Molecular dynamics simulation of thermomechanical fatigue properties of Ni-based single crystal superalloys

•TMF behavior at atomistic scale is studied by MD simulation for the first time.•The cyclic deformation mechanisms of superalloys under TMF loadings are revealed.•Stress–strain and stress response curves are obtained under TMF and IF loadings.•The failure reason and fatigue life of superalloys are analyzed under TMF loadings. In this paper, the thermomechanical fatigue (TMF) properties of Ni-based single crystal superalloys are studied by molecular dynamics simulations. Two different cyclic deformation mechanisms of superalloys are found under TMF loadings. The sample has a higher cyclic stress range, plastic strain energy density and a shorter fatigue life under Out-of-phase TMF loading than those under In-phase TMF loading. Moreover, the low-temperature tension half-cycle is more favorable for dislocations and stacking faults to cut into the γʹ precipitate phase, causing an earlier failure of superalloys under Out-of-phase TMF loading, which attracts more attention in actual operation.