Oxygen - Dislocation interaction in zirconium from first principles
Abstract
Plasticity in zirconium alloys is mainly controlled by the interaction of 1/3 1210 screw dislocations with oxygen atoms in interstitial octahedral sites of the hexagonal close-packed lattice. This process is studied here using ab initio calculations based on the density functional theory. The atomic simulations show that a strong repulsion exists only when the O atoms lie in the dislocation core and belong to the prismatic dislocation habit plane. This is a consequence of the destruction of the octahedral sites by the stacking fault arising from the dislocation dissociation. Because of the repulsion, the dislocation partially cross-slips to an adjacent prismatic plane, in agreement with experiments where the lattice friction on screw dislocations in Zr-O alloys has been attributed to the presence of jogs on the dislocations due to local cross-slip.
Cite
@article{arxiv.1705.04075,
title = {Oxygen - Dislocation interaction in zirconium from first principles},
author = {Nermine Chaari and David Rodney and Emmanuel Clouet},
journal= {arXiv preprint arXiv:1705.04075},
year = {2017}
}