Prediction of the critical conditions for dynamic recrystallization in metals

Abstract

Abstract Engineering approaches to model dynamic recrystallization (DRX) explicitly assume the existence of a critical strain for DRX. Since the strain is not a state variable of crystal plasticity, however, there is no critical strain, rather there are critical conditions for microstructural instability. It was proposed recently that these critical conditions can be expressed in terms of a point of inflection on the θ(σ) curve, where σ is the flow stress and θ is the hardening rate. A theoretical framework is presented to predict these critical conditions on the basis of a dislocation work hardening model. Once tuned to a specific hardening curve the model allows to predict the onset of DRX for different temperatures and strain rates, and, in principle, for changing materials chemistry.