(1. 齊齊哈爾大學 物理系，齊齊哈爾 161006； 2. 哈爾濱工業(yè)大學 材料科學與工程學院，哈爾濱 150001)
摘 要: 通過熔體抽拉法制備了直徑為40~50 μm、長度為5~10 cm的多晶Ni50Mn25Ga25-xFex (x=1, 2, 3, 4, 5, 6, 摩爾分數，%)纖維，對制備態(tài)纖維采用步進式有序化后熱處理，利用場發(fā)射掃描電子顯微鏡、透射電子顯微鏡、X射線衍射對其微觀組織和成分進行表征，使用差示掃描量熱分析儀和動態(tài)機械拉伸儀測試其相變行為和力學性能。結果表明：熱處理后隨著Fe摻雜的增加，纖維實現(xiàn)了從奧氏體相到馬氏體相的轉變，熱處理態(tài)纖維具有不同的晶體類型，馬氏體孿晶界更為平直、清晰，原子有序度明顯提高。熱處理可以提高相變溫度，減小相變滯后，使馬氏體相變更容易進行，提高了抗拉強度和斷裂應變。綜合分析闡明了Fe摻雜及有序化熱處理影響微觀結構、相變行為和力學性能的微觀機制。
關鍵字: 形狀記憶纖維；熔體抽拉；馬氏體相變；有序化熱處理；力學性能
（1. Department of Physics, Qiqihar University, Qiqihar 161006, China; 2. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China）
Abstract:The polycrystalline Ni50Mn25Ga25-xFex (x=1, 2, 3, 4, 5, 6, mole fraction, %) microwires with diameter of 40- 50 μm and length of 5-10 cm were prepared by meld extraction technique. A step-wise chemical ordering annealing heat treatment was carried out. The microstructure and composition of microwires were characterized using field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD). The phase transition behavior and mechanical properties were tested using differential scanning calorimetry (DSC) and dynamic mechanical analyzer (DMA). The results show that, after heat treatment along with the increase of the Fe doped, the microwires have realized from the austenite phase to the martensite phase transformation. The annealed microwires have different crystal types, the martensite exhibits straight clear twin boundary, and the atomic ordering increases. The annealing increases the transformation temperature and decreases the transformation hysteresis, and makes martensite transition easier. The annealing improves the tensile strength and breaking strain. Comprehensive analysis illustrates that the microcosmic mechanisms of Fe doping and ordering heat treatment affect the microstructure, phase transition behavior and mechanical properties.
Key words: shape memory microwires; melt extraction; martensite transformation; chemical ordering annealing; mechanical properties
