Creep Behavior and Its Influencing Factors in High-Entropy Superalloys: A Molecular Dynamics Simulation Study.

In aero-engine applications, turbine blades operate under high-temperature and high-pressure thermomechanical cyclic loading conditions, which demand exceptional mechanical performance. High-entropy superalloys, characterized by a stable dual-phase γ/γ' microstructure, have emerged as promising candidates for high-temperature structural materials due to their superior creep resistance. In this study, the creep behaviors of high-entropy superalloys are systematically investigated using molecular dynamics simulations, exploring the effects of stress, temperature, γ/γ' lattice misfit, and γ' volume fraction on creep deformation mechanisms. The results show that both stress and temperature significantly influence creep behavior, with temperature exerting a more dominant effect. As the applied stress increases, the dominant creep mechanism evolves from atomic diffusion to dislocation nucleation and motion, eventually leading to phase transformation. Additionally, the γ/γ' lattice misfit and γ' volume fraction are found to critically affect the alloy's creep resistance. Specifically, creep resistance initially increases and then decreases with increasing lattice misfit magnitude, while a negative misfit yields better performance than a positive one. Moreover, increasing the γ' volume fraction enhances the alloy's ability to resist creep deformation. Microstructural analysis and atomic diffusion data further reveal that the creep resistance of high-entropy superalloys is closely associated with the structural stability of the γ/γ' dual-phase system. These findings provide useful insights for optimizing the high-temperature performance of high-entropy superalloys through microstructural design.