Significantly improvement in formability and ductility of AZ31 Mg alloy by differential temperature rolling

The implementation of asymmetric deformation proves to be an effective approach towards optimizing the basal texture of wrought Mg alloys, ultimately leading to improved plasticity and formability. This work performs differential temperature rolling (DTR) on AZ31 Mg alloy to achieve asymmetric deformation. After the DTR process, the ductility and formability of the RT-200 sample are comparable to the traditional cold rolling and annealing combination process. Combined with the annealing treatment (AT), the fracture elongation and Erichsen value of the RT-200/AT sample are reached 32.4% and 4.49 mm, respectively. The improvement of the ductility and formability is mainly attributed to the texture weakening, which originates from the temperature gradient formed in the DTR process. The gradient temperature field modifies the dynamic recrystallization behavior during the rolling deformation process, as well as the static recrystallization behavior during annealing. The microstructure evolution and the texture weakening mechanism are discussed in detail. The findings can serve as a theoretical reference for the development of high-ductility Mg alloys and for optimizing the continuous hot-rolling process of Mg alloys.