Ge含量对Fe-24%Mn合金γ→ε马氏体转变的影响

Effect of Ge Content on the γ→ε Martensitic Transformation of Fe-24%Mn Alloys

通过 X射线衍射 (XRD)、拉伸性能的测定 ,分析了 Ge对 Fe- 2 4 % Mn形状记忆合金 γ相点阵参数和马氏体转变的影响 .发现随着 Ge含量的上升 ,Fe- 2 4 % Mn合金 γ相点阵参数增大 ,Fe-2 4 % Mn合金的 γ→ ε马氏体相变有明显抑制作用 ,γ奥氏体相趋于稳定 ,合金的拉伸强度和屈服强度逐步降低 ,塑性上升 .尽管 Ge与 Si具有相同的外层电子结构 ,且原子半径都比 Fe小 ,但两者对奥氏体的点阵参数影响完全相反 ,Si降低γ相点阵参数能促进γ→ε马氏体相变 ,Ge增加γ相的点阵参数却抑制相变 .

The effect of Ge content (0%~5.88%) on the γ lattice parameter and γ→ε martensitic transformation of Fe 24%Mn SMA was investigated by X ray diffraction (XRD) method and tensile properties measurement. The results show that Ge increases the lattice parameter of austenite. It depresses the γ→ε matensitic transformation evidently, and stabilized the γ austenite phase. Moreover, with the increase of Ge content from 0% to 5.88%, the tensile strength and yield strength decrease simultaneously while the plasticity increases. Although Ge and Si have the same outer electron structure, and both atom radii are smaller than Fe, they have different effect on the latter parameter of austenite. Si decreases the latter parameter of austenite and promotes the γ→ε martensite transformation, Ge increases the latter parameter of austenite and inhibits the γ→ε martensite transformation.