Research progress of effects of surface integrity and microstructure on high cycle fatigue performance of Nickel-based single crystal superalloys

• From the macroscopic to microscopic scales, the effects of surface integrity, microstructure, and loading conditions on the high-cycle fatigue behavior of Nickel-based single crystal superalloys are systematically reviewed. • The underlying mechanisms by which various factors affect high-cycle fatigue performance are critically reviewed. • High cycle fatigue crack initiation and propagation characteristics are summarized with crystallographic and fracture features. Nickel-based single crystal superalloys (hereafter referred to as Ni-SXs), with their superior high-temperature strength, are widely applied in turbine blades for aero-engines. However, repeated high-frequency stresses during service may lead to high cycle fatigue (HCF) failure. Fractographic observations indicate that cracks typically initiate at the surface or internal defects, linking HCF performance closely to surface integrity and microstructure. Moreover, the combined effects of elevated temperature and stress amplitude under service conditions strongly influence fatigue behavior. This review summarizes recent progress on the influence of surface integrity, microstructure, and experimental parameters on the HCF performance of Ni-SXs. The underlying mechanisms of fatigue crack initiation and propagation are discussed, with emphasis on dislocation activity, defect interactions, and environmental effects. The review aims to establish a link between HCF performance, surface integrity and microstructure from the macroscopic view to the microscopic view, providing some perspectives for future research.