The stamping formability of AZ31 magnesium alloy sheet improved by equal-channel angular pressing

Equal channel angular pressing (ECAP) processing and annealing were applied to the AZ31 magnesium alloy sheets to evaluate the potential improvement in the mechanical properties and formability. The ECAP experiment was conducted at 300 °C in a die having an included angle of 90° between two channels by the BCZ route with the sheets rotated by 90° about the normal axis of plate plane. The tensile tests and conical cup tests were conducted at various temperatures from 20 to 250 °C. The experimental results indicated that improving the working temperatures could lead to the soft in the material and the enhancement of ductility. Comparatively, the ECAPed AZ31 alloy sheets showed the lower yield strength and smaller conical cup value (CCV) than the unECAPed counterpart in the room temperature. The difference in yield strength between them became small in the elevated temperature, but the ECAPed samples still had the smaller CCV value, implying the improved formability. The texture of the AZ31 alloy sheets could be modified by ECAP and the decrease in the yield strength and more uniform deformation realized in the material, so the formability of AZ31 alloy sheets was improved.