形状记忆合金Ni2MnGa材料的磁热效应

摘要

利用电弧熔炼法制备了形状记忆合金Ni2MnGa块体,X射线衍射表明样品的晶体结构为立方晶系的L21,利用振动样品磁强计测量了磁化强度M随温度的变化和不同温度下的等温磁化曲线,由dM/dT随温度变化的曲线得到居里温度约为395.5 K,外加磁场等于5.0,10和17 kOe时磁熵变化的最大值出现在388 K,分别为0.5,1.2,1.9 J/kg·K.%The sample of shape memory alloy Ni2MnGa ingot was prepared by arc-melting method, X-ray diffraction indicates that the crystal structure is L21, we made use of vibrating sample magnetometer to measure the magnetizationM changing with temperature as well as isothermal magnetization curve under different temperature. And from the dM/dT vs. temperature curve Curie temperature can be derived as 395.5 K. The maximum magnetic entropy change was 0.5, 1.2, 1.9 J/kg·K, respectively, all appearing at 388 K, for applied magnetic fields of 5.0, 10 and 17 kOe.