JPH0547614B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to rotors for rotary compressors and rotary vacuum pumps, and in particular for rotary compressors and pumps mounted on vehicles, which are lightweight, have excellent wear resistance and seizure resistance, and have high strength. It concerns a rotor made of superior aluminum alloy. (Prior Art) In recent years, equipment mounted on automobiles has been required to be smaller and lighter from the standpoint of fuel consumption and improved performance. Therefore, the parts used in these devices are also required to be lighter. Traditionally, the rotors of rotary compressors for air conditioning used in automobiles and the rotors of rotary vacuum pumps for brakes have traditionally been manufactured by machining steel-based materials or made from iron-based sintered alloys. Ta. Items made of iron-based sintered alloys were made hollow inside by sintering and joining to reduce weight, but since the material was iron, there was a limit to how much weight could be reduced. For this reason, in recent years, aluminum alloys for rotors have been actively studied for the purpose of weight reduction. Furthermore, by making the rotor of aluminum alloy, the cylinder can also be made of aluminum alloy, and it is possible to further reduce the weight of these parts. Furthermore, if the rotor's coefficient of thermal expansion is not nearly the same as that of the cylinder material, the amount of leakage will increase due to changes in clearance, so if the rotor is made of aluminum, it is desirable for the cylinder to be made of an aluminum alloy in terms of equipment performance. The rotor will be explained below using a rotary compressor for air conditioning installed in a car as an example. Conventionally, the rotor of a rotary compressor has a groove portion 2 in which a vane is housed, for example, as shown in FIG.
The purpose is to reduce the stress concentration coefficient at the bottom of the groove 2, to form a relief part for the tool during finishing machining of the groove, to facilitate machining, and to improve sealing performance by applying back pressure to the vane. Formed cylindrical part 3
and a shaft hole 4 into which a steel shaft is press-fitted. The cylindrical portion 3 at the bottom of the groove of the rotor 1 is subjected to tensile stress in the circumferential direction due to the press-fitting of the shaft, and furthermore, when the compressor is operating,
Since gas pressure is applied to the vanes that have protruded from the rotor, tensile stress as shown by the arrows is repeatedly applied to the cylindrical portion 3 at the bottom of the vane groove. This material with high fatigue strength is required for the rotor. Compressors for such applications usually compress refrigerant in a gaseous state, but depending on the operating temperature conditions and when the refrigerant is injected, the refrigerant may become liquefied. In that case, a very large pressure is applied to the vane, so that a very large tensile stress is impulsively applied to the cylindrical part 3 at the groove bottom of the rotor via the vane. For this reason, the cylindrical portion 3 needs to have high toughness. The rotor 1 slides on the vanes going in and out of the groove 2, and further slides on the side plates on both end surfaces. Therefore, high wear resistance and seizure resistance are also required. Considering the wear resistance and seizure resistance of the Al-Si alloy, a high-silicon aluminum alloy containing 10% by weight or more of Si (all percentages are expressed in weight% below) is suitable. Although it is easy to manufacture a rotor shape using such a high-silicon aluminum alloy using a casting method, the strength and toughness of the alloy in the cast structure are low, so the repetitive stress applied to the groove bottom of the rotor and the impact during liquid compression are low. It cannot withstand stress. For this reason, the rotor must be made of high strength and toughness by plastically working the cast structure or forging by extrusion to destroy the cast structure. Further, since the shape of the rotor would be expensive to manufacture by machining, it is preferable to manufacture it by using a plastic working method. There is an invention proposed in JP-A-64-5621 as a method for manufacturing an aluminum alloy rotor using a plastic working method. The gist of this proposed method is that from the perspective of rotor performance, it is necessary to use an aluminum alloy for the rotor that has both high strength and wear resistance, but extruding such an alloy is difficult due to the strength of the die. By devising an extrusion method and extruding by setting a soft aluminum alloy backing plate at the tip of a large-diameter aluminum alloy billet, we reduced the initial extrusion pressure and extended the life of the die. It is possible to obtain a long material with the cross-sectional shape of the rotor material. Also, within this proposal, Si is 10-25%, Cu
An aluminum alloy containing 0.5 to 5% of Mg and 0.2 to 1.5% of Mg, and one or more of Fe, Ni and Mn in total of 0.2 to 1.5%.
A rotor made of an aluminum alloy containing 10% aluminum alloy or an aluminum alloy whose starting material is a rapidly solidified powder having the above composition has been introduced. (Problem to be solved by the invention) However, within the composition range of the above proposal, Si
If it exceeds 14%, primary Si becomes coarse during casting, and even if the cast material is hot extruded for the purpose of strengthening and shaping, the extruded material will lack toughness and coarse primary Si will become coarse.
The test results of the rotor by the present inventor have revealed that the rotor cracks during extrusion and generates voids around it, resulting in internal defects, and that rotors with such internal defects cannot withstand the stress applied by impact during liquid compression. Summer. Therefore, when selecting a high Si% composition from the viewpoint of wear resistance, it is rational to use an aluminum alloy powder that is rapidly solidified and has fine primary Si crystals. Processing methods for rapidly solidified aluminum powder are effectively limited to hot extrusion. However, such an extruded material made of rapidly solidified aluminum powder has a drawback of poor sliding properties due to the small Si particles. Therefore, in order to improve sliding properties such as wear resistance and seizure resistance, it is necessary to further increase the Si content or
It is necessary to contain large amounts of transition elements such as Fe, Ni, and Mn. This will reduce toughness and elongation,
The rotor may crack due to impact load stress such as when compressing liquid, and the cost also increases.
Therefore, we used an aluminum alloy manufactured by a casting method instead of rapidly solidified aluminum powder, and the Si
It is desirable to manufacture the rotor from a material with a composition of 14% or less. The inventor conducted a test in which a conventional aluminum alloy rotor having such a composition was installed in a compressor, and as a result, seizure occurred on the sliding surface with the vanes and the sliding surface with the side plate, and abnormal wear occurred. I found out what to do. Therefore, the present invention solves the conventional sliding problems as described above, and also achieves high dimensional accuracy at low cost without relying on strengthening by destruction of the structure due to full-scale plastic working by conventional hot extrusion method. Our objective is to provide an aluminum alloy rotor that has been strengthened by plastic working and has a good surface condition. (Means for Solving the Problems) The aluminum alloy rotor of the present invention solves the above problems by determining the amount of Si so that seizure and abnormal wear do not occur and the strength is not significantly impaired. The hardness is set at H _RB 80 or higher to suppress friction and improve strength. Furthermore, in order to suppress seizure and abnormal wear and improve strength, the sliding parts and parts where strength is required (groove bottom) are The problem was solved by destroying the cast structure through plastic working. That is, the rotor according to the present invention has Si: 10 to
The essential components are 14% by weight, Cu: 4-8%, Mg: 0.3-2%, and Fe, Mn, Ni, Cr,
0.5 to 3% of one or more of Zr
and has an alloy composition in which the remainder is substantially Al, and has a hardness of _HRB 80 or more, and further has dendrites destroyed at least in the vane storage part and contains one or more of the above elements. In this case, the acicular intermetallic compound is fragmented, and the cast structure remains except in some parts. Further, a rotor according to a preferred embodiment of the present invention is characterized in that the size of Si particles dispersed in the aluminum alloy is 2 μm or more in average particle size. In a rotor according to yet another preferred embodiment, the area ratio of Si particles dispersed in the aluminum alloy with a size of 5 μm or more is 5% of the total cross-sectional area.
It is characterized by the above. The reasons for limiting the composition of the present invention will be explained above. Among the above components, if Si is less than 10%, the diameter of the Si particles dispersed in the matrix is small and the area ratio thereof is also low, making it impossible to exhibit good sliding properties. If it exceeds 14%, many primary Si particles will precipitate, which will cause internal cracks during plastic working as described below, reducing the impact value of the resulting rotor. The particularly preferable range of Si content is
It is 11-13%. Next, Cu lowers the coefficient of thermal expansion, increases the size of Si particles dispersed in the matrix, and increases the strength and hardness in the temperature range of about 150 to 200 degrees Celsius through age hardening. The purpose is to ensure the sliding characteristics and strength of the steel. If the content is less than 4%, these effects are insufficient, while if it exceeds 8%, the toughness and corrosion resistance will deteriorate. particularly preferred
The Cu content ranges from 5 to 7%. Like Cu, Mg is included to increase strength and hardness, and is particularly intended to ensure strength and hardness in a temperature range up to 150°C. Below 0.3%,
Age hardening is insufficient to increase strength and hardness and ensure the sliding characteristics and strength of the rotor.
On the other hand, if it exceeds 2%, the material becomes brittle and difficult to plastically flow, and the impact value of the resulting rotor is reduced. A particularly preferable Mg content range is 0.5
~1.5%. When aluminum alloy rotors are used in applications such as compressors for automobiles equipped with particularly high-speed engines, Fe, Mn, Ni,
One or more of Cr and Zr combined 0.5
If ~3% is further contained, the high temperature strength and high temperature hardness will increase, and the dimensional stability at high temperatures will also improve. The effect of one type or two or more types combined is 0.5
If it is less than 3%, the effect will not be significant, and if it exceeds 3%, coarse intermetallic compounds will precipitate, making the material brittle and difficult to plastically flow, and will also reduce the impact value of the resulting rotor. The rotor according to the present invention has a groove portion 2, a cylindrical portion 3, and a shaft hole portion 4 as shown in FIG. 2, and finishing machining may be performed to improve the dimensional accuracy of these portions. , its basic shape and dimensions are made by plastic working of cast ingots, billets, and elongated materials. For the plastic working method, forging, especially hot casting, etc. is preferable, and extrusion method, which has high equipment costs and running costs such as dies, is not preferable. The amount of plastic working such as forging is 5 to 5 in terms of blank area reduction rate.
50% is appropriate. If extrusion is used, the product will be expensive. Next, another problem to be solved, which is a means for withstanding repeated stress under use conditions and impact stress under liquid compression conditions, will be explained. Since the above materials have low fatigue strength and impact value while retaining the cast structure,
Failure occurs at the stress-concentrated parts of the rotor. Therefore, it is necessary to destroy and strengthen the cast structure by plastic flow. In the present invention, by plastically working a portion where load stress is concentrated during use, reliability against load stress in that portion is improved. In other words, the vane housing part is required to have particularly excellent fatigue strength, toughness, and seizure resistance, so the dendrites in this part are destroyed and the intermetallic compounds crystallized in needle shapes are divided to form fine particles. The processed structure is recrystallized and refined by heat treatment after plastic working. A specific example of a method for destroying the cast structure using only the vane housing will be described with reference to FIG. 5. A continuously cast round bar is turned on the outer peripheral side to remove surface defects, and then cut to obtain a forging blank of a predetermined size. Next, the blank 15 heated and held at 400 to 450°C is inserted into the container 12 which is heated and held in the same manner (see Fig. 5a), and placed into the hole of the soybean 8 which is backed up by the die plate 13 and kept heated. The blank 15 is pushed in with the punch 16 to fill the 8 holes of the die (see Fig. 5b),
The blank 15 is removed through the container 12 by a knockout punch 14 in the die plate 13 (FIG. 5c). At that time, pressure is applied from inside the container into the coaxial die hole where the ratio of the cross-sectional area perpendicular to the axial direction of the die hole to the cross-sectional area perpendicular to the axial direction inside the container is 1:1 to 1:2. When the blank 15 is pushed in, the structure in the groove of the vane storage portion of the rotor and in the vicinity of the cylindrical portion at the bottom of the groove plastically flows, and the cast structure is destroyed and strengthened. On the other hand, although plastic flow occurs in other parts, the cast structure remains. The manufacturing method described with reference to FIG. 5 has the following advantages in addition to being able to locally destroy the cast structure. Because the blank is forged into a mold rather than being extruded into a long material, it is resistant to twisting and does not bend or warp, resulting in good dimensional accuracy and high yield during finishing. The stress on the mold is low and the life of the die is long. In the forging method, a lubricant is sprayed onto the die after each forging process, so it is possible to provide a lubricating effect between the forging die and the blank. Therefore, no galling or cracking occurs on the rotor surface. If there are such kinks or cracks in the outer periphery, which serves as a processing reference during finishing processing, the processing shaft will become eccentric, making it impossible to ensure positional accuracy with respect to the groove that accommodates the vane. In addition, galling or cracking scratches that occur on the cylindrical portion of the groove bottom act as notches when stress is applied during use, and are likely to break from that portion, reducing reliability. According to the method of the present invention described above, a rotor with high positional accuracy and excellent reliability can be obtained. In the case of the extrusion method, a large pressurizing force of 800 tons or more is required, so large and expensive equipment is required, but according to the forging method described above, a hammer of several tens of tons is required, depending on the weight of the blank. It is possible to manufacture rotors. In the case of extrusion, there are many parts where the die and the extruded material come into sliding contact, so if the speed is not low, cracks will occur in the extruded material. For this reason, although it is an expensive facility, productivity is low, and the cost of the rotor is high. On the other hand, the forging method has a higher processing speed and superior productivity than the extrusion method. In the present invention, it is not essential to destroy the cast structure other than the vane storage portion. In other words, a light processing method is used that leaves (does not destroy) the casting structure in areas other than the vane storage area. Generally, in extrusion methods, etc., the cast structure of the workpiece is destroyed as a whole, but the life of the die is short and the cost of the product is increased. In the present invention, sufficient strength as a rotor can be obtained by destroying the cast structure of only a specific portion of the rotor. Furthermore, the reason for limiting the hardness will be explained. Note that the hardness of the rotor as used in the present invention refers to the hardness of the entire rotor including the part where the cast structure is destroyed. The hardness of the rotor
If _HRB is less than 80, wear resistance and seizure resistance will be insufficient. In addition, in high Si-Al alloys with Si of 14% or more, if primary Si is coarsely and/or dispersed in large amounts,
Even if the hardness is low, the wear resistance will still deteriorate, but
In the present invention, since Si is limited to 14% or less,
Hardness H _RB 80 to ensure good wear resistance
Above, it is necessary to preferably have an _HRB of 85 or more.
In order to obtain such hardness, the Al alloy of the present invention containing a large amount of Cu must be subjected to a sufficient solid solution treatment for Cu after plastic working, and then subjected to an aging treatment. The solution treatment is preferably carried out at 480 to 510°C, and the aging treatment is preferably carried out at 180 to 200°C. In the continuous casting method in which the molten metal having the chemical composition of the present invention is made into a long round bar by a continuous casting method, the cooling rate is slowed down by reducing the amount of cooling water, and the continuous cast round bar obtained is By holding the rod at a temperature of 500 to 530°C for 2 to 10 hours, the Si particles become coarser and the structure becomes more uniform. As a result, the size of the Si particles dispersed in the base can be reduced from 2 to 2
It has become possible to set the cross-sectional area to 30 μm and to increase the area ratio of the cross-sectional area exceeding 5 μm to 5% or more of the total cross-sectional area. In materials with a structure in which the hard phase is dispersed in this way,
Even if the composition is the same, wear resistance and seizure resistance are greatly affected by the size of the hard phase. That is,
If the hard phase is large, the contact with the mating material will be such that the hard phase supports the load, and the oil film between the sliding surfaces will be difficult to break. Therefore, the coefficient of friction is low, seizure is less likely to occur, and the amount of wear is small. When the hard phase is small, it is difficult to form an oil film, and the hard phase comes off together with the base as abrasion powder, resulting in a large amount of wear and seizure. In particular, when the sliding mating material has a high hardness and a rough surface, the influence of the size of the hard phase is significant. (Function) Normally, in Al-Si aluminum alloys, how much Si is added to improve toughness and plastic workability?
The problem was how to make the particles smaller, but if the Si particles were made finer, the wear resistance and seizure resistance required for rotors would deteriorate. Therefore, in the present invention, the composition is designed to contain a large amount of Cu and to increase the size of Si particles dispersed in the base. Note that Cu mainly forms a solid solution in the aluminum matrix, has the effect of lowering the eutectic point of the Al-Si alloy, and has the effect of increasing the size of crystallized Si particles. Even if an aluminum alloy has a composition that takes such considerations into consideration, it alone is insufficient to make the average Si particle size 2 to 30 μm. In addition, by slowing down the cooling rate during casting and heating and holding the resulting continuously cast round bar at high temperatures, we can improve the sliding properties by controlling the size and area ratio of Si particles dispersed in the matrix. Make it even better. Hereinafter, the present invention will be explained in more detail with reference to Examples. (Example) Three types of ingots having the chemical composition shown in Table 1 were prepared, and each ingot was remelted and made into a round bar with a diameter of 53 mm using an experimental continuous casting machine. Alloy composition No.
A, B, and C are the composition ranges of the present invention, and the alloy composition
No. D is a comparative material, JIS-
It is AC8A. Forging blank samples as shown in Table 2 were prepared by changing the casting conditions and the conditions for maintaining the cast material at high temperatures.

【table】

[Table] Next, an example of a method for manufacturing a rotor using this blank will be described in detail. As shown in Fig. 2, the outer diameter D = 50.2 mm, the circumferential diameter D ₁ = 14.33 mm, where the cylindrical part 5, which is the groove bottom, is arranged.
Inner diameter d of cylindrical portion 5 = 4.5 mm, width t of vane groove 6 =
A rotor material 1 for a rotary compressor for an air conditioner mounted on a five-vane vehicle was manufactured by a hot forging method. In FIGS. 3 and 4, the mold 8 has an inner peripheral part 9 corresponding to the outer peripheral part of the rotor material 7, a fin part 10 corresponding to the vane storage part, and a small cylindrical part 11 corresponding to the bottom part of the vane groove. is formed. The inner diameter of the die 8 is made to be the same as the outer diameter of the rotor material 1 shown in FIG. FIG. 5 shows the structure of the mold, in which 12 is a container and 8 is the aforementioned die, each of which is heated and maintained at 300 to 450 DEG C. by a heater (not shown). Reference numeral 13 denotes a die plate, which has a structure that completely contacts the fin portion 10 of the die 8 and the small cylindrical portion 11 at the tip thereof, and a knockout punch 14 is provided in the center of the die plate 13. After dovetail forging is completed, the rotor material 15 is knocked out upward in the figure. Further, a pressure punch 16 is attached to the platen (not shown) at the top. The inner diameter of the container 12 is 50.3 mm, and the ratio of the cross-sectional area perpendicular to the axial direction of the hole of the mold to the cross-sectional area perpendicular to the axial direction of the container 12 is 1:1.1. Each blank sample shown in Table 2 was machined into a forged material, or blank, with a diameter of 50 mm and a height of 45 mm. This blank was heated to 430°C and hot forged as shown in FIG. 5 under the conditions of a container temperature of 430°C and a die temperature of 400°C. The maximum pressure during forging was 15 tons. A, b, and c in Fig. 5 show the order of the steps, and in a in the figure, a blank 15 heated from an external continuous preheating furnace (not shown) is automatically inserted into the container 12, and a pressurized punch is inserted into the container 12. 16 shows a state in which forging has started. For lubrication, graphite-based liquid was sprayed onto the die and the inside of the container. FIG. 5b shows a state in which the pressure punch 16 has completed a predetermined stroke. In this state, the blank 15 is almost sealed inside the die 8, and is finished to a predetermined size. In FIG. 5c, the pressure punch 16 is inserted into the container 12.
The forged blank 1 is then moved by a predetermined stroke from
5: Take out the rotor material from the container. As a result of the cutting investigation, the rotor material obtained in this way has the following properties:
The cast structure is destroyed by plastic flow during the forging process. Next, the rotor material of each sample was subjected to T7 treatment, which involves artificial aging after solution treatment at 495℃, and the hardness and structure were quantified. Tissue quantification, magnification
Using an image analyzer (Ruzex 500) at 800x magnification, the particle size and area ratio of Si particles dispersed in the base were measured in detail in 50 fields of view for each sample and averaged.
The results are shown in Table 3.

[Table] In addition, the rotor material made from each sample was treated with T-7, finished to the specified rotor dimensions, and a steel shaft was press-fitted into the shaft, and the outer diameter, both end faces, and grooves were finished with the final finish and compressed. Built into the machine. The conditions for the durability test using the compressor were low speed and high load, which is a severe wear condition. The number of rotations is
500rpm, discharge pressure 28Kg/mm ² , suction pressure 4Kg/mm ²
The engine was operated continuously while monitoring the torque and oil contamination status. The side plate of the compressor has an aluminum alloy (AC4A) base material on the clutch side, and a Ni-based plating layer (Ni-P base) with silicon nitride with an average grain size of 0.8 μm at an area ratio.
15%, and the hardness is Hmv 700)
A material with a thickness of 10 μm provided on the sliding surface was used.
The opposite side plate was made of cast iron (FC25). Vane is 20%Si-7.5%Fe-4%Cu-1
%Mg with the balance being Al, and the same plating as the side plate described above was provided with a thickness of 10 μm on both sides that slide on the groove of the rotor and on the curved surface that slides on the inner peripheral surface of the cylinder. A combination of things was tested. As a result of the test, compressors incorporating rotors made from blank samples Nos. 2, 3, and 4, which are the rotors of the present invention, were hot-forged as rotor materials.
The compressor was able to operate for hours without any abnormalities, and no abnormalities were found when the compressor was disassembled and investigated. In addition, abrasion powder was observed in the oil after 150 hours in the compressor in which a rotor was hot-forged from blank sample No. 1 as a rotor material, and a disassembly investigation revealed slight abrasion marks on the sliding surface with the vane. was observed. On the other hand, in a compressor in which a rotor was assembled using blank sample No. 5 as a rotor material by hot forging as a comparative material, abrasion powder was observed in the oil after 50 hours, and as a result of disassembly investigation, sliding with the vane was observed. Deep wear scratches were observed on the sliding surfaces of the surface and the side plate. Next, blank samples 1, 2, 3 after the durability test,
The compressor incorporating 4 was reassembled and tested by repeating startup 500 times under liquid compression conditions. As a result of disassembly and investigation, no cracks were observed in the stress concentration area of the rotor. In addition, a compressor incorporating a rotor machined from blank samples 1, 2, 3, 4, and 5 (that is, the stress concentration part remains as a cast structure) was subjected to repeated startup tests under the same liquid compression state. The results of a disassembly investigation revealed that cracks had occurred in stress concentration areas. (Effects of the Invention) The aluminum alloy rotor according to claim 1 of the present invention is made of a low-Si alloy that is easy to plastically work, and
By increasing the content and making the hardness higher than conventionally known materials, it was possible to significantly reduce wear. In addition, regarding fracture from the bottom of the groove of the vane, where stress is concentrated, the cast structure was destroyed by plastic working in that part, and even repeated startup tests under liquid compression to allow for practical margins did not result in fracture. Judging from the fact that no cracks were generated, destruction at the bottom of the groove does not occur even in practical rotors. Furthermore, in rotors extruded from conventionally known high-silicon aluminum powder, the raw material powder is rapidly cooled, which inevitably results in smaller Si particles and poorer sliding properties. For this reason, it was necessary to improve the sliding properties by increasing the si% and adding more transition elements (Fe, Ni, Mn) to increase the hardness. As a result, the rotor became susceptible to cracking due to impact load stress such as during liquid compression. In other words, in a rotor extruded from quenched high-silicon aluminum alloy,
It has been difficult to improve both sliding properties and toughness, but in the present invention, toughness can be improved by means such as breaking the casting structure at stress concentration areas, and sliding properties can be improved by increasing the Cu content. We succeeded in achieving both of these favorable properties. In addition, the rotor of the present invention is less expensive than the rotor produced by the powder extrusion method, has high dimensional accuracy, has less bending and warping, and has a good surface.
For this reason, in addition to advantages on the manufacturing side, such as high product yields and low finishing costs, there are also advantages on the equipment side, such as high reliability when incorporated into compressors. Furthermore, in the aluminum alloy rotor according to claims 2 and 3, the average particle diameter of the Si particles dispersed in the matrix is 2 μm or more, and the area ratio of particles having a size of 5 μm or more is 5% or more, so that the amount of wear is further reduced. Decrease.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the rotor, Fig. 2 is a plan view of the rotor, Fig. 3 is a plan view of the mold, Fig. 4 is a sectional view taken along the dashed line in Fig. 3, and Fig. 5a, b, c. The figure is a diagram explaining the rotor forging process, showing the mold and its surroundings in cross-section. Figure a shows the process of inserting the blank into the mold, figure b shows the punching process, and figure c shows the knockout process. It is a drawing. 2...Groove portion, 2, 3...Cylindrical portion, 4...Shaft hole portion, 12...Container, 13...Die plate,
14...Knockout punch, 15...Blank, 16...Pressure punch, 18...Dice.

Claims (1)

[Claims] 1 Si: 10 to 14% by weight (all weight% hereinafter),
Cu: 4-8%, Mg: 0.3-2% are essential components,
It has an alloy composition containing a total of 0.5 to 3% of one or more elements of Fe, Mn, Ni, Cr, and Zr as necessary, and the remainder substantially consisting of Al,
In addition, if the hardness is _HRB 80 or more, and if the dendrite is destroyed and one or more of the above elements is contained at least in the vane storage part, the acicular intermetallic compound is fragmented and partially broken. This is an aluminum alloy rotor that has a cast structure that remains. 2. The aluminum alloy rotor according to claim 1, wherein the Si particles dispersed in the aluminum alloy have an average particle size of 2 μm or more. 3. The aluminum alloy rotor according to claim 1, wherein the Si particles dispersed in the aluminum alloy have a size of 5 μm or more and an area ratio of 5% or more of the total cross-sectional area.