JPH0234740A - Heat-resistant aluminum alloy material and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture the title alloy material having excellent compactibility by rapidly cooling the molten metal of an Al alloy constituted of specific compsn. at specific cooling speed into solidified powder, compacting the powder and subjecting it to age-hardening treatment at specific temp. CONSTITUTION:The molten metal of an Al alloy contg., by weight, 0.7 to 8% Cr, 0.3 to 8% Zr and 0.5 to 8% Mn, contg. one or more kinds among 0.3 to 3% Si, 0.1 to 5% Mg and 0.3 to 10% Ce, in which the total amt. of the elements to be added is regulated to <25% and the balance Al with inevitable impurities is rapidly cooled at >=10<2> deg.C/sec cooling speed and is solidified into powder having <=1mu average size of an intermetallic compound. The powder is then compacted at about <=400 deg.C and is thereafter subjected to age-hardening treatment at 300 to 500 deg.C. By this method, the heat resistant Al alloy having excellent compactibility and suitable for engine parts, etc., can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an aluminum alloy material with excellent heat resistance and a method for manufacturing the same using a powder metallurgy method.

(Prior Art) Materials for automobile engine parts, gas turbine impellers, aircraft parts, etc. are required to have high-temperature strength at 100 to 400°C. If these materials are aluminum alloys, many advantages associated with weight reduction can be obtained. However, aluminum and its alloys generally have low strength at high temperatures.
For example, aluminum alloy (AA2) has excellent strength at room temperature.
018.2218.4032 etc.) is also 200°
At temperatures above C, the strength decreases significantly.

In contrast, in recent years, an aluminum powder metallurgy method has been developed in which a large amount of various transition elements are added to aluminum, and the molten metal is rapidly cooled and solidified by IM, and the resulting powder or ribbon-like thin strip is subjected to high-temperature compression processing to produce a heat-resistant aluminum alloy material. was developed and AJI
-8Fe-4Ce, Al-8Fe-2M0. Al1-8
Alloy materials such as Fe-2Go have been proposed.

(Problem to be solved by the invention) However, the above AfL-8Fe-4Ce.

Al-8Fe-2M0. In alloys such as Al1-8Fe-2Go, thermally stable intermetallic compounds are finely dispersed by rapidly cooling and pseudo-solidifying the molten metal, and high high-temperature strength is obtained by dispersion strengthening of these compounds. Therefore, when rapidly solidified powder is processed by aluminum powder metallurgy, the hot processing temperature during extrusion processing, forging processing, etc. must be kept low to prevent coarsening of the compound and decrease in strength due to heating. However, these alloys have problems in that they have poor formability at low temperatures and require high forming forces.

Therefore, an object of the present invention is to provide a heat-resistant aluminum alloy material with excellent formability and a method for manufacturing the same.

(Means for Solving the Problems) As a result of intensive research conducted by the present inventors to solve the above problems, the present inventors formed rapidly solidified powder from a molten metal of a specific aluminum alloy composition, compressed it, and then processed it to a high temperature. It was discovered that the above object could be achieved by aging treatment, and based on this knowledge, the present invention was completed.

That is, the present invention includes (1) 0.7 to 8% by weight of Cr (hereinafter simply referred to as %), 0.3 to 8% of Zr, 0.5 to 8% of Mn, and 0.3 to 3% of Si. , Mg0.1-5%, Ce0.3
~10%, the total amount of added elements does not exceed 25%, the balance is Al and unavoidable impurities, and the average size of the intermetallic compound is 1 gm
A heat-resistant aluminum alloy material characterized by the following (J! below, referred to as the first invention): (2) Cr 0.7-8%, Zr 0.3-8%, M
n005 to 8%, and Si0. :1~3%, M
gO11-5%, Ce 0. : Contains one or more of 1 to 10%, Cu 0.5 to 10%, Fe
0.1-8%, Ni0.3-8%, Co0.1-8%,
V0.1-5%, w0. i~s%, Ti0.1~5%,
Contains one or more of Mo0.1 to 5%, the total amount of added elements does not exceed 25%, and the remainder is A! ;L
A heat-resistant aluminum alloy material (hereinafter referred to as the second invention) characterized in that it has inevitable impurities and the average size of the intermetallic compound is 1 lm or less, (:l) Cr 0.7 -8%, Zr0.3-8%,
Contains 0.5-8% Mn, and 0.3-3% Si, M
Contains one or more of g0.1 to 5% and Ce 0.3 to 10%, the total amount of added elements does not exceed 25%, and the balance is Al and unavoidable impurities. Rapidly solidified powder is formed from molten aluminum alloy at a cooling rate of 102°C/sec or more, and after compression molding,
A method for producing a heat-resistant aluminum alloy material characterized by performing an age hardening treatment at 00 to soo'c (hereinafter referred to as the third invention) and (4) Cr 0.7 to 8%, Zr0
j~8%, Mn0.5~8%, and Si0.3
~3%, Mg0. Contains one or more of i to s%, Ce 0.3 to 10%, and roughly Cu 0.5 to 10
%, Fe0.1-8%, Ni0.3-8%, Co0.1
~8%, V0.1~5%, W0.1~5%, Ti0.1
5%, Mo 0.1 to 5%, the total amount of added elements does not exceed 25%, and the balance is Al and inevitable impurities. Rapid cooling at a cooling rate of 102° (:/sec or more!2
After forming a solid powder and compression molding it,
The present invention provides a method for producing a heat-resistant aluminum alloy material (hereinafter referred to as the fourth invention) characterized in that an age hardening treatment is performed at 500°C.

The action of each component in the aluminum alloy material according to the present invention and the reason for limiting its content are as follows.

In the first, second, third and fourth inventions, the Cr content is 0.7 to 8%, the Zr content is 0.3 to 8%, and the Mn content is 0.5%. ~8%. Cr, Zr,
Most of Mn is dissolved in solid solution in Ml during rapid solidification, and is precipitated as fine intermetallic compounds by performing age hardening treatment at 300 to 500 °C for a predetermined time after forming.
It acts to increase room temperature strength and high temperature strength. This effect is not sufficient when the contents of Cr, Zr, and Mn are less than their respective lower limits, and when the contents of Cr, Zr, and Mn exceed their respective upper limits, the degree of this effect not only becomes saturated, but also During rapid cooling and solidification, many compounds cannot be dissolved and crystallize, reducing processability.

In the first, second, third and fourth inventions, Si, Mg, C
e, Si013~3%, Mg0.1~5%, Ce0
．． One type or a combination of two or more types is added at a content in the range of 3 to 10%. Si is Cr during the age hardening treatment performed after molding.
, Zr, and Mn, and has the effect of making the precipitates finer. This effect is not sufficient when the Si content is less than 0.3%, and the effect is saturated when the Si content exceeds 3%. Like C, Zr, and Mn, Mg forms a solid solution in the steel during rapid solidification, and precipitates finely during the age hardening treatment after molding and compression processing, which has the effect of increasing strength.

This effect is not sufficient when the Mg content is less than 0.91%, and the effect is saturated when the Mg content exceeds 5%. Ce has the effect of making precipitates finer during aging treatment and increasing strength. This effect is not sufficient when the Ce content is less than 0.3%, and the effect is saturated when the Ca content exceeds 10%.

Further, in the second and fourth inventions, Cu, Fe, Ni, C
0. V, W, Ti, Mo with Cu 0.5~1O%, F
e0.1~8%, Ni0.3~8%, Co
0.1~8%, V0.1~5%, W0.1~5
%, Ti 0.1 to 5%, and Mo 0.1 to 5%.

Cu, like Mg, is dissolved in solid solution in the steel, and is finely precipitated during the age hardening treatment after compression molding after molding, and has the effect of increasing strength. This effect is not sufficient when the Cu content is less than the lower limit, and the effect is saturated when the Cu content exceeds the upper limit. Fe, Ni, C0. V, W, Ti, and Mo are finely dispersed as thermally stable intermetallic compounds during rapid solidification of the molten metal, and have the effect of increasing high-temperature strength. This effect is caused by Fe, Ni, C0. When the content of V, W, Ti, and Mo is less than the respective lower limit, it is not sufficient, and when each content exceeds the upper limit, not only the effect is saturated, but also the moldability is reduced.

Further, in the present invention, the total amount of added elements does not exceed 25%. If the total amount of added elements exceeds 25%, not only will their effects become saturated, but moldability will deteriorate.

Further, even if 0.5 to 500 p.mu.m of unavoidable impurities such as Be, B, Na, and Ca are contained in AJI, the characteristics are not affected.

Next, in the present invention, the average size of the intermetallic compounds in the aluminum alloy having the above composition is 1 μm or less.

In the third and fourth inventions, in manufacturing the aluminum alloy material, rapidly solidified powder is formed from the molten aluminum alloy having the above composition at a cooling rate of 102°/sec or more, and after compression processing, the powder is compressed at 300-500°. Age hardening treatment is performed at C.

If the cooling rate of the molten metal is less than 102°C/see, Cr
, Zr, Mn, Mg, and Cu are no longer sufficiently dissolved in Al, and Fe, Ni, C0. The average size of the intermetallic compounds formed by V, W, Ti, and Mo becomes coarse, exceeding 1 μm, and the workability and strength decrease. In addition, the engineering temperature is 02°C/se
Examples of rapid solidification methods that achieve a cooling rate of c or more include an atomization method, a rapid cooling roll method, and a melt spinning method, and there is no problem in using any of these methods.

The compression molding temperature of the rapidly solidified powder is preferably 400"C or less. The alloy material of the present invention is made of Cr, Cr,
By making Zr, Mn, Mg, and Cu into a supersaturated solid solution, it is made into a solidified material with good moldability, and after being molded, precipitation treatment is performed to give it high strength, so the molding temperature is high. If the temperature is too high, precipitation may occur during preheating, resulting in reduced workability. Therefore, it is preferable that the molding temperature be set to a temperature at which precipitation does not proceed, and that the preheating time be as short as possible.

Next, the temperature for age hardening treatment performed after molding is 300℃.
If the temperature is lower than .degree. C., the precipitation rate is low and the processing time to obtain the peak strength is significantly long, several tens of hours or more, resulting in a decrease in productivity. If the treatment temperature is higher than 500°C, the precipitation rate will be high and the treatment time will be too short to 30 minutes or less, making it difficult to control the time to obtain the peak intensity.

(Example) Next, the present invention will be explained in more detail based on examples.

Example A alloy having the chemical composition shown in Table 1 (sample No. 0.1)
~20) Powder with an average particle size of 70 μm was produced from the molten metal by Ar gas atomization. The cooling rate in the atomization method was 10 to 104°C/sec.

Each of the obtained alloy powders was cold preformed (compressed to 80% of true density, diameter 100 mm, i.d. 200 m).
m) → Aluminum can enclosure → High temperature vacuum degassing (300℃
)→Hot press molding (up to true density)→External cutting/decanning to produce a billet with a diameter of 80 mm and a length of 150 mm, which was extruded at a temperature of 300° C. to form an extruded rod with a diameter of 30 mm. The surface pressure applied to the billet during this extrusion operation was measured.

Next, the extruded rods of alloy samples No. 1 to 17 were heated to 400°C.
Age hardening treatment was performed for the required time (1 to 3 hours) to reach peak strength at a temperature of .

The average size of intermetallic compounds in each alloy extrusion sample obtained as described above was measured using a transmission electron microscope, and the Mechanical properties were measured and the results are shown in Table 2.

/ As is clear from the results in Table 2, the average size of intermetallic compounds in the aluminum alloy materials of the present invention (samples N091 to 17) is IJLm or less, and the surface pressure during extrusion is equal to that of the comparative example (
The extrusion moldability is extremely low compared to samples No. 0.18 to 20), and the room temperature and high temperature strengths are equal to or higher than those of the comparative examples. That is, the alloy material of the present invention has excellent moldability and high temperature strength (heat resistance strength).

(Effects of the Invention) According to the present invention, a heat-resistant aluminum alloy material suitable for engine parts, turbine impellers, aircraft parts, etc. that require heat-resistant strength can be obtained by a rapidly solidified powder method. The aluminum alloy material of the present invention has excellent moldability and has remarkable effects on reducing the weight of the above-mentioned parts or members, as well as mass production and cost reduction.

Claims (4)

[Claims] (1) Cr 0.7-8%, Zr 0.3-8%, Mn
Contains 0.5-8%, and Si 0.3-3%, M
Contains one or more of g 0.1 to 5% and Ce 0.3 to 10%, and the total amount of added elements does not exceed 25% (the above % indicates weight %), A heat-resistant aluminum alloy material, characterized in that the balance is Al and unavoidable impurities, and the average size of intermetallic compounds is 1 μm or less. (2) Cr 0.7-8%, Zr 0.3-8%, Mn
Contains 0.5-8%, and Si 0.3-3%, M
Contains one or more of g 0.1 to 5%, Ce 0.3 to 10%, and further Cu 0.5 to 10%, Fe
0.1-8%, Ni 0.3-8%, Co 0.1-8%
8%, V 0.1-5%, W 0.1-5%, Ti 0
．． 1 to 5%, Mo 0.1 to 5%, the total amount of added elements does not exceed 25% (the above % indicates weight %), and the balance is Al and A heat-resistant aluminum alloy material containing unavoidable impurities and having an average size of intermetallic compounds of 1 μm or less. (3) Cr 0.7-8%, Zr 0.3-8%, Mn
Contains 0.5-8%, and Si 0.3-3%, M
Contains one or more of g 0.1 to 5% and Ce 0.3 to 10%, and the total amount of added elements does not exceed 25% (the above % indicates weight %), 10 from a molten aluminum alloy containing the balance Al and unavoidable impurities
A method for producing a heat-resistant aluminum alloy material, which comprises forming a rapidly solidified powder at a cooling rate of ^2°C/sec or more, compression molding the powder, and then subjecting it to age hardening at 300 to 500°C. (4) Cr 0.7-8%, Zr 0.3-8%, Mn
Contains 0.5-8%, and Si 0.3-3%, M
Contains one or more of g 0.1 to 5%, Ce 0.3 to 10%, and further Cu 0.5 to 10%, Fe
0.1-8%, Ni 0.3-8%, Co 0.1-8%
8%, V 0.1-5%, W 0.1-5%, Ti 0
．． 1 to 5%, Mo 0.1 to 5%, the total amount of added elements does not exceed 25% (the above % indicates weight %), and the balance is Al and From molten aluminum alloy containing unavoidable impurities to 10^2℃/
A method for producing a heat-resistant aluminum alloy material, which comprises forming a rapidly solidified powder at a cooling rate of sec or more, compression molding the powder, and then subjecting the powder to an age hardening treatment at 300 to 500°C.