JP2001316746A - Aluminum alloy having high strength, wear resistance and slidability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy having high strength, wear resistance and slidability by adding Zn, Cu, B and Mg to a hypereutectic Al-Si alloy. SOLUTION: This aluminum alloy having high strength, wear resistance and slidability has a composition containing, by weight, 12 to 16% Si, 5 to 15% Zn and 1 to 5% Cu and containing, at request 0.01 to 0.1% B and/or 0.005 to 0.08% Mg, and the balance Al with inevitable matters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum-based alloy having high strength and excellent wear resistance and slidability.

[0002]

2. Description of the Related Art In recent years, as the use of aluminum castings with light weight and good workability is increasing, hypereutectic Al-Si alloys are known as alloys having excellent wear resistance. Standard aluminum alloys are also standardized as A390, and are widely used for various mechanical parts such as compressor parts and cylinder blocks that require wear resistance. For the purpose of high-temperature strength and wear resistance, there have been proposed aluminum-based composite materials containing SiC and fibers, and high-strength aluminum alloys manufactured by powder metallurgy.

[0003] For example, 7000 manufactured by the spray deposition method
Based on the system, in weight%, Si: 3-22% and Cu:
An aluminum-based alloy containing 0.2 to 5%, Mg: 1.2 to 6%, and Zn: 5 to 15% is introduced in JP-A-5-179384. In Japanese Patent Application Laid-Open No. 8-109429, weight%
Thus, Si: 6 to 10%, Zn: 10 to 25%, and Cu: 0.5 to
3.0% and Mn: 0.1 to 0.5% and Mg: 0.02 to 0.
It is described that an Al-Zn-Si alloy containing 5% is an aluminum-based alloy for die-casting having high strength and excellent wear resistance and suitable for sliding parts.

[0004] However, conventional hypereutectic Al-Si alloys have excellent wear resistance due to primary Si grains in the matrix, but under conditions of wear and lubrication, primary Si grains may fall off during sliding. As a result, adhesive wear or abrasive wear may occur, resulting in poor conformability. In addition, composite materials and
The method using the spray deposition method described in 179384 publication (the method of depositing a powdered aluminum alloy and hot working the obtained deposit) and the like are difficult to manufacture under limited conditions and the like, High production cost and poor productivity.

On the other hand, when the aluminum-based alloy described in JP-A-8-109429 is used as a sliding member,
Since the Si content is regulated in the range of 6 to 10% by weight, the strength is high, but the wear resistance is poor. Besides, Zn content is 10 ~
Since it is as high as 25% by weight, there is a problem that the strength is easily deteriorated at high temperature and the wear resistance is also reduced.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem.
It is an object of the present invention to provide an aluminum-based alloy having high strength and excellent wear resistance and slidability by adding Zn, Cu, B, and Mg to a hypereutectic Al-Si alloy.

[0007]

According to the present invention, there are provided (1) by weight: 12 to 16% of Si, 5 to 15% of Zn, and 1 to 5% of Cu.
A high-strength aluminum-based alloy having a composition consisting of Al and inevitable substances, the balance being excellent in wear resistance and slidability. (2) By weight%, Si: 12-16%, Zn: 5-15%, Cu: 1-5%
And B: an aluminum-based alloy containing 0.01 to 0.1%, with the balance being Al and unavoidable substances, and having high strength and excellent wear resistance and slidability. (3) In weight%, Si: 12-16%, Zn: 5-15%, Cu: 1-5%
And B: 0.01-0.1% and Mg: 0.005-0.08%, with the balance being
It is an aluminum-based alloy having a composition consisting of Al and unavoidable substances and having high strength and excellent wear resistance and slidability. The alloy used in the present invention, that is, an alloy having high strength and excellent wear resistance and slidability, which was not found in conventional aluminum cast alloys, was found by incorporating the components and compositions described below.

Hereinafter, the function of each element will be described. Si: 12 to 16% by weight Si is an essential alloy element effective for improving wear resistance.
If the content is less than 12% by weight, the wear resistance will be insufficient. Conversely, if the Si content exceeds 16% by weight, the primary crystal Si grains will be large and will attack the mating material of the sliding part, and the wear resistance and The slidability deteriorates. In addition, the liquidus temperature of the alloy rises due to the increase in the amount of Si, so that the melting and casting properties deteriorate and the mechanical properties decrease.

Zn: 5 to 15% by weight Zn is a solid alloy in the primary crystal and is an effective alloying element for improving tensile strength, hardness and slidability, and also lowers the melting point and improves castability. . If the Zn content is less than 5% by weight, the effect is small, and if the Zn content exceeds 15% by weight, tensile strength and toughness are reduced, and slidability is also deteriorated.

Cu: 1 to 5% by weight Cu is an alloy element effective for improving strength, hardness and wear resistance, and the effect of adding Cu becomes remarkable in a solid solution state. If the Cu content is less than 1% by weight, the effect is small, and if the Cu content exceeds 5% by weight, toughness and corrosion resistance deteriorate. When a large amount of Cu is contained, an intermetallic compound is formed at the time of casting, and casting cracks easily occur.

B: 0.01 to 0.1% by weight B is effective in improving the structure of the hypereutectic Al-Si alloy into acicular eutectic Si by adding primary Si grains in the coexistence with Zn. It is an effective alloying element for improving wear properties. When the B content is less than 0.01% by weight, the effect is small, and when the B content exceeds 0.1% by weight, mechanical properties are deteriorated.

Mg: 0.005 to 0.08% by weight Mg is an effective alloy element for improving the hardness and mechanical strength of an aluminum alloy. If the Mg content is less than 0.005% by weight, the effect is small. If the Mg content exceeds 0.08% by weight, the mechanical properties are deteriorated, and the wear resistance and slidability are also deteriorated.

Examples 1 to 4 and Comparative Examples 1 to 8 An Al alloy having the chemical composition shown in Table 1 was melted by a usual melting method, and a mold was used as a JIS No. 4 tensile test piece (parallel part φ).
14mm, distance between gauges 50mm, length 205mm) and (width 25mm, thickness 15m)
m, 195mm in length) at a casting temperature of 700-740 ° C. From this slab (width 10mm, thickness 6mm, length 37m)
An abrasion test piece having the dimensions of m) was cut out. For comparison, the alloys of the present invention deviated from the composition range of the alloys of Comparative Example 1 to
7 and Comparative Example 8 (ASTM standard aluminum alloy: A39
0) was similarly prepared.

Test Examples Mechanical tests were carried out on the alloys shown in Table 1 using these test pieces. Table 2 shows various mechanical properties obtained for these alloys. Further, the wear amount was measured with an Amsler type wear tester. The test was performed under rolling conditions with rolling wear. The mating material is SKD11, friction speed of 0.4m / s, 3000m
And the amount of wear at a load of 1960 MPa were measured. Table 3 shows the results.

The following is evident from Table 2. Invention alloy 1
The strength at ~ 4 is excellent at 205-225 MPa and the elongation is 0.6-0.9%, and the hardness is Hv120-150, which is equal to or better than that of ASTM standard aluminum alloy: A390. Comparative alloy 1 has low strength. Comparative alloy 2 had excellent hardness but low elongation and lacked toughness. Comparative Alloy 3 has low strength and poor hardness. Comparative alloy 4 has insufficient strength and elongation. Comparative alloy 5 has excellent hardness but low elongation and lacks toughness. Comparative alloy 6 is insufficient in both strength and elongation. Comparative alloy 7 is not practical because of low elongation and poor toughness.

The following was found from Table 3. All of the alloys of the present invention have excellent wear resistance. Further, by adding B, wear resistance and slidability are further improved. Comparative alloys 1-4, 7 and 8 (ASTM standard aluminum alloy: A390) have low wear resistance. Comparative alloys 5 and 6 had good abrasion resistance, but were not practical due to insufficient mechanical properties as described above. Therefore, when the results of the tests in Tables 2 and 3 are combined, the alloy of the present invention has further improved wear resistance by adding B, and has a mechanical strength (tensile strength and tensile strength) by adding Mg. Hardness) without substantially deteriorating the wear resistance, and it has become clear that the mechanical properties, especially the wear resistance, are superior to those of the conventional alloy.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

1 to 3 are micrographs of the metal structure of the alloy of the present invention. To obtain good wear resistance and slidability, 1
Needle-like eutectic Si having a diameter of 0 μm or more is preferable, but this is developed in the alloy of the present invention. The granular crystallization product shown in FIG. 1 was primary crystal Si, and the acicular crystallization product was eutectic Si, and the acicular eutectic Si crystallized in 10 to 30 μm. In FIG. 2, no granular crystallized matter, that is, primary crystal Si observed in the invention alloy 1 by adding B is observed, and acicular eutectic Si is dendritic over the entire surface.
100 μm was crystallized. In FIG. 3, it was confirmed that the addition of B and Mg did not affect the crystallization of acicular eutectic Si, and that acicular eutectic Si had crystallized in a dendritic shape on the entire surface in a 50 to 100 μm shape. As described above, in the alloy of the present invention, crystallization develops in a dendritic manner. On the other hand, Comparative Example 8 (ASTM
For standard aluminum alloy: A390), acicular eutectic S
i is not crystallized in a dendritic manner.

[0021]

The aluminum alloy of the present invention has excellent mechanical properties with high strength and further exhibits excellent wear resistance and slidability. For this reason, for example, shift forks for manual transmissions that require high wear resistance,
It is suitable for various sliding parts and the like, including automobile parts such as compressor cylinders and oil pump housings, and by applying the aluminum alloy of the present invention,
Further weight reduction of these mechanical parts can be realized.

[0022]

[Brief description of the drawings]

FIG. 1 is a micrograph showing a 200 times metallographic structure of Invention Alloy 1.

FIG. 2 is a micrograph showing a 200 times metal structure of Invention Alloy 3.

FIG. 3 is a micrograph showing a 200 times metal structure of Invention Alloy 4.

FIG. 4 Comparative Example 8 (ASTM standard aluminum alloy: A39)
Micrograph showing 200 times the metallographic structure of 0)

Claims (3)

[Claims] Claims: 1% by weight of Si: 12 to 16% and Zn: 5 to 15%.
Cu: An aluminum-based alloy containing 1 to 5%, with the balance being Al and unavoidable substances, characterized by high strength and excellent wear resistance and slidability. 2. In weight%, Si: 12 to 16% and Zn: 5 to 15%.
An aluminum-based alloy having high strength, excellent wear resistance and excellent slidability, characterized by containing 1 to 5% of Cu and 0.01 to 0.1% of B and having a balance of Al and inevitable substances. 3. The composition according to claim 1, wherein the content of Si is 12-16% and the content of Zn is 5-15%.
Cu: 1-5%, B: 0.01-0.1%, Mg: 0.005-0.08%, with the balance being Al and unavoidable substances, characterized by high strength, wear resistance and slidability Excellent aluminum base alloy.