铁磁形状记忆合金C050Ni18Ga32相变的研究

采用交流磁化率测试系统和X射线衍射仪，研究了感应熔炼多晶Co50Ni18Ga32合金的相变特性．研究发现多晶Co50Ni18Ga32合金的马氏体相变温度(Tm)低于居里温度(Tc)，马氏体相变时交流磁化率急剧下降．随退火温度升高，Tc升高．在500℃到900℃温度范围内，随热处理温度升高，Tm、逆相变温度(Ta)降低，相变热滞(Ta-Tm)减小．感应熔炼多晶Co50Ni18Ga32合金升温时析出γ相，γ相的含量随着温度的升高逐渐增加，在高温下全部转变为γ相，γ相的出现是不可逆的，即把温度降到室温或者长时间退火都不会改变γ相的结构．

Phase Transformation of Co50Ni18Ga32 Ferromagnetic Shape Memory Alloy

The precursor ingot was prepared by melting pure metals in proportion in an induction furnace under the argon atmosphere. The X-ray diffraction patterns for the sample were measured using a Philips X'pert MPD X-ray diffractometer with Non-ambient sample stage. The ac magnetic susceptibility was measured in a 77 Hz magnetic field of 5 Oe and over a temperature range of 93 K to 450 K. It was found that the martensitic transformation temperature was lower than the Curie temperature. The ac magnetic susceptibility decrease sharply when the martensitic transformation occurred. With increasing the heat treatment temperature, the Curie temperature increases, but the martensitic transformation temperature and reverse transformation temperature decrease.