Martensitic transformation and magnetocaloric effect in Mn–Ni–Nb–Sn shape memory alloys: The effect of 4d transition-metal doping

The influence of 4d transition-metal Nb substitution for Ni in Mn50Ni50−ySny (y = 9, 10) alloys on the phase transitions and magnetocaloric effect was investigated. Austenitic phase of Nb-doped Mn50Ni50−ySny alloys have the cubic structure, and Nb addition results in the expansion of cell volume. The martensitic transformation temperatures decrease with the increase of Nb content, which could be explained by the decrease of valence electron concentration. Our results indicate that 4d transition-metal doping may provide an alternative way to tailor the martensitic transformation and the magnetocaloric effect in ferromagnetic shape memory alloys.

► The first study of 4d transition-metal addition in Ni–Mn-based ferromagnetic shape memory alloys. ► The martensitic transformation temperatures decrease with the increase of Nb content. ► 4d transition-metal doping provide an alternative way to tailor the phase transitions and magnetocaloric effect Ni–Mn–X (X = In, Sn, Sb) alloys.