Deformation microstructures and textures of some cold rolled Mg alloys

Electron Backscatter Diffraction (EBSD) is employed to characterize the deformation microstructures and textures established during the cold rolling of pure Mg, Mg–0.2Ce and Mg–3Al–1Zn (also known as AZ31). The maximum cold rolling reductions achievable in these alloys prior to failure were ∼30, >90 and ∼15%, respectively. The dominant features of the microstructure were twins and shear bands. The frequency of the former decreased while that of the latter increased with rolling reduction. Each alloy displayed a fibre texture in which the c-axis was closely aligned with the sheet normal direction. There was little change to the rolling textures with increasing rolling reduction beyond ∼10%. Much of the deformation appeared to be concentrated in the shear bands. It is speculated that the striking effect of alloying addition on cold rollability can be understood in terms of differences in severity, frequency and lifetime of shear bands.