Effect of Simultaneous Addition of Mn and Mischmetal on the High Temperature Deformation Behavior of AZ61 Magnesium Alloy

Abstract

The high temperature deformation behavior of a modified AZ61 magnesium alloy was investigated by means of an isothermal compression test on a Gleeble-2000D elevated temperature simulation tester at strain rates of 0.1 s⁻¹ and 1 s⁻¹ and deformation temperatures of 523 K, 623 K and 723 K. The microstructure evolutions and second phases of the experimental alloys were analyzed. Compared to the conventional alloy, the modified specimen shows a higher degree of dynamic softening and a lower deformation resistance. The improved deformability becomes more apparent when temperature decreases or strain rate increases, and it is attributed to a great reduction in Mg₁₇Al₁₂ phase and to the formation of Al₄RE and Al₁₀RE₂Mn₇ phases caused by the simultaneous addition of Mn and mischmetal.