JPH02225635A - Manufacture of al-si alloy member having low thermal expansion coefficient, excellent wear resistance and high toughness - Google Patents

Abstract

PURPOSE:To manufacture the Al-Si alloy member having low thermal expansion coefficient and having excellent wear resistance and toughness by subjecting powder or foil obtd. by rapidly solidifying an Al-Si series alloy having specified compsn. from the melting state to hot forming at a specified temp. CONSTITUTION:The molten metal of an Al-Si series alloy having the compsn. contg., by weight, 18 to 28% Si, 0.5 to 3.5% Cu, 0.2 to 2.0% Mg and at least one kind among 0.03 to 0.40% Ti, 0.03 to 0.40% V, 0.03 to 0.40% Zr, 0.03 to 1.00% Cr and 0.3 to 2.5% Ni, satisfying <0.40% Ti+V+Zr, contg. <0.6% Fe and <0.3% Mn as impurities and the balance Al is rapidly cooled at 10<2> deg.C/sec cooling rate to solidify into the shape of powder or foil. As it is or after once subjected to preforming, the Al-Si alloy having the shape of powder or foil is subjected to hot forming such as forging, extruding and die forming at <=550 deg.C, by which the lightweight Al alloy member having high density and low thermal expansion coefficient and having excellent wear resistance and toughness can be manufactured.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention hot-forms an aluminum alloy solidified body produced by a rapid solidification powder metallurgy method, and has a low coefficient of thermal expansion and excellent wear resistance. , and has high toughness. The present invention relates to a method of manufacturing an Al1-5i alloy member having a predetermined shape.

[Prior Art] In recent years, new types of alloys produced by rapid solidification powder metallurgy are expected to be applied in various fields.

Rapid solidification powder metallurgy enables uniform solid solution of contained alloying elements and fine fragmentation of intermetallic compounds, which was previously considered difficult, and in some cases, ultrafine crystal structures can be obtained. Significantly improves the properties of the alloy.

Further, by using the rapid solidification powder metallurgy method, it is possible to put into practical use alloys with compositions that were previously impossible.

One of the aluminum alloys manufactured by such a rapid solidification powder metallurgy method is Al-3i alloy. Al
The 1-9i alloy has been widely used as a casting alloy and partly as a drawing alloy. The above-mentioned AM-5i alloy is characterized by a low coefficient of thermal expansion.

It has excellent wear resistance and high temperature strength. These characteristics are achieved in the rapid solidification process of the rapid solidification powder metallurgy method.
It is brought about by Si particles crystallized and dispersed in aluminum ground. In order to further improve these properties, it is necessary to increase the S1 content. However, in the conventional casting method, the solidification rate of the alloy is slow, so as the Si content increases, the primary crystal S1 particles become coarser, which leads to the deterioration of the above-mentioned properties. On the other hand, with the advent of rapid solidification powder metallurgy, it has become possible to sufficiently suppress the coarsening of primary Si particles. Furthermore, with the advent of the rapid solidification powder metallurgy method, transition metal elements such as Fa and Fe, which were not included in conventional Al-3i alloys, have been added to reduce the coefficient of thermal expansion of the alloy, improve wear resistance and high temperature resistance. In recent years, various types of Al-5i alloys have been proposed containing several to 0% or more of Al-5i for the purpose of improving properties.

[Problems to be Solved by the Invention] However, the An-5i-transition metal element alloy produced by these rapid solidification powder metallurgy methods is one of the main uses of the Al-5i alloy produced by the conventional casting method. For example, when applied to the piston of a reciprocating internal combustion engine,
When the reciprocating internal combustion engine is subjected to mechanical shock and thermal shock during operation, there is a problem in that the members often crack or even break. Also, in terms of the characteristics of the material itself, for example.

In terms of elongation at break in a tensile test or impact value in a Charpy test, Afl-5i alloys produced by rapid solidification powder metallurgy are often lower than alloys produced by conventional casting methods.

Therefore, it is an object of the present invention to not only optimize the S1 content but also to control the type and content of additional elements such as other transition metal elements in a method for manufacturing An-5i alloy by rapid solidification powder metallurgy. The coefficient of thermal expansion is low by strictly controlling the oxidation film on the powder surface, which is unique to the rapid solidification powder metallurgy method, and minimizing the adverse effects on component properties caused by the oxide film on the powder surface.

AQ-3 with excellent wear resistance and high toughness
An object of the present invention is to provide a method for manufacturing an i-alloy member.

[Means for Solving Problem 11] The inventors have conducted intensive research on the composition and solidification molding technology of Afi-3i alloy by rapid solidification powder metallurgy in accordance with the above-mentioned problems and objectives, and have arrived at the following invention. did.

This invention.

Si: 18-28 wtJ, Cu: 0.5~3.5@tJ, Mg: 0.2-2.0vtJ.

At least one element selected from the group consisting of: Ti: 0.03 to 0.40wt, %, V: 0.03
~0.40wt, %, Zr: 0.03~0.40vtJ, Cr: 0.
03~1.00wt. % and Ni: 0.3~
2.5 wt, %, provided that the total amount of Ti, V and Zr is 0.40 wt, % or less, and.

Remaining: 10 alloys consisting of Al and unavoidable impurities were melted, and then the aluminum alloy was rapidly solidified at a cooling rate of 101° C./sec or more to prepare powder or flaky solidified bodies.

Next, the solidified body is either as it is or preformed, and hot-formed at least once at a temperature of 550° C. or lower, thereby obtaining an alloy member of a predetermined shape, and further, Specifically, as an unavoidable impurity, Fs: less than 0.6 wt%, and.

Mn: 0.3wt. %less than It is characterized by the fact that it is regulated.

In this invention, the reason why the chemical composition range of the Al1-Si alloy is limited as described above will be described below.

(1) Si: Sl has a eutectic relationship with All. Most of the Si contained in Al crystallizes in the ground as Si particles.

The eutectic composition of Sl is approximately 12 wt, %Si, and the Si contained in excess of this crystallizes as primary Si, and the other Sl crystallizes as eutectic Si in the ground. Primary Si is eutectic Si
In addition, the shape of the primary crystal S1 may be acute-angled or acicular, and in this case, if the solidification rate and cooling rate of the primary crystal S during alloy production are slow, Decreases the toughness of Afl-Si alloy.

Even when producing an Al-Si alloy by the rapid solidification powder metallurgy method, the particle size of primary Si is larger than that of eutectic Si, but the particle size of primary Si must not exceed about 20 μm. It's easy. Si particles have a lower coefficient of thermal expansion and higher hardness than Al base.

Furthermore, An-
In the Si alloy, intermetallic compounds are finely dispersed. Thus, Al1-S produced by rapid solidification powder metallurgy method
i-alloy has a low coefficient of thermal expansion and is excellent in wear resistance and high temperature strength.

In the present invention, the lower limit of the Si content is lower than that for conventional casting^
Established in comparison with Q-3i alloy.

That is, the Afl-12wtJSi alloy is widely used as an alloy for I-progress, especially pistons, and the Al-17wt%SL alloy is used as an alloy for casting with wear resistance. It is used for a purpose.

Furthermore, although An-23wt and %St alloys have the disadvantage of too low toughness, they are used in small quantities for special purposes as casting alloys. so that the rate is the same or lower.
The content of Si was limited to 18 wt.% or more. The coefficient of thermal expansion of one alloy decreases in proportion to the increase in Si content, but
On the other hand, when the Si content exceeds 28 wt.l, the toughness of the alloy rapidly decreases. Therefore, the Si content is 18~
It should be limited within the range of 28vtJ. However, since the toughness of the first alloy may be greatly reduced depending on the content of other simultaneously added elements, in this case, it is preferable to reduce the Si content to less than 28 wt.%.

(2) Cu: Even if a pure binary An-Si alloy is produced by rapid solidification powder metallurgy, it is impossible to obtain sufficient strength.
Other additive elements are required to impart practical strength to the alloy. Cu has the effect of causing solid solution hardening of the alloy and precipitation hardening of the alloy due to aging by subjecting the alloy to heat treatment consisting of appropriate quenching and tempering. On the other hand, when Cu forms an intermetallic compound with Afi and other additive elements and coarsely crystallizes, it reduces the toughness of the alloy.In the present invention, the Cu content is 0.5wt.
, less than 1, the desired effect cannot be obtained in the above-mentioned action,
Sufficient strength cannot be obtained; on the other hand, Cu content is 3.5w
If it exceeds t,%, the toughness of the alloy will decrease significantly, therefore.

The Cu content should be limited within the range of 0.5-3.5 wt.%.

(3) Mg: Mg has the effect of increasing the strength of the Al2-Si alloy through solid solution hardening. Furthermore, by adding M to the Al1-Si alloy at the same time as CU, M has the effect of increasing precipitation hardening due to aging and increasing the strength of the Afl-Si alloy. On the other hand, Mg forms an intermetallic compound especially with Sl and reduces the toughness of the crystallized alloy No. 1.
Furthermore, when a tragic alloy containing Mg is melted,
The surface of the molten metal is easily oxidized, and an aluminum oxide film and a magnesium oxide film are formed on the molten metal surface. In the process of manufacturing the ^a8 alloy material by the rapid solidification powder metallurgy method, the above-mentioned oxide film is formed on the surface of fine droplets or liquid streams during melting, holding, and rapid solidification of the Al alloy. Then, it was obtained by quenching and hardening.

The above-mentioned oxides remain on the surface of coagulated bodies such as coagulated powders, flakes and ribbons. The remaining oxide.

When the solidified material is solidified and molded, it becomes an inclusion in the solidified and molded alloy member, significantly reducing the toughness of the alloy member. As mentioned above. The formation of an oxide film is influenced by factors such as the temperature of the molten metal, the atmosphere, and the Mg content. Therefore, these factors need to be strictly controlled. In the present invention, when the Mg content is 0.2 wt. If the Kg content is less than 2.0%, the desired effect described above will not be obtained and sufficient strength will not be obtained. If the content exceeds Out,%, the toughness of the alloy will decrease significantly due to the crystallization of intermetallic compounds and the increase in oxides. It should be limited within the range of Owt, %.

(4) Tl+V, Zr, Cr:Ti, V,
Zr and cr are hardly dissolved in Al, and often form intermetallic compounds with Al to coarsely crystallize. However, it contains relatively small amounts of Ti, V, Zr and Cr, ie, Tj.

About 0.2 wt. each for V and Zr. Below Z,
In a wrought Al2 alloy containing about 0.3 vtJ or less of Cr and produced by a conventional casting method at a solidification rate of about 0.degree. C./see or higher, the intermetallic compound of Al and the above elements is It is known that it is dispersed in Al soil as fine precipitates of about 0.1 μm or less, and that this is effective in increasing the strength and toughness of the AI2 alloy from room temperature to high temperature. In the rapid cooling wi homograin powder metallurgy method, the higher the solidification rate of the ingot alloy, the higher the T
Even if i, V, Zr, and Cr are added in amounts exceeding the above-mentioned conventional content limits, crystallization of coarse intermetallic compounds can be suppressed.

Effective in improving the strength and toughness of the alloy. However, by containing Ti, V, Zr, and Cr, the temperature at which an alloy completely melts becomes significantly higher.1For example, the melting point of Al-1,OwtJTi alloy is about 9
It reaches 00℃. For this reason, the inclusion of large amounts of Ti, V, Zr, and Cr not only leads to a decrease in the toughness of the alloy due to bulky products, but also leads to surface oxidation of the molten metal of the Afl alloy, especially the 〇 alloy containing Mg. and reduce the toughness of alloy parts obtained by rapid solidification powder metallurgy6.
In the present invention, when at least one element of Tx, vl Zr, and Cr is contained, each content is 0.03 wt. If it is less than 1, the desired effects described above cannot be obtained, and the effect of improving strength and toughness is insufficient. On the other hand, the contents of Ti, V and Zr are each 0.40wt. %, and Ti, V and Zr
The total content of Cr exceeds 0.40wt%, and
The content of 1. If it exceeds .owt.%, the toughness will be significantly reduced.

Therefore, the Ti, V, and Zr (7) contents are 0.
Within the range of 0.3 to 0.40 wt, L, however, the total content of Ti, V, and Zr must be limited to 0.40 wtJ or less, and the r content must be limited to 0.3 to 2.5 wt, respectively. Should.

(5) Ni: Ni is effective in improving the high temperature strength of the alloy.

Some casting alloys contain up to about 1.5 wt.% N.
It has been known that Ni is mainly effective in improving the high-temperature strength of the alloy. When manufacturing Al-5L alloy parts by rapid solidification powder metallurgy, adding Ni to Al-3L alloy will improve the high-temperature strength of the alloy due to the fine dispersion of Al-Ni intermetallic compounds. In addition, certain effects can be obtained in reducing the coefficient of thermal expansion and improving the wear resistance of the alloy. Further, when the A(1-5i alloy contains about 6.0 wt.% or less of Ni).

The melting point of the ^Q-5i alloy is lowered, and the increase in surface oxidation of the molten metal of the alloy is suppressed. Furthermore, by incorporating an appropriate amount of Ni into the Al-3L alloy, the toughness of the Al-3i alloy increases slightly, or does not affect the toughness8 In the present invention, the Ni content is 0.3 wt. If the Ni content is less than 2.5 wtJ, the desired effects of increasing the high temperature strength, decreasing the coefficient of thermal expansion, and improving the wear resistance of the alloy cannot be obtained. On the other hand, if the Ni content exceeds 2.5 wtJ, the toughness of the alloy decreases.

Therefore, the N1 content should be limited within the range of 0.3 to 2.5 wt.%.

(6) Fe, Mn: Controlling the content of Fe and Mn as inevitable impurities is effective in improving the toughness and thermal shock resistance of the alloy. When Fa and Mn are contained in the high SL^Q-5L alloy, Al1-5L-Fa and A(1-5i
--Intermetallic compounds crystallize in the form of Mn. Although these intermetallic compounds have certain effects on lowering the coefficient of thermal expansion and improving the wear resistance of the alloy, they lower the toughness and thermal shock resistance. In particular, when the molten Afi-5l alloy is solidified by rapid solidification powder metallurgy at a solidification rate in the range of 102 to 10"C/sse, the above-mentioned intermetallic compounds become coarse and acicular crystals, The toughness of the alloy is significantly reduced. In addition, Mn has a large effect of reducing the thermal conductivity of the alloy and deteriorating its thermal shock resistance. Therefore, in the present invention, the Fe content, which is an unavoidable impurity, is 0.6 w.
By limiting the content of 1 to less than 0.3wt and X, the toughness of the A11l-5l alloy member can be further improved.

Next, the reason why the conditions for rapid solidification and solidification molding were limited as described above will be described below.

Alloys having the above-mentioned composition range are melt-produced by known means. By limiting the composition range described above, the alloy can easily achieve completely uniform alloying of all components by melting at a predetermined temperature of less than about 800°C and around goo°C.

The melted alloy is formed into a powder or flake-like solidified body by cooling at a cooling rate of 103° C./see or higher.

The melted alloy is rapidly solidified with a suitable cooling medium, and because of the need to achieve rapid heat transfer to the cooling medium, the IX solid is formed into a powder or flake form.

The reason why a cooling rate of 102℃/98c or higher is required is as follows.
This is to avoid the fact that if the cooling rate is 102° C./see, coarse crystallized substances will be produced and the strength and toughness of the alloy will be insufficient.

As the rapid solidification method, it is preferable to use air atomization, which is the most economical and mass-producible method.

Other rapid solidification methods 5 Rapid cooling and solidification methods that can obtain higher cooling rates than air atomization methods, such as the single roll method, are also being put into practical use, but the single roll method is disadvantageous due to its poor economic efficiency, and is also excessively expensive. If rapid solidification is performed by changing the cooling rate, the S1 particles may become too fine, which may actually reduce the wear resistance of the alloy.

Next, the solidification molding conditions will be described.

In the present invention, it is necessary to hot-form the solidified body subjected to rAsl by rapid solidification, either as it is or after preforming, at least once at a temperature of 550° C. or lower.

The powder or flake-like solidified material is solidified and formed into an alloy member by an appropriate method, but assimilation of Al-gold alloy powder or flakes is inhibited by the presence of a strong oxide film, so It is important to destroy the oxide film by applying a relatively large compaction pressure to achieve metallic bonding between the powders or between the flakes. It is preferable to provide sufficient plastic flow during this hot forming to ensure the destruction of the oxide film formed on the alloy surface and the achievement of metallic bonding.
The hot forming temperature is preferably 350°C or higher,
However, hot forming at a lower temperature is possible under conditions where the forming pressure is high and plastic flow is sufficient. on the other hand,
If the hot forming temperature is too high, the intermetallic compounds will become coarse or partially remelted, reducing the strength and toughness of the alloy member. Therefore, the hot forming temperature is 550
It should be below ℃.

The hot forming described above can be performed by known means such as forging, extrusion, die forming, and isostatic pressing. Further, by performing cold preforming by die molding, isostatic pressing, etc. prior to hot molding, economical efficiency and mass productivity can be improved. Furthermore, degassing by evacuation or introduction of an inert atmosphere prior to hot forming or simultaneously with hot forming is effective in obtaining a sound alloy member.

As mentioned above, it is necessary for the solidified and formed alloy member to have a relative density of almost 100% of the theoretical density and to have substantially no voids inside the member. can be achieved.

[Example] Next, the present invention will be explained using examples.

10 kinds of alloy members of the present invention having the compositions shown in Table 1 -
10. and eight comparative alloy members NQI-8 were manufactured as described below. That is, 1 inventive alloy members &1 to 10 and comparative alloy members Milli to 3, each melted and held at a temperature approximately 100°C higher than the melting point for each alloy composition estimated in advance so as to have a predetermined composition.
The holding temperature for No. 8 was about 760-840°C. On the other hand, the holding temperature for comparative alloy members NQ4 to 7 was 870.
Next, the molten alloys of each composition were solidified into rapidly solidified powder by air atomization, which required a temperature of ~940°C. Then, from the solidified powder, powder having a size of 132 meshes (sieve opening 500 μm) was sorted out by sieving. When a part of the 132 mesh powder was further sieved and the particle size distribution was examined, the cumulative weight percent of the 1350 mesh powder (sieve opening 44 μm) for each composition was approximately 50. ~60% 1 Then, a small amount of rapidly solidified powder of each composition was embedded in the resin, polished and optical! The cross-sectional structure of the powder was examined using a 11-microscope, and the secondary dendrite arm spacing was measured to investigate the cooling rate, and the cooling rate of the powder with a diameter of approximately 500 μm was approximately 102° C./see.

These rapidly solidified powders were vacuum hot pressed using a special mold at a temperature of 400 DEG C. to degas them, and at the same time, they were solidified into a billet having a relative density of about 90% and a diameter of 200 cm. These billets were molded by hot extrusion at a temperature of 450°C.

A round bar with a diameter of 40 na was produced at an extrusion ratio of 25. No particular tempering was performed, and the extrusion was left as it was (Fil).

For comparison with conventional Al-5i alloy for casting, JISA
C8A and JIS AC9A (component compositions are also shown in Table 1) were melted, cast into a JIS boat shape, and tempered to obtain a 511 quality.

The above-mentioned alloy member islands 1 to 10 of the present invention. Comparison alloy parts magic 1
~8, and comparative cast members JIS AC8A and A
C9A was subjected to the following tests to examine its tensile properties, toughness, abrasion resistance, and thermal expansion. The results of these tests are shown in Table 2.

(1) Tensile properties Each member was subjected to a tensile test at room temperature and 300° C., and the tensile strength (kgf/m”) and elongation (%) of each member were investigated.

(2) Toughness Each member was subjected to a Charpy impact test at room temperature, and the Charpy impact value (kg-m/aJ) was determined.

(3) Abrasion resistance A dry type wear test was performed on each component.

The specific wear amount (101■'/kg) was investigated. What are the test conditions?

The mating material is FC30g steel, surface pressure is 2kgf/d,
The sliding distance was 200 m, and the sliding speed was 3.8 m/sec.

(4) Thermal expansion The thermal expansion of each alloy member in the temperature range of 25 to 300°C was measured multiple times, and the average coefficient of thermal expansion (10-7°C) was determined.

As is clear from Table 1 and Table 2, the alloy members &1 to 10 of the present invention all have a tensile strength of about 40k at room temperature.
gf/■1 or more, conventional 1-51 alloy JIS for casting
The tensile strength of AC8A and AC9A is 10kgf/1
JXS AC8A exceeds I12 and grows by more than 4%
This is more than three times as large. Furthermore, the tensile strength at 300℃ is 1
At 2kgf/■2 or more, it is improved by about 50% or more compared to AC8A.

The Charpy impact value of the invention alloy member &1 to 10 is 1.8
kg-m/aj or more, it has a toughness comparable to that of conventional high-strength elongated Al-gold alloys (not shown).

The specific wear amount and coefficient of thermal expansion of the alloy members NG1 to NG10 of the present invention are almost comparable to JIS AC9A.

JIS AC9A has extremely poor toughness due to the presence of coarse Si crystallized substances, and also has major problems with machinability, so its uses are extremely limited.

In the alloy of the present invention, the 81 crystallized substances are made fine by the rapid solidification method, and the toughness and machinability are significantly improved, and the alloy exhibits properties equivalent to or better than JIS AC9^ in terms of wear resistance and thermal expansion. Therefore, its application range is very wide.

In the alloy member of the present invention, hot forming such as extrusion is performed, and then the obtained alloy member is subjected to tempering treatment to obtain T5 refining, or alternatively, hot forming is performed in the same manner, followed by solution treatment and quenching. Treated and left at room temperature
It is also possible to increase the strength from room temperature to about 300° C. at the expense of some toughness, by heat treatment such as 4 heat refining, and further tempering to obtain T6 or T1@ quality after standing at room temperature.

On the other hand, comparative alloy members Mal~8 were prepared by a rapid solidification powder metallurgy method in the same manufacturing method as the alloy member of the present invention, but in terms of chemical composition components, they were all outside the limited range of the present invention. There is.

Comparative alloy member Motion 1, which did not contain the transition metal elements Ti, V, Zr, Cr and N1, had poor tensile strength at a temperature of 300°C.

Comparative alloy member &2, in which the S1 content was higher than the limited range of the present invention, had a low Charpy impact value and poor toughness.

Comparative alloy member 3, in which the Ni content was higher than the limited range of the present invention, had a low Charpy impact value and poor toughness. The reason for this is the crystallization of coarse intermetallic compounds.

Comparative alloy member with high Cr content outside the limited range of the present invention &4. Comparative alloy member Nn5. whose Zr content is higher than the limited range of the present invention. Comparative alloy member &6 whose total content of Ti, V and Zr is outside the limited range of the present invention is
All had low Charpy impact values and poor toughness.

The reason for this is that the amount of oxides in the powder increased as a result of the crystallization of coarse intermetallic compounds and the increase in melting and holding temperature of the first alloy.

Comparative alloy member 47 in which the content of Fa as an impurity exceeds the regulation range of the present invention. Comparative alloy member NQ8, in which the Mn content exceeds the regulatory range of the present invention, has a low Charpy impact value and poor toughness, indicating that an increase in Fe or n content lowers the Charpy impact value. There is.

[Effects of the Invention] As explained above, according to the manufacturing method of the present invention, it has wear resistance equal to or higher than that of conventional Al-5i alloy for casting, has a low coefficient of thermal expansion, and has remarkable toughness. Improved AΩ
-5i alloy members are provided.

In addition, the A (A-5i alloy member of this invention has improved machinability and high-temperature strength. Therefore, for example, if it is used as a material for a piston of a reciprocating internal combustion engine such as an automobile or a two-axle vehicle, it can improve dimensional accuracy. By improving and reducing weight,
It becomes possible to improve the characteristics of the internal combustion engine. Also,
It can also be applied to sliding parts of industrial equipment, for which it has been difficult to use lightweight aluminum alloy members due to lack of toughness. As described above, the present invention brings about a number of industrially useful effects.

Applicant: Mitsubishi Aluminum Corporation Agent Ushio Tani Kyo Tsuo

Claims (1)

[Claims] 1 Si: 18 to 28 wt. %, Cu: 0.5-3.5wt. %, Mg: 0.2-2.0wt. %, at least one element selected from the group consisting of: Ti: 0.03-0.40wt. %, V: 0.03-0.40wt. %, Zr: 0.03-0.40wt. %, Cr: 0.03-1.00wt. %, Ni: 0.3-2.5wt. %, however, the total amount of Ti, V and Zr is 0.40wt.
% or less, and the remainder: Al and unavoidable impurities. Next, the Al alloy is rapidly solidified at a cooling rate of 10^2°C/sec or more to prepare a powder or flaky solidified body, and then the solidified body is The alloy member is characterized by having a low coefficient of thermal expansion and excellent wear resistance, which is obtained as it is or by preforming and hot forming at least once at a temperature of 550° C. or lower to obtain an alloy member of a predetermined shape. Moreover, a method for manufacturing an Al-Si alloy member having high toughness. 2 The content of Fe and Mn as the unavoidable impurities is Fe: 0.6 wt. %, and Mn: 0.3wt. %. The method for producing an Al-Si alloy member according to claim 1, which has a low coefficient of thermal expansion, excellent wear resistance, and high toughness.