Phase-field Simulation of Recrystallization in Cold Rolling and Subsequent Annealing of Pure Iron Exploiting EBSD Data of Cold-rolled Sheet

A unified theory for continuous and discontinuous annealing phenomena based on the subgrain growth mechanism was proposed by Humphreys around twenty years ago. With the developments in the unified subgrain growth theory, a number of Monte Carlo, vertex, and phase-field (PF) simulations have been carried out to investigate the nucleation and growth mechanisms of recrystallization by considering the local alignment of the subgrain structure. In this study, the effects of the microstructural inhomogeneities created in the deformed state on recrystallization kinetics and texture development were investigated. Numerical simulations of static recrystallization were performed in three-dimensional polycrystalline structures by coupling the unified subgrain growth theory with PF methodology. To prepare the initial microstructures, two-dimensional electron back scattering diffraction (EBSD) measurements were carried out on 90% and 99.8% cold-rolled pure iron. Our previous experimental study has shown that there are large differences in the texture formation processes during the recrystallization of cold-rolled iron samples. In cold-rolled iron with 90% reduction, the simulated texture exhibited nucleation and growth of gamma-fiber (ND//< 111 >) grains at the cost of alpha-fiber (RD//< 011 >) components, where ND and RD denote normal direction and rolling direction, respectively. In contrast, the simulation results for cold-rolled iron with 99.8% reduction reproduced the high stability of the rolling texture during recrystallization. As a result, we conclude that the simulation results agreed with the experimentally observed textures in both the samples.