A phase-field model coupling with elastoplastic deformation and creep damage has been built to study the microstructural evolution and deformation behavior for Ni‒Al single crystal alloy during the whole creep processing. The relevant experiments were conducted to verify the model validity. The simulation results show that under the tensile creep at 1223 K/100 MPa, cubic γʹ phases coarsen along the direction parallel to the axis of tensile stress during the first two creep stages; and spindle-shaped and wavy γʹ phases are formed during tertiary creep, similar to the experimental results. The evolution mechanism of γʹ phases is analyzed from the perspective of changes of stress and strain fields. The “island-like” γ phase is observed and its formation mechanism is discussed. With the increase of creep stress, the directional coarsening of γʹ phase is accelerated, the steady-state creep rate is increased and the creep life is decreased. The comparison between simulated and experimental creep curves shows that this phase-field model can effectively simulate the performance changes during the first two creep stages and predict the influence of creep stresses on creep properties. Our work provides a potential approach to synchronously simulate the creep microstructure and property of superalloys strengthened by γʹ precipitates.

建立了具有弹塑性变形和蠕变损伤的相场模型，研究了Ni‒Al单晶合金在整个蠕变过程中的组织演变和变形行为。进行了相关实验以验证模型的有效性。仿真结果表明，在前两个蠕变阶段，在1223 K / 100 MPa的拉伸蠕变下，立方晶γʹ相沿平行于拉伸应力轴的方向粗化。在三次蠕变过程中形成了纺锤形和波状的γʹ相，与实验结果相似。从应力场和应变场的变化角度分析了γʹ相的演化机理。观察到“岛状”γ相，并讨论了其形成机理。随着蠕变应力的增加，加速了γdirectional相的定向粗化，增加了稳态蠕变速率，降低了蠕变寿命。模拟和实验蠕变曲线的比较表明，该相场模型可以有效地模拟前两个蠕变阶段的性能变化，并预测蠕变应力对蠕变特性的影响。我们的工作提供了一种潜在的方法来同步模拟由γʹ析出物增强的高温合金的蠕变组织和性能。