In-plane anisotropic deformation behavior of rolled Mg-3Al-1Zn alloy by initial {10-12} twins

In-plane deformation characteristics of rolled Mg-3Al-1Zn alloy, which was previously compressed along the rolling direction, were investigated by carrying out tension and compression tests in combination with the in-situ electron backscatter diffraction technique and Schmid factor (SF) analysis. The specific crystallographic orientation of twinned regions (i.e., twin texture), caused by the {10-12} twinning during the pre-compression, gave rise to in-plane anisotropic activities of slips and twinning by affecting their SF and this led to an anisotropy in in-plane deformation characteristics of the pre-compressed material. The amount of the pre-compression was also found to be important in the deformation because it is directly related to the volume fractions of twinned and untwined regions, {10-12} twin boundary induced grain size change, and dislocation interaction related hardening. By considering the combined effects of active deformation modes in twinned and untwined regions, volume fractions of twinned and untwined regions, Hall-Petch hardening for slips and twinning, and dislocation interaction related hardening, the deformation characteristics of the pre-compressed material were successfully interpreted. In addition, the combined effect of the SF and grain size (i.e., the Hall-Petch hardening for twinning) was found to control the twinning behavior, when subjected to the condition where multiple twinning modes are possible.