Study on Creep–Fatigue Properties of GH2070P Iron–Nickel‐Based Superalloy

ABSTRACT The creep–fatigue interaction behavior and underlying micro‐mechanisms of the FeNi‐based superalloy GH2070P were investigated under the conditions of 650°C, 0.5% strain amplitude, and varying dwell times. Through a series of creep–fatigue experiments integrated with analyses of cyclic stress response, fracture morphology, microstructural characterization, and dislocation structures, the evolution of damage mechanisms with increasing dwell time was comprehensively elucidated. The results demonstrate that the alloy exhibits cyclic softening behavior in the early stage of creep–fatigue testing. However, in the later stage, the mechanical response of the material undergoes significant changes due to the occurrence of age‐hardening effects during prolonged high‐temperature dwell of the solution‐treated alloy. This study provides critical experimental evidence and theoretical insights for a deeper understanding of the damage evolution mechanisms of GH2070P alloy under complex service conditions.