Wear Characteristics of Particle-Reinforced Aluminum Matrix Composites in Lubricated Reciprocating Contacts

The wear behavior of two types of aluminum alloy-based matrix composites (6061-Al/10% Al2O3 and 359-Al/10 and 20% SiC) against Mo/Ni-based alloy blend coated cast iron in lubricated reciprocating contacts was investigated. Wear mechanisms for the composite materials tested were polishing, abrasion, and surface fatigue. Surface fatigue was the dominant wear mechanism. A wear process with the following steps has been proposed: matrix wear and reinforcement protrusion to carry the applied load, then cracking of the interface between the matrix and reinforcement, followed by reinforcement cracking and pull-out. Extrusion during manufacturing enhanced the wear resistance which resulted in a lower wear rate of 6061-Al/10% Al2O3 as compared to cast 359-Al/10% SiC. The 20% volume fraction of SiC in metal matrix composites (MMC) reduced fracture toughness and caused high wear. Surface roughness played an important role in the wear process, but its influence was minor when the roughness was below a certain level.