A study was made of the structure and of the formation and migration energies of single kinks in ½<111> screw dislocations in body-centered cubic iron, by performing static calculations using the Ackland–Mendelev empirical potential, which correctly accounts for the non-degenerate core structure. The methodology for constructing simulation cells with fully periodic boundary conditions based on the quadrupolar arrangement of dislocation dipoles, with a single kink on each dislocation line was presented. The two types of kinks – left and right – were found to have similar widths, namely ~20 Burgers vectors. The convergences of the formation energies with cell-size along the dislocation line, as well as with the distance between the two dislocations were investigated. A dependence proportional to the inverse of the distance between kinks along the dislocation line was found when kinks overlap. The formation energies of the left and right kinks were significantly different: 0.57 and 0.08 eV, respectively. The Peierls potentials of the second kind were evaluated with the drag method: the energy barriers were found to be lower than 0.1 meV for both kinks.

Atomistic Simulation of Single Kinks of Screw Dislocations in α-Fe. L.Ventelon, F.Willaime, P.Leyronnas: Journal of Nuclear Materials, 2009, 386-388, 26-9