Abstract 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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