Ni-Mn-Ga-Fe合金纤维的马氏体相变与超弹性  

Martensitic transformation and superelasticity of Ni-Mn-Ga-Fe alloy microwires

作　　者：刘艳芬[1] 郎子锐 李爽 LIU Yanfen;LANG Zirui;LI Shuang(Department of Physics,Qiqihar University,Qiqihar 161006,Heilongjiang,China)

机构地区：[1]齐齐哈尔大学物理系,黑龙江齐齐哈尔161006

出　　处：《材料工程》2023年第6期120-130,共11页Journal of Materials Engineering

基　　金：国家自然科学基金项目(51701099);黑龙江省自然科学基金(LH2019E091);2022年黑龙江省省属本科高校基本科研业务费面上项目(145209133);2020年度黑龙江省省属本科高校基本科研业务费青年创新人才项目(135509218)。

摘　　要：通过高真空电弧熔炼炉和熔体抽拉液态成形设备制备Ni-Mn-Ga和Ni-Mn-Ga-Fe纤维,并对纤维进行阶梯式有序化热处理。利用场发射扫描电子显微镜(SEM)、透射电子显微镜(TEM)、射线衍射仪(XRD)对其微结构和相结构进行表征;利用差示扫描量热仪(DSC)对纤维的马氏体相变过程进行分析;利用动态机械分析仪对纤维的超弹性进行测试。结果表明:有序化热处理后纤维内部原子排列有序性提高,相邻孪晶间沿近90°大角度晶界方向生长,晶界处平直。Fe掺杂使得纤维内部晶粒细化,晶格体积缩小,纤维整体致密性提高。Fe掺杂使得晶格内自由电子数量增多,电子浓度升高,致使马氏体相变(martensitic transformation,MT)的相变温度(M s)明显提高;通过有序化热处理,高温下的自由电子自由排列,形成有差异性的新布里渊区,构成新的孪晶界,进一步提高晶格内部的致密程度。同时Fe具备耐高温、抗拉强度高的特性,Fe掺杂的Ni-Mn-Ga纤维降低了其本征脆性。超弹性曲线显示了热弹性马氏体相变的两个基本特征:完全超弹性(superelasticity,SE)和低温恢复特性。在超弹性实验中,Ni_(50)Mn_(25)Ga_(20)Fe 5纤维在355 K测试温度时达到完全SE;在测试温度T test>M_(s)+8 K时,达到100%的应变恢复率(strain recovery rate),较Ni-Mn-Ga纤维(≈90%)有所提高。与其他合金(如Ti-Ni和Cu-Al-Ni合金)相比,Ni-Mn-Ga-Fe纤维显示出更大的临界应力值和更宽的SE温度空间。Ni-Mn-Ga and Ni-Mn-Ga-Fe microwires were prepared by high vacuum arc melting furnace and melt drawing liquid forming equipment,and the microwires were subjected to step-ordered heat treatment.The microstructure and phase structure of the microwire were characterized by field emission scanning electron microscopy,transmission electron microscopy and X-ray diffractometer,the martensitic transformation process of the microwires was analyzed by differential scanning calorimeter,and the superelasticity of the microwires was tested by dynamic mechanical analyzer.The results show that the orderly arrangement of atoms inside the microwires is improved after the ordering heat treatment,and the adjacent twin crystals grow in the direction of the grain boundaries at a large angle of nearly 90°,with the grain boundaries being straight.Fe doping can refine the cell structure and improve the structure density.Fe doping increases the number of free electrons in the lattice and increases the concentration of electrons,resulting in a significant increase in the phase transformation temperature(M_(s))of martensitic transformation(MT);through the ordering heat treatment,the free electrons at high temperatures are freely arranged,forming new Brillouin zones with differences,constituting new twin boundaries and further increasing the density of the interior of the lattice.At the same time,Fe has the characteristics of high temperature resistance and high tensile strength,and Fe-doped Ni-Mn-Ga microwires reduce their intrinsic brittleness.The superelasticity curves show two basic characteristics of thermoelastic martensitic transformation:complete superelasticity(SE),and low temperature recovery property.In the superelasticity experiments,Ni_(50)Mn_(25)Ga_(20)Fe_(5)microwires reach complete SE at 355 K;at a test temperature of T test>M_(s)+8 K,100%strain recovery rate is achieved,which is an improvement over Ni-Mn-Ga microwires(≈90%).Ni-Mn-Ga-Fe fibres show larger critical stress values and a wider SE temperature space than other a

关 键 词：铁磁形状记忆合金纤维 马氏体相变 超弹性 有序化热处理 Ni-Mn-Ga多晶合金纤维 

分 类 号：O731[理学—晶体学] O782[一般工业技术—材料科学与工程] TG139.6[金属学及工艺—合金]