基于耦合损伤的镍基单晶高温合金DD6同相热机械疲劳寿命预测

Based on the in-phase thermomechanical fatigue experiments under stress control, the damage mechanism of in-phase thermomechanical fatigue of DD6 superalloy was investigated. Based on the continuous damage mechanics, a lifetime prediction model reflecting the coupling of creep damage and fatigue damage was established, and the damage parameters in the model were obtained through using the experiment data of creep and fatigue. Furthermore, the experiments of in-phase thermomechanical fatigue with dwells of DD6 superalloy were conducted in the present paper, and the experiment lifetimes are within a factor of 2.3 of the prediction lifetimes based on the coupling damage. Results indicate that the coupling damage based lifetime prediction model developed in the present paper could accurately predict the in-phase thermomechanical fatigue lifetimes of DD6 superalloy and provides a basis for the lifetime prediction of DD6 superalloy structure in engineering applications.