C28Phase Transformation Behaviors and Effects of Terbium in Polvcrvstalline Ni-Mn-Ga Magnetic Shape Memory Alloys
会议名称：《2004年国际稀土研究应用研讨会》
会议日期：2004年
学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）]
关 键 词：metal materials martensitic transformation rare earths Ni-Mn-Ga alloy
摘 要：NiMnGa, with strong ferromagnetism, large reversible strains and high response frequency, is a new functional material. In addition to temperature and stress, the change in shape and dimensions of this kind of material can be controlled by an external magnetic field. The material demonstrates large magnetic-fleld-induced strains based on reorientation of the martensite variants in magnetic field. Therefore, the martensitic transformation temperature and Curie temperature are quite important parameters. In the present work, The phase transformation behaviors of two kinds of magnetic shape memory alloys Ni50Mn25+xGa25-x and Ni50Mn29Ga21-xTbx were studied. When the composition of Ni in these alloys was constant, increasing Mn and reducing Ga contents make martensitic transformation temperatures to rise obviously. Simultaneously, thermal hysteresis of phase transformation reduced but Curie temperature unaltered. When terbium was added, phase transformation temperature went up further and Curie temperature kept constant. The alloys still show strong ferromagnetism and properties of thermoelastic martensite phase transformation.