Microstructure and mechanical properties of high-temperature and high-pressure sintered TiC-based composites with Al and cBN additions

The mechanical properties of titanium carbide (TiC) ceramics are limited by poor densification during sintering and their intrinsic brittleness. In this study, 5 wt% Al was introduced as a sintering aid, and 10 wt% cubic boron nitride (cBN) was added to fabricate TiC-based ceramic composites via high-pressure high-temperature (HPHT) sintering. The microstructure and mechanical properties were systematically investigated. The composites sintered at 4 GPa and 1400 ℃ exhibited optimal properties, with a Vickers hardness of 37.43 GPa and a fracture toughness of 11.41 MPa·m 1/2 , representing increases of 69% and 132% compared with monolithic TiC, respectively. Microstructural analysis shows that Al promotes densification by enhancing interparticle bonding, while cBN participates in interfacial reactions under HPHT conditions, leading to formation of rod-like TiB 2 phases distributed along grain boundaries. The results demonstrate that the synergistic effect of Al-assisted densification and cBN-induced TiB 2 formation governs the microstructure evolution and mechanical performance of TiC-based ceramic composites, providing a feasible strategy for designing high-performance TiC-based ceramic.