Mechanical Properties of Hot-Pressed B<sub>4</sub>C-TiB<sub>2</sub> Composites Synthesized from B<sub>4</sub>C-TiO<sub>2</sub> and B<sub>4</sub>C-TiC

In this study, B 4 C-TiB 2 ceramic composites were manufactured by hot pressing method. The raw materials for the in-situ synthesis of TiB 2 were TiO 2 and TiC. After being sintered at 1900°C for 60min under a pressure of 30MPa, compact composites samples with a TiB 2 volume fraction range from 0 to 11.05% were prepared. The relative density, fracture toughness and flexural strength of different sample were tested. Microstructures on the fracture surface were studied by SEM. The result shows that B 4 C-TiB 2 ceramic composites sintered from B 4 C-TiC had a better mechanical property than the one sintered from B 4 C-TiO 2 . When the content of TiB 2 (reacted from TiC) was 11.05vol.%, the strength and toughness of B 4 C-TiB 2 ceramics can reach 598MPa and 6.45MPa·m 1/2 . The toughening mechanisms of B 4 C-TiB 2 composites include micro-crack toughening and energy consumption by the pulling out process of second phase.