TiC起始粉末粒径对TiC/Al_2O_3复合陶瓷热震行为的影响

Effect of TiC Starting Powder Size on Thermal Shock Behaviors of TiC/Al_2O_3 Ceramics

通过使用不同粒径TiC起始粉末热压制备了AT1和AT2两种不同晶粒大小的TiC/Al_2O_3复合陶瓷。研究了TiC/Al_2O_3复合陶瓷的热震循环疲劳机制和TiC起始粉末粒径对热震循环疲劳抗力的影响。TiC起始粉末粒径的调整可以控制TiC/Al_2O_3复合陶瓷的晶粒大小。AT2材料晶粒细化,其力学性能的改善是其热震循环疲劳抗力改善的根本原因。热震循环过程中的微裂纹,裂纹桥接和偏转,热震裂纹间的“碎粒”等是引起TiC/Al_2O_3复合陶瓷热震疲劳的机制。热震循环疲劳机制和细晶强化的综合作用导致了AT2材料的热震抗力有较大改善。

In this paper, hot-pressed TiC/Al2O3 composites were fabricated by adding difference size TiC starting powder. The thermal shock fatigue mechanisms of TiC/Al2O3 composite were studied and the influence of different TiC starting powder size on the thermal shock fatigue resistance was discussed. The improvement of AT2 ceramic mechanical properties is due to its fined grain. The thermal shock fatigue mechanisms of TiC/Al2O3 composites include micro-cracks, cracks deflection and bridge, the ＂crushed particles＂ between cracks. The fatigue mechanisms and fine grain strengthen lead primary contributes to the improvement of AT2 thermal shock fatigue resistance.