Martensitic Transformation in NiCoMnSn Metamagnetic Shape Memory Alloy Powders

Abstract

Martensitic and magnetic properties of NiCoMnSn metamagnetic shape memory alloy powders obtained by a gas atomization method were investigated. The as-atomized powders showed a dendritic structure which changed to a single-phase one by annealing at 1173 K for 2 h. Although the martensitic transformation behavior was almost the same as that in bulk samples, the transformation thermal interval, namely, M_s−M_f, of the as-annealed powders decreased with increasing annealing time. In the powders annealed at 1173 K for 144 h, a reversible metamagnetic phase transition was confirmed by the application of a magnetic field of 7 T.