用基于密度泛函理论的自洽离散变分方法研究了轻元素S对bcc Fe中[100](010)刃型位错上扭折的电子结构的影响，计算了杂质偏聚能、原子间相互作用能、电荷密度及态密度等物理参量。计算结果表明：S引入体系后，电荷发生了重新分布，S得到电子，其周围Fe原子失去电子，分析发现S原子的3p轨道与近邻Fe原子的3d4s4p轨道之间杂化，S与近邻Fe原子之间有较强的相互作用，而近邻基体原子本身之间相互作用比未掺杂时减弱，有利于扭折的迁移，杂质S原子与基体原子间的成键主要是d 、p轨道起作用，使得它们之间的成键有较强的方向性，使材料的强度降低、韧性减小。
Using the first-principles self-consistent discrete variational method (DVM) based on density functional theory, we investigated the effect of impurity S on the electronic structure of the kink on the [100](010) edge dislocations(ED) in bcc iron. We calculate the segregation energy, the interatomic energy, the local density of states and the charge density. The results show that S obtains electrons from its neighboring Fe atoms when a S atom is introduced into interstitial sites in the kink. It is found that there are the strong hybridizations between impurity S-d with Fe-3d4s4p states. The interaction between impurity S atom and neighboring Fe atoms are strengthen, while the interaction between the host Fe atoms are decreased, which is beneficial to the migration of kink. The bonding between the impurity S and the host Fe atoms are mainly ascribed to contribution of p and d states, which leads to the bonding between them has strong orientation, and the strength and toughness of materials both are decreased.
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