Персона: Бородин, Владимир Алексеевич
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Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
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Руководитель группы "Моделирование физических процессов"
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Бородин
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Владимир Алексеевич
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- ПубликацияОткрытый доступМоделирование атомной структуры когерентной границы раздела между железом и магнетитом(НИЯУ МИФИ, 2025) Комаров, Н. Д.; Бородин, В. А.; Бородин, Владимир АлексеевичВ данной работе проведено моделирование атомной структуры границы раздела между металлическим железом и его оксидом Fe3O4 (магнетитом). Такие границы возникают, например, при формировании оксидного слоя на поверхностях труб из ферритно-мартенситных сталей, используемых для защиты от высокотемпературной коррозии в агрессивных кислородосодержащих средах, в частности – в среде жидкого свинца и свинцово-висмутовой эвтектики, которые рассматриваются в качестве теплоносителей в перспективных реакторах на быстрых нейтронах. В рамках исследования были рассмотрены теоретически возможные варианты когерентного поверхностного сопряжения кристаллических решеток железа и магнетита и проведены оценки энергий образования соответствующих поверхностей раздела с использованием первопринципных расчетов и различных потенциалов межатомного взаимодействия. В результате расчетов удалось идентифицировать атомное строение границ раздела между железом и магнетитом, выявить конфигурации с минимальной энергией для каждого использованного потенциала, а также определить наиболее подходящий потенциал межатомного взаимодействия для дальнейших исследований влияния облучения на границу раздела «железо-магнетит».
- ПубликацияОткрытый доступBubble-to-void transition promoted by oxide nanoparticles in ODS-EUROFER steel ion implanted to high He content(2021) Gentils, A.; Vladimirov, P. V.; Golovchanskiy, I. A.; Lindau, R.; Emelyanova, O.; Borodin, V. A.; Ganchenkova, M. G.; Dzhumaev, P. S.; Емельянова, Ольга Владимировна; Бородин, Владимир Алексеевич; Джумаев, Павел Сергеевич© 2020The paper deals with a detailed study of He-filled cavity ensemble development in ODS-EUROFER steel implanted with 10 keV helium ions to a high peak concentration of 8.5 × 103 appm both with and without simultaneous irradiation with 4 MeV gold ions, which allowed us to strongly vary the ratios of dpa/He introduction. The subsequent transmission electron microscopy examination reveals excellent radiation stability of He-implanted sample in the single-beam implantation mode. In contrast, after the simultaneous dual-beam irradiation a bubble-to-void transition was observed for bubbles that were associated with yttria nanoparticles. The relative importance of different He bubble families observed in the He-implanted samples for the swelling accumulation is quantitatively assessed, emphasizing the potential risks of abrupt swelling acceleration in the case of bubble-to-void transition launched by nanoparticles. A model of bubble-to-void transition for gas bubbles associated with spherical second-phase particles is developed and used to rationalize experimental observations.
- ПубликацияТолько метаданныеSynthesis of Nano-Oxide Precipitates by Implantation of Ti, Y and O Ions in Fe-10%Cr: Towards an Understanding of Precipitation in Oxide Dispersion-Strengthened (ODS) Steels(2022) Jublot-Leclerc, S.; Owusu-Mensah, M.; Borodin, V. A.; Ribis, J.; Largeau, L.; Schoell, R.; Kaoumi, D.; Descoins, M.; Mangelinck, D.; Gentils, A.; Бородин, Владимир АлексеевичThe properties of oxide dispersion-strengthened steels are highly dependent on the nature and size distribution of their constituting nano-oxide precipitates. A fine control of the processes of synthesis would enable the optimization of pertinent properties for use in various energy systems. This control, however, requires knowledge of the precise mechanisms of nucleation and growth of the nanoprecipitates, which are still a matter of debate. In the present study, nano-oxide precipitates were produced via the implantation of Y, Ti, and O ions in two different sequential orders in an Fe-10%Cr matrix that was subsequently thermally annealed. The results show that the oxides that precipitate are not necessarily favoured thermodynamically, but rather result from complex kinetics aspects related to the interaction between the implanted elements and induced defects. When Y is implanted first, the formation of nanoprecipitates with characteristics similar to those in conventionally produced ODS steels, especially with a core/shell structure, is evidenced. In contrast, when implantation starts with Ti, the precipitation of yttria during subsequent high-temperature annealing is totally suppressed, and corundum Cr2O3 precipitates instead. Moreover, the systematic involvement of {110} matrix planes in orientation relationships with the precipitates, independently of the precipitate nature, suggests matrix restriction effects on the early stages of precipitation. © 2022 by the authors.
- ПубликацияТолько метаданныеVacancies and interstitials in yttrium(2019) Vladimirov, P. V.; Borodin, V. A.; Бородин, Владимир АлексеевичThe paper deals with the first principles simulation of formation energies and migration barriers of self point defects, including vacancies, di-vacancies and single interstitial atoms, in metallic yttrium. The vacancy formation energy in yttrium is shown to be relatively high (similar to 1.8 eV), whereas the migration barriers are very similar for the jumps inside the basal planes and between basal planes, being equal to similar to 0.65 eV. The sum of these numbers reasonably reproduces the experimental values of the self-diffusion activation barriers. The vacancy pairs at the first nearest neighbor separation (divacancies) have binding energy of similar to 0.2 eV, which is only weakly sensitive to the divacancy orientation in the lattice, whereas vacancy pairs at the second and third nearest-neighbor separations are energetically unfavorable, suppressing the dissociation of divacancies. Together with the noticeably lower divacancy migration barriers with respect to single vacancies, this makes divacancies efficient mediators for mass transfer in Y. Among multiple possible configurations of a single interstitial, only the basal octahedral one is found to be the true energy minimum, while all the other considered possibilities are either unstable, or saddle points on the potential energy surface. This is in contrast to other hcp metals, where several metastable interstitial configurations often coexist. The lowest migration barriers for single interstitial diffusion along the basal plane and between planes are practically equal, similar to 0.4 eV, implying isotropic diffusion of interstitials in yttrium. Overall, the predicted properties of point defects in yttrium are in line with the general trends for hcp metals with the cla ratio below root 8/3.
- ПубликацияОткрытый доступMicrostructural evolution in ODS-EUROFER steel caused by high-dose He ion implantations with systematic variation of implantation parameters(2023) Emelyanova, O. V.; Gentils, A.; Borodin, V. A.; Dzhumaev, P. S.; Емельянова, Ольга Владимировна; Бородин, Владимир Алексеевич; Джумаев, Павел СергеевичThe paper presents a detailed analysis of helium (He) bubble development in ODS-EUROFER steel caused by helium ion implantation in different regimes, with a particular attention to the role of the oxide nanoparticles in promoting the growth of He bubbles, helium accumulation and gas-driven swelling. The Transmission Electron Microscopy (TEM) characterization of steel samples implanted applying systematic variation of experimental parameters has allowed clarifying the trends of the bubble microstructure evolution depending on the implantation dose, flux, and sample temperature. It was found that in all investigated implantation regimes He bubbles formed both in the grain bulk and on various structural defects (dislocations, grain boundaries, oxide particles and carbide precipitates), but the sizes and densities of bubbles in different bubble populations were sensitive to particular irradiation conditions. In the majority of cases the main traps for implanted helium and the main contributors to the estimated swelling were bubbles associated with grain boundaries, though in some cases (high implantation dose or lower temperature) the bubbles in the grain bulk were competitive with the grain boundary bubble population. Oxide particles in ODS-EUROFER were found to be excellent nucleation sites for He bubbles and practically each observed particle hosted a single relatively large bubble, sometimes as large as the particle itself. However, the contribution of oxide-associated bubbles to the estimated swelling and He inventory was found to be minor as compared to other bubble populations because of a relatively low number density of nano-oxides. Comparison of ODS-EUROFER and EUROFER 97 samples implanted with He ions in identical regimes has demonstrated lower efficiency of ODS-EUROFER for accumulating implanted helium in bubbles and noticeably higher share of helium atoms trapped in the vacancy defects invisible by TEM.
- ПубликацияОткрытый доступIn situ TEM thermal annealing of high purity Fe10wt%Cr alloy thin foils implanted with Ti and O ions(2019) Owusu-Mensah, M.; Jublot-Leclerc, S.; Gentils, A.; Baumier, C.; Borodin, V. A.; Бородин, Владимир Алексеевич© 2019 Elsevier B.V.ODS steels are ferritic-martensitic steels reinforced with (Y,Ti) oxide dispersions to enhance the creep and radiation resistance at elevated temperatures. Their conventional fabrication is achieved by ball milling followed by high-temperature consolidation. An alternative approach of ion beam synthesis has been suggested recently to study the early precipitation stages of oxide nanoparticles. To clarify the details of Ti-based oxide nanoparticle precipitation, Ti+ and O+ ions were implanted into high-purity Fe-10 wt%Cr thin foils at room temperature and subjected to thermal annealing. Nano-size oxide particles and larger surface oxide islands with pronounced Cr enrichment were observed after in situ Transmission Electron Microscopy (TEM) annealing at 600 °C and were identified as a mixed iron-chromium spinel. The features observed after ex situ annealing at 800 °C were also identified as iron-chromium oxide, but with a certain titanium enrichment. The observations thus suggest that titanium plays no major role in the early stages of oxide precipitation.