Microstructure and performance of solidified TiB2 TiC composites prepared by high pressure and high temperature

Dense TiB₂TiC composites were synthesized by high pressure method at 5.5 GPa and 1400–1800 °C with pure Ti and B₄C powders as raw materials. The phase composition, density, microstructure, hardness and thermal conductivity of TiB₂TiC composites were analyzed. The results indicated that, the formation of intermediate phases were strongly depended on the synthesis temperature. TiB₂TiC composites prepared under high pressure condition had a dense microstructure without obvious pores, which could achieve the bulk density and the relative density about 4.40–4.57 g/cm³ and 95.1%–98.7%. Vickers hardness values was up to 22.1–30.1 GPa with the load of 4.9 N and 20.3–28.9 GPa with the load of 9.8 N. Thermal conductivity of the TiB₂TiC composites was measured to be 51.2–74.5 W/m⁻¹ K⁻¹. The density and grain size of the TiB₂TiC composites changed with the increase of temperature, leading to the change of hardness and thermal conductivity.