部分循环对FeMnSi基合金形状记忆效应的研究

The Partial Thermal Cycling Studies on Shape Memory Effect of Fe-Mn-Si alloy

用Ｘ射线衍射及热膨胀法研究了预应变量为３％的两种ＦｅＭｎＳｉ形状记忆合金在室温—４５０℃区间加热时形状恢复量及ε－马氏体量随温度的变化，结果表明ε马氏体在晶体中处于不同的能量状态，４５０℃加热后仍有部分应力诱发ε马氏体没有转变，这是该系列合金形状不能完全恢复的原因之一；同时发现，预应变后，合金中贮存弹性内应力，使得在Ａｓ～Ａｆ之间同一温度区间膨胀、收缩系数不同。

\ The change of recovery strain and the volume fraction of thermal ε martensite and stress induced ε martensite as a function of temperature for two FeMnSi SMA prestrained by 3% was investigated by dilatometric and X ray diffraction. It suggest that there exists an energy distribution among ε martensite shears. Part of ε martensite could not be transformed after heated at 450℃, which account for one of the reason of no full rexovery strain obtained. The internal elastic stress inprestrained FeMnSi SMA, which result in the different between constract rate and expansion rate when heated at same temperature range, was showed on partial thermal cycle curve.