Tribological behavior of squeeze cast aluminum matrix composites

Tribological behavior of squeeze cast aluminum alloy (2618, 6082, 7012 and 7075) matrix SiC particle-reinforced (50 vol.%) composites was examined using a reciprocating wear tester by rubbing a 10 mm diameter Al₂O₃ ball on the composite surfaces in air and in water. Wear tests conducted in air revealed that, at low test loads (≤3 N), the tribological performance of the composites were not remarkably influenced by the properties of the matrix alloy. At high test loads (≥4.5 N), where 7012 and 7075 aluminum alloy matrix composites exhibited superior tribological performance relative to 2618 and 6082 aluminum alloy matrix composites, the wear rate and coefficient of friction decreased with increasing matrix hardness. When compared to the sliding conditions during testing in air, the coefficient of friction and the wear rate of the composites were dramatically lower in water. Even at test loads as high as 24 N, tribological performance of composites tested in water was comparable to that of in air low load (≤4.5 N) testing conditions.