JPH07197149A - Production of aluminum composite material containing tial3 - Google Patents

Abstract

PURPOSE:To produce an Al composite material in which a fine TiAl3 intermetallic compound is dispersed uniformly in an Al base body by immersing a compact consisting of a Ti fine leaf, an Al fine leaf and a carbon powder in an Al molten metal to cause an exothermal reaction, and swelling, crumbling and settling it. CONSTITUTION:About 25wt.% Ti fine leaf and about 25wt.% carbon powder are mixed to the Al fine leaf, and the compact is formed by compression molding, etc. This compact is immersed in a molten metal of Al (about 800-900 deg.C) to cause the exothermal reaction of Ti+Al TiAl3. When immersing is continued further, Al is impregnated in the compact, and the compact is allowed to swell and crumble and begin to settle. When the settling is over, the Al composite material in which the fine TiAl3 intermetallic compound having about 5-10mum/grain size is dispersed uniformly in the Al base body is produced.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for manufacturing an aluminum composite material containing a TiAl ₃ intermetallic compound.

[0002]

2. Description of the Related Art Intermetallic compounds are a group of materials that fills the space between metal and ceramics, and are noted for their unique properties.
Many applications are currently under study. As a method for producing such an intermetallic compound, a metal powder consisting of the constituent elements of the intermetallic compound produced is mixed, and this mixture is subjected to HIP.
There are known a solid-phase method in which the molded body is molded by, for example, sintering, and a melting method in which the mother alloy containing the constituent elements of the intermetallic compound to be manufactured is arc-melted (Japanese Patent Laid-Open No. 63- (See Japanese Patent No. 247321).

However, since sintering and arc melting require a long time and consume a relatively large amount of energy, the above method efficiently and inexpensively produces intermetallic compounds and various composite materials containing intermetallic compounds. Difficult to manufacture.

In order to solve this problem, Japanese Patent Laid-Open No. 4-2148
In Japanese Patent No. 25, a method for producing a TiAl ₃ intermetallic compound is proposed, which comprises immersing a molded body composed of Ti fine pieces and Al fine pieces in an Al molten metal, removing the molten aluminum from the molten metal, and leaving it in the air. . By this method, the TiAl ₃ intermetallic compound can be produced efficiently and inexpensively, but the TiAl ₃ intermetallic compound obtained has a size of 30 μm or more, and its particle size distribution also varies.

[0005]

The present invention is based on the conventional Ti
To eliminate the above such disadvantage with the method for manufacturing the Al ₃ intermetallic compounds, it is intended to provide a finer TiAl ₃ intermetallic complexes homogeneously containing compound.

[0006]

The inventors of the present invention have described the above T
As a result of intensive studies to solve the above problems of the iAl ₃ intermetallic compound, as a result, powders of a reactive intermetallic compound forming component and a base metal component were mixed and formed, and the formed body was melted into a base metal. The present invention has been completed by discovering that the molded body collapses and precipitates when immersed and allowed to swell, and that this precipitation is a composite material in which the desired fine intermetallic compound is uniformly dispersed.

That is, according to the method for producing an aluminum composite material containing a TiAl ₃ intermetallic compound of the present invention, a compact is formed from fine Ti particles, fine Al particles and carbon powder, and the compact is immersed in molten Al. It is characterized in that it is soaked to cause an exothermic reaction, and then the molded body is allowed to stand in an Al molten metal to swell, disintegrate and settle.

In the method of the present invention, first, fine Ti pieces, fine Al pieces and carbon powder are mixed and a compact is produced by compression molding or the like. The form of each fine piece may be any shape such as powder, short fiber, whisker, and thin piece,
It is preferably a powder. The amount of each component is
In order to cause the collapse phenomenon more easily, it is preferable to mix Al in an amount of 25% by weight or more with respect to Ti and C in an amount of about 25% by weight.

Next, this molded body is immersed in a molten aluminum. The temperature of the molten Al is preferably about 800 to 900 ° C. When the temperature is low, the disintegration phenomenon is unlikely to occur, while when the temperature is high, the molded body melts to form needle-like TiAl ₃ or TiC.
This is because other products may be produced.

The molded body causes an exothermic reaction of the following formula Ti + Al → TiAl _{3 in} the molten Al. When the immersion is further continued, Al is impregnated into the molded body within about 1 minute from the start of the immersion, and the molded body begins to swell after about 1 minute. If this state is maintained, the swollen body collapses and begins to settle in about 10 minutes from the start of immersion. After swelling, it is possible to disintegrate the molded body by stirring or applying vibration, but in this case,
Since TiAl ₃ is partially dissolved in Al and the volume ratio of TiAl ₃ in the obtained composite is lowered, it is preferable to cause self-disintegration. Approximately 30 minutes after immersion TiAl ₃
Settling is complete. Thus, a fine TiAl ₃ intermetallic compound having a particle size of 5 to 10 μm is uniformly dispersed in the Al matrix, and a composite is obtained from the precipitated portion.

[0011]

In the method of the present invention, the reaction between Ti and Al is promoted by using the heat of the Al molten metal to homogenize the reaction and obtain a fine TiAl ₃ intermetallic compound having a particle size of 5 to 10 μm. Further, by mixing carbon into the compact, the compact can be self-disintegrated and the TiAl ₃ intermetallic compound can be uniformly dispersed in the Al matrix.

[0012]

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention.

Example 1 Al powder (Showa Denko KK, SHORIC, particle size 100 μm or less) 200 g, Ti powder (Osaka Titanium KK, TSP-35)
800 g (0, 350 mesh or less) and 200 g of carbon powder (manufactured by Nippon Graphite Industry Co., Ltd., ACP-1000, average particle size 6 μm) were put in a V-type mixer and mixed for 30 minutes. Weigh 12g from this mixed powder, put it into a mold of φ30 with a surface pressure of 8 tons, and mold it.
100 pieces of φ30 × 5 mm compacts were obtained.

The two molded articles thus obtained are simultaneously subjected to 850
It was immersed in 150 g of Al melt at 0 ° C. An exothermic reaction occurred 0.5 minutes after the immersion, and Al was impregnated in 1 minute. Then, swelling of the molded body was observed 2 minutes after the immersion, and after 10 minutes, the molded body began to self-disintegrate. And after 30 minutes, it settled completely. After cooling, the upper section and the lower section on which the TiAl ₃ intermetallic compound settled were observed with a light microscope. The results are shown in FIGS. 1 and 2.
FIG. 1 shows the upper metallographic structure, and FIG. 2 shows the lower metallographic structure. In the lower part where the TiAl ₃ intermetallic compound precipitated, fine TiAl ₃ having a particle size of 5 to 10 μm was uniformly distributed. The Vickers hardness of the upper and lower samples was measured, and the results are shown in Table 1.

[0015]

[Table 1] It is clear that the hardness is significantly improved in the lower part.

Example 2 By changing the blending ratio of Al powder, Ti powder and C powder,
A molded body was manufactured in the same manner as in Example 1, and then immersed in an Al melt to observe the swelling / collapse phenomenon. The results are shown in Table 2.
Shown in.

[0017]

[Table 2]

The smaller the amount of Al, the less likely the swelling / collapse phenomenon occurred, and the amount of C was about 25% by weight relative to Ti, and the swelling / collapse phenomenon was most likely to occur.

Example 3 The molded body produced in Example 1 was immersed in a molten metal at various temperatures of 700 to 1000 ° C. The results are shown in Table 3.

[0020]

[Table 3]

Although a swelling phenomenon was shown at 700 ° C., it did not reach the point of collapse. At 1000 ° C, the compact melted and TiC was formed. Meanwhile, 800 ℃ and
At 900 ℃, it showed swelling and collapse phenomenon.

[0022]

EFFECTS OF THE INVENTION According to the present invention, compacts of Ti, Al and C are reacted in an Al melt, swollen / disintegrated, and allowed to settle in the Al melt to obtain fine TiA particles of 5 to 10 μm.
A complex in which the l ₃ intermetallic compound is uniformly dispersed in the Al matrix is obtained. Further, by using the method of the present invention, a plurality of casting molds arranged in parallel under a fixed melting furnace are moved by a belt conveyor method, the base metal is melted in the melting furnace, and swelling / collapse phenomenon occurs. An Al composite body containing TiAl ₃ can be continuously produced by adding a molded body to be raised at any time.

[Brief description of drawings]

Fig. 1 Molded body was impregnated with molten aluminum for 30 minutes and TiAl
₃ is a photograph instead of a drawing, which shows the metal structure of the upper part of the Al matrix after ₃ is precipitated.

[Fig. 2] A molded body is impregnated with molten Al for 30 minutes, and TiAl
₃ is a photograph replacing a drawing showing a metal structure of a lower portion of an Al matrix after ₃ is precipitated.

Claims (1)

[Claims] 1. A molded body is formed from Ti fine particles, Al fine particles and carbon powder, the molded body is immersed in an Al molten metal to cause an exothermic reaction, and then the molded body is left in the Al molten metal. Characterized by swelling, disintegrating and settling,
A method for manufacturing an aluminum composite material containing TiAl ₃ .