Ni50Mn25Ga22Cu3形状记忆合金纤维的磁热性能OA

Ni50Mn25Ga22Cu3 ferromagnetic shape memory alloy microwires were successfully fabricated by the melt extraction method.The effects of Cu doping on the microstructure,martensitic transformation,magnetic transition,and magnetocaloric properties of the alloy were investigated.The microwires,with an average diameter of approximately 25 μm,exhibited uniform composition and microstructure.Post-fabrication heat treatment effectively increased the martensitic transformation temperature to near room temperature.X-ray diffraction analysis revealed distinct structural evolution,indicating a partially coupled magnetostructural transition.Magnetic measurements showed that under a magnetic field change of 5 T,the alloy microwires achieved a maximum magnetic entropy change of approximately 8.0 J·kg-1·K-1 around 308 K and 4.0 J·kg-1·K-1 around 350 K.The corresponding refrigeration capacities and relative cooling powers were 34.8,43.3 J·kg-1 for the low-temperature peak,and 173.1,228.3 J·kg-1 for the high-temperature peak,respectively.The results demonstrate that Cu doping combined with fiber morphology is an effective approach to tailor the magnetocaloric properties of Ni-Mn-Ga alloys,highlighting their potential for room-temperature magnetic refrigeration applications.