He-vacancy interaction and multiple He trapping in small void of silicon carbide
2015 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 457, 36-41 p.Article in journal (Refereed) Published
In fusion environment, large amounts of helium (He) atoms are produced by transmutation along with structural damage in the structural materials, causing material swelling and degrading of physical properties. To understand the microscopic mechanism of He trapping in vacancies and voids, we explored He-vacancy interactions in HenVam (Va for vacancy) clusters (n, m = 1-4) and multiple He trapping in a 7-atom void of silicon carbide (SiC) by first-principles calculations. The binding energy between He and the HenVam clusters increases with the number of vacancies, while the vacancy binding energy gradually increases with the number of He atoms. Furthermore, a small cavity of about 0.55 nm in diameter can accommodate up to 14 He atoms energetically and the corresponding internal pressure is estimated to be 2.5 GPa. The tendency of He trapping in small voids provides an explanation for the experimentally observed He bubble formation at vacancy defects in SiC materials.
Place, publisher, year, edition, pages
2015. Vol. 457, 36-41 p.
Atoms, Binding energy, Calculations, Silicon, Silicon carbide, Swelling, Vacancies, Crystal atomic structure, First-principles calculation, Large amounts, Microscopic mechanisms, SiC materials, Silicon carbides (SiC), Small cavities, Structural damages, Vacancy Defects
IdentifiersURN: urn:nbn:se:kth:diva-159217DOI: 10.1016/j.jnucmat.2014.10.062ISI: 000349169100005ScopusID: 2-s2.0-84910628889OAI: oai:DiVA.org:kth-159217DiVA: diva2:783359
QC 201501262015-01-262015-01-262016-02-18Bibliographically approved