In the present work, thermomechanical fatigue behavior and life prediction of P92 steel welded joints under various mechanical strain amplitudes and phase angles are investigated. Results demonstrate that the welded joints exhibit significant cyclic softening during fatigue process and the thermomechanical fatigue life is strain amplitude and phase angle dependent. The decrease in strain amplitude and the increase in phase angle induce the increase in fatigue life. Fracture analysis indicates that the fracture position changes significantly with the strain amplitude and phase angle. Finally, a modified energy-based life prediction model is proposed by considering the effects of phase angle and mean stress.

在本工作中，研究了P92钢焊接接头在各种机械应变幅度和相角下的热机械疲劳行为和寿命预测。结果表明，焊接接头在疲劳过程中表现出明显的周期性软化，并且热机械疲劳寿命与应变幅度和相角有关。应变振幅的减小和相角的增加引起疲劳寿命的增加。断裂分析表明，断裂位置随应变幅度和相角的变化而显着变化。最后，通过考虑相角和平均应力的影响，提出了一种改进的基于能量的寿命预测模型。