元素合金化对NiFeGa合金马氏体相变特性的影响

Effect of Element Alloying on Martensitic Transformation Properties of Ni-Fe-Ga Alloys

采用电弧炉熔炼和急冷快淬吸铸的方法制备Ni-Fe-Ga-X(X=Si,Ge,Al,Co)合金,利用光学显微镜、X射线衍射和示差扫描量热仪,研究了Si,Ge,Al,Co元素合金化对Ni-Fe-Ga合金显微组织、晶体结构和马氏体相变特性的影响.研究结果表明,Si,Ge,Al替代Ga元素后,室温下表现出良好的热弹性马氏体特征,随着其含量增加,合金的马氏体相变特征温度线性下降;而Co替代Ga元素,具有M+γ双相显微组织结构,其相变特征温度随Co含量增加而显著提高.电子浓度和晶胞体积是影响Ni-Fe-Ga-X合金马氏体相变特征温度两个重要的因素.一方面,随着电子浓度的增加,合金的马氏体相变特征温度升高;另一方面,晶胞体积收缩也有利于提高马氏体相变特征温度.

Ni-Fe-Ga-X(X=Si,Ge,Al,Co)ferromagnetic shape memory alloys were prepared by an arc melting and copper-mold vacuum suction casting.The effects of alloying with Si,Ge,Al,Co on microstructure and martensitic transformation properties of Ni-Fe-Ga alloys were investigated using optical microscopy,X-ray diffraction,differential scanning calorimeters,respectively.Results show that the good thermoelasticmartensite is determined at room temperature.The martensitic transformation temperaturesof the alloys decrease almost linearlywith increasing Si,Ge or Al content.The matrix is M+γphase as the substitution of Ga for Co.The transformation temperaturesof the alloys the substitution of Ga for Co increase notably with increasing Co.