Grain refining mechanism of Al-containing Mg alloys with the addition of Mn-Al alloys

The ɛ-AlMn phase acts as the heterogeneous nucleus of α-Mg phase during the solidification of the AZ31 Mg alloy, not the γ-Al8Mn5 phase. The grain refinement effect is very clear with the addition of only 0.5 wt% Mn-28Al alloy (pure ɛ-AlMn). The grain refinement does not deteriorate up to the holding time of 60 min at 740 °C.