Wear characteristics of copper-based surface-level microcomposites and nanocomposites prepared by friction stir processing

In this study, microsized and nanosized silicon carbide particles (SiCps) were successfully incorporated into commercial pure copper to form a surface metal matrix composite by friction stir processing (FSP) at low-heat-input conditions. A cluster of blind holes on a copper plate was used as particle deposition technique during the fabrication of the composite. Pin-on-disc testing was performed under dry sliding conditions to determine the wear characteristics of prepared composite surfaces. The homogeneity of particle distribution both inside the copper matrix and in the wear scar was determined via microstructural observations. It was observed that both microsized and nanosized SiCps were well distributed and homogenous in a stir zone; particles observed were without defects, and good bonding was observed between SiCps and the copper matrix. Comparisons between Cu/SiCp composite layers and friction stir processed (FSPed) Cu and as-received Cu showed that Cu/SiCp nanocomposite layers exhibited superior microhardness and dry sliding wear characteristics.