Flow Curve and Microstructure Analysis of a ZK60 Magnesium Alloy during Hot Compression Tests

In this work, a commercial extruded Mg-6Zn-0.5Zr (ZK60) magnesium alloy was compressed to investigate the correlations among flow curve shape, microstructure evolution and loading parameters in terms of strain rate and deformation temperature. According to the results, twinning played an important role during deformations below 250 °C and the number of twinning bands increased with the increase in strain rate. Twinning caused initially softening followed by hardening. The flow curve shape before peak stress was determined by the number of twinning bands that were initiated. Dynamic recrystallization (DRX) was initiated during deformations at temperatures higher than 150 °C, and the DRX grain size decreased with strain rate and increased with deformation temperature. At 400 °C, twinning was not initiated and the microstructure of the specimens was composed of both DRX and SRX (static recrystallization) grains.