Structural, mechanical and tribological properties of A356 aluminium alloy reinforced with Al2O3, SiC and SiC plus graphite particles

Abstract

Particulate composites with A356 aluminium alloy as a matrix were produced by compocasting process using ceramic particles (Al2O3, SiC) and graphite particles. The matrix alloy and the composites were thermally processed applying the T6 heat treatment regime. Structural, mechanical and tribological properties of heat treated matrix alloy and the composites were examined and compared. It was shown that heat treatment affected microstructure of the composites matrix. The fracture of the composites matrix was ductile, while transition from ductile to brittle fracture occurred in the zone of reinforcing particles. The values of elasticity modulus of all the composites were higher in relation to the matrix alloy. It was also established that wear resistance and coefficient of friction were better at the SiC particulate composites than at the Al2O3 particulate composite, while the addition of graphite particles improved tribological properties further.