金属间化合物Ni＿3Al中超点阵位错的原位加热观察

In-situ observations on the superlattice dislocation in Ni_3Al single crystal

利用透射电子显微镜弱束成像技术对金属间化合物Ｎｉ＿３Ａｌ单晶中的超点阵位错进行原位动态观察。结果发现，在（００１）面上分解的位错，其分解宽度在室温至７７３Ｋ之间没有明显变化，在７７３Ｋ恒温３０分钟后两分解位错之间出现连结点，在８９８Ｋ恒温２０分钟后两分解位错完全束集。说明（００１）面上反相畴界的能量随着温度升高而增加。本文讨论了这一现象对材料力学性能的影响。

In-situ heating observations have been performed by the weak-beam dark dark field method of TEM to investi-gate the thermal behavior of dissociated dislocation in Ni_3Al single crystal.The results show that the seperationof distance of the dissociated dislocation on(001)plane did not vary in the temperature rang from room tempera-ture to 773K. After waiting 30 minutes at 773K,a jog between the superpartials has been found and after waiting 20 minutes at 898K,the dissociated dislocation constricted completely. The experimental observations havebeen discussed in this paper.