Fe-Mn-Ge合金γ→ε马氏体相变的研究

STUDY OFγ→εMARTENSITE TRANSFORMATION OF Fe-24Mn-Ge ALLOYS

利用金相组织观察、透射电子显微镜（ＴＥＭ）分析和点阵参数测定方法研究了 Ｇｅ含量对 Ｆｅ－２４Ｍｎ合金马氏体相变和显微组织结构的影响．结果表明，Ｆｅ－２４Ｍｎ合金在冷却过程中产生大量的ε马氏体．在较低 Ｇｅ含量合金中的后形成马氏体可以穿越或终止在另一取向的先形成马氏体片中．宽大的马氏体片是由大量相互平行的层错构成．随Ｇｅ含量的增加，马氏体片之间以交截或平行为主．这一结果表明：Ｇｅ的加入使Ｆｅ－２４Ｍｎ合金中奥氏体层错能增加，合金中的ε马氏体数量减少．马氏体转变开始点 Ｍｓ降低 Ｇｅ增大 Ｆｅ－２４Ｍｎ合金奥氏体的点阵常数，但对

The effect of Ge content (0%-5.88%) on the γ→Ε martensite transformation of Fe-24Mn alloys has been investigated by the optical microscopy, transmission electron microscopy (TEM), X-ray diffraction and measurement of shape memory effect (SME). The results show that with an increase of Ge content, the amount of martensites decreases. Later-formed martensites can penetrate through or terminate inside the former ones with another orientation in the low Ge content alloys. In Fe-24Mn alloy with higher Ge content intersecting or mutually paralleling of the martensite laths dominates, which implies that Ge raise the staking fault energy of γ phase in Fe-24Mn alloys, and depresses the nucleation site for martensite and Ms of the alloys. The Ε martensite plates with 1 μm are composed of numerous overlapped staking faults. Ge addition increases the lattice parameter of γ phase and has no obvious effect on the SME of alloys.