Interaction between antiferromagnetic transition and martensitic transformation in Fe-Mn-Si based shape memory alloys

Internal friction and elastic modulus of Fe-Mn-Si, Fe-Mn-Si-RE and Fe-Mn-Si-Cr shape memory alloys were measured from 150 K to 600 K by using an electrostatic audio-frequency internal friction instrument. The mtei-nal friction characteristies of the antiferromagnetic transition and γ-ε martensitic transformation as well as the interaction between these two transitions have been investigated. The results show that the γ→ε martensitic transformation is partly restrained, but can still continue below the Neel temperature ( TNγ) . When the temperature TN is slightly below the MS temperature, the internal friction peak associated with the paramagnetic → antiferromagnetic transition disappears upon cooling due to the occurrence of the γ→ε martensitic transformation, and only the internal friction peak associated with the γ→ε martensitic transformation can be observed. When the Neel temperature ( TNγ) is much below the temperature MS, the internal friction peaks appear near TNγ and MS respective