Enhanced rollability of Mg alloys by directly activated {101¯2} twinning during asymmetric rolling: Experiments and finite element analysis

Mg-rare earth (RE) alloy, i.e., Mg1Gd (G1), was deformed by electroplastic-asymmetric rolling (EASR) and symmetric electroplastic rolling (ER), respectively. EBSD, XRD and TEM observations were utilized to characterize the microstructure and texture evolutions of two rolled alloys. Tensile tests were used to evaluate mechanical properties of rolled samples. The results showed that both the rollability and tensile properties of EASR processed sample were much better than those of ER processed sample, which was closely connected with the abnormal activity of {101¯2} twinning and concomitant texture evolution during EASR. The results of effective Schmid factor calculation and twin variant identification indicated the abnormal twinning behavior agreed well with the Schmid law, which could be depicted as a synergy of “internal” (grain orientation) and “external” (stress state) effects enabled by the participation of additional shear stress. The present study shows it is feasible to largely activate {101¯2} twinning of Mg alloys directly through rolling process, and therefore provides a novel scheme to deal with the poor rollability of Mg alloys.