DEFORMATION BEHAVIOR OF AZ31 MAGNESIUM ALLOY DURING MULTIAXIAL COMPRESSION BY EBSD TRACKING

Cross rolling and multidirectional forging deformation modes are effective methods to improve the plastic forming ability of magnesium alloy. In these plastic forming process, multidirectional compression deformation is often involved. In this study, the deformation behavior during multi-directional compression of a AZ31 magnesium alloy was investigated using a micro-grid method in combination with electron backscatter diffraction (EBSD) tracking method. The sheets were compressed along transverse direction (TD) followed by compression along normal direction (ND). The experimental results show that {10 (1) over bar2}<10<(1)over bar>1> tensile twinning dominates the deformation process during initial compression along TD, and that for most grains detwinning of these {10 (1) over bar2}<10<(1)over bar>1> tensile twins dominates the deformation process during a following compression along ND. For some grains with a large deviation from the basal texture, a different deformation behavior is seen. No new twin variants are found in grains that underwent detwinning during compression along ND. This indicates that detwinning of {10 (1) over bar2}<10<(1)over bar>1> tensile twins is favored over the activation of a different twin variants during deformation of the AZ31 magnesium alloy. The remaining twin area fraction can reduce to near-zero even when the local strain subjected during ND compression is less than that subjected during the initial TD compression, demonstrating that a smaller strain is required for detwinning than for the initial twinning.