反铁磁Mn-Fe(Cu)合金在马氏体相变过程中的组织演化

Microstructural evolution during martensitic transformation in antiferromagnetic Mn-Fe(Cu) alloy

采用电阻-温度曲线、X射线衍射分析仪(XRD)、调制示差扫描热分析仪(DSC)及原位透射电子显微镜(TEM)等,研究了的Mn-Fe(Cu)合金在马氏体相变过程中的组织演化。研究结果表明,Mn-Fe(Cu)合金孪晶面为{011}面的FCT板条状马氏体孪晶组织。原位TEM观察可见,板条状马氏体孪晶具有良好的可动性。在较高温度下降温时,会出现由于反铁磁畸变产生的"花呢"状组织,导致原有孪晶的位置与取向发生变化。Landau自由能方程的解可证明反铁磁转变对马氏体孪晶形貌的影响。

In this paper, the microstructural evolution in antiferromagnetic Mn-Fe（Cu） alloy was studied by X-ray diffraction （XRD） analysis, electric resistance vs temperature curve, differential scanning calorimetry （DSC）, transparent electronic microscopy （TEM）. The results showed that at room temperature, the alloy＇s microstructure was twins with {011} twin plane. The martensitic twins were movable driven hy temperature. However, when the alloy was cooled from higher temperature, there exists tweed microstructures induced by antiferromagnetic transition,by which the sites and orientations of the original twins changed. The solutions of Landau free energy equation indicated that the morphography of martensitic twins was affected by antiferromagnetic transition.