Ab initio study of interaction of helium with edge and screw dislocations in tungsten
Ab initio study of interaction of helium with edge and screw dislocations in tungsten
Bakaev, A.; Terentyev, D.; Grigorev, P.; Posselt, M.; Zhurkin, E. E.
Abstract
The interaction of a single He atom with edge and screw dislocations in tungsten has been studied using ab initio calculations. It was revealed that He is strongly attracted to the core of both dislocations with the interaction energy of -1.3 and -3.0 eV for screw and edge dislocations, respectively, which corresponds to the detrapping temperature in thermal desorption spectroscopy experiments of about 500 K and 1050 K, respectively. The lowest energy positions for He around the dislocation cores are identified and the atomic structures are rationalized on the basis of elasticity theory considerations. Both types of dislocations exhibit a higher binding energy for He as compared to the He-He binding (known as self-trapping) and are weaker traps as compared to a single vacancy. It is, thus, concluded that the strong attraction to dislocation lines can contribute to the nucleation of He clusters in the temperature range which already excludes He self-trapping.
Keywords: Dislocations; Helium; Tungsten; Ab initio
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Nuclear Instruments and Methods in Physics Research B 393(2017), 150-154
DOI: 10.1016/j.nimb.2016.11.036
Cited 17 times in Scopus
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Permalink: https://www.hzdr.de/publications/Publ-25081