Microstructural Characterization and Sliding Wear Behavior of Cu/TiC Copper Matrix Composites Developed Using Friction Stir Processing

The relatively new severe plastic deformation method, friction stir processing (FSP), is a cutting-edge process to synthesize surface and bulk metal matrix composites. The present work is focused to produce Cu/TiC copper matrix composites (CMCs) and investigate the microstructure and sliding wear behavior at room temperature without lubrication. In the beginning of the process, TiC particulates were pressed in a machined groove on the surface of copper plates. The dimensions of the groove were altered to produce four different volume fractions of TiC particulates (0, 6, 12, and 18 vol%). FSP was accomplished by an optimized set of process parameters. The microstructure was observed using optical microscopy, scanning electron microscopy, and electron back-scattered diffraction. The microstructures showed a consistent dispersion of TiC particulates in the copper matrix irrespective of the volume fraction. The dispersion was observed to be uniform across the whole stir zone region. The interfacial bonding with the copper was proper. The reinforcement of TiC particulates enhanced the microhardness and led to a reduction in the wear rate of the composite remarkably. TiC particulates changed the wear mechanism and the geometry of wear debris. Highest hardness and lowest wear rate were observed in Cu/18 vol% TiC CMC.