Investigation of the alloying effect on deformation behavior in Mg by Visco-Plastic Self-Consistent modeling

Abstract

Alloying elements can drastically alter the deformation behavior of Mg. In the present work, Visco-Plastic Self-Consistent (VPSC) modeling was employed to investigate the effect of alloying elements on Mg's tensile behavior, in particular the relative activity of different slip and twinning modes. Mg-0.47 wt.% Ca, Mg-2 wt.% Nd, and AZ31 extruded alloys were deformed by micro-tensile tests in a scanning electron microscope (SEM). Texture and grain size measured by electron backscatter diffraction (EBSD) were used as the input for VPSC. After parameter optimization, the VPSC model successfully reproduced the stress-strain curve of each alloy. Simulation results indicate that the slip/twinning activity in the three alloys are different. Mg-0.47 wt.% Ca shows strong extrusion texture, and prismatic slip was quite active during its tensile deformation. In contrast, Mg-2 wt.% Nd shows weak extrusion texture, and basal slip was dominant. This alloy also developed more twinning activity than the other two alloys. AZ31 shows strong extrusion texture similar as Mg-0.47 wt.% Ca, but prismatic slip was less active in it. The slip/twinning activity revealed by the VPSC model can explain the difference in the tensile behavior of the three alloys. Keywords: Mg alloys, Crystal plasticity, Slip, EBSD, Tensile test