JPS63297277A - SiC whisker-reinforced metal composite and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a SiC whisker-reinforced metal composite material having high strength and high toughness as a heat-resistant structural material, and a method for producing the same.

[Conventional technology]

SiC whiskers have excellent specific strength, specific modulus, heat resistance, and corrosion resistance, so SiC whisker-reinforced metal composites, which are dispersed and composited with various matrix metals, are used for various applications and applications that require advanced metal properties. It is considered useful as a structural member in the field.

Conventional metal composites with dispersed SiC whiskers are lighter,
From the viewpoint of improved strength characteristics, AI or A1 alloy is mainly used as the matrix metal. A1
The reason why A1 alloy is used is that AI is soft, has good malleability and ductility, and has a low melting point (660°C), making it easy to process.

[Problem that the invention seeks to solve]

However, metal composite materials having these low melting point metals as a matrix have the disadvantage that the operating temperature is limited to a relatively low temperature atmosphere. Therefore, in order to obtain a composite material intended for use in trays, it is necessary to use a metal with a higher melting point as the 7 trix metal.

The present invention provides a metal composite material in which SiC whiskers are dispersed and composited using a high melting point metal such as Si or Si alloy as a matrix, and a method for manufacturing the same.

[Means for solving problems]

Of course, the SiC whisker-reinforced metal composite material of the present invention has Si or a Si alloy as a matrix metal, and SiC whiskers are homogeneously dispersed in the matrix metal, and the manufacturing method thereof uses SiC whiskers. The formed preform is heated to a temperature higher than the melting point of the matrix metal, and molten Si or Si alloy is brought into contact with the matrix metal at normal pressure to impregnate it.

The SiC whiskers used in the present invention have a diameter of 01 to l.
It is a fine fibrous material consisting of needle-shaped single crystals with a μ shoulder and a length of 30 to 100 μm. Because there are almost no lattice defects in the crystal, it has extremely high mechanical strength and is useful as a reinforcing material. There is.

The matrix metal in the present invention is a high melting point metal such as S11 or Si (Ti, Cr, Mn).

An alloy to which Fe, Ni, etc.) is added is applied.

SiC dispersed and composited in these matrix metals
It is preferable that the volume content (Vf) of the whiskers is set to 5 to 50%. This is because when Vf is less than 5%, the effect of composite reinforcement is small and the strength properties are not sufficiently improved. Further, if Vf exceeds 50%, there is not only a limit to the improvement of strength properties, but also a tendency to decrease.

This metal composite is made by heating a preform made of SiC whiskers into a predetermined shape to a temperature higher than the melting point of the matrix metal, and then bringing the molten matrix metal into contact with the preform at normal pressure to form the molten matrix metal. It can be manufactured by impregnating and compositing with.

For example, when St is used as the matrix metal, since St has good interfacial wettability with SiC whiskers, molten Si easily penetrates into the SiC whiskers and preforms by just contacting them, homogeneously impregnating the inside of the preform and forming a composite. can. In this case, in order to uniformly impregnate the inside of the preform with molten Si, it is necessary to heat the preform to a temperature equal to or higher than the melting point of Si. As a result, a homogeneous composite material can be obtained without the need to apply a pressure casting method that applies large pressure during impregnation with molten matrix metal.

Note that in order to prevent oxidation of the matrix during composite, the above impregnation step is preferably performed in an inert atmosphere.

[For production]

Based on the above structure, the SiC whisker-reinforced metal of the present invention has a matrix of Si or Si alloy which has a high melting point. This makes it possible to use it in the high 12 range. Furthermore, since matrix metals such as Si have good interfacial wettability with SiC whiskers, they can be impregnated and composited very easily under normal pressure by heating the preform.

[Example 1] SiC whiskers with a diameter of 0.1-1 μm and a length of 30-100 μI were uniformly dispersed and mixed in ethanol, filtered and dried, and then molded to obtain a 1OX20×50π preform. Ta. The Brifeam was placed in a furnace with an argon gas atmosphere and heated at a temperature of 1500° C. for 5 hours. Next, the preform suspended from carbon fibers was immersed for 1 minute in molten Si heated and melted at 1500° C. in a graphite crucible to form a composite.

After that, the furnace was cooled and the SiC whiskers were homogeneously dispersed.
An i-composite was obtained. The Vr of SiC whiskers is 13%.
Met.

The mechanical strength properties of the composite material were measured and shown in Table 1.

For comparison, the strength characteristics of Si alone are also shown. This composite material shows an improvement of 2.8 times in strength and 1.6 times in toughness compared to Si.

[Example 2] Using the same method as Example I, the size is IOX20X50M.
, v after fabricating the SiC whisker preform,
The preform and Si were composited at a temperature of 1500°C. The method of compounding is also the same as in Example 1. However, since the Vf of the preform was 42%, the holding time at 1500° C. before Si impregnation was set to 7 hours.

The mechanical strength properties of the composite material were measured and shown in Table 1.

The composite material has 4.5 times the strength and 2.5 times the toughness compared to Si.
This is an improvement of 6 times.゛Table 1 Note 1) vf is the volume content of SiC whiskers.

2) The bending strength was measured according to the three-point bending test method of JIS R+601-81.

3) Toughness is S E N B (SIr+gle-E
dge 1 lotched beam) method.

〔effect〕

As described above, according to the present invention, the matrix metal, which was conventionally limited to AI and its alloys, can be replaced with Si or Si.
By replacing it with an alloy and avoiding composites with SiC whiskers, a completely new type of high-temperature structural material can be provided. In other words, the fields of application of the St or Si alloys described in this text are limited because they do not have sufficient mechanical strength, but by combining them with SiC whiskers, they can be used as structural materials.

Furthermore, since the matrix metal used in the present invention has a high melting point, it is difficult to apply conventional composite technology, but if the procedure shown in the present invention is taken into account, SiC whiskers and matrix metal can be combined at normal pressure. It becomes possible to combine

Claims (1)

[Claims] 1. An SiC whisker-reinforced metal composite material, characterized in that Si or a Si alloy is used as a matrix metal, and SiC whiskers are homogeneously dispersed in the matrix metal. 2. The volume content (Vf) of SiC whiskers is 5 to 50
% of the SiC whisker reinforced metal composite according to claim 1. 3. A SiC whisker-reinforced metal composite material, which is characterized in that a preform formed using SiC whiskers is heated above the melting point of the matrix metal, and the molten matrix metal is brought into contact with it at normal pressure to impregnate and composite it. Production method.