Martensitic Transformations and Magnetic-Field-Induced Strains of Ni{sub}48Mn{sub}31Ga{sub}21 Melt-Spun Ribbons with Different Quenching Rates

摘要

Magnetic shape memory alloy Ni2MnGa has been developed in recent years as a new actuator material due to the fact that its shape memory effect can be controlled by magnetic field in addition to conventional controls by temperature and stress. The ferromagnetic Heusler alloy exhibits large magnetic-field-induced strain (MFIS) and high response frequency in magnetic field. At present, there are many studies about the single crystal Ni2MnGa alloy. But it is hard to grow the single crystal alloys. Furthermore, non-homogeneity of the composition in the single crystal is easy to lead to the unstability of the martenisitic transformation temperatures and the MFIS, which is an obstacle to its use in many applications. Melt-spinning technology is a method to produce the alloy with high efficiency and improve the properties of the alloy. In this paper, we prepared polycrystalline ribbons by using melt-spinning technique and investigated the martensitic transformation and the MFIS of Ni2MnGa alloys with different quenching rates.