JPS62294144A - Production of aluminum alloy having excellent high-temperature strength - Google Patents

Abstract

PURPOSE:To easily produce an Al alloy molding having excellent high-temp. strength by subjecting alloy fibers consisting of specifically composed Fe and Al obtd. by a melt-spinning method to cold compression molding and drying then to hot extrusion molding. CONSTITUTION:The alloy consisting of 3-9wt% Fe, and if necessary, further >=1 kinds among 10-25% Si, 1-5% Mn, 1-5% Ni, 1-5% Cu, and 0.1-5% Mg and the balance Al is made into the alloy fibers by the melt spinning method of injecting said alloy in the molten state directly into the atm. air and quickly solidifying the melt. Such fibers are used as a starting raw material and are preformed by cold compression. After the above-mentioned preform is dried, the preform is subjected to the hot extrusion molding at about 400 deg.C. The Al alloy molding which is uniformly dispersed with the fine intermetallic compd. of Fe in the matrix and has the excellent mechanical strength in a high-temp. region is thus obtd.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing an aluminum alloy with excellent high-temperature strength.

<Prior art and its problems> JIS standard AC8A,
There are alloys such as AC9 and Renjin 390, but since these alloys do not have a very high withstand temperature, research has been actively conducted in recent years to further improve the high-temperature strength using the rapid solidification method.

However, the currently used rapid solidification method uses powder or flake raw materials based on the idea of cooling the rapidly solidified material used as a raw material as rapidly as possible. Powder and flake materials can certainly increase the cooling rate, but because the surface area is too large, there are many impurities such as oxides attached to the surface, and the subsequent hot forming step It was confirmed that because the area that must be closely bonded becomes large, it is not possible to expect a significant improvement in the strength of the molded product itself.

Of course, if measures such as cooling in an inert gas are taken when obtaining powder or flakes, the amount of oxides on the surface will be reduced, but it will be more expensive and less effective.

<Means for solving the problems> The present invention aims to eliminate the above-mentioned problems and provide a method that can easily produce a molded product with excellent high-temperature strength. Fe3 obtained by
Using an alloy fiber having a composition of ~9% by weight and the balance being Al as a starting material, the starting material is cold compression molded and then dried,
3 to 9% by weight of Fe and 10 to 25% by weight of Si obtained by a method for producing an aluminum alloy with excellent high-temperature strength and a melt spinning method, which is characterized in that hot extrusion is then carried out.

1-5% by weight Mn, 1-5% by weight Ni, 1-5% by weight
One or more of 5 weight% Cu, 0.1 to 5 weight% Mg, and the remainder! This method of producing an aluminum alloy with excellent high-temperature strength is characterized by using alloy fibers having a composition as a starting material, cold compression molding the starting material, drying, and then hot extrusion molding.

<Function> The method of the present invention can produce alloy fibers obtained by directly jetting a molten alloy into the atmosphere and rapidly solidifying it, as disclosed in, for example, Japanese Patent Application Laid-open No. 82411/1987, which the applicant previously filed. The major advantage is that the starting material is The alloy m fibers obtained in this way form fine intermetallic compounds of Fe and other alloying elements by rapid solidification.
It not only has the effect of improving mechanical strength in a high temperature range, which is unique to a so-called rapidly solidified material, but also differs from ordinary powder or flake-like rapidly solidified materials in that it has a smaller specific surface area. Therefore, the amount of impurities adhering to the surface of oxides, etc. is small, and the area that must be closely bonded to each other during subsequent hot extrusion molding is also reduced, which greatly improves the high-temperature strength of the resulting molded product. .

The reasons for limiting the composition of the aluminum alloy used in the present invention are as follows.

First, Fe forms fine intermetallic compounds through rapid solidification and is uniformly dispersed in the matrix, improving mechanical strength in high temperature ranges, but if the amount is less than 3% by weight, the effect is not sufficient; Even if the weight percentage is exceeded, there is little increase in high-temperature strength, and conversely, the elongation rate decreases and workability deteriorates.
~9% by weight. Next, Si, M added in addition to Fe
Regarding n, Ni, Cu, and Mg, at least one of these is added depending on the use, and Si (,) is used to improve high-temperature strength, reduce the coefficient of thermal expansion, and improve wear resistance. However, such an effect is hardly expressed at less than 10% by weight, and conversely there is not much difference even when it exceeds 25% by weight.
It forms a moldy intermetallic compound that coexists with the metal and increases high-temperature strength, but if it is less than 1% by weight, the effect is not sufficient, and if it exceeds 5% by weight, no significant improvement in high-temperature strength can be expected.
Next, Cul has the effect of improving room temperature and high temperature strength,
If it is less than 1% by weight, the effect will be small (on the contrary, if it exceeds 5% by weight, the corrosion resistance and workability will deteriorate. Mi has the effect of improving room temperature strength, but if it is less than 01% by weight, the other effects will be small). Even if it exceeds 5% by weight, the effect will not increase much and the processability will be poor.

<Example> Examples of the present invention will be described in detail below along with comparative examples.

Alloys having compositions as shown in Table 1 No. 1 to No. 14 are jetted into the atmosphere from a molten state by a method shown in JP-A-59-82411, and rapidly solidified. Alloy fibers with an average fiber diameter of 100 μm were obtained. Is this alloy fiber made by cold compression? ) 50n+mφX IIOm
After preforming into mL (filling rate approximately 70%), it was dried at 200°C for 2 hours, and the preformed material was subsequently hot extruded at 400°C to produce a round bar of 20III1φ (extrusion ratio 6.2). . These extruded materials were heated at 300°C for 72 hours and then cooled to room temperature to prepare high-temperature tensile test pieces.
The results of the tensile test at 0°C and the mechanical properties are shown in the second
Shown in the table.

In addition, conventional alloys No. 15 to No. 17 are melted in a graphite crucible, subjected to prescribed molten metal treatment, and then cast into a mold to form an ingot. After T6 treatment, the same high temperature is applied. The results of the tensile test are shown in Table 2.

As is clear from Table 2 of B, alloy N, which is the alloy of the present invention
Nos. 1 to 11 have high-temperature strength that is greatly improved compared to conventional heat-resistant alloys &15 to No. 17, and similarly alloy fibers are used as starting materials, but the alloys of the present invention Nα12~N, which is a comparative alloy with a different composition.

Compared to No. 14, it can be seen that the balance between tensile strength and elongation is better.

<Effects of the Invention> As described above, according to the method of the present invention, since alloy fibers produced by melt spinning are used as the starting material, the characteristics as a rapidly solidified material are sufficiently maintained, while forming It is possible to reduce impurities contained in the body as much as possible, and also takes advantage of the feature that the area that must be closely bonded is small, resulting in a molded product with excellent high-temperature strength. Furthermore, the method of the present invention has the advantage that alloy fibers with arbitrary diameters and aspect ratios can be obtained by changing the melt-spinning conditions, so that molded bodies with various porous properties can be produced depending on the use of the final product. It also has

Claims (1)

[Claims] 1. An alloy fiber having a composition of 3 to 9% by weight of Fe and the balance of Al obtained by a melt spinning method is used as a starting material, and the starting material is cold compression molded and then dried, and then hot A method for producing an aluminum alloy with excellent high-temperature strength, which involves extrusion molding. 2. 3 to 9% by weight of Fe obtained by melt spinning method;
10-25 wt% Si, 1-5 wt% Mn, 1-5
wt% Ni, 1-5 wt% Cu, 0.1-5 wt%
A high-temperature method characterized by using an alloy fiber having a composition of one or more types of Mg as a starting material and the balance Al, the starting material being cold compression molded, dried, and then hot extrusion molded. A method of manufacturing aluminum alloy with excellent strength.