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

Abstract

［中文文摘］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%时为单一fcc结构的γ相,在x≤5.6时为含有ε马氏体相和γ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。［英文文摘］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 microstructure consists of γ phase and ε martensitic phase with hcp 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.国家自然科学基金(50771086); 福建省新世纪优秀人才支持计划项目资助