Molecular dynamics study of the effect of rolling process on subsurface strengthening of nickel-based superalloy GH4169 plastic deformation

Abstract

In this paper, the molecular dynamics (MD) method is used to establish a rolling model at the nanoscale, the same depth of rolling is rolled, and three rolling methods are used, namely, one time, two times and three times respectively. The effects of three rolling methods on the workpiece are studied, and the evolution of dislocation and defect atoms, subsurface damage, surface quality and subsurface micro-strengthening mechanism of the rolled workpiece are mainly analyzed. The results show that the dislocation density increases most significantly by one rolling, and the difficulty of material deformation is reduced by multiple rolling, with the increase of rolling times, the surface roughness increases. We found that the rolling process has a directional effect on the micro-strengthening of nickel-based single crystal alloys, and the strengthening effect is most significant in the normal direction. The subsurface strengthening effect of rolled workpiece is positively correlated with dislocation density and rolling force. Compared with the previous macro rolling test research, we observed the strengthening effect of dislocation density on rolling plastic deformation of nickel-based single crystal alloy from the microscopic level, which can provide a reference for understanding the strengthening mechanism of rolling process on nickel-based single crystal alloy and the optimization of rolling parameters.