Browsing by Author "Bezshkurenko, Oleksii G."

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High-Entropy Alloys. A New Concept for the Design of Innovative Structural Materials
(Ukrainian State University of Science and Technologies, Dnipro, 2026) Kamkina, Liudmyla V.; Proidak, Yurii S.; Mianovska, Yana V.; Guba, Roman M.; Bezshkurenko, Oleksii G.
ENG: Modern technologies require state-of-the-art materials that meet their conditions, regardless of operating conditions. Alloys with high entropy can replace traditional materials, work under impacts, dynamic loads, elevated temperatures, etc. These alloys are used for the manufacture of tools, molds, dies, mold casting in parts that require high strength, resistance to oxidation and wear, can also be used in environments with high corrosion resistance parameters (plumbing, marine conditions), in aggressive conditions and in the chemical industry. High entropy alloys are quite easy to investigate and control, and can be obtained by the same methods as traditional alloys, such as: casting, rapid melt quenching, film sputtering, electrolysis, and mechanical alloying. Electroslag remelting (ESD) can greatly improve the purity, hardening structure, and transverse mechanical properties of steel. However, the increasing demands on the mechanical properties of steel are prompting metallurgists to make more efforts to eliminate defects in steel microstructures such as shrinkage and segregation. The combination of directional crystallization technology with electroslag melting technology effectively eliminates macrosegregation in the cast ingot through a shallow molten metal bath controlled by directional crystallization. Increasing the strength of alloys can be achieved either by alloying a solid solution (elements in the internodes) or by isolating the solidification phases or artificially introducing microparticles. Curing phases (carbides, nitrides, carbonitrides, intermetals) can be endogenous (formed from elements introduced into the melt in a liquid state or during its solidification and subsequent cooling) or exogenous (usually introduced into the melt just before crystallization begins, and there is also an increase in size and deterioration in the distribution of solidification phases.
Modeling of Temperature-Concentration Ranges of Phase Stability and Liquidus Surface in the Ternary Fe–P–C System and Phase Composition Experimental Study
(Ukrainian State University of Chemical Technology, Dnipro, 2023) Proidak, Andrii Yu.; Hasyk, Mykhailo I.; Proidak, Yurii S.; Bezshkurenko, Oleksii G.
ENG: This paper reports thermodynamic properties and phase equilibria in the iron-phosphorus-carbon system for developing a technology for smelting ferrophosphorus as well as for utilizing them in the processes of phosphorus-alloying of metals. According to the results of thermodynamic calculations, we plotted a ternary Fe–P–C phase equilibrium diagram (liquidus surface) in the form of graphical dependences, which indicate the concentration fields of phase coexistence. The results of simulation allowed finding out five nonvariant points, three of which are new: E1eutectic (teutectic=12170 °C), U1 peritectic (tperitectic=1095 °C), and E3 eutectic (teutectic=3380 °C). The experimental studies of the phase composition of ferrophosphorus showed that the phosphorus microstructure is represented by Fe3P phosphide, Fe3C carbide, and carbophosphide eutectic. We carried out the thermodynamic calculation of the temperature-concentration ranges of phase stability in the Fe–P–C system that are at equilibrium with the smelts of both the carbon solid solutions and phosphorus ones in α- and γ-iron, FeP, Fe2P, Fe3P phosphides, and graphite. In this study, three previously unknown nonvariant equilibria have been determined: a eutectic equilibrium at 1216.58 °C; a peritectic one with a transformation point at 1095.19 °C; and a eutectic one at a temperature of 337.51 °C. In experiments, we obtained an equilibrium concentration of carbon which decreases in the Fe–P–C system when the content of phosphorus increases. The research findings largely reveal special features of preparation of ferrophosphorus by carbon reduction of phosphorites.