂ Si ₂ compound particles.

The Al-Cu-Fe compound particles preferably contain Al ₇ Cu ₂ Fe compound particles. Further, the intermetallic compound particles preferably have an average particle size of 1.5 μm or less.

Further, the Si particles preferably have an average particle size of 4 μm or less.

The peak intensity of the (214) plane of the Al ₇ Cu ₂ Fe compound particles in the X-ray diffraction profile is preferably 0.5 to 6.0 when the peak intensity of the (111) plane of Al is 100.

Further, the aluminum alloy member is preferably a compressor member. The tensile strength of the compressor member at room temperature and 150 ° C. is preferably 500 MPa or more and 360 MPa or more, respectively, and the coefficient of thermal expansion between room temperature and 200 ° C. is 18.0 × 10 ^-6 / K or more. Is preferable.

Further, the compressor member is preferably a vane.

Further, the compressor member is preferably a rotor.

Since the aluminum alloy member of the present invention has a small amount of Si added, it is possible to suppress a decrease in the coefficient of thermal expansion as compared with a member containing a large amount of Si. For example, even if the aluminum alloy member of the present invention is applied to the vane of the compressor part and the surrounding members are changed from Fe-based materials to general-purpose aluminum alloys, the difference in coefficient of thermal expansion between the members can be suppressed to a small value, and the initial operation can be performed. It is possible to avoid a decrease in the capacity of the compressor. Further, since the amount of hard and brittle Si is small, the workability in hot extrusion is improved, and it is possible to apply it to a member having a complicated shape. Further, since the aluminum alloy member of the present invention has an increased Cu content under the condition of containing Fe, the Al-Cu-Fe-based intermetallic compound is added to the Al-Fe-Si-based intermetallic compound. Can be finely crystallized or precipitated to maintain high strength in the operating temperature range (room temperature to about 150 ° C.), and can withstand use in harsh environments.

It is a figure which showed the outline of the cross section of the example of the rotary type compressor to which the aluminum alloy member of this invention is applied. It is a figure which showed the secondary electron image photograph by the field emission scanning electron microscope (FE-SEM) of the plane perpendicular to the extrusion direction of the extruded material of Example 1. FIG. It is a figure which showed the reflected electron image photograph by the field emission scanning electron microscope (FE-SEM) of the plane perpendicular to the extrusion direction of the extruded material of Example 1. It is a figure which showed the secondary electron image photograph by the field emission scanning electron microscope (FE-SEM) of the plane perpendicular to the extrusion direction of the extruded material of Example 1. FIG. It is a figure which showed the reflected electron image photograph by the field emission scanning electron microscope (FE-SEM) of the plane perpendicular to the extrusion direction of the extruded material of Example 1. It is a figure which showed the result of the energy dispersive X-ray (EDX) analysis of the intermetallic compound (13) which exhibited the clear color of FIG. It is a figure which showed the result of the energy dispersive X-ray (EDX) analysis of the intermetallic compound (14) which exhibited the dark white color of FIG. It is a figure which showed the X-ray diffraction (XRD) profile of the quenching solidification powder of Example 1. FIG. It is a figure which showed the X-ray diffraction (XRD) profile of the plane perpendicular to the extrusion direction of the extruded material of Example 1. FIG. Al-Si-Cu-Mg-Fe alloy of the present invention (excluding Cu content, Si: 14.0%, Mg: 1.2%, Fe: 5.0%, balance: fixed to Al) Cu content of heat treatment material It is a figure which showed the relationship between the room temperature tensile strength and the Cu content in the range of the amount of 3.3 to 9 mass% (Comparative Example 1, Example 1 to 3).

From the viewpoint of strength, heat resistance, and coefficient of thermal expansion, the aluminum alloy member of the present invention has Si: 10.0 to 16.0%, Cu: 4.5 to 9.5%, Mg: 0.2 to 3.0%, Fe: 3.0 to 9.0 in mass%. %, The balance is composed of Al and unavoidable impurities.

Si is generally a metalloid, hard and brittle substance, and is finely dispersed as Si particles in an Al alloy matrix to improve wear resistance and Young's modulus. In addition, a part of Si combines with Mg to form Mg-Si-based precipitates by aging, and the room temperature strength is particularly improved by strengthening the precipitation and dispersion. However, since Si has a considerably lower coefficient of thermal expansion than Al (the coefficient of thermal expansion of Si is about 1/7 of the coefficient of thermal expansion of Al), it lowers the coefficient of thermal expansion of the alloy. In the present invention, the Si content is set as low as 10.0 to 16.0% in order to suppress the reduction of the coefficient of thermal expansion. If the Si content is less than 10.0%, the effect of improving wear resistance and Young's modulus cannot be sufficiently obtained, and conversely, if it exceeds 16.0%, the coefficient of thermal expansion of the alloy becomes too small. Further, the higher the Si content exceeds 16.0%, the lower the elongation tends to be, which is not preferable. The Si content is preferably 12.5 to 15.5%, more preferably 13.0 to 15.0%.

Cu is a 2024-based Al-Cu-based alloy, for example, when Cu is 3.8 to 4.9% by mass, an Al-Cu-based precipitate containing a GP zone is formed by aging to improve the strength. However, if Cu is added above the solid solution limit, a relatively coarse Al ₂ Cu compound remains in the matrix even after solution treatment, which reduces the strength and elongation of the alloy. Despite such findings, the present invention is characterized in that the Cu content is increased above the solid solution limit under the condition of containing Fe, and the Cu content is 4.5 to 9.5%. .. If the Cu content is less than 4.5%, Al-Cu-Fe-based intermetallic compounds are not formed, so the strength cannot be improved at room temperature and high temperature. If it exceeds 9.5%, Al ₂ Cu compounds and Al-Cu-Fe It is not preferable because the intermetallic compound becomes coarse and the strength and elongation decrease. The Cu content is preferably 5 to 9.0%, more preferably 6 to 8.0%.

As described above, Mg combines with Si by aging to form Mg-Si-based precipitates, which improves room temperature strength by strengthening precipitation and dispersion, but also improves corrosion resistance. In particular, since the corrosion resistance decreases when a large amount of Cu is contained, a predetermined Mg is required to suppress the decrease. The Mg content shall be 0.2 to 3.0%. If the Mg content is less than 0.2%, the above effect cannot be sufficiently obtained, and if it exceeds 3.0%, the elongation decreases, which is not preferable. In addition, workability such as extrusion processing also deteriorates. The Mg content is preferably 0.5 to 2.0%, more preferably 0.8 to 1.5%.

Fe forms an Al-Fe-Si-based and an Al-Cu-Fe-based intermetallic compound in the present invention. These intermetallic compounds particularly improve high temperature strength. It also has the effect of improving Young's modulus. The Fe content shall be 3.0 to 9.0%. If the Fe content is less than 3.0%, the above effect cannot be sufficiently obtained, and if it exceeds 9.0%, each intermetallic compound becomes coarse and the strength and elongation are lowered, which is not preferable. In addition, workability such as extrusion processing also deteriorates. The Fe content is preferably 4.0 to 8.0%, more preferably 5.0 to 7.0%.

Further, the aluminum alloy member of the present invention is made of Si: 10.0 to 16.0%, Cu: 4.5 to 9.5%, Mg: 0.2 to 3.0%, Fe: 3.0 to 9.0%, and the balance is Al and unavoidable impurities in mass%. It is produced by using a rapidly cooled solidified powder prepared by an atomizing method from a molten aluminum alloy having the above composition. Although the quench-coagulated powder depends on the pressure of the gas to be atomized, the average particle size is preferably 30 to 80 μm when atomized with air, and the average particle size is 10 to 50 μm when atomized with Ar gas. Is preferable.

In the aluminum alloy member of the present invention, the quenching solidification powder is compactally molded to prepare a preformed body, and the preformed body is held in an inert atmosphere of 570 ° C. or lower for 1 to 10 hours, and then the temperature is 400 ° C. As described above, hot extrusion is performed in the range of extrusion ratio of 10 to 35 to obtain the material (hereinafter, also referred to as “extruded material”). After the hot extrusion, the material is preferably subjected to a heat treatment (so-called T6 treatment) consisting of solution treatment, water quenching, and aging treatment at a predetermined temperature and time. The extruded material after hot extrusion has a microstructure in which Al-Fe-Si-based compound particles, intermetal compound particles containing Al-Cu-Fe-based compound particles, and Si particles are dispersed in an Al alloy matrix. However, the quench-coagulated powder does not contain Al-Cu-Fe compound particles, but Si particles, Al-Fe-Si compound particles containing Al ₃ FeSi ₂ compound particles, and Al ₂ Cu compound particles. Is only formed. The Al-Cu-Fe-based compound particles characteristic of the present invention are contained in the matrix during the steps from heating and holding of the preformed body to hot extrusion, that is, under a condition where the diffusion rate under high temperature and high pressure is increased. Cu in the Al ₂ Cu compound particles is bonded to Al and Fe. As a result, the Al ₂ Cu compound particles present in the rapidly cooled solidified powder disappear after hot extrusion. As the Al-Cu-Fe compound particles, those containing Al ₇ Cu ₂ Fe compound particles are preferable. At the same time, Al ₉ Fe ₂ Si ₂ compound particles are formed during the steps from heat holding of the preformed body to hot extrusion. The Al-FeSi-based compound particles, is intended to include Al ₃ FeSi ₂ compound particles and Al ₉ Fe ₂ Si ₂ compound particles.

From the viewpoint of forming Al-Cu-Fe-based compound particles and Al-Fe-Si-based compound particles, the ratio of Cu content to Fe content (Cu / Fe) in mass% is preferably 1.0 to 3.0. More preferably, it is 1.2 to 1.6.

The size of the Al-Cu-Fe-based and Al-Fe-Si intermetallic compounds are formed and dispersed Al alloy matrix is in terms of improving the strength, the average particle diameter and 2μm or less. It is preferably 1.5 μm or less , more preferably 1.0 μm or less.

The size of the Si particles dispersed in the Al alloy matrix, the average particle size and 5μm or less. It is preferably 4 μm or less , more preferably 3 μm or less.

Further, in the aluminum alloy member of the present invention, the peak intensity of the Al ₇ Cu ₂ Fe (214) plane is preferably 0.5 to 6.0 when the peak intensity of the Al (111) plane in the X-ray diffraction profile is 100. .. The peak intensity of the Al ₇ Cu ₂ Fe (214) plane is more preferably 1.0 to 5.0.

When the aluminum alloy member of the present invention having the above material composition and microstructure is used as a compressor member, the compressor member must have tensile strengths of 500 MPa or more and 360 MPa or more, respectively, at room temperature and 150 ° C. Is preferable. The tensile strength at 150 ° C. is more preferably 400 MPa or more.

Further, the compressor member of the present invention preferably has a coefficient of thermal expansion between room temperature and 200 ° C. of 18.0 × 10 ^-6 / K or more, and more preferably 18.5 × 10 ^-6 / K or more.

Example 1
Prepare an aluminum alloy molten metal having a composition of Si: 14.0%, Cu: 7.0%, Mg: 1.2%, Fe: 5.0%, and the balance substantially Al in mass%, and prepare a quench-cooled solidified powder by the air atomization method. did. The median diameter (D ₅₀ ) of the obtained powder was 59.8 μm. A preformed body was prepared from the obtained alloy powder by powder molding, held for 60 minutes in an argon atmosphere at a predetermined temperature, and then hot-extruded at an extrusion ratio of 12, and a round bar-shaped extruded material having a diameter of 25 mm was extruded. Was produced. Then, the extruded material was cut to an appropriate length, solution-treated, water-quenched, and heat-treated (T6 treatment) consisting of aging treatment. Hereinafter, the material after the heat treatment is referred to as a heat treatment material.

[1] Observation of microstructure The secondary electrons observed by a field emission scanning electron microscope (FE-SEM) (Hitachi S4800) in FIGS. 2 and 3 for the cross section of the mirror-polished extruded material perpendicular to the extrusion direction. The image and the backscattered electron image are shown. From the secondary electron image (Fig. 2), it was observed that the black Si particles (12) and the white intermetallic compound were dispersed in the Al alloy matrix (11), which is clear from the backscattered electron image (Fig. 3). Colored intermetallic compounds (13) and dark white intermetallic compounds (14) were identified and observed. In the backscattered electron image, the one with a large mass looks bright, so it is possible to distinguish between two types of intermetallic compounds by utilizing its characteristics. FIG. 4 (secondary electron image) and FIG. 5 (backscattered electron image) are observed at a high magnification. A relatively large amount of intermetallic compounds have been observed with a size of about 1 to 2 μm.

[2] EDX (Energy Dispersive X-ray) Analysis of Intermetallic Compounds In order to qualitatively analyze the composition of the intermetallic compounds (13 and 14) in Fig. 5, the energy dispersive X-ray analyzer (Horiba) attached to FE-SEM The results of spot analysis at EMAX ENERGY EX-350) are shown in Fig. 6 (intermetallic compound 13) and Fig. 7 (intermetallic compound 14). Since Al, Cu and Fe were detected in the intermetallic compound 13 (Fig. 6), it is presumed to be an Al-Cu-Fe-based intermetallic compound, and Al, Fe from the intermetallic compound 14 (Fig. 7). And Si were detected, so it was presumed to be an Al-Fe-Si-based intermetallic compound.

[3] X-ray diffraction measurement X-ray diffraction measurement (Rigaku Smart Lab, Cu-Kα ray, output: 45 kV, 200 mA) to identify the constituent phases of the rapidly cooled solidified powder and the extruded material whose structure was observed. , 2θ: 20 to 50 °, scan speed: 5.0 deg./min, step width: 0.02 deg.). The XRD profiles of the rapidly cooled solidified powder and the extruded material are shown in FIGS. 8 and 9, respectively. In the quench-coagulated powder shown in FIG. 8, in addition to Al (PDF No. 00-004-0787) and Si (PDF No. 01-071-4631), FeAl ₃ Si ₂ compound (PDF No. 01-083-0614) and Al ₂ Cu compound (PDF No. 01-076-3073) was detected, while in the extruded material of Fig. 9, in addition to Al and Si, Fe Al ₃ Si ₂ compound and Al ₉ Fe ₂ Si ₂ compound (PDF No. 01-082-0546) and Al ₇ Cu ₂ Fe compound (PDF No. 00-025-1121) were detected. However, no Al ₂ Cu compound was detected in the extruded material. From this, it can be seen that the Al ₉ Fe ₂ Si ₂ compound and the Al ₇ Cu ₂ Fe compound were formed during the steps from the heat holding of the preformed body to the hot extrusion, and at the same time, the Al ₂ Cu compound disappeared. X-ray diffraction measurement was also performed on the heat-treated material, and in the heat-treated material, a small amount of Al ₂ Cu compound was detected in addition to the constituent phases of the extruded material. The peak intensity of the (214) plane of the Al ₇ Cu ₂ Fe compound was 2.7 when the peak intensity of the (111) plane of Al was 100.

[4] Tensile test A tensile test piece with a diameter of 6 mm, a scoring distance of 30 mm, and a parallel part length of 50 mm was prepared by cutting from a heat-treated material in accordance with JIS Z 2241 No. 14 A test piece. The tensile test was performed twice in the air at a strain rate of 0.3% per minute until fracture under two temperature conditions of room temperature and 150 ° C. Tensile strengths were 526 MPa and 523 MPa at room temperature, 401 MPa and 406 MPa at 150 ° C, and elongations were 1% both times at room temperature and 4% and 3% at 150 ° C.

[5] Measurement of coefficient of thermal expansion A cylindrical test piece with a diameter of 5 mm and a length of 15 mm was cut out from the extruded material, and an alumina standard sample of the same shape was used as a reference. Using a differential thermal expansion meter (TD5000 manufactured by Bruker AXS), measure the thermal expansion in the temperature range: room temperature to 400 ° C (calculated on the temperature lowering side) at an elevating temperature rate of 5 K / min, and between room temperature and 200 ° C. The coefficient of thermal expansion of The results are represented by the average value of the results measured three times with the same sample. The coefficient of thermal expansion between room temperature and 200 ° C in Example 1 was 18.7 × 10 ^-6 / K. A similar test was performed on the heat-treated material, but the result was 19.0 × 10 ^-6 / K.

Examples 2-3
A quench-coagulated powder was prepared in the same manner as in Example 1 except that the Cu content was 5% (Example 2) and 9% (Example 3) in mass%, and the same as in Example 1. The extruded material was prepared and heat-treated to prepare a heat-treated material. Table 1 shows the results of the measurement of the coefficient of thermal expansion and the tensile test on the heat-treated material together with the results of Example 1. It can be seen that the tensile strength is 500 MPa or more at room temperature and 360 MPa or more at 150 ° C., and the elongation is 1% or more at room temperature and 3% or more at 150 ° C. The coefficient of thermal expansion was also 18.5 × 10 ^-6 / K or higher. It was also found that when the Cu content was 7% or more (Examples 1 and 3), the tensile strength at 150 ° C. was improved to 400 MPa or more and the coefficient of thermal expansion was improved to 19.0 × 10 ^-6 / K or more. The peak intensities of the (214) plane of the Al ₇ Cu ₂ Fe compound were 1.1 (Example 2) and 4.5 (Example 3), respectively.

Examples 4-7
For Examples 4 and 5, the Si content was 10% (Example 4) and 16% (Example 5) in mass%, and for Examples 6 and 7, the Fe content was mass%. Then, except that 3% (Example 6) and 9% (Example 7) were used, a quench-coagulated powder was prepared in the same manner as in Example 1, and an extruded material was prepared in the same manner as in Example 1. , Heat treatment was performed to prepare a heat-treated material. Table 2 shows the results of measurement of the coefficient of thermal expansion and tensile test of the heat-treated material.

Comparing the difference in the coefficient of thermal expansion between Example 4 and Example 5 (1.7 × 10 ^-6 / K) and the difference in the coefficient of thermal expansion between Example 6 and Example 7 (0.9 × 10 ^-6 / K), Si It showed a tendency to strongly depend on the composition of.

Comparative example 1
A quench-coagulated powder was prepared in the same manner as in Example 1 except that the Cu content was 3.3% by mass, an extruded material was prepared in the same manner as in Example 1, and a heat-treated material was prepared by heat treatment. did. The tensile strength of the heat-treated material is 476 MPa at room temperature and 356 MPa at 150 ° C, the elongation is 1.6% at room temperature and 9.0% at 150 ° C, and the coefficient of thermal expansion is 19.9 × 10 between room temperature and 200 ° C. It was ^-6 / K.

Comparative example 2
A quench-coagulated powder was prepared in the same manner as in Example 1 except that the Si content was 20.0% by mass, an extruded material was prepared in the same manner as in Example 1, and a heat-treated material was prepared by heat treatment. did. Tensile strength of the heat-treated is 452 MPa at room temperature 537MPa, 150 ℃, elongation, 0.8% at room temperature, was 1.5% at 0.99 ° C., a coefficient of thermal expansion between 200 ° C. from room temperature 17.5 × 10 ^- It was ⁶ / K.

FIG. 10 shows the room temperature tensile strengths of Examples 1 to 3 and Comparative Example 1 fixed to Si: 14.0%, Mg: 1.2%, Fe: 5.0%, and the balance: Al in mass% except for the Cu content. , Cu content. The tensile strength tends to increase as the Cu content increases, and when the Cu content increases from 3.3% by mass to 5.0% by mass, the tensile strength rises sharply and reaches the level of 520 MPa. I understand.

It was confirmed that the aluminum alloy member of the present invention can surely increase the coefficient of thermal expansion by reducing the Si content as compared with Comparative Example 2.

The aluminum alloy member of the present invention has applications other than the vanes and rotors described above. For example, housings for compressors, swash plates, shoes, scrolls, pistons, cylinder liners for automobiles, pistons, synchronizer rings, connecting rods, valve retainers, brakes, lifters, tabets, secondary structural materials for aircraft, and VTR cylinders as others. There are various gears, shafts, pulleys, IC boards, heat sinks, etc.

1 rotor
2 cylinder
3 vanes
4 Inhalation port
5 Discharge port
6 Working space
7 shaft
11 Al alloy matrix
12 Si particles
13 Intermetallic compounds (Al-Cu-Fe series)
14 Intermetallic compound (Al-Fe-Si system)

Claims (10)

By mass%, Si: 10.0 to 16.0%, Cu: 4.5 to 9.5%, Mg: 0.2 to 3.0%, Fe: 3.0 to 9.0%, the balance consists of Al and unavoidable impurities, and the average particle size in the Al alloy matrix. An aluminum alloy member in which intermetallic compound particles of 2 μm or less and Si particles with an average particle size of 5 μm or less are dispersed, and the intermetallic compound particles are Al-Fe-Si-based compound particles and Al-Cu-Fe-based compounds. It comprises particles, aluminum alloy member, characterized in that the Al-FeSi compound particles comprise Al ₃ FeSi ₂ compound particles and Al ₉ Fe ₂ Si ₂ compound particles. The aluminum alloy member according to claim 1, wherein the Al-Cu-Fe compound particles contain Al ₇ Cu ₂ Fe compound particles. The aluminum alloy member according to claim 1 or 2, wherein the intermetallic compound particles have an average particle size of 1.5 μm or less. The aluminum alloy member according to any one of claims 1 to 3, wherein the Si particles have an average particle size of 4 μm or less. Claim 2 is characterized in that the peak intensity of the (214) plane of the Al ₇ Cu ₂ Fe compound particles in the X-ray diffraction profile is 0.5 to 6.0 when the peak intensity of the (111) plane of Al is 100. 4. The aluminum alloy member according to any one of 4. The aluminum alloy member according to any one of claims 1 to 5, wherein the aluminum alloy member is a compressor member. The aluminum alloy member according to claim 6, wherein the compressor member has tensile strengths of 500 MPa or more and 360 MPa or more, respectively, at room temperature and 150 ° C. The aluminum alloy member according to claim 6 or 7, wherein the compressor member has a coefficient of thermal expansion between room temperature and 200 ° C. of 18.0 × 10 ^-6 / K or more. The aluminum alloy member according to any one of claims 6 to 8, wherein the compressor member is a vane. The aluminum alloy member according to any one of claims 6 to 8, wherein the compressor member is a rotor.