Properties and Decomposition of Heusler Alloys

摘要

Martensitic transformations of rapidly quenched and less-rapidly cooled Heusler alloys of type Ni-Mn-X with X=Ga, In, and Sn are investigated by abinitio calculations. For alloys rapidly cooled from 1173K, we obtain the well- known magnetocaloric properties near the magnetocaloric phase transition. For the less-rapidly cooled alloys with secondary heat treatment these magnetocaloric properties start to change considerably, because each alloy transforms during temper-annealing into a dual-phase composite alloy. These two phases are identified to be cubic stoichiometric Ni2MnX and tetragonal disordered NiMn.