Ferromagnetic to weak-magnetic transition accompanied by bcc to fcc transformation in Fe–Mn–Al alloy

Magnetic properties and phase change in $\text{Fe-}36\text{at}.\%\text{Mn-}15\text{at}.\%\text{Al}$ ternary alloy were investigated. Direct evidence of a ferromagnetic to weak-magnetic transition accompanied by martensitic transformation from the bcc-$\alpha$ (A2) phase to the fcc-${\gamma }^{\prime }$ (2M) phase was obtained, where the magnetic state of the parent and the martensite phases are ferromagnetic and weak-magnetic, respectively. The origin of this unique phase change is caused by the peculiar $\gamma$ -loop of $\alpha ∕\gamma$ equilibrium formed in Fe–Mn–X (X: ferrite stabilizing element) system due to the magnetic effect.