Hot-section components made by single crystal (SC) Ni-based superalloys with geometrical discontinuities such as film holes suffer from spatially inhomogeneous rafting of the γ'/γ microstructure due to harsh circumstances. Therefore, low cycle fatigue (LCF) life prediction is critical for ensuring the safety of engineering structures. Within this regard, an energy-based LCF life model is proposed based on the concept of the strain energy gradient by introducing the effect of rafting into the plastic and elastic parts of the strain energy density. The inhomogeneous microstructure degradation of a centre-hole specimen is depicted by stress-assisted rafting and stress-free isotropic coarsening, whereas the inelastic deformation behaviour of materials near the central hole is simulated by a microstructure-sensitive constitutive model. Combined with the concepts of modified strain energy density, effective damage zone and weight function, the proposed life model achieves a good prediction accuracy in ± 2 scatter bands against the experimental data of the centre-hole specimens with different rafting treatments. Finally, the uncertainty of the proposed life prediction model induced by the statistical dispersion of the microstructure is estimated. The results show that the uncertainty of the predicted lifetimes decreases with the rafting extent and fatigue life, even though the distribution of the γ channel width of the alloy with heavily rafting alloys is highly dispersed.

由具有几何不连续性的单晶 (SC) 镍基高温合金制成的热截面部件（例如薄膜孔）由于恶劣的环境而遭受 γ'/γ 微观结构的空间不均匀漂流。因此，低周疲劳（LCF）寿命预测对于确保工程结构的安全至关重要。在这方面，基于应变能梯度的概念，通过将筏板效应引入应变能密度的塑性和弹性部分，提出了基于能量的LCF寿命模型。中心孔试样的非均匀微观结构退化通过应力辅助漂流和无应力各向同性粗化来描述，而中心孔附近材料的非弹性变形行为则通过微观结构敏感的本构模型来模拟。结合修正应变能密度、有效损伤区和权重函数的概念，所提出的寿命模型与不同漂流处理的中心孔试样的实验数据相比，在±2个散射带内实现了良好的预测精度。最后，估计了由微观结构的统计离散引起的所提出的寿命预测模型的不确定性。结果表明，尽管重度漂流合金的γ通道宽度分布高度分散，但预测寿命的不确定性随着漂流程度和疲劳寿命的增加而降低。所提出的寿命模型与不同漂流处理的中心孔试样的实验数据相比，在±2个散射带内实现了良好的预测精度。最后，估计了由微观结构的统计离散引起的所提出的寿命预测模型的不确定性。结果表明，尽管重度漂流合金的γ通道宽度分布高度分散，但预测寿命的不确定性随着漂流程度和疲劳寿命的增加而降低。所提出的寿命模型与不同漂流处理的中心孔试样的实验数据相比，在±2个散射带内实现了良好的预测精度。最后，估计了由微观结构的统计离散引起的所提出的寿命预测模型的不确定性。结果表明，尽管重度漂流合金的γ通道宽度分布高度分散，但预测寿命的不确定性随着漂流程度和疲劳寿命的增加而降低。