【摘要】 研究了新型Cr Ni Mo铸造热作模具钢在应力控制下的热机械疲劳寿命、应力应变响应以及疲劳断裂特征。试验中发现 ,在相同的应力幅下 ,同相热机械疲劳寿命低于上限温度的等温疲劳寿命。疲劳过程中热作模具钢发生了循环软化和沿着拉伸方向的循环蠕变 ,热作模具钢的热机械疲劳裂纹往往穿晶萌生 ,沿晶扩展更多还原

【Abstract】 The thermomechanical fatigue (TMF)life,stress strain responses and fracture characteristics of Cr Ni Mo casting hot work die steel under stress controlling were studied At the same stress levels,the life under in phase thermomechanical fatigue conditions is lower than that under isothermal fatigue conditions at the upper limit temperature In TMF tests,the circular softening and the circular creeping in the tensile direction occur in hot work die steel (HWDS),the TMF crackles of the steel initiate through the grains and grow along grain boundaries frequently更多还原