PURPOSE: To easily and inexpensively manufacture a composite material in which reinforcement is uniformly dispersed in high volume percentage by heating a composite material containing a mixture of short fibers and large-diameter lubricating grains as a reinforcement and then allowing a part of molten matrix to exude under pressure.
CONSTITUTION: A composite material is formed by using a mixture of short fibers and lubricating grains as a reinforcement and also using a metal as a matrix. At this time, the value of the ratio of the average diameter of the lubricating grains to the average diameter of the above short fibers is set up at ≥2.5, and the upper limit is regulated to ≤ about 100, preferably ≥ about 50. Further, proper volume percentages of the short fibers and the lubricating grains in the above composite material are about 2-30% and about 5-30%, respectively, and proper value of the ratio between both is about 1/2 to 7. The above composite material is heated to melt at least a part of the matrix. Then, this composite material is pressurized, by which a part of the matrix is allowed to exude out of the region of this composite material. At this time, the movement of the lubricating grains with large diameter is inhibited by the short fibers. By this method, the composite material in which the fiber reinforcement and the lubricating grains are uniformly dispersed in the prescribed high volume percentages can be obtained.
MORIKAWA TAKASHI
KUBO MASAHIRO
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