Machinability of Graphitic Metal Matrix Composites as a Function of Reinforcing Particles

Abstract Aluminum Metal Matrix Composites (MMCs) reinforced with ceramic particles have been developed for high wear resistance applications such as cylinder liners and brakes as a replacement for gray cast iron. Ceramic particles in an aluminum matrix improve its wear resistance property, but also cause high abrasive wear on cutting tools, which results in poor tool life and inconsistent part quality. A new family of MMCs (GrA-Ni®) consisting of an aluminum matrix reinforced with nickel-coated graphite particles and SiC or Al2O3 particles was recently developed. This paper presents the results of machining tests conducted to assess the machinability of the new graphitic ceramic reinforced MMCs. It was found that graphitic aluminum MMC reinforced with alumina is easier to machine than those reinforced with both SiC and graphite or SiC particles only. The incorporation of graphite into these composites and the variation of hard particle content improve their machinability.