JPS6283444A - Heat and wear resistant aluminum alloy - Google Patents

Abstract

PURPOSE:To provide superior heat and wear resistances to an Al alloy contg. Si, Fe and Ni by properly regulating the ratio between Fe and Ni as transition elements in the alloy and adding a specified amount each of Cu and/or Mg. CONSTITUTION:The ratio between Fe and Ni in an Al alloy consisting of 5-40wt% Si, 2-15wt% Fe+Ni and the balance Al with inevitable impurities is regulated to 1:4-4:1, and 0.1-8wt% each of Cu and/or Mg is added to the alloy. The resulting Al alloy has high tensile strength at high temp., superior shock and wear resistances.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improving the strength of AQ-8t-Fe-Ni heat-resistant and wear-resistant aluminum alloys.

Problems to be solved by conventional techniques and inventions In recent years, materials for automobile engines and aircraft have become energy-saving and
The need for higher performance has led to smaller size, lighter weight, and higher output, and along with this, the materials used for pistons, etc. are required to withstand use under harsher conditions of higher loads and higher temperatures than before. There is.

Taking an automobile piston as an example, which requires heat resistance and wear resistance, conventional aluminum alloys for pistons are AC8A, AC
AQ-8i cast material such as 8B is used.

However, when large amounts of Si, Fe, Ni, etc. are added to further improve wear resistance and heat resistance in the casting method, properties such as strength, elongation, and toughness deteriorate significantly due to element segregation and coarsening of the initial product. However, the required characteristics cannot be fully satisfied.

In recent years, development of heat-resistant and wear-resistant aluminum alloy materials with pore-free, uniform, fine crystal grains has begun using quenched high-Si-containing aluminum alloy powder as a starting material and hot extrusion methods.

Although the alloy made in this way contains a large amount of elements such as Si, Fe, and Ni as a solid solution due to the expansion of the solid solubility limit due to the effect of rapid solidification, it does not have the coarse grains seen in cast materials. Almost no precipitates or segregated substances occur.

However, when rapidly solidified powder is used, there are problems such as grain growth due to heating during molding for densification, which naturally limits the manufacturing method. For example, in heat-resistant and wear-resistant alloys manufactured by quenched powder metallurgy, the main amount is 20 to 30% by weight.
Aluminum alloys containing transition elements such as Si and 2 to IO weight percent of Fe or Ni are produced by hot extruding rapidly solidified powder, but the aluminum alloys obtained in this way have improved heat and wear resistance. The material elongates and the toughness significantly decreases. The cause of this is initial product precipitates and intermetallic compounds generated during hot extrusion. This low elongation and low toughness limit the applications of highly alloyed aluminum alloys produced by quenched powder metallurgy.

Means for Solving the Problems The present invention was made in order to improve the toughness and elongation of a highly alloyed aluminum alloy consisting of AQ + s + + and Fe or Ni elements.
By containing the transition elements e and Ni in an appropriate proportion, conventional AQ-8i-Fe or AQ-3t-Ni
The purpose of this invention is to improve the toughness of a highly alloyed heat-resistant and wear-resistant aluminum alloy mainly composed of three elements, and at the same time to improve its strength at room temperature or high temperature.

Si, which is an additive element in the aluminum alloy of the present invention, is effective in improving wear resistance. When a large amount of Sj is added to AQ, it precipitates as primary Si particles during solidification, improving the wear resistance of the alloy. The size and amount of the initial Si powder particles largely depend on the solidification rate of the alloy and the amount of Si added; the faster the solidification rate, the smaller the Si primary crystal particles, but as the amount of Si increases, the larger the Si primary crystal particles become. This limit is set at 40% by weight. S
If the amount of i exceeds this range, the initial Si powder particles will become coarse, resulting in a significant decrease in alloy strength. Moreover, if it is less than 5% by weight, the effect of improving wear resistance is very small, making it difficult to use it as a wear-resistant material.

Fe and Ni improve the heat resistance of aluminum alloys, but the effect of Fe is greater. However, the elongation and toughness are lower than that of NNI. This Al2-8i-Fe and AQ-8i-N
By replacing some of the Fe and Ni in the i alloy with Ni and Fe, an alloy with better properties than the original alloy is obtained. In other words, the AQ-8i-Fe-Ni alloy has slightly lower heat resistance than the AQ-8i-Fe alloy, but has improved elongation, and has improved heat resistance, although the elongation has slightly lower than the AQ-8i""Ni alloy. will improve. Of particular note is the toughness of Al2-8i-Fen Ajl.
It is higher than either Si-Ni. The reason for this is thought to be as follows.

The solid solubility limit in AQ for both Fe and Ni is very small at 0.04% by weight, but the solid solubility limit is expanded by rapid solidification, and the maximum solid solubility range is 4 to 12% by weight for Fe and 3 to 15% for Ni.
It is known that % by weight. The supersaturated portion of Fe or Ni added to AQ that exceeds the solid solubility limit expanded by rapid cooling precipitates as precipitates such as compounds, which significantly reduces the toughness of the alloy. However, some of the Fe is N
By replacing part of Ni with Fe, the degree of supersaturation of each element can be reduced, and the precipitates can become fine and uniform. For this reason, the toughness is thick (and is thought to be improved). Although only Fe and Ni are shown here, the same idea can be applied to combinations with other elements, so it is expected that the toughness will be improved by element replacement. This AQ-8i-Fe-Ni alloy is AQ
Fe:Ni exhibits almost the same toughness value as -81-Ni alloy
The ratio ranges from 1:4 to 4:1.

Most preferably, Fe:Ni is 1=1. Fe+Nj
If the amount of FenNi is 12% by weight or more, both toughness and elongation will be significantly reduced, so the amount of FenNi is set to be 12% by weight or less. Furthermore, if the FenNi amount is 2% by weight or less, the effect of improving heat resistance is almost lost, so the FenNi amount is set to be 2% by weight or less.

Other cuts Mg+ Zn+ TL Cr, Zr+
Cur Mo, W.

Among the group consisting of Ce + , Cur Mg + Zn is mainly an age hardening element and improves the strength and hardness of the alloy up to about 200'C. At low temperatures of 200°C or less, the hardness increases due to aging, and the wear resistance is also significantly improved. The elemental amounts for these effects to be fully exhibited are 0.5 to 6.0% by weight for Cu and 0.1% for Mg.
-8.0% by weight and Zn is 0.05-0.5% by weight
It is. Also T I+ Crl Z rl Cur M
o+ W and Ce are effective in improving heat resistance. These elements improve heat resistance by forming stable intermetallic compounds in the alloy, but when added in large amounts, the amount of intermetallic compounds increases, significantly impairing the elongation toughness of the alloy.
In addition, if the amount is too small, the effect of improving heat resistance will not be sufficiently exhibited.

As mentioned above, AI containing a large amount of Sin Fen Ni etc.
When manufacturing two alloys by conventional melting and casting methods,
Because the solidification rate is slow (1° C./sec or less), the initial N Si material and intermetallic compounds become coarse, and the material strength significantly decreases.

Methods for suppressing coarse precipitates include the rapid solidification method and the hot top method, but the hot top method has a low limit on the amount of elements added. In the quenching method, if the material is quenched at a solidification rate of 100° C./sec or more, the size of the precipitates will be about 50 μm at maximum within the range of the amount of added elements shown in the present invention, and will not cause a significant deterioration of material properties.

Such a solidification rate can be easily achieved by turning the alloy from a molten state into a powder using an atomization method or the like. Considering the moldability or solidification rate of the powder, the particle size of the powder suitable for use is preferably 40 mesh or less. Since these high alloy powders have high hardness as powder particles themselves, it is necessary to apply strong plastic working such as hot extrusion to form an alloy.

EXAMPLES Alloy powders having the composition shown in Table 1 were produced by air atomization, and these powders were hot extruded at a temperature of 450°C to form extruded materials. Table 2 shows the properties of the obtained material. AQ- produced by the same method for comparison
8t-Fe and AQ-3i-Ni-Fe alloys were also described. Those containing aging elements such as Cu9Mg were subjected to solution death at 470°C for 2 hours, cooled in water, and then subjected to aging treatment at 170°C for 6 hours.

As can be seen from the table, the alloy to which the age-hardening elements of Cu + Mg are added has a higher tensile strength at room temperature, and its wear resistance is lower than that of AQ-8i-F without Cu + Mg.
It is higher than e-Ni alloy.

The tensile strength at 300° C. is improved in those to which a transition element such as Crl Z rl C01Mo is added.

Applications of these alloys include heat-resistant and wear-resistant parts such as engine parts such as automatic type parts, fan rods, pistons, and vanes of parts of compressors. By using the aluminum alloy of the present invention in these parts, it will be possible to further reduce the weight and to develop products with even higher performance.

Effects of the Invention As mentioned above, the aluminum alloy of the present invention has high tensile strength at high temperatures and excellent impact resistance and abrasion resistance.

6. Subject of amendment 2, Title of invention Heat-resistant 1fF1 Abrasive aluminum alloy 3. Relationship with the case of the person making the amendment Patent application Name: President of the Aluminum Powder Metallurgy Technology Research Association Osamu Saeki 4, Agent address: Osaka Sumitomo Electric Industries, Ltd., 1-1-3 Shimaya, Konohana-ku, Japan, January 28, 1985, 7, the following line is inserted between lines 13 and 14 on page 2 of the statement of contents of the amendment.

"3. Detailed explanation of the invention"

Claims (4)

[Claims] (1) In an aluminum alloy containing Si, Fe, and Ni, the Si element is 5.0% to 40% by weight, and the Fe and Ni elements (Fe + Ni) are 2 to 15% by weight,
and the ratio of Fe and Ni is Fe:Ni = 1:4 to 4:1, and 0.1 to 6.0% by weight of Cu and 0.
．． One or two types of Mg from 1 to 8.0% by weight
1. A heat-resistant and wear-resistant aluminum alloy, characterized in that the remainder is substantially made of aluminum. (2) Si from 5.0% to 40% by weight, Fe and N
i containing 2 to 15% by weight of (Fe+Ni), and Fe
and Ni in a ratio of Fe:Ni=1:4 to 4:1, and also 0.5 to 6.0% by weight of Cu, 0.1 to 8.0% by weight of Mg, and 0.05% by weight. to 5.0% by weight of Zn
and 0.05 to 5.0% Ti, 0.05 to 60 wt% Cr, 0.05 to 3.0 wt% Zr, and 0.05 to 5.0 wt% Co. 4.0% by weight M
o and 0.05 to 40 wt% W and 0.05 to 4.0
1. A heat-resistant and wear-resistant aluminum alloy, characterized in that it contains one or more members from the group consisting of Ce and Ce in an amount of % by weight, and the remainder consists essentially of aluminum. (3) Obtained by solidifying at a solidification rate of 100°C/sec or more, or the size of intermetallic compounds and precipitates is 50 μm
The heat-resistant and wear-resistant aluminum alloy according to claims 1 and 2, characterized in that: (4) Claim 1 obtained by molding an atomized powder with a particle size of 40 mesh or less or a powder in which the particle size of primary crystal precipitates is 50 μm or less by hot plastic working.
The heat-resistant and wear-resistant aluminum alloy according to item 1 or 2.