Oxidation susceptibility of UN E5(210) grain boundary with Al/Cr/Ni dopant: A first-principles study

The oxidation susceptibility of UN E5(210) grain boundary (GB) decorated with Al, Cr or Ni is assessed by first-principles modelling. The predictions show that the low segregation energy of O at the Al-doped GB leads to increasing O enrichment, which explains the high O concentration observed in experiments. GB with Ni exhibits formidable antioxidant capability but enhances sensitivity to embrittlement. Cr dopant not only effectively reduces O segregation but also improves the cohesive capability of oxidized GB. Our work clarifies the mechanisms of (un)-doped UN GB oxidation from an atomic perspective, in which analysis so far rests on experiments only. (c) 2023 Elsevier B.V. All rights reserved.

Automated summary

This study assesses the oxidation susceptibility of UN E5(210) grain boundaries (GBs) decorated with Al, Cr, or Ni using first-principles modeling. The predictions reveal that the low segregation energy of O at the Al-doped GB leads to increased O enrichment, explaining the high O concentration observed in experiments. The Ni-doped GB exhibits formidable antioxidant capability but enhances sensitivity to embrittlement, while the Cr dopant effectively reduces O segregation and improves the cohesive capability of the oxidized GB. This work provides atomic-level insights into the mechanisms of (un)-doped UN GB oxidation, complementing previous experimental analyses.