In this work, a dislocation-based crystal plasticity finite element (CPFE) framework was implemented to investigate the effects of loading conditions on dwell-fatigue crack initiation life. Experimentally, a large number of strain-controlled dwell-fatigue tests were carried out at 650 °C in a nickel-based superalloy. The combinations of CPFE simulations and post-test examinations were used to reveal the dwell-fatigue crack initiation mechanisms. Then, a life prediction approach was presented on the basis of accumulated energy dissipation at half-life cycle. Good agreement between the experimental and simulated lives verifies the robustness as well as the accuracy of the present approach. Finally, a new three-dimensional (3-D) damage tolerance diagram was proposed by introducing a CP-based physical parameter to describe the degradation levels and evaluate the residual dwell-fatigue life.

在这项工作中，实施了基于位错的晶体塑性有限元 (CPFE) 框架来研究加载条件对驻留疲劳裂纹萌生寿命的影响。实验上，在镍基高温合金中在 650 °C 下进行了大量的应变控制驻留疲劳试验。CPFE 模拟和测试后检查的组合用于揭示驻留疲劳裂纹的萌生机制。然后，提出了一种基于半生命周期累积能量耗散的寿命预测方法。实验和模拟生活之间的良好一致性验证了本方法的鲁棒性和准确性。最后，