Dislocation loop evolution in Kr-irradiated ThO2

Lingfeng He, Tiankai Yao, Kaustubh Bawane, Miaomiao Jin, Chao Jiang, Xiang Liu, Wei Ying Chen, J. Matthew Mann, David H. Hurley, Jian Gan, Marat Khafizov

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The early stage of microstructural evolution of ThO2, under krypton irradiation at 600, 800, and 1000°C, was investigated using in situ transmission electron microscopy (TEM). Dislocation loops grew faster, whereas their number density decreased with increasing irradiation temperature. Loop density was found to decrease with ion dose. Interstitial dislocation loops, including Frank loops with Burgers vector of a/3〈111〉 and perfect loops with Burgers vector of a/2〈110〉, were determined by traditional TEM and atomic resolution–scanning TEM techniques. Atomistic and mesoscale level modeling are performed to interpret experimental observations. The migration energy barriers of defects in ThO2 were calculated using density-functional theory. The energetics of different dislocation loop types were studied using molecular dynamics simulations. Loop density and diameter were analyzed using a kinetic rate theory model that considers stoichiometric loop evolution. This analysis reveals that loop growth is governed by the mobility of cation interstitials, whereas loop nucleation is determined by the mobility of anion defects. Lastly, a rate theory model was used to extract the diffusion coefficients of thorium interstitials, oxygen interstitials, and vacancies.

Original languageEnglish (US)
Pages (from-to)5419-5435
Number of pages17
JournalJournal of the American Ceramic Society
Volume105
Issue number8
DOIs
StatePublished - Aug 2022

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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