Microstructural analysis and phase transformation in Ni-Mn-Ga ferromagnetic shape memory alloys

作者：Mahendran M^*

来源：Smart Materials and Structures, 2005, 14(6): 1403-1409.

DOI：10.1088/0964-1726/14/6/033

The martensitic thermoelastic and magnetic transformations have been investigated for the Ni-Mn-Ga ferromagnetic shape memory alloys. The martensitic phase of the shape memory alloy responds to the application of stress and, as a result, the martensite variants are rearranged to accommodate the applied stress, which results in the macroscopic shape change. The shape recovery property of Ni-24.7 Mn-24.8 Ga (at.%) alloy with martensitic transformation temperatures has been analysed. The mechanisms of the magnetic microstructure, which cause the martensite band domains and run diagonally in a micrograph from left to right, have been observed. The micrograph also shows that the martensitic transformation of Ni-24.7 Mn-24.8 Ga (at.%) alloy not only depends on the structural rearrangement but also responds to a magnetic field. It is observed that upon cooling from the high-temperature austenite parent phase, the ferromagnetic shape memory alloys exhibit transition from paramagnetism to ferromagnetism. It is studied that the Ni-Mn-Ga alloy is an intrinsically suitable ductile material.

• 出版日期2005-12