Giant elastocaloric effect in V-doped Ni–Mn–In alloys

Abstract

Solid state elastocaloric refrigeration exploits the elastocaloric effect in shape memory alloys to achieve cooling, primarily depending on the entropy change of martensitic transformation (ΔStr). In this work, we demonstrate that replacing In by V leads to a substantial increase in the ΔStr of Ni–Mn–In alloys, thereby significantly improving the elastocaloric performance. Owing to an enhanced ΔStr of 45.0 J kg−1 K−1 induced by V alloying, a giant cooling adiabatic temperature change (ΔTad) of –25.1 K is attained in a directionally solidified Ni50Mn34In13V3 alloy characterized by ⟨001⟩A oriented columnar-shaped grains, far exceeding those of previously reported in Ni–Mn-based alloys. Moreover, microstructure texturing contributes to reduced driving stress of martensitic transformation, resulting in a high specific adiabatic temperature variation (|ΔTad/σmax|) of 82.4 K/GPa.