Simulating Grain Growth in a Deformed Polycrystal by Coupled Finite-Element and Microstructure Evolution Modeling

Abstract

The interplay between deformation and microstructure evolution can be strong and is the basis of a large majority of thermomechanical processing techniques for metals. We present simulations of this interplay, using a sharp-interface front tracking model for grain growth and a finite-element polycrystal plasticity model of deformation that includes anisotropic linear elasticity. The two approaches are iteratively coupled, so that grain growth affects the deformation behavior, and vice versa. Analyses of both purely elastic and of elastic-plastic materials are presented through coupled simulations of static loading of model polycrystalline microstructures. In the elastic case, stored elastic energies can reach relatively high values, and the mechanical driving force can locally exceed the curvature driving force, causing boundaries to assume noncompact (rippled) shapes. These large driving forces also serve to accelerate the grain growth process. In the elastic-plastic case, under relatively low strains, plasticity provides a stress relief mechanism that prohibits the generation of large stored elastic energies; thus, substantial deviations from compact interface morphologies were not observed, and growth kinetics did not accelerate substantially.