Particle effects on friction and wear of aluminium matrix composites

Particle effects on friction and wear of 6061 aluminium (6061 AI) reinforced with silicon carbide (SIC) and alumina (AI203) particles were investigated by means of Vickers microhardness measurements and scratch tests. Unreinforced 6061 AI matrix alloy was also studied for comparison. To explore the effect of heat treatment, materials subjected to three different heat treatment conditions, i.e. under-aged, over-aged and T6, were used. Multiplescratch tests using a diamond and a steel indenter were also carried out to simulate real abrasive wear processes. Vickers microhardness measurements indicated that T6 heattreated composites had the highest hardness. Single-scratch tests showed that the variation of friction coefficient was similar to that of Vickers hardness and the peak-aged composites exhibited the best wear resistance. The wear rate of fine particle-reinforced composites was mainly affected by hardness. However, thewear rate of large particle-reinforced composites was influenced by both the hardness and fracture of the particles.