(上海交通大學 材料科學與工程學院，上海 200240)
摘 要: 反鐵磁MnFeCu合金的形狀記憶效應來自于FCC-FCT馬氏體相變。相比于其他合金，MnFeCu合金體系的點陣畸變度較小。通過極小形變近似理論計算點陣不變形變?yōu)閷\晶切變的FCC-FCT馬氏體相變的相關晶體學參數(shù)，得到形式簡單的解析解，與實驗測量結果相吻合。比較ID近似理論計算結果與經典的WLR理論計算結果，可以發(fā)現(xiàn)前者是后者的高階近似，在點陣畸變度較小的情況下，兩者的精度幾乎相同。由此可見，對于點陣畸變度較小的合金體系，應用ID近似理論預測相變晶體學極其便利，可以給出形式簡單且精度較高的解析解。
關鍵字: 形狀記憶合金；MnFeCu合金；ID近似理論；FCC-FCT馬氏體相變；晶體學；孿晶切變；點陣畸變度
（School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract:Shape memory effect in MnFeCu antiferromagnetic alloy comes from the FCC-FCT martensitic transformation (MT). Compared with many other alloys, MnFeCu alloys have small lattice distortion. The infinitesimal deformation (ID) approach theory was applied to study the crystallography of FCC-FCT MT with the twinning shear as the lattice invariant shear in the MnFeCu alloy. Simple analytical solutions were derived, which were in good agreement with the experiment results. Compared the calculated results with those obtained from the classical WLR theory, it was found that the former are the approximation by neglecting the higher-order terms of the latter. In the condition of small lattice distortion, they almost have the same accuracy. Therefore, for the alloys with small lattice distortion, ID approach theory can be applied to predicate the crystallography conveniently, which can derive simple analytical solutions with high accuracy.
Key words: shape memory alloy; MnFeCu alloy; ID approach theory; FCC-FCT martensitic transformation; crystallography; twinning shear; lattice distortion
