Dynamic recrystallization and deformation behavior of an extruded Zn-0.2 Mg biodegradable alloy

Abstract

In this study, deformation behavior of a Zn alloy containing 0.2 wt. % magnesium was studied using compression tests. The compressive deformation was applied up to 1.6 true strain at a wide temperature range of −40 to 300 °C under strain rates of 0.003, 0.03 and 0.3 s−1. Microstructural observations indicated that dynamic recrystallization occurred at the all deformation conditions. Electron back scattered diffraction results implied that continuous dynamic recrystallization (CDRX) was operative during compression through progressive lattice rotation mechanism. Moreover, the new grains are rotated not only around the c-axis but also around the prismatic and pyramidal poles. The DRX progression was discussed considering the orientation factors provided for different slip systems. After compression, the initial extrusion texture was replaced by a new one including basal plane normal to the compression axis. Also, as the deformation temperature and the strain rate decreased, the volume fraction of DRX grains increased. The flow stress of the experimental alloy was successfully modeled based on an exponential constitute equation. An activation energy of 80.5 kJ/mol was obtained for deformation, which was justified according to the cooperation of limited grain boundary migration and dynamic dislocation recovery.

Keywords

• Zinc based bioalloy
• Compressive deformation
• Dynamic recrystallization
• Flow curve
• EBSD map