Effect of Co Doping on the Elastocaloric Effect of Ni-Mn-Ga-Co Alloy

Abstract

Large latent heat is produced in the stress-induced martensitic phase transition process of Ni-Mn-Ca-based materials, i.e., elastocaloric effect. That makes such materials show tremendous potential for solid-state refrigeration which is identified as one of the most promising non-vapor-compression cooling devices. However, the still low refrigeration ability of these materials restricts further commercially promoting of solid-state refrigeration. In this work, we adjusted the Co content to regulate the elastocaloric effect for the NiSUB51.5/SUBMnSUB25/SUBGaSUB23/SUBCoSUB0.5./SUB According to the results, the transformation strain and ratio of loading stress/transformation temperature (dσ/dT) were increased by replacing the Ni atoms with a little more Co, leading to an improvement of the stressinduced transformation entropy-change ΔSσ. As a result, a huge ΔSσ of 45.0 JKgSUP-1/SUPKSUP-1/SUP is achieved in NiSUB50/SUBMnSUB25/SUB-GaSUB23/SUBCoSUB1/SUB alloy.