Microstructure and Mechanical Properties of Hot-pressed TiB_2 Ceramics

TiB2 ceramics with Y2O3-Al2O3 as sintering aids were fabricated by hot-pressing. The effects of sintering temperature, holding time, and crystallization annealing on microstructure and mechanical properties were investigated. The experimental results show that the flexural strength and fracture toughness of TiB2 ceramics decrease and the weight loss increases with sintering temperature rising up; with holding time prolonged, the uniformity of microstructure decreases and this is disadvantageous to the mechanical properties. The grain diameter has a significant infiuence on the mechanical properties of TiB2 ceramics. The crystallization annealing can result in YAG phase from grain boundaries and enhance the flexural strength at high temperature of TiB2 ceramics.