Recently, the demands for lightweight materials having high strength and high stiffness have attracted much interest in the development of the fabrication processes for metal matrix composites (MMCs). In this research is focused on Al 2 O 3 -alloy aluminum (A356) composite obtained via infiltration by squeeze casting `into porous ceramics of aluminum oxide (Al 2 O 3 ). Applied pressures for infiltration melt aluminum into perform of alumina were 50, 75, 100 and 125 MPa under casting temperatures 700, 750 and 800 ? C. The microstructural features, mechanical properties and wear characteristics of the composites and alloy were investigated. The results indicated that a homogenous distribution of Al 2 O 3 particle in the aluminum matrix, which is almost free of pores, can be obtained by squeeze casting method. The size of the ? Al phase and eutectic silicon phase decreased with increasing applied pressure. Higher strength and lower wear rates were observed in the composite materials than the unreinforced aluminum alloy part. However, a marked decrease in ductility of the composites arising from adding of perform of alumina was obtained. By increase in applied pressure from 50 to 100 MPa,at 700 ? C, yield strength and ultimate compression strength in the composite include 20 Vol.% alumina preform were up 15% and 26% ,respectively. Also in the composite include 25 Vol.% alumina preform, yield strength and ultimate compression strength were up to 25% and 4/8% ,respectively. In the applied pressure more than 125 MPa happened crushing of alumina preform consequently decreased the mechanical properties. The fracture surface of the Al 2 O 3 /A356 composite include 20 Vol.% alumina showed brittle fracture characteristics: on the fracture surfaces of the composite, broken and cleaved alumina preform were observed and the cracks were initiated in the brittle eutectic silicon phase.
