Search academic texts

Information × Registration Number 0211U006886, 0109U006378 , R & D reports Title Interphase boundaries during phase separation in bulk metallic glasses: theory and experiment. popup.stage_title Head Bakai Olexander Stepanovich, Доктор фізико-математичних наук Registration Date 12-05-2011 Organization National Science Center "Kharkiv Institute of Physics and Technology popup.description2 The subject of investigation is the structure of interphase boundaries in bulk metallic glasses (BMG). In order to clarify fundamental laws of interface boundaries formation at liquid-solid phase transitions concomitant to the growth of bulk amorphous alloys, the theoretical methods of statistical physics of condensed matter and physics of phase transitions (and, particularly, the methods of the heterophase state theory) are used. The inhomogeneous state of BMG is represented as a heterophase state of liquid that experiences glass phase transitions and is characterized by long-range correlations of short-range ordering resulting in developed structure of interphase boundaries. Completed is the construction of a new theory of heterophase states of liquid and glass which is based on the proposed fluctuon model of non-perturbative heterophase fluctuations. Within the framework of this model: the processes of crystallization and glass transition of liquid have been described theoretically; the role of frustration of solid-like fluctuons in such phase transitions has been revealed; the cooperative dynamics of fluctuon systems has been described; the correlations of empirical temperatures of glass transitions have been explained; the equations for the pair correlation function of interacting fluctuons have been derived and solved analytically, the theory of fractal aggregation of fluctuons due to their bulk and surface interactions has been built, and the formulae for fractal dimension and correlation length of fluctuon aggregates have been obtained along with the conditions of formation of long-range correlations; the thermodynamic criterion of miscibility of amorphous phases has been found, and applied to the theoretical explanation of the experimentally observed phenomenon of mutual wetting of amorphous phases at interphase boundaries of Ni–Nb–Y BMG. The developed theory of heterophase states is a novel approach for description of phase transitions at interphase boundaries of a BMG. It has allowed revealing of valuable peculiarities of BMG heterophase state that agree well with experimental data. Product Description popup.authors Бакай Олександр Степанович Дюльдя Сергій Володимирович Лазарєв Микола Петрович popup.nrat_date 2020-04-02 Close