In this study, a new framework for the fatigue life prediction of nickel-base single crystal (SX) superalloys with different drilling film cooling holes (FCHs) at high temperatures (900 ℃ and 980 ℃) is investigated based on surface integrity quantification and fracture mechanics. For all the tested SX superalloys with anisotropy (smooth and FCHs specimens), the initial damage state is regarded as the equivalent initial flaw size (EIFS) that is independent of the specimens and hole geometry in the same drilling, and the rationality of EIFS is verified for the first time by conducting numerous fatigue tests and comprehensive surface integrity analysis. Subsequently, the fatigue crack path and microstructure of different specimens at different temperatures are analyzed to reveal the crack initiation mechanism and propagation modes, and a new equivalent stress intensity factor, $\mathrm{\Delta }{\mathrm{K}}_{\mathrm{e}\mathrm{q}}$, is proposed to describe the crack propagation driving force. The EIFS and $\mathrm{\Delta }{\mathrm{K}}_{\mathrm{e}\mathrm{q}}$ are combined, and a fatigue crack growth rate (FCGR) with better fit is obtained to comprehensively reflect the different fracture modes (the mixture of Stage I and Mode I). Finally, based on the experimental observation and FCGR description, the fatigue life of the FCHs structure at room and high temperature is predicted to be 3–5 times the dispersion zone of the total fatigue life, and the ultimate defect length is proposed to guide the engineering practices.

在这项研究中，基于表面完整性量化和断裂研究，研究了具有不同钻孔膜冷却孔（FCH）的镍基单晶（SX）高温合金在高温（900 ℃和 980 ℃）下疲劳寿命预测的新框架。力学。对于所有测试的具有各向异性的 SX 高温合金（光滑和 FCHs 试样），初始损伤状态被视为与同一钻孔中的试样和孔几何形状无关的等效初始缺陷尺寸（EIFS），EIFS 的合理性为通过进行大量疲劳测试和全面的表面完整性分析，首次进行了验证。随后，分析了不同试样在不同温度下的疲劳裂纹路径和微观结构，揭示了裂纹的萌生机制和扩展模式，$\mathrm{\Delta }{\mathrm{ķ}}_{\mathrm{e}\mathrm{q}}$, 用于描述裂纹扩展驱动力。EIFS 和$\mathrm{\Delta }{\mathrm{ķ}}_{\mathrm{e}\mathrm{q}}$结合，得到拟合较好的疲劳裂纹扩展速率（FCGR），以综合反映不同的断裂模式（Ⅰ期和Ⅰ期的混合）。最后，基于实验观察和FCGR描述，预测FCHs结构在室温和高温下的疲劳寿命为总疲劳寿命分散区的3~5倍，并提出极限缺陷长度指导工程实践。