Microstruture and Mechanical Properties of Ti.Grade12-Ti/TiN/WC Composite Produced by Spark Plasma Sintering Process

Ti.Grade12 is widely used in chemical processing, power generation, and nuclear industries because of its excellent corrosion resistance and mechanical strength, enhanced by alloying elements such as Ni and Mo. Ceramic reinforcements such as TiN have been reported to significantly improve the surface hardness and wear resistance of titanium-based materials. Furthermore, nano-sized WC particles can suppress excessive intermetallic compound formation and stabilize the Ti matrix through grain boundary pinning and microstructural control mechanisms. However, strong interfacial bonding between Ti and ceramic reinforcements generally requires high temperatures and prolonged sintering times, which may induce undesirable secondary phase formation. Therefore, optimizing the mixing ratio of Ti, TiN, and WC is essential to achieve a homogeneous interface and a stable composite structure. In this study, a composite layered structure was fabricated on a Ti.Grade12 substrate using mixed Ti, TiN, and nano-sized WC powders via Spark Plasma Sintering. A composition of 60 wt% Ti, 35 wt% TiN, and 5 wt% WC formed a stable coating layer without secondary phases and achieved a micro vickers hardness of approximately 2400 Hv.