(1. 曲靖师范学院 化学与环境科学学院，曲靖 655011；
2. 曲靖师范学院 物理与电子工程学院，曲靖 655011；
3. 曲靖师范学院 磁性材料及器件研究中心，曲靖 655011)
摘 要: Ni-Mn基合金在磁驱动器、传感器、固态磁制冷、负热膨胀材料等领域具有潜在的应用价值。相变温度跨度较窄制约了Ni-Mn基合金的实际应用。为了有效拓宽相变温度跨度，以Ni55.5Mn18Ga26.5为研究对象，利用实验手段研究合金的结构、相变特性以及相变温度跨度与等静压的内在关系。结果表明：合金在室温下为四方马氏体结构，其马氏体相变温度高于室温。马氏体相变温度与相变温度跨度均随等静压的增大而逐步增大。在正、反马氏体相变过程中，相变峰值温度与相变温度跨度对等静压的敏感度分别约为29.35、25.88 K/GPa和42.11、39.46 K/GPa。显然，等静压的应用不仅有利于驱动Ni-Mn-Ga合金的马氏体相变，而且有助于其相变温度跨度的拓宽。这些研究结果为Ni-Mn-Ga合金相变的调控与相变温度跨度的拓宽具有较好的指导意义。
关键字: Ni-Mn-Ga合金；马氏体相变；等静压；相变温度；相变温度跨度
（1. College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China;
2. College of Physics and Electronic Engineering, Qujing Normal University, Qujing 655011, China;
3. Center for Magnetic Materials and Devices, Qujing Normal University, Qujing 655011, China）
Abstract:Ni-Mn based alloys have potential applications in magnetic actuators, sensors, solid state magnetic refrigeration, negative thermal expansion materials and other fields. The narrow phase transition temperature span restricts the practical application of Ni-Mn based alloys. The structure, phase transition properties and hydrostatic pressure dependence of phase transition temperature and phase transition temperature span were investigated experimentally in Ni55.5Mn18Ga26.5 alloy to broaden the temperature span of phase transition. The results show that the alloy sample crystallizes in a tetragonal martensite structure at room temperature and the martensitic transformation temperatures are higher than room temperature. All the martensitic transformation temperatures and the transformation temperature span increase gradually with the increase of hydrostatic pressure. Importantly, the average sensitivity of phase transition peak temperature and phase transition temperature span to hydrostatic pressure are about 29.35, 25.88, 42.11 and 39.46 K/GPa, respectively, during the direct and reverse martensitic transformation. It is obvious that the application of hydrostatic pressure is not only beneficial to drive the martensitic transformation, but also helpful to broaden the transformation temperature span in Ni-Mn-Ga alloy. These findings are very meaningful to adjust the phase transition temperature and the broadening of phase transition temperature span in Ni-Mn-Ga alloy system.
Key words: Ni-Mn-Ga alloy; martensitic transformation; hydrostatic pressure; transformation temperature; martensitic transition temperature span
