JPH01319644A - Heat-resistant aluminum alloy material and its manufacture - Google Patents

Abstract

PURPOSE:To easily manufacture the subject alloy material by forming the molten metal of an Al alloy having the compsn. in which the content of Fe, Si, etc., is specified into powder by a gas atomizing method, subjecting it to hot compression molding and limiting the size of an iron-contg. intermetallic compound. CONSTITUTION:An alloy contg., by weight, 5.5-15% Fe, 0.5-2.5% Si and one or more kinds among 0.5-15% Ni, 0.5-15% Co, 0.3-10% Zr, 0.5-10% Ce, 0.5-10% Ti, 1-4.5% Cu, 0.1-5% Mg and 0.1-5% Zn, in which the total amt. of the elements to be added is regulated to <=25% and the balance Al with inevitable impurities is refined. The molten metal is subjected to rapid solidification by a gas atomizing method to form powder. After that, the powder is subjected to hot forming to manufacture an Al alloy material in which the average size of an Fe-contg. intermetallic compound is regulated to 0.07-1mum. By this method, the Al alloy material having excellent heat resistance can easily be mass-produced.

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 made of aluminum alloy, many advantages associated with weight reduction can be obtained. However, aluminum and its alloys generally have low strength at high temperatures. For example, aluminum Uno alloy (A) has excellent strength at room temperature.
A2018.2218.4032) also has 20
At temperatures above 0°C, the strength decreases significantly.

In response to this, in recent years, an aluminum powder metallurgy method has been developed in which a heat-resistant aluminum alloy is produced by high-temperature compression processing of powder or ribbon-shaped thin strip obtained by adding large amounts of various transition elements to aluminum and rapidly solidifying the molten metal. and Al-8
Fe-4Ce, A! :L-8F e-2Mo, A
Alloys such as l-8F e-2G o are provided.

The manufacturing process using the powder metallurgy method for aluminum alloys includes a) rapid solidification of the molten alloy by the maize method, twin roll method, or spray roll method to form powder, ribbon, or flake. It is made into a green compact with a density ratio (ratio to true damage) of 70% or more by cold forming, sealed in a can, vacuum degassed, and then hot processed to a density ratio of 10.
A commonly used method is to mold a 0% billet I~, and further mold it by extrusion, forging, etc. in order to increase the bonding force between the particles.

(Invention or problem to be solved) However, there are two Al-8Fe-4Ce, A-8F
e-2Mo, A9. The -8Fe-2Go alloy is an alloy that exhibits excellent heat resistance only by compression molding the molten metal, which is ultra-rapidly solidified at 105°C/sec or higher, and is easy to manufacture. Inexpensive gas atomized powder (cooling rate 102~) 05°C/5eC
), there was a problem that sufficient strength and heat resistance could not be obtained.

On the other hand, ultra-rapid solidification methods that can achieve a cooling rate of 105°C/sec or higher include the rapid-cooling roll method and the Svininck method, all of which require special manufacturing equipment and solidification technology. Kos I-J- brings about the rise. moreover,
The ultra-rapid solidification method produced by the quench roll method is in the form of ribbons or flakes, and as it is unsuitable for compression molding, it is necessary to cut it into small pieces, which leads to high costs. There was a problem with that.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a heat-resistant aluminum alloy that is easy to manufacture and inexpensive, and which is obtained by compression molding a casualized powder, and a method for manufacturing the same.

(Means for Solving the Problems) The present inventors have conducted intensive research to solve the problems described in 2. As a result, by forming a gas atomized powder using a molten metal of a specific aluminum alloy composition, They found that it was possible to achieve the following, and based on this knowledge, they completed the present invention.

That is, the present invention contains (+,) Fe 5.5 to 15% by weight (hereinafter simply referred to as %), Si 0.5 to 2.5%, and N
i0.5-15%, Co 0.5-15%, Zr 0.
:1~10%, Ce 0.5~1.0%, T10.5~
10%, Cu]~4.5%, Mg0.1~5% and Z
n0.1 to 5%, the total amount of added elements is 25% or less, the balance is Al and unavoidable impurities, and the average size of the intermetallic compound containing Fe is 0. Heat-resistant aluminum alloy rate characterized by being .07~llLm or (2) Fe 5.5~15%, Si 0.5
~2.5%, and N i 0.5-15%,
Co 0.5~]5%, Zr 0. :l-]00%C
e 0.5~], 0%, Ti0.5~10%, Cu
1-4.5%, Mg 0.1-5% and Zn (],
A molten A1 alloy containing one or more of 1 to 5% of additive elements, the total amount of added elements is 25% or less, and the remainder contains A and unavoidable impurities is rapidly solidified by gas atomization to form a powder. A heat-resistant aluminum alloy having the above composition and having an average size of Fe-containing intermetallic compound of 0.07 to Igm. The present invention provides a method for manufacturing.

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.

Fe content shall be 5.5-15%. Fe is finely dispersed as an intermetallic compound containing Fe during rapid solidification by gas atomization, and has the effect of increasing high-temperature strength. When the Fe content is less than 5.5%, Li is not sufficient for this effect, and when the Fe content exceeds 15%, the degree of this effect not only becomes saturated, but also the intermetallic compound becomes coarse.

The Sj content is 05 to 25%. Sl has the effect of making intermetallic compounds containing Fe finer, and this effect increases high-temperature strength. This effect is not sufficient when the Si content is less than 0.5%, and on the other hand, when it exceeds 2.5%, this effect becomes saturated, leading to an increase in cost.

Ni, Co, Zr, Ce, and Ti have the effect of thermally stabilizing the intermetallic compound containing Fe, thereby increasing the high-temperature strength. Cu, Mg, and Zn have the effect of improving the strength by solid solution in Au, and the effect of improving the strength by partially precipitating finely. Ni, Co, Zr, Ce, Tj, Cu, Mg, Zn
are Ni 0.5-15% and Co 0.5-15%, respectively.
l-5%, Zr[]j ~1.0%, Ce 0.5~1
0%, Ti 0.5-10%, Cu 0. ]~1.0%
, Mg 0.5-5%, Zn 0.1-5% 1
Species or two modes] - Combined addition. If the amount added is less than the lower limit, the effect will not be sufficient, and if it exceeds the upper limit, the degree of effect will not only be saturated, but will not result in an increase in cost.

Further, the total amount of all additive elements shall be 25% or less. If the total amount exceeds 25%, the effect will not be saturated;
No increase in - to Kos 1.

Further, even if 0.5 to 500 ppm of unavoidable impurities such as Be, B, Na, and Caq are contained in Au, the characteristics are not affected in any way.

Next, in the present invention, the average size of the intermetallic compound containing Fe in the aluminum alloy having the above composition is 0.07~
1 lm.

In producing the aluminum alloy of the present invention, a molten aluminum alloy having the above composition is rapidly solidified by the Kasua 1-Meiss method at a cooling rate of preferably 10 to 10"C/sec to form a powder, This is then subjected to hot compression molding.The Kasua 1-Mais method is a method that has been widely used for producing pure An powder for paints and rocket solid fuel, and its production equipment δ is utilized. By doing so, it is possible to easily produce a large amount of alloy powder.Therefore, the production technology has been established, and it is cost-effective to use the Casualmais method, which is already available for mass production. In addition, since the rapidly solidified material produced by the gas aluminization method is in the form of particulate powder, it can be shaped into ribbon-shaped thin strips, flakes, etc. produced by the quenching roll method, etc. In comparison, it has the advantage of being easier to handle and compression mold, and is advantageous in terms of manufacturing costs.

However, in the gas atomization method, it is currently difficult to reduce the size of the Fe-containing intermetallic compound finely dispersed during rapid solidification to less than 0.07 gm.

The powder below has a size of 0.0.
07) The ratio of powder having a particle size of less than Lm or less than 5 gm in the powder produced by the gas amalization method is as low as about 2 to 3%, and classifying and using only it brings about a significant cost LA. Therefore, in this case, it is virtually impossible to make the size of the intermetallic compound containing Fe smaller than Q, 07 gm. However, normally, the size of the intermetallic compound containing Fe in the molded material obtained by compression molding the 6Fe powder is 0.07 to 18 Lm. If it is within this range, it will exhibit sufficient heat resistance.

Next, hot compression molding of the powder itself can be carried out according to a conventional method, or preferably at a temperature of 400°C or less. From the viewpoint of moldability, the higher the processing temperature, the better. However, although the addition of Ni, Co, Zr, Ce, and Ti thermally stabilizes intermetallic compounds containing Fe and prevents them from becoming coarse, processing temperatures exceeding 400°C may cause intermetallic compounds to deteriorate. It may become coarse and its strength and heat resistance may decrease.

Further, it is preferable that the molded material processed at high temperature be rapidly cooled by water quenching or the like immediately after processing. As a result, Cu, Mg, Zn
It can be seen whether the amount of solid solution is increased and the strength is further improved.

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

Example Aluminum alloy (No. 1) having the composition shown in Table 1
-No., 20) were each made into a molten metal by a conventional method, and a powder having an average particle size of 70 m was produced from this molten metal by an Ar caster method. The cooling rate in this ahemization was 10 to 104°C/S e C.

Next, each of the obtained alloy powders was subjected to cold pre-forming (compression at a density ratio of 80%, diameter 100 mm, f
fl 120mm) -> Aluminum can enclosure → High temperature vacuum degassing (300°C) → Hot press forming (true density)
→Diameter: 80mm, length: 150mm due to external grinding and removal process
A fillet l-mm in diameter was prepared and extruded at 300°C to obtain an extruded material with a diameter of 30 mm.

For each of the alloy extruded materials obtained as described above, a tensile test was conducted at room temperature and 300°C (holding time: 100 hr), and the average rice of intermetallic compounds containing Fe was measured. The results are shown in Table 2.

Note that the average size of the intermetallic compound containing Fe was determined as follows. In other words, the structure of the extruded material is transferred to the transmission electron W.
Observe with a J microscope and determine the size of the compound from the tissue photograph using image analysis. Many (
Measurements are made for iooo (or more) compounds, and the sizes are averaged and taken as the average size of the 'C compound.

As is clear from the results in Table 2, the aluminum alloys (Nos. 1 to 17) produced by the method of the present invention were compared to the comparative examples (Nos. 18 to 17) used in the ultra-rapid solidification method.
, 20), it is superior in both strength at room temperature and after being kept at high temperature.

(Effects of the Invention) According to the present invention, it is possible to produce materials suitable for engine parts, turbine impellers, aircraft parts, etc. that require heat-resistant strength (high-temperature strength) by a customization method without using an ultra-rapid solidification method. It is possible to obtain a heat-resistant aluminum alloy.

Moreover, the rapidly solidified aluminum alloy material according to the present invention is not only easy to manufacture, but also can be obtained as aluminum powder, so it can be used as it is for compression molding. It has excellent effects.

Claims (1)

[Claims] (1) Contains 5.5-15% Fe, 0.5-2.5% Si, and 0.5-15% Ni, 0.5-15% Co,
Zr0.3-10%, Ce0.5-10%, Ti0.5
~10%, Cu1~4.5%, Mg0.1~5% and Z
n0.1 to 5%, the total amount of added elements is 25% or less (herein, % indicates weight %), and the remainder contains Al and inevitable impurities, One or two types of heat resistance 0.1 to 5%, characterized by the average size of the intermetallic compound containing Fe being 0.07 to 1 μm
The total amount of added elements is 25% or less (or more, %
indicates weight %. ) having the above-mentioned composition, which is characterized in that a molten Al alloy having the remainder Al and unavoidable impurities is rapidly solidified by gas atomization to form a powder, which is then hot compression molded. and a method for producing a heat-resistant aluminum alloy material, wherein the average size of the intermetallic compound containing Fe is 0.07 to 1 μm.