Molecular dynamics simulation of rhenium effects on creep behavior of Ni-based single crystal superalloys

Abstract

The tensile creep behavior of Ni-based single crystal superalloys was investigated by molecular dynamics simulations. The effects of rhenium (Re) on the creep behavior and microstructural evolution mechanism during nanoscale creep tests were discussed. The results indicate that the addition of Re can effectively enhance the creep resistance of the alloys. The reason is that Re plays an important role in the evolution of microstructure at each stage of the creep. Firstly, Re has a pinning effect to delay the failure of the dislocation network at the primary creep stage. And then, the addition of Re decreases dislocation density and increases steady creep time at the steady-state creep. Finally, Re segregates at the dislocations in the γ′ precipitates phase and prevents the dislocation from cutting into the γ′ phase by dragging dislocations at the tertiary creep stage, which enhances effectively the creep resistance of superalloys. These mechanisms help to further understand the creep behavior and derive an atomistic description of the Re effects on creep behavior and creep mechanisms in Ni-based single crystal superalloys.