# Oxygen - Dislocation interaction in zirconium from first principles

## TL;DR

This study uses first-principles calculations to analyze how oxygen atoms interact with screw dislocations in zirconium, revealing a strong repulsion that influences dislocation behavior and cross-slip, impacting alloy plasticity.

## Contribution

It provides a detailed atomic-level understanding of oxygen-dislocation interactions in zirconium using density functional theory, highlighting the role of stacking faults and dislocation cross-slip.

## Key findings

- Strong repulsion occurs when oxygen atoms are in the dislocation core.
- Dislocations can cross-slip to adjacent prismatic planes due to oxygen interaction.
- Results align with experimental observations of lattice friction and jog formation.

## 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.