Intrinsic defect migration in Be12Ti
File(s)
Accepted version
Author(s)
Jackson, matthew
Burr, patrick
Grimes, Robin
Type
Journal Article
Abstract
Be12Ti is a leading candidate neutron-multiplier material for fusion breeder blankets; yet the evolution of the crystal defects under irradiation is poorly understood. Here, the migration of intrinsic defects in tetragonal Be12Ti was predicted using atomic scale computer simulation. Transport of titanium and beryllium through the interstitial, interstitialcy and vacancy-mediated models was considered, along with the migration of divacancy clusters, previously identified as important to the defect chemistry of Be12Ti. It was found that titanium defects exhibit much higher migration energies than beryllium for most migration pathways, leading to a dramatic difference in migration isotropy. Both beryllium vacancy and interstitial diffusion is close to isotropic with vacancy transport exhibiting the highest self-diffusion coefficient. Migration of beryllium di-vacancies is also isotropic with activation energy equal to that of isolated vacancies. The titanium interstitial exhibits significantly lower migration energy than its vacancy (1.00 eV and 6.75 eV respectively), with both mechanisms strongly anisotropic: the activation energy for [001] migration is at least 5 eV lower than other directions. Even the more exotic mixed titanium beryllium vacancy migration exhibits a much higher migration energy than [001] titanium interstitial transport. The framework used for predicting defect transport kinetics, including vacancy-mediated, interstitial and interstitialcy mechanisms, can be applied to any complex-structured intermetallic compound.
Date Issued
2021-01
Date Acceptance
2020-08-13
Citation
Intermetallics, 2021, 128, pp.1-10
ISSN
0966-9795
Publisher
Elsevier
Start Page
1
End Page
10
Journal / Book Title
Intermetallics
Volume
128
Copyright Statement
© 2020 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
https://www.sciencedirect.com/science/article/pii/S0966979520304155?via%3Dihub
Subjects
0306 Physical Chemistry (incl. Structural)
0912 Materials Engineering
0914 Resources Engineering and Extractive Metallurgy
Materials
Publication Status
Published online
Date Publish Online
2020-10-17