Berlin 2018 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 47: Poster Session II
MM 47.12: Poster
Mittwoch, 14. März 2018, 18:30–19:45, Poster C
Structure and energetics of Y-Ti-O nanoclusters in bcc Fe — •Muthu Vallinayagam1, Matthias Posselt2, and Jürgen Faßbender3 — 1Helmholtz-Zentrum Dresden-Rossendorf (HZDR) — 2HZDR — 3HZDR
In this research project the nature of yttria-based oxide nanoclusters in a bcc Fe matrix is be investigated by DFT calculations. The main goal of these studies is the better understanding of the nucleation as well as the structure and composition of the clusters. In the first part of the work three types of structures are considered: (i) clusters consisting of parts of the bixbyite (Y2O3) or pyrochlore (Y2Ti2O7) structure embedded in bcc Fe, (ii) clusters with Y, Ti, and O on substitutional sites, and (iii) clusters with of Y, Ti, on substitutional sites and O on octahedral interstitial sites of the bcc lattice. Simulation cells containing different structures but the same composition of different atoms (Fe, Y, Ti, O) are compared. It is found that the energetics of three different structure types, i.e. there total binding energy, is very similar. This modifies the statement of Barnard et al. [1] who only considered the first type of structure and concluded that this is most favorable. Further, more stable cluster structures are constructed using another model with the nanocluster core similar to the metal monoxide structure. Also the binding energy of monomers like O, Y, Ti, and the vacancy to the cluster are studied. O and the vacancy are strongly attracted by the nanoclusters, while the interaction with metal atoms is weaker. [1] L. Barnard et al. Acta Mater. 60 935 (2012)