Electro-magnetic characteristics of Ti-50.8at%Ni in martensite transition

Abstract

摘要 研究Ti-50.8at%Ni合金在马氏体-奥氏体相变温度附近的电磁性质.由M-H曲线分析了传导电子的顺磁性以及少量局域电子引起的铁磁性.在M-T曲线中，降温曲线在180K附近有突降，升温曲线在230K附近有突升.在电阻率测量中，降温和升温的ρ-T曲线也有类似的突变.升温过程的质量热容cp曲线在230K附近出现了由奥氏体相变引起的跳跃.这些实验结果表明，样品的马氏体相变温度约 关键词: TiNi合金 / 电磁性质 / 马氏体-奥氏体相变 / 质量热容 Abstract Electric and magnetic properties of TiNi alloy have been investigated near the temperatures of martensite-austenite phase transition. The paramagnetism resulted from conduction electrons and the ferromagnetism resulted from a few located electrons have been analyzed from M-H curves. There is an abrupt drop of magnetization at about 180K in cooling M-T curve, and there is an abrupt rise at about 230K in heating curve. The temperature dependence of resistivity shows similar behavior to the M-T curve, i.e. the resistivity ρ-T of the samples also experiences abrupt change at similar temperatures. Furthermore, the temperature dependence of specific heat capacity for the sample displays an obvious peak during heating process. All the results show that the temperatures of martensite and austenite phase transition are about 180 and 230K respectively. On the other hand, the M-T curves show that the magnetization of martensite phase is smaller than that of austenitic phase at the same temperature. Moreover, when the strain is no more than 6%, the mechanical strain weakens the magnetism of TiNi alloy samples, while it does not change the temperature of martensite-austenite phase transition. Keywords: TiNi alloy / electro-magnetic characteristics / martensite-austenite phase transition / specific heat capacity 作者及机构信息 侯碧辉, 周 茜, 段 苹, 苏少奎, 毛圣成, 韩晓东 基金项目: 国家重点基础研究发展规划(批准号：2006CB705601)资助的课题. Authors and contacts 参考文献 施引文献