Formation of anomalous twinning and its effect on texture development in a cold-rolled Mg-Zn-Ca alloy sheet

An Mg-6Zn-0.3Ca (mass%) alloy sheet with a strong basal texture feature was cold-rolled using a small pass reduction, and the microstructure development during the annealing was tracked by quasi-in-situ electron backscattered electron analysis. Anomalous double twinning with the (0001) pole being aligned to the transverse direction was formed after the cold-rolling. This twinning became the nucleation sites for statically recrystallized grains during the annealing, and the annealed sheet formed weak texture features with transverse-direction split (0001) poles. Static recrystallization also occurred at grain boundaries, and the new grains have a similar texture feature as the parent grains. Therefore, the basal-textured components were still preserved even after the cold-rolling and annealing.