合金元素Mn对bcc Fe中刃型位错上扭折电子结构影响的第一原理研究

First-principles Investigation of the Alloying Effect of Mn in the Kink on the Edge Dislocation in bcc Iron

用基于密度泛函理论的自洽离散变分方法研究了合金元素Mn对bcc Fe中[100](010)刃型位错上扭折的电子结构的影响,计算了格位能、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:Mn引入扭折后,由于Mn原子的3d轨道与近邻Fe原子的3d之间的杂化,使Mn与近邻原子之间及基体原子之间的相互作用加强,阻碍扭折的侧向运动,即对位错运动起了较强的钉扎效应,导致固溶强化。

Using the first-principles self-consistent discrete variational method（DVM） based on density functional theory, we investigated the effect of alloying element Mn on the electronic structure of the kink on the [100]（010） edge dislocations（ED） in bee iron. We calculate the structural energy, the interatomic energy, the local density of states and the charge density. The results show that Mn in the kink can enhance the interatomic interaction between the impurity atom and the neighboring Fe atoms as well as between the host atoms due to the hybridization of Mn 3d-Fe 3d orbitals. The introduction of the Mn impedes the sideward motion of the kink, and leads to a strong pinning effect on the dislocation motion in bee iron, which may explain the solid solute hardening of Mn.