Vacancy trapping mechanism for multiple helium in monovacancy and small void of vanadium solid
2013 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 440, no 1-3, 557-561 p.Article in journal (Refereed) Published
Using first-principles methods, we have investigated the microscopic mechanism for He trapping in two kinds of vacancy defects (monovacancy and 9-atom void) inside vanadium host lattice. In the monovacancy, single He prefers to occupy the octahedral site near vacancy rather than vacancy center. Inside vacancy defects, the He-He equilibrium distances range in 1.6-2.2 angstrom. After more He atoms are incorporated, the magnitude of trapping energy decreases and the host lattice expand dramatically. A monovacancy and 9-atom void can host up to 18 and 66 He atoms, respectively, with internal pressure up to 7.5 and 19.3 GPa. The atomic structures of selected He clusters trapped in vacancies are compared with the gas-phase clusters. The strong tendency of He trapping at vacancies and 9-atom voids provides an explanation for experimentally observed He bubble formation at vacancy defects in metals.
Place, publisher, year, edition, pages
2013. Vol. 440, no 1-3, 557-561 p.
Equilibrium distances, First principles method, Gas-phase clusters, Microscopic mechanisms, Octahedral sites, Trapping energy, Vacancy Defects, Vacancy trapping
IdentifiersURN: urn:nbn:se:kth:diva-159219DOI: 10.1016/j.jnucmat.2013.03.068ISI: 000323396600070ScopusID: 2-s2.0-84885295185OAI: oai:DiVA.org:kth-159219DiVA: diva2:783364
NuMat Conference, OCT 22-25, 2012, Osaka, Japan
QC 201501262015-01-262015-01-262016-02-18Bibliographically approved