Mechanical alloying of Mn-30at. % Al powder mixture resulted in the formation of an α-Mn solid solution in the early stage of milling with the subsequent formation of β-Mn phase after 30h milling. Thermal treatment at 10600 C, confirmed the recently extension of the high temperature ε-phase. However, the presence of impurity atoms, mainly iron, impeded the expected ε→β transformation during quenching. Such transformation is obtained by annealing the metastable ε-phase at 4000 C and was found to be time dependent. Magnetic properties assessments of both as milled and annealed alloy are carried out.