Sr偏析Al晶界结构的第一性原理计算

采用基于密度泛函理论和局域密度近似的第一性原理赝势方法，计算了纯Al晶界和杂质Sr偏析Al晶界的原子结构和电子结构.结果表明Sr偏析引起了晶界膨胀和晶界处电子密度的大幅度降低,从而导致晶界结合力的减弱.这应为Sr杂质偏析引起的Al晶界脆化的主要根源所在. 关键词： Al晶界 Sr 杂质偏析 第一性原理计算

First-principles study of the effects of Sr segregated on Al grain boundary

The atomic and electronic structures of an Al grain boundary with segregated Sr (substitutional) impurity atoms have been calculated by the first-principles pseudopotential method based on the local density functional theory. The results show that the boundary expands and the charge density decreases significantly over the whole boundary due to Sr segregation. This suggests grain boundary weakening, which should be responsible for the experimentally observed Sr-induced Al intergranular embrittlement.