JPH02138426A - Method for manufacturing short carbon fiber reinforced metal composite material - Google Patents

Abstract

PURPOSE:To easily produce the title short carbon fiber-reinforced metal composition material having excellent wear resistance by mixing short carbon fibers and whiskers or short ceramic fibers to form a preform, and impregnating molten metal into the preform under pressure. CONSTITUTION:Short carbon fibers and at least one kind between whiskers and short ceramic fibers are mixed to form a preform. In this case, the whisker or short ceramic fiber acts as a binder, and a stable preform having excellent formability and easy to handle is obtained. The molten metal of an Al alloy, etc., is then impregnated into the preform under pressure. The molten metal impregnates between the fibers, the short fibers are almost uniformly dispersed in the metal, and both fibers and metal are sufficiently adhered to one another into a composite material. By this method, a fiber-reinforced metal composite material having excellent wear resistance is easily obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing short carbon fiber reinforced metal composite materials for use in various applications.

Conventional technology Fiber-reinforced metal composite materials (hereinafter referred to as FRM), which are a composite of metal materials and m-fiber materials, have been used for various purposes as materials with improved properties such as strength and wear resistance of metal materials. It is used. For example, FR using carbon II fiber
M improves wear resistance.

In this case, rather than using long carbon fibers, the diameter is 20 μm or less,
By using fine carbon short #a fibers (hereinafter referred to as milled) having a length of 5 rsm or less, the volume ratio of the fibers in the FRM can be increased, and the wear resistance can be further improved. In addition, F using whiskers such as silicon carbide (hereinafter referred to as SIC)
RM and others! ) Improves wear resistance.

Problems to be Solved by the Invention As mentioned above, FRM, which is a composite of milled fibers and metal, improves the wear resistance of the metal, but milled fibers have poor intertwining and are difficult to preform. Manufacturing-
There was a problem with F. In other words, when making a preform, an appropriate amount of water is added to the mill, stirred, molded into a certain shape, and then dried. However, after drying, even small vibrations can easily cause the shape to collapse, making it difficult to pressurize the next molding rod. Have difficulty. FRMs using SiC whiskers, etc., also have poor wear resistance, and often cause problems in practical use because they often scratch the surface of other materials.

The present invention solves the above-mentioned interrib problem, and the present invention solves the problem of the above-mentioned interribs.
The object of the present invention is to provide a method for manufacturing a short carbon fiber-reinforced metal composite material that improves the moldability of a preform body in the manufacture of FRM using milling.

Means for Solving the Problems In order to solve the above problems, the method for manufacturing a short carbon fiber reinforced metal composite material of the present invention includes at least 61 [! The method is characterized in that after a preform is formed by mixing the two, the metal is infiltrated under pressure in a molten state.

Effect In the above configuration, at least one of the whiskers and the ceramic short fibers mixed with the short carbon fibers plays the role of a binder, and the moldability of the preform body is improved, making it possible to form a stable preform body that is easy to handle. In addition, since the molten metal is infiltrated under pressure, it infiltrates between each single fiber and can be composited in a state where the single fibers are almost uniformly dispersed in the metal, making it easy to manufacture fiber-reinforced metal composite materials with excellent wear resistance. be able to.

Examples Example 1 Single fibers are short carbon fibers (milled: specific gravity 1.77 g/cm') with a diameter of 13 μm and a length of 100 to 500 μm, and single fibers with a diameter of 0.4 to 1.5 μm and a length of 10 to 500 μm 100μm
of potassium titanate (specific gravity 3.3 g/(2)3) at a weight ratio of 4:1, put it in water, stirred thoroughly, and then formed into a circle by press molding (pressure 20 kOf/cd) using a mold. It was molded into a plate shape and dried to produce a preform.

The obtained preform did not lose its shape and was easy to handle. This preform body has a volume ratio of 40
%, and was composited with an aluminum alloy (JIS standard AC8A>) by pressure casting method.The conditions of pressure casting were as follows.

Pouring temperature: 780℃ Pressure: 577m f/cd Mold preheating temperature: 300℃ Pressure time: 2 minutes In general, carbon 1IiA fibers have poor wettability with metals, but
The pressure casting method allows sufficient contact between the two,
Moreover, since it is pressurized and solidified in a short time, it does not generate a compound of aluminum and carbon, and the material does not become extremely brittle.The pressing force is 300 kr f/
− or more is desirable.

Example 2 The same short carbon fibers and potassium titanate as used in Example 1 were mixed at a weight ratio of 1:1, and a preform was molded in the same manner as in Example 1. This preform was composited with an aluminum alloy in the same manner as in Example 1 so that the volume ratio was 57%. Note that the handleability of the preform was extremely good.

Example 3 Short carbon fibers similar to those used in Example 1 above and single fibers having a diameter G, 1 to i μm r k or 50 to 200 μm
SiC whiskers (specific gravity: 3.2 g/medium 3) were mixed at a weight ratio of 4:1, and a preform was molded in the same manner as in Example 1, so that the preform had a volume ratio of 35%. Then, it was made into a composite with an aluminum alloy in the same manner as in Example 1. Note that the preform body cannot be handled very easily.

PM mirror photographs of the metal structure of the cross section of the FRM obtained in this example are as shown in Figure 1 (100x) and Figure 2 (400x), which is a partially enlarged photograph of Figure 1. As shown in FIG. 3 of the explanatory diagram of FIG. 2, the milled 1 is almost uniformly mixed and dispersed with the SiC whiskers 2, and the aluminum alloy 3 is closely adhered to the milled 1.

Example 4 Short carbon fibers similar to those used in Example 3 above and SiC whiskers were mixed at a weight ratio of 2:1, and a preform was molded in the same manner as in Example 1. It was made into a composite with an aluminum alloy in the same manner as in Example 1 so that the volume ratio was 40%. Note that the preform cannot be handled very easily.

Comparative Examples 1 to 3 As Comparative Example 1, a molded product having the same shape as that molded in Example 1 was produced using only the same aluminum alloy as that used in Example 1.

As Comparative Example 2, a preform was molded in the same manner as in Example 1 using only the same mill as that used in Example 1, and the preform had a volume ratio of 35%. It was composited with an aluminum alloy in the same manner as in Example 1. Note that the preform body easily loses its shape and is difficult to handle.

As Comparative Example 3, a preform was molded in the same manner as in Example pA1 using only the same SiC whiskers as used in Example 3, and this preform had a volume ratio of 26%.
It was made into a composite with an aluminum alloy in the same manner as in Example 1. Note that the preform was easily removed.

The products obtained in Examples 1 to 4 and Comparative Examples 1 to 3 above were subjected to an abrasion test using an Otsuki abrasion tester under the following conditions. The test results obtained are shown in FIG.

Sliding distance...88m Sliding speed...1m/sac Load...2kf Mating material...High speed steel ff! As shown in Figure 4, the FRM produced in each of Examples 1 to 4 of the present invention has a specific drag amount (nun' / kg
+m) is much better than the FRM using only milled fibers in Comparative Example 2, and this value can be changed by changing the mixing ratio of potassium titanate and SIC whiskers and the volume fraction of these fibers in the FRM. In contrast, although the FRM using only SiC whiskers in Comparative Example 3 has high wear resistance,
Depending on the application, it may be too high, and if you try to lower the volume fraction, the molding of the glyphome body will become rough, and the uniformity of dispersion in the FRM will decrease17
Quality deteriorates.

As described above, by the method of the present invention, it is possible to extremely easily form a preform during the production of FRM using milling, and it is also possible to improve the wear resistance to a desired value. FRMs using such milled or SiC whiskers, even when used alone, generally tend to be more brittle and have lower toughness than when metal is used alone. On the other hand, by using the method of the present invention which can obtain a preform body with excellent handling properties, the preform body is placed only on the surface area that requires wear resistance, and the entire body is pressure cast. By doing so, it is possible to manufacture a product with toughness and IT abrasion resistance, in which only the surface portion is made of FRM, without greatly reducing the toughness of the metal.

Effects of the Invention As described above, in the method for producing a short carbon fiber reinforced composite material of the present invention, a preform body is formed by mixing short carbon fibers (milled) with at least 61 types of whiskers and ceramic short fibers. After that, by infiltrating the metal under pressure in a molten state, at least one of the whiskers and short ceramic fibers plays the role of a binder, and a stable preform body that is easy to handle can be formed. This makes it possible to obtain a product that penetrates between each single fiber, disperses the short fibers almost uniformly in the metal, allows the metal and short fibers to be fully adhered to each other, and provides a product with excellent wear resistance. Moreover, the wear resistance can be adjusted arbitrarily, which is a special effect.

[Brief explanation of the drawing]

Figure 1 is a through-the-head mirror photograph of the short carbon fiber reinforced composite material obtained in Example 3 of the present invention without showing the metal III weave, and Figure 2 is a photograph of the composite material reinforced with carbon short fibers obtained in Example 3 of the present invention.
Enlarged photograph of a part of the figure, Figure 3 is an explanatory diagram of the 2nd section, 4th
The figure shows the abrasion test results of each product obtained in Examples 1 to 1 and 1 and Comparative Examples 1 to 3 of the present invention. 1... Milled (short carbon fiber), 2... SiC whisker 3... Aluminum alloy. Agent Yoshihiro Moriki

Claims (1)

[Claims] 1. A carbon short fiber reinforced metal composite characterized by mixing short carbon fibers and at least one of whiskers and ceramic short fibers to form a preform, and then infiltrating the metal under pressure in a molten state. Method of manufacturing the material.