Phase transformation and microstructure of Ni-Mn-Ga ferromagnetic shape memory alloy particles

摘要

In the present paper, ball milling is used to produce Ni49.8Mn28.5Ga21.7 particles of micrometer size. Although the characteristics of transformation are not observed in the as-milled particles from 150 to 523K from differential scanning calorimetry (DSC) study, the particles exhibit the same transformation behaviour as the bulk sample after annealing at 1073K for 2h. The as-annealed particles show good thermal cycling stability even after five thermal cycles. Temperature memory effect during the reverse martensitic transformation is found in the as-annealed particles. The particles exhibit regular shape, with 10M martensite structure at room temperature.