To obtain a composite material having wear resistance equal to that of cast iron, reduced in specific gravity, increased in high temp. strength and thermal conductivity, and having high rigidity by sintering a powder mixture consisting of specific percentages of aluminum-base matal powder and cast iron powder.
A powder of cast iron in the amount of 5-80vol.% is added to a 95-20vol.% of Al or Al alloy powder, and these are mixed, and the resultant powder mixture is compacted and sintered. At this time, it is preferable that pressure sintering is performed in vacuum or in a nonoxidizing atmosphere at 550-800°C under a pressure of ≥5kg/cm2. By this procedure, the composite material having, preferably, (70 to 230)W/(m.K) thermal conductivity and ≤10% porosity can be obtained. By properly selecting the mixing ratio of raw material powders, specific gravity, wear resistance, thermal conductivity, and coefficient of thermal expansion can be regulated to desired poperties, Further, because Al is used as the matrix, high thermal conductivity is obtained and heat radiation characteristic is improved and specific gravity can be reduced and weight reduction is made possible. Moreover, because the cast iron powder is dispersed, sufficient mechanical properties and wear resistance at high temp. can be obtained and the occurrence of thermal deformation due to high temp. can be prevented.
SUWABE HIROHISA
OSHIMA MASAHIKO
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