Martensitic transformation behavior and structural characteristics of annealed Ni-Mn-Sn-Fe-In Heusler alloy

Abstract

Ni-Mn based heusler alloy with Ni50-xFexMn30Sn20-yIny where 1<=x<=4; 2<=y<=8 are studied for their structural as well as mechanical characteristics using various testing facility such as field emission scanning electron microscope, energy dispersion spectrometry, differential scanning calorimetry and Vickers hardness equipment. From the general understanding the materials are to display a transformation of austenite-martensite. The materials are seen to be showing this transformation in and around near room temperature. The optical and FESEM imaging of the specimen show that during annealing heating to high temperature to longer time, the diffusion kinetics are activated at faster rate so that the dendritically structure is annihilated to develop well distributed grain structure. The coarser dendrites seems to be broken and fine grain, well dispersed phases are formed. X-ray diffraction confirms the peak split and martensitic transformation in the system of alloys. DSC results confirm the martensitic transformation around room temperature.