Nanodevices and Nanomaterials for Ecological Security
This book is devoted to a wide range of problems concerning applications of nanomaterials and nanodevices as effective solutions to modern ecological problems. Leading experts in nanoscience and nanotechnology present the key theoretical, experiment
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Interaction Between Oxygen and Yttrium Impurity Atoms as well as Vacancies in fcc Iron Lattice: Ab Initio Modeling A. Gopejenko, Yu.F. Zhukovskii, P.V. Vladimirov, E.A. Kotomin, and A. M€ oslang
Abstract Synthesis of advanced radiation-resistant steels as construction materials for nuclear reactors, which contain the uniformly distributed yttria precipitates (ODS steels), is an important task for ecological security of nuclear plants. The initial stage of theoretical simulation on oxide cluster growth in the steel matrix is a large-scale ab initio modeling on pair- and triple-wise interaction between the Y and O impurity atoms as well as Fe vacancies, including their different combinations, in the paramagnetic face-centered-cubic (fcc) iron lattice. Calculations on the pair of Y atoms have shown that no bonding appears between them, whereas a certain attraction has been found between Y substitute atom and Fe vacancy. Inter-defect bonding is also formed between the impurity atoms in Y-O and O-O pairs. These calculations have led to the assumption that inclusion of O atom is necessary to form a stable bonding between the impurity atoms, however, the calculations of Y-O-Y defect cluster (where O atom is positioned in the interstitial position), have shown that it is not enough. The main conclusion from these calculations is that the role of Fe vacancies in the inter-defect bonding is quite significant, which was proved by the calculations of Y-O-Y cluster with O atom in the substitute position as well as by the calculations of the Y-VFe-Y cluster. Keywords ODS steels • Yttrium oxide precipitates • g-Fe lattice • DFT calculations • VASP plane-wave code
A. Gopejenko (*) • Yu.F. Zhukovskii • E.A. Kotomin Institute of Solid State Physics, University of Latvia, 8 Kengaraga str., LV-1063 Riga, Latvia e-mail: [email protected] P.V. Vladimirov • A. M€ oslang Forschung, Institut f€ur Materialforschung-I, Institut f€ ur Technologie, Karlsruhe, Germany Y.N. Shunin and A.E. Kiv (eds.), Nanodevices and Nanomaterials for Ecological Security, NATO Science for Peace and Security Series B: Physics and Biophysics, DOI 10.1007/978-94-007-4119-5_14, # Springer Science+Business Media Dordrecht 2012
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Introduction
Reduced activation steels strengthened by yttria precipitates are considered as promising construction materials for fusion- and advanced fission-reactors [1]. In particular, their use for fusion reactor blanket structure would allow increasing the operation temperature by ~100 K [1–3]. The development of the oxide dispersion strengthened (ODS) steels for fission and fusion reactors requires a deep understanding of the mechanism and kinetics of Y2O3 cluster precipitation in the steel matrix as nanoparticles size and spatial distribution significantly affect both mechanical properties and radiation resistance of ODS steels [3]. Ferritic-martensitic steels containing Cr with concentration 9–12% used as construction materials for reactors (with mainly wall and blanket applications) have better
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