Dresden 2020 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 49: Structural Materials (Steels, light-weight materials, high-temperature materials) - I
MM 49.2: Talk
Thursday, March 19, 2020, 10:30–10:45, BAR 205
Interaction of helium, self-interstitial atoms and vacancies with YTiO clusters in bcc Fe — •Muthu Vallinayagam1,2, Matthias Posselt1, and Jürgen Faßbender1,2 — 1Helmholtz-Zentrum Dresden-Rossendorf,Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400,01328 Dresden,Germany — 2Technische Universität Dresden,01062 Dresden,Germany
In nanostructured ferritic/martensitic Fe-Cr alloys YTiO clusters act as sinks for the irradiation-induced defects He, self-interstitial atoms(SIA), and vacancies(v). In this manner, irradiation swelling can be retarded significantly. In this ab-initio simulation work, interactions of He and other defects with YTiO cluster in bcc Fe are investigated considering cluster structures studied in a previous work[1]. It is found that the most stable position of He is in the center of the cluster, then interfacial vacant sites and other interstitial positions between metal or oxygen atoms, and sites away from the cluster[2]. Calculations on the addition of two and three He atoms to the cluster show that the total binding energy is equal to the sum of binding energies of individual He atoms. Therefore, He trapping depends mainly on the availability of regions with low electron density. A significant attraction between cluster and SIA is observed. This results in annihilation of SIA due to the existence of interfacial vacant sites. Vacancies are also trapped by YTiO clusters and their binding energy increases if the vacancy approaches O terminated sites. [1]Vallinayagam et al 2019 J. Phys.: Condens. Matter 31 095701 [2]Vallinayagam et al 2019 J. Phys.: Condens.Matter 31 485702