Martensitic Transformation and Microstructure of Ni-Mn-Ga Magnetic Shape Memory Alloy

Abstract

The effect of annealing on microstructure, crystal structure, martensitic transformation temperature, and magnetization of the as-prepared and annealed Ni-Mn-Ga alloy has been investigated. The present study infers that annealing stabilizes the microstructure and reduces the range of martensitic transformation temperature and improves the magnetic properties of the Ni-Mn-Ga ferromagnetic shape memory alloys. Also, the result presented here shows that coexisting austenite and martensite phases in the as-prepared specimen are separated upon annealing. As the magnetic hysteresis of Ni49.5Mn29.3Ga21.2 alloy is very narrow, the potential utilization of this composition may be expected in micro-actuators.