(1. 曲靖師范學院 化學與環(huán)境科學學院，曲靖 655011；
2. 曲靖師范學院 物理與電子工程學院，曲靖 655011；
3. 曲靖師范學院 磁性材料及器件研究中心，曲靖 655011)
摘 要: Ni-Mn基合金在磁驅動器、傳感器、固態(tài)磁制冷、負熱膨脹材料等領域具有潛在的應用價值。相變溫度跨度較窄制約了Ni-Mn基合金的實際應用。為了有效拓寬相變溫度跨度，以Ni55.5Mn18Ga26.5為研究對象，利用實驗手段研究合金的結構、相變特性以及相變溫度跨度與等靜壓的內在關系。結果表明：合金在室溫下為四方馬氏體結構，其馬氏體相變溫度高于室溫。馬氏體相變溫度與相變溫度跨度均隨等靜壓的增大而逐步增大。在正、反馬氏體相變過程中，相變峰值溫度與相變溫度跨度對等靜壓的敏感度分別約為29.35、25.88 K/GPa和42.11、39.46 K/GPa。顯然，等靜壓的應用不僅有利于驅動Ni-Mn-Ga合金的馬氏體相變，而且有助于其相變溫度跨度的拓寬。這些研究結果為Ni-Mn-Ga合金相變的調控與相變溫度跨度的拓寬具有較好的指導意義。
關鍵字: Ni-Mn-Ga合金；馬氏體相變；等靜壓；相變溫度；相變溫度跨度
（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
