Magnetic Transitions and The Magnetic Characteristics of The Martensitic Transformations in A Fe-Mn-Co Alloy

In this study, the magnetic transitions and the magnetic characteristics of the thermally induced martensitic transformations in Fe-13.2%Mn-5.3%Co alloy have been investigated. The microstructure analysis of difusionless phase transformations forming in the alloy were performed by scanning electron microscopy (SEM), and the magnetic properties were revealed by Mössbauer spectroscopy and AC susceptibility. SEM observations reveal that two types of thermal-induced martensites, ε (h.c.p.) and α′ (b.c.c.) martensites, form in the austenite grains of the alloy. Mössbauer spectra at room temperature reveal a paramagnetic character with a singlet for the γ (f.c.c.) austenite and ε martensite phases and a ferromagnetic character with a broad sextet for α′ martensite phase. In addition, measurement of the AC susceptibility of the alloy shows that the magnetic transition from the paramagnetic order to magnetic disordered occurs below room temperature at 258 K.