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Information × Registration Number 0224U033509, (0121U108687) , R & D reports Title A theory of phase transformations, kinetic and diffusion phenomena in condensed media popup.stage_title Кінетика рівноважних та нерівноважних фазових перетворень і хімічних реакцій в гетерогенних конденсованих системах. Дослідження впливу довготривалої релаксації структури скла при низьких температурах (нижче температури склування) на процес зародження кристалічної фази Head Bakai Oleksandr S., Registration Date 29-12-2024 Organization National Science Center "Kharkiv Institute of Physics and Technology" popup.description1 Development of theoretical and computer models to describe phase transformations and states, including nucleation theory in amorphous and multicomponent materials; kinetic and diffusion phenomena in condensed and disordered media; the emergence of dynamic chaos; study of memory effects in diffusion and their impact on equilibrium and nonequilibrium phase transformations; stability study and interactions of chemical reaction systems in a heterogeneous medium and in a medium with phase transformations; study of thermodynamic properties of interacting electron systems and phonons in nanostructures. Perform MD modeling of the influence of compositional ordering on martensitic transformations in binary NiAl alloy. Describe the properties of quark – gluon matter. popup.description2 We investigated diffusion processes and phase transformations involving chemical reactions in heterogeneous media, taking into account memory effects in diffusion and their influence on the interaction of equilibrium and nonequilibrium phase transformations. It was found that for a positive velocity of the phase transformation front, when the state with a higher concentration value propagates, both the applied field and the viscosity (i.e., the presence of dissipation) generally reduce the memory corrections. For a negative velocity, the self-consistency of the model imposes stronger restrictions on the allowed interval of parameter values. The standard form of the thermodynamic potential with a constant coefficient in the gradient term and a fourth-degree polynomial may be insufficient to describe highly heterogeneous systems using the Cahn-Hilliard equation. A modified form of the thermodynamic potential with a sixth-degree polynomial and a quadratic dependence of the coefficient in the gradient term is considered. The exact solutions in the form of a static traveling wave and the conditions of their existence depending on the symmetry of the potential are obtained. The interaction between structural relaxation and crystallization kinetics below the glass transition temperature Tg is studied using the example of a model silicate glass 5BaOꞏ8SiO2. By analyzing the number of crystals, their size, and crystallized volume as a function of the processing time, it is demonstrated that only one parameter that takes into account structural relaxation effectively describes these three crystallization parameters. It is found that glasses prone to rapid crystallization below Tg can completely crystallize before achieving full structural relaxation. These results indicate a complex interaction between relaxation dynamics and crystallization in deeply supercooled glasses, which has implications for understanding and controlling these processes in various materials. Product Description popup.authors Abyzov Oleksandr S. Alekseiechkin Mykola V. Bakai Oleksandr S. Bezuhlyi Oleksii I. Borysenko Oleksandr O. Davydov Leonid M. Kotliar Volodymyr V. Lavrova Halyna M. Lazariev Mykola P. Mchedlov-Petrosian Petro O. Poluektov Yurii M. Soroka Oleksii O. Stepanovskyi Yurii P. Turkin Anatolii A. Chechkin Oleksii V. popup.nrat_date 2024-12-29 Close