Processing and mechanical properties of Ti–6Al–4V/TiC in situ composite fabricated by gas–solid reaction

Titanium carbide (TiC) reinforced Ti–6Al–4V powder metal (P/M) composites were developed using a gas–solid in situ reaction process. The elemental blended powders were cold compacted in a die and reacted with methane (CH4) to form titanium carbide. The reacted compacts were then sintered in vacuum and HIPed without canning to close residual pores. Titanium carbide, aluminum carbide and vanadium carbide were formed during the reaction but only titanium carbide remained after the sintering. Although sintering densified the composites to fairly high densities (over than 95% of the theoretical), full densification could not be obtained by sintering alone. The fully densified composites after HIPing showed higher hardness, higher elastic modulus and tensile strength, and better wear resistance than wrought Ti–6Al–4V alloys, but were much less ductile at room temperature.