杂质P对α-Fe中刃型位错上扭折电子结构的影响

利用离散变分方法和DMol方法，研究了P对bcc Fe中［100］(010)刃型位错上扭折电子结构的影响，计算了杂质偏聚能、原子间相互作用能、电荷密度及态密度.计算结果表明：微量P引入体系后，电荷发生了重新分布，P原子得到电子，其周围Fe原子失去电子，由于P原子的3p轨道与近邻Fe原子的3d4s4p轨道之间杂化，使P原子与近邻Fe原子间有较强的相互作用，不利于扭折的迁移，使位错运动受阻，有利于材料强度的提高.同时，杂质P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，有可能 关键词： 电子结构 刃型位错 扭折 杂质元素

Effect of impurity P on electronic structure of kink in the edge dislocation of α-iron

Using the first-principles self-consistent discrete variational method based on density functional theory, we have investigated the effect of impurity P on the electronic structure of the kink on the ［100］(010) edge dislocations in bcc iron. Furthermore，we have calculated the segregation energy, the interatomic energy, the local density of states and the charge density. Our results show that the P atom proeures electrons from its neighboring Fe atoms when trace P is introduced into interstitial sites in the kink. It is found that the interactions between impurity P atom and neighboring Fe atoms are strengthened due to the strong hybridizations between P-p with Fe-3d4s4p states. The migration of kink and dislocation motion are impeded by P, which may be beneficial to increase the strength of material. Meanwhile, the bonding between the impurity P and the host Fe atoms are mainly ascribed to contribution of p and d states, which leads to the bonding between them to have strong orientation. This is not beneficial to the toughness of materials.