LAUSR

Abstract The magnetic-field-induced strain (MFIS) is investigated in a directionally solidified Ni-Mn-Ga polycrystalline alloy. A 0.2% reversible MFIS is achieved after superelastic training, which is a large value as reported in polycrystalline samples without any external stress. Such prominent behavior is attributed to the oriented internal stress induced by superelastic training. On the basis of the phase-field simulation combined with experimental studies, the field induced strain behavior and the underlying microstructure evolution of Ni-Mn-Ga polycrystalline alloy are studied. The results show that the preferential orientation of martensite variants formed by the oriented internal stress is responsible for the large reversible MFIS. It is demonstrated that superelastic training would be an effective processing way to improve the MFIS in polycrystalline Ni-Mn-Ga alloys.