Microstructure and friction/wear behavior of (TiB+TiC) particulate-reinforced titanium matrix composites

This study examined the microstructure and friction/wear behavior of (TiB+TiC) particulate-reinforced titanium matrix composites (TMCs) fabricated by in situ synthesis. Boron carbide (B4C) particles with 1500 μm (1500 μm B4C) or 150 μm (150 μm B4C) diameter were added to a titanium matrix during vacuum induction melting to provide in situ synthesized (TiB+TiC) particulate reinforcement. The reinforcements prepared with 150 μm B4C were finer than those prepared with 1500 μm B4C. The size of the reinforcement particles affected their tendency to fragment under the applied load and thus produce more wear of the TMCs. Therefore, the friction and wear behavior of the TMCs is discussed on the basis of the coefficient of friction, hardness, and reinforcement fragmentation during sliding wear. The fine TMC reinforcements prepared with 150 μm B4C were more easily fragmented from the Ti matrix than the coarse reinforcements, and this debris further decreased the wear resistance. An adherent transfer layer on the worn surface was formed from hardened particles of oxide debris, reinforcements, and base material. Its presence produced two-body abrasion.