Deformation and texture evolution during high-speed rolling of AZ31 magnesium sheets

Deformation of AZ31 sheets during high-speed rolling at various temperatures was investigated. The thickness of 2.5 mm was reduced 60% by single-pass operation at a speed of 2000 m/min. Textures, microstructures, mechanical properties and bendability of the sheets processed were examined. In the sheets rolled at elevated temperature, equiaxed fine grains (<5 mu m) having a basal texture with double peaks were formed around the center of the thickness. The surface layer was sheared very severely by friction to form coarse grains having a well-developed basal texture with a single peak. With increasing the rolling temperature, the grain size increases and the texture weakens slightly at the center. The bendability of the sheet improves with increasing the rolling temperature. The cold-rolled sheet having a deformation microstructure with shear bands and twins shows limited ductility.