Size- and shape-adjustable multiscale precipitate model for three-dimensional discrete dislocation dynamics

Abstract

Precipitate strengthening is a key mechanism allowing materials scientists to design alloys with desirable strength characteristics. From a computational perspective, this calls for accurate modeling techniques able to describe the interaction of complex dislocation networks with the quenched pinning field created by precipitates of different sizes and shapes. Here, we present a multiscale modeling study of dislocation-precipitate interactions in BCC iron containing cementite precipitates, combining molecular dynamics and discrete dislocation dynamics simulations. Using input from molecular dynamics simulations of an individual dislocation driven through individual precipitates of different sizes and shapes, we construct a coarse-grained precipitate model in discrete dislocation dynamics simulations, considering both isotropic and anisotropic elasticity. The resulting model allows one to obtain quantitative predictions of material strength for micrometer-scale precipitation-hardened crystals.