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

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 (T-M) and Curie temperature (T-C) simultaneously. T-M and T-C 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. (C) 2022 Author(s).