Modelling discontinuous dynamic recrystallization using a physically based model for nucleation

A physically based model for nucleation during discontinuous dynamic recrystallization (DDRX) has been developed and is coupled with polyphase plasticity and grain growth models to predict the macroscopic stress and grain size evolution during straining. The nucleation model is based on a recent description for static recrystallization and considers the dynamically evolving substructure size. Model predictions are compared with literature results on DDRX in pure Cu as a function of initial grain size, deformation temperature and strain rate. The characteristic DRX features such as single to multiple peak stress transitions, convergence towards a steady-state stress and grain size, and a power-law relationship between the stress and grain size are quantitatively reproduced by the model. The critical conditions for the onset of nucleation in the model are shown to compare well with Gottstein et al.'s experimentally determined critical stress criteria. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.