Effects of 0.5 wt.% Nd Addition on the Microstructure and Mechanical Properties of As-Extruded and Aged Mg-6Al-3Sn-2Zn Alloys

The effects of the addition of Nd as a minor alloying element on the microstructure and mechanical properties of the Mg-6Al-3Sn-2Zn (ATZ632) alloy were investigated. The results show that the addition of Nd refined the grains and weakened the (0001) basal texture, which increased the elongation (EL) of as-extruded ATZ632-0.5Nd alloy to 22.5%. The appearance of an Al3Nd phase consumes Al and reduces the volume fraction of the Mg17Al12 phase in the as-extruded ATZ632-0.5Nd alloy, resulting in relatively minor changes to the yield strength (YS) and ultimate tensile strength (UTS). After aging, Mg17Al12 precipitation improved the YS and UTS of ATZ632-0.5Nd alloy to 242 and 354.9 MPa, respectively. Static recrystallization (SRX) occurred during aging, and the pyramidal slip and <c+a> slip of the grains formed during SRX were activated by Nd, which caused the reorientation of grains undergoing partial SRX to the rare-earth texture.