Damping mechanism associated with coupling between antiferromagnetic transition and martensitic transformation

摘要

To study the relationship between the martensitic transformation and the antiferromagnetic transition and to develop new twin-based high damping materials, the internal friction and modulus in γ Mn-based Mn-Fe and Mn-Ni alloys were measured. Three internal friction peaks were observed between -100 and 400℃, namely at the Neel temperature T_N, the martensitic transformation temperature M_S and 0℃. They are related to the antiferromagnetic transition, the martensitic transformation and twins in the fct phase. The first is accompanyied by a rapid decreases of modulus at T_N. The third, high damping peak is similar to the one observed in Mn-Cu alloys, and is attributed to the fcc-fct martensitic transformation or to fine twins in the antiferromagnetic domains.