Molecular Dynamics Simulation on Interaction between Screw Dislocation and Pseudo Yttrium Oxide in Bcc-Fe

Abstract

For an atomistic insight in oxide dispersion strengthened (ODS) steels, we have performed molecular dynamics simulations on interaction between screw dislocation and nanoparticle of “pseudo” oxide, by using simple Johnson potential. Various dislocation–obstacle interactions are investigated for 2 nm oxides of coherent bcc, incoherent hcp and “hollow” without oxide, on each slip planes of {\\bar{1}10} and {\\bar{1}\\bar{1}2}, respectively. Although it is not a feature of oxide, we have found “Saturn ring” defects around the incoherent oxide and hollow on the {\\bar{1}\\bar{1}2} slip plane, and revealed the mechanism; that is, screw dislocation should leave vacancies to shorten or elongate its length between the incoherent interfaces or surface of hollows. Screw dislocation on the {\\bar{1}10} slip plane doesn’t form such ring due to the cross-slip; however, it forms “entanglement” around the incoherent oxide. On the other hand, the screw dislocation never “splits” against the coherent precipitates so that it leaves little defect around the coherent oxide.