Modified kinetic model for describing continuous dynamic recrystallization behavior of Al 2219 alloy during hot deformation process

摘要

A unidirectional thermal compression test was applied to study the flow behavior and softening mechanism of Al 2219 alloy during hot deformation with a temperature range of 623 K-773 K, and strain rate range of 0.01s(-1)-1s(-1). The true stress-strain curves obtained show that flow stress increases with the increase in strain rate and/or the decrease in temperature. Moreover, dynamic softening occurs on Al 2219 alloy during the hot deformation process. The continuous dynamic recrystallization (CDRX) of 2219 aluminum was observed using electron backscattered diffraction (EBSD) technique. Mean misorientation angle deviation and the reduction percentage in subgrain boundaries were proposed to describe recrystallization fraction qualitatively and quantitatively. The results show that the recrystallization fraction increases with the increase in temperature and the decrease in strain rate. Furthermore, a modified kinetic model of Al 2219 alloy using the specified initial microstructure and hot deformation conditions was developed, which is based on the traditional Avrami model. The modified model shows higher prediction accuracy, and also makes the steady-state strain physically significant. (C) 2019 Elsevier B.V. All rights reserved.