Registration Number
0212U007752,
0112U003495
, R & D reports
Title
Investigation of the grain boundary evolution (in particular, non-equilibrium grain boundaries) in the supersaturated solid solutions and two-phase alloys. Theory and experiment
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Head
Gusak Andriy, Доктор фізико-математичних наук
Registration Date
24-12-2012
Organization
B. Khmelnitsky state university in Cherkasy
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An atomistic model of the nonequilibrium grain boundaries generated by repeating local melting (perturbations) of randomly selected clusters has been developed output limits. Asymptotically achievable excess energy limit is directly proportional to the square root of perturbations frequency. The theory of spreading and wetting phase transitions has been generalized: considering nucleation on rough surface we found (for the first time) an opportunity of phase transition of one-dimensional spreading along the triple junction interfaces and grain boundaries. By measuring the temperature of transition from partial wetting boundaries to full wetting in poly- and bicrystalls we managed (for the first time) to experimentally evaluate the width and place of inclination boundaries energy in the full spectrum of energies of grain boundaries in polycrystals. It turned out that inclination boundaries represent only 5-10% of the full range of energies of grain boundaries in polycrystals. Theory of diffusive phase competition has been generalized for the case of phase growth by flow along the moving interface. We found criteria of kinetic inhibition of phase Cu3Sn1 nucleation in cases of diffusion through the volume and through interfaces. Mean-field model of nonlinear diffusion in Martin-Erdelyi-Beke approach has been generalized for modeling of phase growth on three-dimensional lattices. In the presence of strong diffusion asymmetry in the bcc lattice ordered phase A1B1 was born at concentrations that are far from stoichiometric. In these simulations we observed at first ordering and after that - reaching of necessary composition. The presence of asymmetry leads to poor nucleation and growth of some phases, and, conversely, acceleration of others. The incubation time for the slowest phase depends on the asymmetry exponentially. Growth of ordered phases can occur in oscillation mode.
Product Description
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Гусак Андрій Михайлович
Запорожець Тетяна Василівна
Ковальчук Андрій Олександрович
Король Ярослав Дмитрович
Ляшенко Олексій Юрійович
Ляшенко Юрій Олексійович
Пасічний Микола Олександпрович
Сопіга Костянтин Володимирович
Сторожук Надія Вікторівна
Турло Владислав Володимирович
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2020-04-02
