JPS609568A - Production of fiber-reinforced composite metallic material - Google Patents

Abstract

PURPOSE:To obtain a fiber-reinforced composite metallic material in which short fibers are uniformly distributed and which has high strength by mixing short fibers for reinforcement, mild fibers, whiskers and matrix metallic powder, putting the mixture into a mold and pouring a molten matrix metal under pressure into the mold. CONSTITUTION:Short fibers such as carbon fibers and metallic fibers, mild fibers or whiskers and matrix metallic powder are mixed at a prescribed ratio and the mixture thereof is put into a mold. The melt of the same or different kind of the matrix metal as or from the matrix metal is pressurized and poured into the mold to form a fiber-reinforced composite metallic powder. The matrix is formed of both of the initially mixed powder and the molten metal to be poured later in this method and therefore the ratio of the matrix metal is easily adjustable. The composite material is uniformly distributed with the short fibers, has uniform and high strength and is easily workable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a fiber-reinforced metal composite material.

So-called fiber-reinforced metal composite materials (hereinafter referred to as fiber-reinforced metal composite materials) are made by reinforcing matrix metal with reinforcing fibers such as short fibers, milled fibers, or whiskers (hereinafter collectively referred to as short fibers, etc.). Compared to FRM, which is made by arranging reinforcing miscellaneous continuous fibers aligned in one direction, and FRM, which is made by arranging such unidirectionally aligned continuous fibers in a so-called cross-layered arrangement, Although it is difficult to develop high strength only in a specific direction, it has excellent isotropy because short fibers can be arranged in random directions, and it is relatively easy to manufacture, so it does not require much strength. It is useful when configuring parts that will not be used.

Conventionally, the method for producing FRM using short fibers as reinforcing fibers is to place only the short fibers in a mold, and then
A known method is to pressurize and inject molten matrix metal into the mold. However, this conventional method has drawbacks as explained below.

In other words, in the conventional method described above, only the short fibers, etc. are placed in the mold, so when the molten matrix metal is pressurized, poured, and covered, the short fibers, etc. are directly subjected to static force. When using short fibers that have poor wettability with metals, the short fibers are pushed in one direction, creating areas with too much short fibers and areas with too much matrix metal, resulting in uniform FRM.
is difficult to manufacture. Furthermore, since a static force is directly applied to the short fibers, etc., the m-thickness volume content tends to become abnormally high, and there is also the drawback that it is difficult to control the content. If the content is abnormally high, the resistance to deformation increases and the FRM not only becomes very brittle, but also becomes difficult to perform post-processing such as rolling or extrusion.

The purpose of this invention is to solve the above-mentioned drawbacks of the conventional method, and to produce an FRM that not only has a uniform distribution of short fibers, but also has easy control of the content, is homogeneous, has high strength, and is easy to process. The purpose is to provide a method for manufacturing.

In order to achieve the above object, in the present invention, a mixture of reinforcing short fibers, milled fibers or whiskers and matrix metal powder is placed in a mold, and then a mixture of the same type or different type as the matrix metal is placed in the mold. A method for manufacturing a fiber-reinforced metal composite material is provided, which comprises pressurizing and injecting a molten matrix metal.

To explain the method of this invention in detail, in this invention, first, a mixture of short fibers etc. and matrix metal powder in a desired mixing ratio is made, and the mixture is filled into a mold having a desired shape. do. Next, in the above mold, a molten metal of 71 to 60% is added, preferably at a temperature of 200 to 2000K]/C
l112 (1) Inject with pressure. In other words, it is cast. The temperature of the molten metal is preferably in the range from the melting point of the matrix metal to 250° C. above the melting point.

In the above, short fibers etc. are carbon, silicon carbide, alumina, alumina, etc., which constitute reinforcing fibers of FRM.
It consists of silica, boron, metal, etc. When the short fibers etc. are short fibers, the length thereof may be short as long as it can be uniformly mixed with the matrix metal powder, and a length of 10111111 or less is usually used. The preferred length is 1 to 5 mm in average length. Moreover, in the case of milled fibers, the average length is preferably about 30 to 1000 μm. Furthermore, in the case of whiskers, the average length is about 50 to 200 microns. Further, the diameter of short fibers and milled fibers is usually about 5 to 20 μm. Whiskers are usually thinner than this.

The matrix metal powder is made of aluminum, magnesium, copper, titanium, nickel, tin, lead, or an alloy containing at least one of these as a main component, which are commonly used as matrix metals for FRM. The average particle size of such powder is not particularly limited, but
Usually, one with a trace of 10 to 60 μm is used.

Mixing of short fibers, etc. and matrix metal powder (for example, this can be done using a mixer or a ball mill. In this case, the mixing ratio of the two can be determined as appropriate depending on the fiber volume content of the FRM to be manufactured. I can't stand it.

Preferably, the molten matrix metal is also made of the same type of metal or alloy as the powder. However, the two may be different. That is,
If they are of the same type, they will fuse together and become integrated; if they are of different types, they will form an alloy, or the powder will be dispersed as precipitates in the matrix.

In this invention, as a result of the matrix being formed by both the initially mixed powder and the molten metal that is subsequently injected,
It is very easy to control the ratio of 71 to Lix metal, in other words, the Li fiber volume content.

Furthermore, according to the method of the present invention, an FRM containing a so-called third component is produced by further mixing Reramix powder such as alumina powder into a mixture of short fibers and matrix metal powder. It will also be possible to do so.

Hereinafter, the method of the present invention will be explained in more detail based on Examples.

Example Carbon fiber "Trading Card" M40 manufactured by Toshi Co., Ltd. was cut into a length of about 2111 m to obtain short fibers.

Next, the above mmu and aluminum powder with an average particle size of 20μ are mixed in a volume of 1 part carbon fiber to 2 parts aluminum powder, and this mixture is placed in a mold having a cylindrical cavity. , 50% of the molten aluminum alloy (Jts AC4C) (temperature 750°C) was placed in the mold.
The FRM was obtained by injection at a pressure of 0 K (j/cm2). The fiber volume content of this FRM was about 25%.

Next, when the cross section of the above FRM was observed using an optical microscope, it was found that the aluminum powder and the aluminum alloy were completely integrated, and it was not possible to distinguish between the two. In addition, the short fibers were dispersed extremely uniformly, and no areas with a significant excess of short fibers were observed.

Next, the above FRM was heated at 500°C and at an extrusion ratio of 1:10.
When hot extrusion was carried out, a good round bar-shaped FRM with no cracks was obtained.

Next, using a three-point bending tester, the above round bar (length approximately 85 m
When a bending test was conducted with a diameter of approximately 10IllIIl), the bending strength was approximately 17K(]/1111112).

Comparative Example An FRM was obtained in the same manner as in the above example, but only short fibers were placed in the mold and no mixture of short fibers and matrix metal powder was used. The fiber volume content of this FRM was very high at about 60%.

”-The FRM was hot extruded in the same manner as in the example, but
Since the fiber volume content was too high and it was difficult to deform, cracks were severe and a good round bar-shaped FRM could not be obtained. The bending strength of this round bar was tested in the same manner as in the above example and was only about 0.3 kg/aun2.

Patent applicant: Toshi Co., Ltd.

Claims (1)

[Claims] After placing a mixture of short reinforcing fibers, milled fibers, or whiskers and matrix metal powder into a mold, pressurizing and injecting a molten metal of the same type or different type as the matrix metal into the mold. characterized by
A method for manufacturing a fiber-reinforced metal composite material.