Modelling dynamic recrystallisation in magnesium alloy AZ31

In this paper, a dynamic recrystallisation (DRX) viscoplastic self-consistent (VPSC) model is created to predict the continuous DRX (CDRX) and twin-assisted DRX (TDRX) behaviour within an AZ31 magnesium (Mg) alloy over temperatures ranging from 25 degrees C to 200 degrees C. At this temperature range, the active deformation mechanisms and physical phenomena participating in the strain accommodation and texture evolution of Mg alloys are: a basal slip, a prismatic slip, c + a pyramidal slip, {1012} tensile twinning, and DRX. In order to predict which deformation modes are activated for this particular alloy and their influence on the DRX mechanism, a temperature sensitive VPSC model combined with a dislocation density hardening law and a composite twin grain model is used. The model is validated against a comprehensive set of experimental data including flow curves and texture evolution, realised on a hot-rolled AZ31 Mg alloy deformed at different temperatures between 25 degrees C and 200 degrees C under uniaxial tensile loads parallel to, perpendicular to, and at 45 degrees offset from the rolling direction of the processed material. Furthermore, a parametric study into parameters such as grain size, dislocation density, and crystallographic orientation of the nucleating DRX grains influencing the DRX kinetics and, subsequently, the plastic material behaviour of the alloy is carried out and discussed.