Cyclic plasticity modeling of nickel-based superalloy Inconel 718 under multi-axial thermo-mechanical fatigue loading conditions

High temperature components work mainly under thermo-mechanical loading conditions. Recent investigations reveal significant effects of the thermo-mechanical coupling on material behavior. In the present work, extensive experiments are performed for nickel-based superalloy Inconel 718 under both isothermal and thermo-mechanical loading conditions. Within the framework of the Ohno-Wang cyclic plasticity, a modified constitutive model is suggested to describe cyclic hardening/softening, non-proportional hardening, non-masing effects observed in the experiments. The implicit integration algorithm is developed and implemented into a commercial finite element code. Comparison between experiments and computations confirms that the suggested model can predict the cyclic plastic behavior under most different varying temperatures and multi-axial loading paths reasonably.