Martensitic Transformation and Magnetic-Field-Induced Strain in Magnetic Shape Memory Alloy NiMnGa Melt-Spun Ribbon
A non-stoichiometric polycrystalline Ni50Mn27Ga23 magnetic shape memory alloy was prepared by melt-spinning technology. The effects of melt-spinning on the martensitic transformation and magnetic-field-induced strain (MFIS) of the melt-spun ribbon were investigated. The experimental results show that the melt-spun ribbon undergoes the thermal-elastic martensitic transformation and exhibits the thermo-elastic shape memory effect. But the martensitic transformation temperature decreases and Curie temperature remains unchanged. A particular internal stress induced by melt-spinning made a texture structure in the melt-spun ribbon, which made the melt-spun ribbon obtain larger transition-induced strain and MFIS. The internal stress was released under cycling of magnetic field. This resulted in a decrease of MFIS of the melt-spun ribbon.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
S. H. Guo et al., "Martensitic Transformation and Magnetic-Field-Induced Strain in Magnetic Shape Memory Alloy NiMnGa Melt-Spun Ribbon", Materials Science Forum, Vols. 475-479, pp. 2009-2012, 2005