Superelastic behavior of a metamagnetic Ni–Mn–Sn single crystal

Abstract

A single-crystalline specimen with the composition of Ni49.5Mn38.4Sn12.2 shows a 4.9% recoverable transformation strain upon compressive loading. The critical compressive stress increases with temperature at the step of 5.6 MPa/K, whereas upon cycling it decreases by 18.1 MPa/cycle. The microstructure of the specimen undergoes considerable refinement upon superplastic training; however, it is only able to sustain a limited number of cycles (≤ 5). Martensite training, resulting in a single-variant microstructure, has a profound influence on the austenite start transformation temperature (ΔT = 29 K), resulting partially from the dissipation of the elastic strain energy. The Ni-Mn-Sn system is an interesting candidate for multiferroic applications given its mechano-magnetic properties and a huge value of the martensitic transformation entropy change (~ 50 J/kg K).