Plasticity driven elemental redistribution in microstructural evolution of multicomponent Ni-based superalloys: A thermodynamic-driven multicomponent crystal plasticity phase field modeling

Abstract

Elemental partitioning in multicomponent Ni-based superalloys is fundamentally governed by thermodynamic driving forces and in turn controls the kinetics of precipitate growth, coarsening and rafting under service conditions. Among these forces, elastic strain energy plays a key role in altering elemental partitioning and thus feeding back on microstructural evolution, but the contribution of plastic deformation remains insufficiently understood. Here, we employ crystal plasticity coupled phase field simulations to thoroughly examine the elemental partitioning and microstructural evolution in multicomponent Ni–Al–Cr–Mo superalloy under applied strain conditions. The results reveal a pronounced tensile-compressive asymmetry in elemental partitioning under plasticity conditions, arising from the combined effects of γ/γʹ lattice mismatch and applied strain. In addition, the partitioning behavior of Mo is reversed under compressive strain conditions due to a reduction in the elastic potential difference. Furthermore, the γʹ coarsening rate displays contrasting trends under tensile and compressive strains due to variations in the γ/γʹ lattice mismatch. These findings underscore the importance of plasticity in regulating elemental partitioning and microstructural stability in Ni-based superalloys, providing new insights for future research on creep processes and stress-assisted aging heat treatment.