含20%Ni金属基陶瓷的热冲击疲劳

Thermal Shock Fatigue Behavior of Ceramets Containing 20% Nickel

研究了含２０％Ｎｉ的Ｔｉ（Ｃ，Ｎ）基金属陶瓷的热冲击疲劳。试验结果表明：随循环温度的上升和冷却速率的加快，热冲击疲劳裂纹的形成孕育期缩短，裂纹扩展速率加快。缺口也使裂纹形成的孕育期缩短。观察还表明，热冲击疲劳断口中存在疲劳条纹。

The thermal shock fatigue behavior of Ti(C,N) based ceramets containing 20% nickel has been studied The results show that the formation of thermal shock fatigue cracking is related to the nucleation, growth and joining of microvoids distributed at the interfaces of Ti(C,N)/Ni phases The incubation period of crack formation decreases and the rate of crack propagation increases with increasing cyclic temperature and cooling rate within the cycles The effects are mainly caused by increases of thermal stress and temperature gradients within the specimens The introduction of a notch also has the same effect SEM examination has some striae on the thermal shock fatigue fracture surfaces The crack propagation is a continuous process on a macroscopic scale although discontinuous microscopically