Full field modeling of recrystallization: Effect of intragranular strain gradients on grain boundary shape and kinetics

Abstract

The effect of stored energy field heterogeneity on the microstructure evolution during static recrystallization (SRX) was assessed by performing three dimensional (3D) full field simulations. These simulations were performed by using the Level set (LS) method in a finite element (FE) framework with unstructured tetrahedral FE mesh. An extension of classical LS-FE for SRX was developed to account for average stored energies in zones adjacent to grain boundaries (GBs) in each grain. Annihilation of dislocations by a passing GB was taken into account. The results of 3D simulations were analyzed to compare the “per interface” LS model to the usual “per grain” LS method (with averaging stored energy per grain). Recrystallization is faster at the beginning of the heat treatment when using the “per interface” model. The analysis of the evolution of grain volume and grain surface scattering reveals that the “per interface” approach results in complex shapes of grains which are closer to those observed in experiments. Local simulations for few grains with refined FE mesh were also performed to study the effect of stored energy heterogeneity along interfaces, and even higher complexity of grain topology was observed compared to the results of “per interface” computations.