Influence of strain rate and crystallographic orientation on dynamic recrystallization of pure Zn during room-temperature compression

Abstract

This work investigates the strain rate dependence of dynamic recrystallization behaviour of high-purity zinc in room temperature compression under strain rates of 10−4 s-1, 10-2 s-1 and 0.5 s-1. Results from electron backscatter diffraction provide insight into the deformation and dynamic recrystallization mechanisms operative. Continuous dynamic recrystallization, twin-induced dynamic recrystallization, and discontinuous dynamic recrystallization are all active under compressive deformation at room temperature. Due to the high stacking fault energy of Zn, continuous dynamic recrystallization is the dominant mechanism while discontinuous dynamic recrystallization only operates in the early stages of compression at 10−4 s-1. Dynamic recrystallization kinetics are enhanced at higher strain rates (10-2 s-1 and 0.5 s-1) due to an increased contribution from twin-induced dynamic recrystallization. The present study reveals that the controlling mechanisms for continuous dynamic recrystallization are basal < a> slip and 2nd order pyramidal < c + a> slip activity. Because the activation of slip systems is mainly determined by crystallographic orientation, continuous dynamic recrystallization behaviour varies with grain orientation according to their propensity for basal and 2nd order pyramidal slip.