Non-affine deformation in microstructure selection in solids: I. Molecular dynamics

Abstract

We study the nucleation dynamics and microstructure selection in a model two-dimensional solid undergoing a square to rhombic transformation, using coarse-grained molecular dynamics (MD) simulations. We find a range of microstructures depending on the depth of quench. The transformations are accompanied by the creation of transient and localized non-affine zones (NAZ), which evolve with the rapidly moving parent-product interface. These plastic regions are created beyond a threshold stress, at a rate proportional to the local stress. We show that the dynamics of NAZs determines the selection of microstructure, including the ferrite and martensite.