Modification of preferred martensitic variant distribution by high magnetic field annealing in an Ni-Mn-Ga alloy

The preferred martensitic variant distribution in Ni₅₃Mn₂₅Ga₂₂ ferromagnetic shape memory alloy (FSMA) samples annealed without and with a high magnetic field of 12 T applied during the annealing process was investigated by electron backscatter diffraction. It is revealed that the high magnetic field applied during annealing enhances the regular arrangement of martensitic variants from the morphological point of view and effectively modifies the preferred orientation distribution of martensitic variants without changing the misorientation between them from the crystallographic point of view. Only one texture component, , exists in the sample annealed without a magnetic field, whereas two additional texture components, and , are developed in the sample annealed in a high magnetic field. The new finding that the preferred martensitic variant distribution can be efficiently modified by introducing a high magnetic field during the annealing process will shed light on the development of high-performance polycrystalline FSMAs via novel processing techniques.