Phase analysis of NI-MN-SN ferromagnetic shape Memory alloys

Abstract

Ferromagnetic shape memory alloys (FSMAs) are the novel materials exhibiting shape memory effect (SME) and magnetism simultaneously. They show magnetic field-induced strains at room temperature greater than any electrostrictive, magnetostrictive or piezoelectric material, and faster frequency response than temperature driven shape memory alloys. Among various FSMA materials, Ni-Mn-X (X =Ga, In, Sn, Sb) have gained considerable interest due to their multifunctional properties such as shape memory effect, magnetocaloric effect, magnetoresistance, etc., associated with first order martensite to austenite structural transition. FSMA spread its application in broad area from aerospace industry to medical application, but not vividly use; because of its high cost. Ni-Mn-Sn FSMAs shows low cost of manufacturing due to its low value of constituting elements. This paper investigates the behavior of Ni-Mn-Sn Heusler FSMA by varying the weight percentage of Sn. Three alloys i.e. Mn50Ni50-xSnx (x = 5, 7.5, and 10) were produced as bulk polycrystalline ingots by arc melting. In order to identify structural phases X-ray diffraction (XRD) measurements were conducted at room temperature using Cu Kα radiation. By Differential Scanning Calorimetric (DSC) study it is found that, the transformation temperatures gradually decreases as increasing the Sn content, which shows it can apply in higher working temperature range than that of Ga-FSMAs.