Electronic States and Doping Effect of Carbon in the Kink of BCC Iron
By the use of the first-principles method, based upon density functional theory, we investigated the effect of C upon the electronic structure of a kink on the ½(1¯10) edge dislocation in bcc iron. The results show that C has a tendency to segregate towards the kink. The structural energies of some atoms of interest in the kink with C are lower than those of corresponding atoms in the clean kink. Furthermore, the interactions between C and the neighboring Fe atoms are very strong due to the hybridization between the C 2p state and the Fe 3d4s4p states. We find that there exists some charge accumulations between C and the neighboring Fe atoms. The analysis of the electronic structure indicates that the introduction of C can stabilize the kink system and impede the sideways motion of the kink. The C induces a strong pinning effect on the ½(1¯10) edge dislocation and may result in solid solute hardening.
David J. Fisher
Z. C. Qiu et al., "Electronic States and Doping Effect of Carbon in the Kink of BCC Iron ", Defect and Diffusion Forum, Vol. 293, pp. 1-9, 2009