The Characterization of High Temperature, High‐Cycle Fatigue Behavior of a Nickel‐Based Superalloy

ABSTRACT Investigating high‐temperature, high‐cycle fatigue properties of nickel‐based superalloys is important since the superalloys are used in crucial high‐temperature components of aerospace engines. In this study, high‐cycle fatigue tests were performed for nickel‐based superalloy plates at 800°C at several stress levels, and a small number sample method was developed to predict equivalent fatigue life distribution of high‐temperature alloys. The high‐temperature S‐N curves were obtained at 800°C. The fatigue life at the maximum stress of 400 MPa is 0.9 × 10 7 . And the 95% confidence interval for the fatigue strength at 800°C was determined to be 415.6 ± 36.1 MPa. Moreover, the microstructure of fatigue fracture surfaces was observed. A microstructural analysis at various stress levels reveals that the dominant fracture mode is brittle fracture, exhibiting typical cleavage features. This research can guide evaluation of fatigue life for hot‐end components in aerospace engines.