Improvement of mechanical properties and elastocaloric effect in Ag doped Ni-Mn-In magnetic shape memory alloys

Abstract

Mechanical properties and elastocaloric effect are the most important parameters of Ni-Mn-In shape memory alloys in the refrigeration field. This paper mainly studies the influence of Ag doping and different preparation methods on the mechanical properties and elastocaloric effect of the alloys. The doping of Ag element not only increases the martensitic transformation temperatures and reduces the critical phase transformation stress, but also improves the mechanical properties and elastocaloric effect of the alloys. The adiabatic temperature change (ΔTad) of Ni50Mn34In15.5Ag0.5 prepared by arc melting was − 7 K at 4% strain, and the alloy fractured after 69 cycles with 3% strain. Furthermore, Ni50Mn34In15.5Ag0.5 powders prepared by gas-atomization were used by SPS sintered to obtain 10 µm grains alloys. This preparation method enables the fracture stress and fracture strain to reach 1625.8 MPa and 17.1%, respectively. At the same time it remains stable after 300 cycles with 6.5% strain, indicating the significant improvement of mechanical properties and cyclic stability in Ni-Mn-In metamagnetic shape memory alloy.