Effects of Annealing on Microstructure and Mechanical Properties of Backward Extruded Mg-0.5Mn-1Nd Alloy

Abstract

Mg-0.5Mn-1Nd (wt.%) alloy has been prepared by zone purifying method followed by backward extrusion (BE) technique. The microstructures, recrystallization behavior from 150 to 400 °C and mechanical properties of Mg-0.5Mn-1Nd alloy were investigated. The alloy exhibited bimodal microstructures after BE deformation. The equiaxed grains changed to more homogeneous after annealing treatment in range of 150 to 250 °C. The similar trend was confirmed after thermal annealing treatment at different annealing temperatures. The abnormal grains growth was clearly observed when the temperature was higher than 350 °C. Compared with BE-Mg-0.5Mn-1Nd alloy, both yield strength and ultimate tensile strength were reduced after annealing treatment, whereas the elongation was increased correspondingly. These results were mostly related to the fine grain size and homogeneous secondary precipitate.