铁磁性Co-Fe记忆合金的马氏体相变特性及形状记忆效应

Martensitic Transformation Behavior and Shape Memory Effect of Co-Fe Ferromagnetic Shape Memory Alloys

采用光学显微镜、X射线衍射、DSC、弯曲试验等方法研究了Co-Fe合金的微观组织结构、马氏体相变特性及形状记忆效应。结果表明：Co-Fe合金的记忆效应源自合金中的fcc／hcp马氏体相变；Co-xFe（X=2％～6％，质量分数）合金在x≥5．65％时为单-fcc结构的y相，在x≤5．6时为含有ε马氏体相和y相的双相组织；该合金的马氏体相变温度随着Fe含量的增加而线性降低，之间关系为：Ms（℃）=417-69．97x（Fe％）Co-4Fe合金的形状记忆可回复应变最大为0．86％，相信通过进一步的热处理和记忆训练，该合金会表现出更好的记忆效应。

Microstructure, martensitic transformation temperature and shape memory effect of Co-Fe alloys were investigated by optical observation, X-ray diffraction, DSC and bending tests. Results show that the shape memory effect of Co-Fe alloys is associated with the fcc/hcp martensitic transformation. When Fe content is higher than 5.65wt%, the microstructure exhibits single γ phase with fcc structure. When Fe content is lower than 5.6wt%, the microstructurc consists of γ phase and ε manensitic phase with hop structure. The martensitic transformation temperatures of Co-xFe alloys are almost linearly decreased with increasing Fe content, following the relationship： Ms （℃） = 417-69.97x（Fe%）. The highest recoverable strain of Co-4Fe （wt%） alloy is 0.86%. It is believed that Co-Fe alloys will exhibit better shape memory effect after proper heat treatment and shape memory training.