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Anisotropic hydrogen diffusion in alpha-Zr and Zircaloy predicted by accelerated kinetic Monte Carlo simulations

dc.contributor.authorZhang, Yongfengen
dc.contributor.authorJiang, Chaoen
dc.contributor.authorBai, Xianmingen
dc.contributor.departmentMaterials Science and Engineering (MSE)en
dc.date.accessioned2019-01-11T15:22:10Zen
dc.date.available2019-01-11T15:22:10Zen
dc.date.issued2017-01-20en
dc.description.abstractThis report presents an accelerated kinetic Monte Carlo (KMC) method to compute the diffusivity of hydrogen in hcp metals and alloys, considering both thermally activated hopping and quantum tunneling. The acceleration is achieved by replacing regular KMC jumps in trapping energy basins formed by neighboring tetrahedral interstitial sites, with analytical solutions for basin exiting time and probability. Parameterized by density functional theory (DFT) calculations, the accelerated KMC method is shown to be capable of efficiently calculating hydrogen diffusivity in alpha-Zr and Zircaloy, without altering the kinetics of long-range diffusion. Above room temperature, hydrogen diffusion in alpha-Zr and Zircaloy is dominated by thermal hopping, with negligible contribution from quantum tunneling. The diffusivity predicted by this DFT + KMC approach agrees well with that from previous independent experiments and theories, without using any data fitting. The diffusivity along < c > is found to be slightly higher than that along < a >, with the anisotropy saturated at about 1.20 at high temperatures, resolving contradictory results in previous experiments. Demonstrated using hydrogen diffusion in alpha-Zr, the same method can be extended for on-lattice diffusion in hcp metals, or systems with similar trapping basins.en
dc.description.notesThe INL authors gratefully acknowledge the support of the INL Laboratory Directed Research and Development Program under project #14-026, "Multiscale modeling on delayed hydride cracking in zirconium: hydrogen transport and hydride nucleation", and the Department of Energy (DOE) Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. This manuscript has been authored by Battelle Energy Alliance, LLC under Contract No. DE-AC07-05ID14517 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. All authors are grateful to Dr. Larry Aagesen at INL who provided proofreading and valuable comments.en
dc.description.sponsorshipINL Laboratory Directed Research and Development Program [14-026]; Department of Energy (DOE) Nuclear Energy Advanced Modeling and Simulation (NEAMS) program; U.S. Department of Energy [DE-AC07-05ID14517]en
dc.format.extent13en
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1038/srep41033en
dc.identifier.issn2045-2322en
dc.identifier.other41033en
dc.identifier.pmid28106154en
dc.identifier.urihttp://hdl.handle.net/10919/86669en
dc.identifier.volume7en
dc.language.isoen_USen
dc.publisherSpringer Natureen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.subjecthydride precipitationen
dc.subjectzirconium alloysen
dc.subjectab-initioen
dc.subjectsolubilityen
dc.subjectphaseen
dc.subjectcoefficienten
dc.subjectmetalsen
dc.titleAnisotropic hydrogen diffusion in alpha-Zr and Zircaloy predicted by accelerated kinetic Monte Carlo simulationsen
dc.title.serialScientific Reportsen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten

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