JPH08176716A - Wear resistant aluminum based sintered alloy and manufacture thereof - Google Patents

Abstract

PURPOSE: To impart an excellent mechanical strength and wear resistance by specifying composition and making an alloy with a mottled structure with an Al-Si based alloy phase having dispersed primary crystal Si and with an Al solid solution. CONSTITUTION: The overall composition by wt.% is such that 2.4-23.5% Si, 2-5% Cu, 0.2-1.5% Mg; 0.01%-1% of one or more than one kind of transition metal selected from Ti, V, Cr, Mn, Fe, Co, Ni, Zr and Nb, and the balance Al with inevitable impurities. In addition, this sintered alloy is such that it shows a mottled structure with an Al-Si based alloy phase having dispersed primary crystal Si and with an Al solid solution phase, that the area of the Al solid solution phase is 20-80% in the cross section of the mottled structure, and that the grain size of the primary crystal Si is 5μm or less in the Al-Si based alloy phase of the surface part or at least of the anticipated sliding surface of the alloy. Furthermore, the thickness of the part, in which the maximum grain size of the primary crystal Si is 5 to 60μm in the Al-Si based alloy phase, is 0.05-1mm from the alloy surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to aluminum suitable for manufacturing various gears, pulleys, compressor vanes, connecting rods, pistons, etc. which are required to be lightweight, high in strength, and wear resistant. The present invention relates to a sintered alloy and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, mechanical elements have been increasingly replaced with lightweight materials in order to improve mechanical efficiency and save energy. Among them, aluminum-based sintered alloys are lighter in weight and can make primary crystal Si finer than cast alloys.
Due to the fact that the i content can be increased, expectations are rising as an aluminum-based alloy having excellent specific strength and wear resistance.

As a conventional aluminum-based sintered alloy,
For example, as disclosed in JP-A-53-128512, the composition is Cu: 0.2-4% by weight and Mg: 0.2-0.2 by weight.
2%, Si: 10 to 35%, the balance being Al,
Al-10 to 35% Si powder, copper powder, Mg powder, Al-Cu
Powder, Cu-Mg powder, Al-Cu-Mg powder, Cu-Mg-
There is a method of manufacturing a desired product by mixing powder selected from Si powder and Al-Cu-Mg-Si powder, and if necessary, Al powder, compacting and sintering. This method is a so-called mixing method of mixing various powders.
According to such a mixing method, since the soft metal powder can be mixed, there is a feature that the powder moldability is good,
Since liquid phase sintering can provide a material having a certain level of strength only in the ordinary steps of powder compaction-sintering, it can be applied to a member that does not require much strength.

Further, as described in Japanese Patent Laid-Open No. 62-10237, the composition is Si: 10 to 3 in weight ratio.
0%, 1 or 2 or more of Ni, Fe, Mn in total of 1 to 15%, and Cu: 0.5 to 5 and M as required.
g: 0.2 to 3%, and manufactured by hot forging a compact of rapidly solidified aluminum alloy powder consisting of the balance Al and unavoidable impurities, and primary crystal S in the Al-Si alloy base.
There is an alloy having a structure in which i is uniformly dispersed. The alloy method achieves higher strength than the mixing method. However, since the rapidly solidified powder is hard, it is difficult to form near net shape by mold forming, the powder has a strong oxide film, and no liquid phase is generated during sintering. However, it is impossible to achieve sufficient bonding between the powders, and several compression steps such as extrusion from a billet shape and forging are required.

Further, as a combination of the mixing method and the alloying method,
As described in Japanese Patent Laid-Open No. 5-156399, it is produced by hot forging a powder obtained by mixing a predetermined amount of pure Al powder with a rapidly solidified Al-Si alloy powder, and the composition thereof is a weight ratio. Si: 12 to 30%, one or two components of Fe and Ni, 1 to 10%, Cu: 1 to 5 if necessary
%, Mg: 0.3 to 2%, one or two components and the balance being Al and inevitable impurities,
There is an alloy having a structure in which Al solid solution grains deformed by hot forging are dispersed in an amount of 5 to 20% by volume in a eutectic Al-Si matrix in which fine primary crystal Si is dispersed. In this alloy, the Al solid solution acts as an adhesive to improve the mutual adhesion of hard grain boundaries and improve the wear resistance and strength.

By the way, the present applicant has filed Japanese Patent Application No. 6-3760.
In No. 6, the composition is Al-13 to 30% Si by weight%.
One or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Zr, and Nb in a powder obtained by mixing alloy powder and Al powder in a ratio of 2: 8 to 8: 2. Cu-transition metal alloy powder containing 0.2 to 30% of 35,
% Or more Mg-containing Al-Mg alloy powder or Mg powder is added and mixed, followed by compacting and sintering, and the total composition by weight ratio is Si: 2.4 to 23.5%, Cu: 2-5
%, Mg: 0.2-1.5%, the transition metal 0.01-1
%, And the balance Al and unavoidable impurities, and 5
An alloy was proposed in which the Al-Si alloy phase in which primary crystal Si of -60 μm is dispersed and the Al solid solution phase are present, and the Al solid solution phase occupies 20% to 80% of the area of the mottled surface. In the method for producing the alloy, the formability is excellent, the alloy is prevented from precipitating the intermetallic compound at the grain boundary, and has a mottled structure, and the maximum grain size of the primary crystal Si in the Al-Si alloy phase is limited. As a result, the tensile strength is about 380 MPa, the elongation is large, and the Al solid solution phase has the effect of embedding the primary crystal Si particles that have fallen off during frictional sliding, so that an alloy with particularly excellent wear resistance is obtained. be able to.

[0007]

Thus, although the above-mentioned sintered alloy has excellent wear resistance and high mechanical strength,
If the alloy has higher mechanical strength, expand its applications,
Moreover, the reliability of the alloy can be improved. An object of the present invention is to provide an aluminum-based sintered alloy having higher mechanical strength and excellent wear resistance.

[0008]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems. That is, the sintered alloy of the present invention has a total composition of Si: 2.4 to 23.5% by weight and C
u: 2-5%, Mg: 0.2-1.5%, Ti, V, C
One or more transition metals selected from r, Mn, Fe, Co, Ni, Zr and Nb: 0.01 to 1
%, Balance Al and inevitable impurities, and primary crystal Si
Is an aluminum-based sintered alloy in which the Al-Si alloy phase in which is dispersed and the Al solid solution phase have a mottled structure, and the area of the Al solid solution phase occupying the cross section of the mottled structure is 20 to 80%. A of the surface part or at least the sliding surface part
The maximum grain size of primary Si in the 1-Si alloy phase is 5 to 60 μm.
m, and the grain size of the primary crystal Si in the other portions is 5 μm or less. The layer of the primary crystal Si of 5 to 60 μm dispersed on the sliding portion of the sintered alloy member or the surface of the entire member has a depth of 0.05 to 5
It is preferably in the range of 1 mm.

Further, in the method for producing an aluminum-based sintered alloy member according to the present invention, the Si content is 13 to 30.
Ti, V, Cr, Mn, Fe, Co, powders prepared by mixing Al-Si alloy powder and Al powder in a weight ratio of 2: 8 to 8: 2,
Cu-transition metal alloy powder containing 0.2 to 30 wt% of transition metal selected from Ni, Zr and Nb, Al-M containing 35 wt% or more of Mg
With the addition of g alloy powder or Mg powder, the total composition is in a weight ratio of Si: 2.4 to 23.5%, Cu: 2 to 5%, Mg:
0.2-1.5%, Ti, V, Cr, Mn, Fe, Co,
One or more transition metals selected from Ni, Zr, and Nb: 0.01 to 1%, a mixed powder consisting of the balance Al and inevitable impurities is formed, and the mixed powder is compacted and sintered. , A sintered alloy exhibiting a mottled structure of an Al-Si alloy phase in which primary crystal Si having a maximum grain size of 5 μm or less is dispersed and an Al solid solution phase, and the surface of this sintered alloy is heated to give the inside of the alloy. In the state in which the grain size of primary crystal Si in the Al-Si alloy phase present in the alloy is 5 μm or less, the maximum grain size of the primary crystal Si in the Al-Si alloy phase present in the alloy surface is 5 to 5 μm. It is characterized in that it is grown to 60 μm and cooled.

In the above-mentioned manufacturing method, heating of the entire surface or a portion which slides when the alloy member is used can be achieved by high frequency heating, plasma heating, laser heating or the like.

[0011]

The function of the present invention will be further described below. (1) Mottled structure The mottled structure is composed of an Al-Si alloy phase in which primary crystal Si is dispersed and an Al solid solution phase. Al with primary crystal Si dispersed
The -Si alloy phase is a solid solution in which Mg, Cu, and a transition metal element are diffused in an Al-Si alloy, and is a relatively hard phase in which primary Si is dispersed in the matrix, and is mainly Contributes to material strength and wear resistance.

The Al solid solution phase is a solid solution in which Si, Mg, Cu and a transition metal are diffused in Al added in the form of pure aluminum powder, is relatively soft, and contributes to the toughness of the alloy. , Al-Si after initial wear
It forms an oil pool between the alloy phases and contributes to lubricity and compatibility with the mating material during friction. Further, since it is easily plastically deformed, hard primary crystal Si particles in the vicinity of the sliding surface are likely to fall off as abrasion powder, or if they fall off, they are buried and the Si particles are prevented from acting as abrasive particles. effective.

Al-Si in which the primary Si particles are dispersed
The two phases of the Al-based alloy phase and the soft Al solid solution phase are Al-S
When the i-based alloy phase is less than 20% in area ratio of the alloy cross section,
Since the amount of primary crystal Si is small, and even when it exceeds 80%, the wear resistance is remarkably lowered because the amount of the Al solid solution phase in which the Si particles dropped by frictional sliding are buried is small. Therefore, when the two phases have a composite structure in which the area ratio of the alloy cross section is mixed in the shape of 20-80: 80-20, the strength and the wear resistance are improved by the mutual action.

(2) Si Si of the aluminum alloy contributes to a reduction in the coefficient of thermal expansion and an improvement in wear resistance. The amount of Si as seen from the overall composition is the same as that of the Al-Si alloy phase in which the above-mentioned primary crystal Si is dispersed and A
It is necessary to select a range in which the solid solution phase exhibits a patchy structure, and a range of 2.4 to 23.5% by weight is suitable. When the amount of Si in the overall composition is too small, the amount of Si in the Al-Si alloy phase in which primary crystal Si is dispersed is small, or the amount of the Al-Si alloy phase becomes small.
Since the amount of primary crystal Si that contributes to the wear resistance is small, the wear resistance becomes insufficient. On the other hand, if the amount of Si is too large, Al-
A large amount of Si in the Si-based alloy phase, or Al-Si
Since the amount of the system-based alloy phase is increased, the toughness is decreased, and the amount of the Al solid solution phase that fills the primary crystal Si particles that have fallen off during sliding is small.

Si is added in the form of Al-Si alloy powder, but in order for the primary crystal Si to precipitate, the Si content in the alloy powder must be 13% by weight or more, and the Si content must be If it exceeds 30% by weight, the temperature of the molten metal at the time of powder production becomes high. Therefore, the Si content in the Al-Si alloy powder is suitably 13 to 30% by weight.

(3) Mg Mg produces a liquid phase during sintering to form a solid solution in the matrix, which promotes sintering, and has the effect of strengthening the matrix and improving wear resistance by Mg ₂ Si that precipitates by aging. Show. If the total amount of Mg is less than 0.2% by weight, the above effect is insufficient.
On the other hand, addition of more than 1.5% does not exhibit the effect of addition, so the range of 0.2-1.5% by weight is desirable.

As a means of addition, the Mg content is 3
It is performed in the form of 5 wt% or more of Al-Mg alloy powder or Mg powder. This is because the Al—Mg binary alloy has a low melting point of about 460 ° C. when the Mg content is 33 to 70 wt%. That is, in the case of pure Mg powder, a liquid phase is generated due to the solid phase diffusion with the Al base material during the sintering process to lower the Mg concentration. On the other hand, when using Al-Mg alloy powder, if the Mg content is 33% by weight,
Similarly to the above, since the Mg concentration decreases due to diffusion with the Al base material, the melting point rises and the liquid phase cannot be effectively utilized, so the Mg content is preferably 35% by weight or more.

(4) Cu and Transition Metals Cu is an element that strengthens the Al alloy substrate, and exhibits a greater effect by aging treatment, but if it is less than 2% by weight, the desired strength improvement is not observed, and 5% by weight. If it exceeds, the intermetallic compound containing Cu as a main component is precipitated in a large amount in the vicinity of the powder grain boundaries, and the toughness decreases, which is not preferable. Cu to C
When added in the form of u powder, if the heating necessary for solid solution of Cu in the matrix is carried out, primary crystal Si will be obtained like a melted material.
However, if the heating temperature is lowered and the time is shortened, the intermetallic compound of Cu remains at the grain boundaries of the base material, resulting in a decrease in strength. Therefore, an appropriate amount of transition metal (Ti, V, C
r, Mn, Fe, Co, Ni, Zr, Nb) coexist with the transition metal and Cu and Si when the supersaturated solid solution Cu in the matrix is aged and precipitated by solution treatment and aging treatment. However, the amount of Cu and Si in the matrix is reduced, and Cu of the intermetallic compound precipitated in the powder grain boundaries is reduced accordingly.
Since it diffuses into the matrix, it becomes possible to eliminate the intermetallic compound that precipitates at the grain boundaries.

The amount of transition metal in the overall composition is the above-mentioned Cu.
If the content is less than 0.01% by weight, the effect is not observed. On the other hand, if it exceeds 1% by weight, an intermetallic compound containing a transition metal as a main component is precipitated to lower the toughness. 1% by weight is preferred. Since it is difficult to diffuse the transition metal when added alone, it is preferable to add it in the form of Cu-transition metal alloy powder, but the amount of transition metal in the alloy powder should be adjusted considering the amount of Cu and the amount of transition metal required for the overall composition. 0.2% by weight or more is required, but if it exceeds 30% by weight, the melting point of the alloy powder becomes high, and even if the melting point is lowered due to solid phase diffusion, a liquid phase is not generated, so that 0.2 to 1%.
A range of 0% by weight is preferred.

(5) Grain size of primary crystal Si in Al-Si alloy phase The cross-sectional shape of primary crystal Si particles is similar to those of small grain size in the vertical and horizontal directions and close to a circle, but large grains are It is considered that small particles aggregated and aggregated, or that they grew.
It shows an irregular shape. The maximum particle diameter represents the longest dimension of the distance between both ends of such irregularly shaped particles.

When the grain size of the primary crystal Si becomes large, the hard primary crystal Si particles scratch the mating material in the state of protrusions and abrade the mating material. On the other hand, when the amount of the primary crystal Si is small or the grain size of the primary crystal Si is small, the primary crystal Si particles fall off from the base material during frictional sliding, and the primary crystal Si particles that have fallen off act as abrasive particles, which promotes wear. Therefore, from the viewpoint of wear resistance, the primary crystal Si grain size needs to be an appropriate value, and the maximum grain size is preferably in the range of 5 to 60 μm.

On the other hand, from the viewpoint of strength, the larger the primary crystal Si, the lower the strength and the ductility, and the smaller the grain size of the primary Si, the higher the strength and the ductility. Therefore, 5 μm or less is preferable. Therefore, the primary crystal Si of the surface of the friction member or at least the sliding portion has a maximum grain size of 5 to 60 μm in consideration of wear resistance, and the primary crystal Si inside
By considering the strength and the ductility, the grain size is set to 5 μm or less, so that it becomes possible to improve both the wear resistance and the strength and the ductility.

Further, primary crystal Si having a maximum grain size of 5 to 60 μm
The thickness of the surface layer of the Al-Si alloy phase in which is dispersed is 0.05 mm, although it depends on the friction environment in which the member is used.
Below, 5 to 60 μm that contributes to wear resistance during initial wear
There is a possibility that the primary crystal Si particles of will fall off and the effect of improving wear resistance will be lost. On the other hand, even if the surface layer thickness exceeds 1 mm,
Wear resistance does not improve further accordingly,
Since the part that contributes to the internal strength and toughness is reduced,
The thickness of the layer in which 5 to 60 μm of primary crystal Si is dispersed is 0.1.
It is preferably in the range of 05 to 1 mm.

FIG. 1 schematically shows a microscopic field of a cross section of the sintered alloy structure of the present invention. The white region is the Al solid solution phase 2, the region having the black dots is the Al-Si alloy phase 2, and the black dots are the primary crystal Si. The average grain size of the primary crystal Si3a near the alloy surface 4 is large, while the primary crystal Si3a inside
The average particle size of 3b is relatively fine. Such a primary crystal S
The structure of i3a and 3b has a pre-crystallized Si
On the surface of the sintered alloy sintered to have a grain size of 5 μm or less by primary heating by a heating means such as high-frequency heating, plasma heating or laser heating to a depth of 0.05 to 1 mm. It can be obtained by heating until the maximum particle size becomes 5 to 60 μm. Further, it is also possible to heat only a necessary portion to modify only a specific surface portion.

[0025]

EXAMPLES The present invention will be further described below with reference to examples. The component amounts are by weight unless otherwise specified. [Example 1] As a raw material powder, Si content is 15%, 17
%, 20%, 25% and 30% of five types of Al-Si
Alloy powder, pure Al powder, Cu-4% Ni alloy powder and Al-
50% Mg alloy powder is mixed at a ratio shown in Table 1 to Table 3, shaped into a predetermined shape, and dewaxed at 400 ° C.,
Sintering was performed at 540 ° C. for 10 minutes. Then, the density ratio was set to 100% by hot forging, and solution treatment was performed at 490 ° C and aging treatment was performed at 240 ° C. The tissue of each sample is A
The cross-sectional area ratio of the 1-Si alloy phase and the Al solid solution phase is the same as the mixing ratio of the Al-Si alloy powder and the pure Al powder, and the maximum grain size of the primary crystal Si in the Al-Si alloy phase. Was 3 to 4 μm.

Next, these samples were heated in a high frequency induction furnace to obtain samples 1 to 19. For each of the obtained samples, the component composition, the area ratio of the Al-Si alloy phase and the Al solid solution phase occupying the cross section of the mottled structure, the maximum grain size of primary crystal Si on the surface of the sample grown by high frequency heating, Tables 1 to 3 show the thickness of the layer from the surface of the portion where the primary crystal Si is dispersed and the maximum grain size of the primary crystal Si inside the sample. Further, the amount of wear of each sample was measured by a pin-on-disk friction and wear test. The results are also shown in Tables 1 to 3. In the pin-on-disk friction and wear test, a sample was used as a pin, a heat-treated product of S48C material (carbon steel for machine structure) was used as a mating disk, and the surface pressure was 49 under mineral oil lubrication.
It was performed under the conditions of MPa and a friction speed of 5 m / sec.

According to the results shown in Tables 1 to 3, the maximum grain size of the primary crystal Si on the surface portion is 24 to 25 μm. Al-
The area ratio of the Si-based alloy phase and the Al solid solution phase is from 8: 2 to 2:
Samples 1, 3, 10, 13, 1 which do not satisfy the range of 8
Nos. 5, 18 and 19 are seized or have a large amount of wear. Other samples, the amount of Si in the entire composition is within a predetermined range, the cross-sectional area ratio of the Al-Si alloy phase and the Al solid solution phase occupying the mottled structure is within a predetermined range,
In that case, the amount of wear is small.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[Example 2] Al-20Si alloy powder, pure A
1 powder, Cu-4% Ni alloy powder, and Al-50% Mg alloy powder were mixed in the ratios shown in Tables 4 and 5, and molding, sintering, hot forging, and solution were performed under the same conditions as in the above-mentioned Examples. Samples 20 to 2 after aging treatment and aging treatment and further high frequency heating
Got 8. Also, aging-treated samples 29 to 32 which were manufactured under the same conditions and were not subjected to high frequency heating were obtained.

Regarding the obtained samples 20 to 32, the component composition, the Al--Si alloy phase and Al occupying the cross section of the mottled structure
Area ratio of solid solution phase, maximum grain size of primary crystal Si in sliding portion grown by high frequency heating, thickness of layer from surface of portion where grown primary crystal Si is dispersed, and primary crystal Si in sample
The maximum particle size of is shown in Tables 4 and 5. In addition, the results of measuring the tensile strength of each sample and the amount of wear of the sample by the pin-on-disk friction and wear test are also shown in the same table.

According to the results shown in these tables, the amount of wear was found in Sample 29 in which the maximum grain size of primary Si in the sliding portion was less than 5 μm.
And sample 28 in which the maximum grain size of primary Si exceeds 60 μm
It can be seen that the amount of wear is extremely large. In addition, the primary crystal S on the surface
Even if the maximum particle size of i is in the range of 5 to 60 μm, the sample 21 having a layer thickness of less than 0.05 mm is significantly worn. On the other hand, when the maximum grain size of primary crystal Si on the surface becomes large, the tensile strength becomes low, but the sample having a small maximum grain size of internal primary Si has a large grain size to the inside.
It can be seen that the tensile strength is higher than that of No. 32, and the smaller the thickness of the grown primary crystal Si layer dispersed on the surface, the higher the tensile strength. From the above, in an aluminum-based sintered alloy showing a mottled structure of an Al-Si alloy phase in which primary crystal Si is dispersed and an Al solid solution phase, the area of the Al solid solution phase in the cross section of the mottled structure is 20 to 80%. And the maximum grain size of the primary crystal Si dispersed on the surface is 5 to 60 μm, and the grain size of the primary crystal Si in the Al—Si alloy phase dispersed in the other portion is 5 μm or less, Maximum particle size is 5-60μ
It can be seen that the member made of the aluminum-based sintered alloy in which the layer of m of primary crystal Si dispersed has a thickness of 0.05 to 1 mm has excellent wear resistance and high tensile strength.

[0034]

[Table 4]

[0035]

[Table 5]

[0036]

As described above, the aluminum-based sintered alloy of the present invention is Al-Si in which primary crystal Si is dispersed.
An Al-Si alloy phase having a mottled structure of a system alloy phase and an Al solid solution phase, the area of the Al solid solution phase occupying the cross section of the mottled structure is 20 to 80%, and a depth of 0.05 to 1 mm from the surface. The primary crystal Si has a maximum particle size of 5 to 60 μm, and the primary crystal Si dispersed in other parts has a particle size of 5 μm or less, and has high mechanical strength and particularly excellent wear resistance. It is a thing. Therefore, it is expected to be applied to various bearings, gears, pulleys, connecting rods, mechanical elements such as pistons, which are required to be reduced in weight, and the use of sintered parts can be expanded.

[Brief description of drawings]

FIG. 1 is an enlarged schematic view illustrating the structure of a sintered alloy of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Al-Si type | system | group alloy phase 2 Al solid solution phase 3a Primary crystal Si (maximum particle diameter 5-60 micrometers) 3b Primary crystal Si (particle diameter 5 micrometers or less) 4 Sintered alloy surface

Front Page Continuation (72) Inventor Hideo Shikata 1-48-1 Okindaira, Matsudo City, Chiba Prefecture (72) Hideo Urata Inventor, Honda Technical Research Institute Ltd. 1-4-1 Chuo, Wako City, Saitama Prefecture (72) Inventor Shoji Kawase 1-4-1, Chuo, Wako-shi, Saitama, Ltd., Honda R & D Co., Ltd. (72) Inventor, Junichi Ueda, 1-4-1, Chuo, Wako, Saitama, Ltd., Honda R & D Co., Ltd.

Claims (4)

[Claims] 1. A total composition of Si: 2.4 to 23 by weight ratio.
5%, Cu: 2-5%, Mg: 0.2-1.5%, Ti,
One or more transition metals selected from V, Cr, Mn, Fe, Co, Ni, Zr and Nb: 0.01
.About.1%, the balance consisting of Al and unavoidable impurities, and the Al--Si alloy phase in which primary Si is dispersed and the Al solid solution phase exhibit a mottled structure, and the area of the Al solid solution phase occupying the cross section of the mottled structure is The aluminum-based sintered alloy is 20 to 80%, and the maximum grain size of primary crystal Si in the Al-Si-based alloy phase of the alloy surface portion or at least the planned sliding surface portion is 5 to 6
0 μm, and the grain size of the primary crystal Si in other parts is 5 μm
A wear-resistant aluminum-based sintered alloy, characterized in that: 2. The thickness of the portion where the maximum grain size of primary Si in the Al—Si alloy phase is 5 to 60 μm is 0.05 to 1 mm from the surface of the alloy. The wear-resistant aluminum-based sintered alloy described. 3. Al- having a Si content of 13 to 30% by weight.
A powder prepared by mixing Si alloy powder and Al powder in a ratio of 2: 8 to 8: 2 is added to one or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Zr and Nb. Cu-transition metal alloy powder having a content of 0.2 to 30% by weight, Al-Mg alloy powder or Mg powder having a Mg content of 35% by weight or more is added, and the total composition is Si: 2.
4 to 23.5%, Cu: 2 to 5%, Mg: 0.2 to 1.5
%, One or more transition metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Zr, and Nb: 0.01 to 1%, with the balance being Al and unavoidable impurities. The mixed powder is compacted and then sintered to obtain a sintered alloy exhibiting a mottled structure of an Al-Si alloy phase in which primary crystal Si having a maximum grain size of 5 μm or less is dispersed and an Al solid solution phase. The surface of this sintered alloy is heated to grow the maximum grain size of primary crystal Si in the Al—Si alloy phase existing in the alloy surface portion to 5 to 60 μm, and then cooled. A method for producing a wear-resistant aluminum-based sintered alloy. 4. The method for heating the surface of the sintered alloy comprises:
The method for producing a wear resistant aluminum-based sintered alloy according to claim 3, wherein the method is any one of high frequency heating, plasma heating and laser heating.