Sliding wear of aluminum-silicon carbide metal matrix composites

The sliding wear of an aluminum matrix composite, reinforced with different volume fraction of particles, against a stainless-steel slider has been studied. In dry conditions, i.e., unlubricated tests, the pairs (slider and specimen), wear. When rubbing against an aluminium alloy (unreinforced), the slider does not wear but the aluminum alloy wears quickly by adhesion. In dry conditions, both slider and composite wear, but there is a minimum wear rate for this pair at a critical volume fraction of reinforcing particles. Under lubricated conditions, the situation changes dramatically. The composite no longer wears, but the slider wears very quickly. Under water, results are a compromise between the two previous situations, dry and lubricated. These results are explained by a simple, descriptive mechanism, which takes in account both the effect of the shear rate, due to the sliding action in the composite, and the abrasive effect of the particles. A general relationship, which describes the effect of the applied pressure and volume fraction of particles in the composite, is proposed.