Phase Transformation Behaviors and Effects of Terbium in Polycrystalline Ni-Mn-Ga Magnetic Shape Memory Alloys

摘要

The phase transformation behaviors of two kinds of magnetic shape memory alloys Ni_(50)Mn_(25+x)Ga_(25-x) and Ni_(50) Mn_(29)Ga_(21-x)Tb_x were studied. When the composition of Ni in these alloys was constant, increasing Mn and reducing Ga contents make martensitic transformation temperatures rise obviously. Simultaneously, thermal hysteresis of phase transformation reduce but Curie temperature unalters. 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.