Study of the martensitic transition in Ni-Mn-Sn-Ti ferromagnetic shape memory alloys

Abstract

In the present work, mechanical spectroscopy measurements as a function of temperature and strain have been performed in (at.%) Ni 50 Mn 37 Sn 13-x Ti x (x=0, 0.5 and 2) ferromagnetic shape memory alloys in order both to study martensitic transition phenomenon and also to determine its temperature of appearance. For mechanical spectroscopy measurements, a five elements piezoelectric device recently developed has been used. In addition, other characterization techniques as, differential thermal analysis and superconducting quantum interference magnetic spectroscopy, were also used. Besides, relaxation processes near the martensitic transition temperature have been also observed.

Processing Effects on the Martensitic Transformation and Related Properties in the Ni55Fe18Nd2Ga25 Ferromagnetic Shape Memory Alloy

“…Ni 2 MnGa is a representative and the most investigated member of this class of materials, which shows a huge magnetic-field-induced strain (MFIS) below the austenite–martensite transformation, of the order of several percent, as evidenced by Ullakko et al [ 12 ]. However, the compound’s brittleness makes it difficult to be used in applications, and for this reason the search for new Heusler alloys that undergo an MT was extended comprising Co-Ni-Ga [ 13 , 14 , 15 ] and Ni-Mn-(Al, In, Sn) [ 16 , 17 , 18 , 19 , 20 , 21 ]. Ni-Fe-Ga alloys [ 22 , 23 , 24 , 25 , 26 ] have emerged as good candidates for replacing the brittle Ni-Mn-Ga in applications [ 27 ].…”