Improving the room-temperature formability of a magnesium alloy sheet by texture control

In this study, a sheet of AZ31 magnesium alloy was compressed by 3%, 5%, and 7% along the in-plane direction while simultaneously applying a compressive load in the normal direction (ND) to avoid buckling during compression. Changes in the microstructure and texture were measured after annealing. Recrystallization and grain growth occurred in grains with higher deformation energy than surrounding grains after annealing at 300 °C. The area fraction of the orientations for which the c-axis and transverse direction (TD) are parallel (twinned grains) and the orientations with an angle between the c-axis and ND ranged from 30° to 60°, a situation that is favorable for accommodating strain along the thickness direction by slip and detwinning, increased compared to the as-received specimen. The favorable orientations tended to increase as the compressive strain increased. As a result, the formability for the bi-axial stretch mode is higher in the specimen annealed at 300 °C for 60 min after 7% compression than in the as-received specimen.