Creep Damage Process of Ni-Base Superalloy Caused by Stress-Induced Anisotropic Atomic Diffusion

Abstract

In order to make clear the mechanism of the directional coarsening of γ' phases (rafting) of Ni-base superalloy under uni-axial strain, molecular dynamics (MD) analysis was applied to analyze the effect of strain on the diffusion characteristics around the interface between different materials. In a Ni (001)/Al (001) interface structure, the stress induced diffusion of Al atoms perpendicular to the interface was found. The stress induced anisotropic diffusion of Al was also found in a Ni (001)/Ni₃Al (001) interface. These results imply that it is highly possible the rafting occurs predominantly by the stress induced anisotropic diffusion of Al atoms.