Electronic structure and doping effect of Ni and Co in the kink on the edge dislocation of bcc iron

Abstract

Using the first-principles self-consistent discrete variational method based upon density functional theory, we investigated the energetics and the electronic structure of the 3d impurities Ni and Co in a kink on the [100](010) edge dislocation (ED) in bcc iron. The calculated results show that the interatomic energies between the impurity atom and the neighboring host atoms decrease. The bonding for the impurity atom (Ni, Co) and the neighboring host Fe atoms is weaker than that for an Fe atom at the X site and the corresponding atoms in the clean kink. These results indicate that sideways motion of the kink in the <100>{010} ED is accelerated by an impurity atom such as Ni or Co and that, consequently, the presence of impurities increases the dislocation mobility, thus leading to solid-solution softening.

First-principles investigation of the impurity-kink interaction in bcc iron

“…When a kink pair meets hydrogen during expanding, the sideward motion of the kink pair is impeded by hydrogen (SSH). However, to our knowledge, there exist few studies [20][21][22][23] in literature on the impurity-kink complex based on first-principles method, while the electronic structure of solute impurity atoms within the kink may play an important role in impurity-kink interactions. In the present study, the attempt of first-principles study on impurity (C and N)-kink interaction in bcc Fe is made.…”

The effect of hydrogen on the electronic structure of kink in bcc iron

“…We studied the electronic effects of B, S, Ni and Co impurities on the kink in the [100](010) edge dislocation (ED) of bcc iron [10][11][12] . The calculated results show that boron in the kink can enhance the interatomic interaction between the impurity atom and the neighboring Fe atoms due to the hybridization of B 2p-Fe 3d4s4p orbitals, which impels the migration of kink and leads to a strong pinning effect on the dislocation (hardening).…”

Electronic States and Doping Effect of Carbon in the Kink of BCC Iron

“…To our knowledge, although the electronic structure of solute impurity atoms within the kink may play an important role in impurity-kink interaction, little work has been done, to investigate the impurity-kink complex, based upon the first-principles method. We studied the electronic effects of B, Ni and Co impurities upon the kink in the [100](010) ED of bcc iron [13,14]. It is found that boron in the kink can enhance the interaction between the impurity atom and the neighboring Fe atoms, due to the hybridization of B 2p-Fe 3d4s4p orbitals.…”