Simultaneous improvement of magnetic-field-induced working temperature and mechanical properties in Ni–Mn–In shape memory alloy

Abstract

Ni–Mn–In magnetic shape memory alloys, which can be stimulated by an external magnetic field, exhibit a fast response and have aroused wide attention in the field of electro-mechanical actuators. However, the low working temperature and the inherent brittleness severely limit their application scenarios. Here, an effective strategy is proposed to improve the magnetic-field-induced working temperature and mechanical properties in Ni–Mn–In shape memory alloys. We predict that the Ni16Mn12In4 alloy with Pt doping can solve the problems simultaneously through a comprehensive first-principles study. The calculations show that Pt occupying Ni sites can increase the martensitic temperature (TM) and Curie temperature (TC) simultaneously. TM and TC of Ni14Mn12In4Pt2 are predicted to be as high as 440 and 476 K, respectively. This is mainly due to the increased phase stability of the martensite and Pt–Mn bonds having stronger ferromagnetic exchange effects than Ni–Mn bonds after Pt doping. Moreover, according to the increase of B/G and v after Pt doping, it can be concluded that the mechanical properties of the alloy have been improved.