Факультет електроніки та інформаційних технологій (ЕлІТ)
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Item DFT calculations of solute-vacancy binding in Zirconium-based Zr–Nb–Sn alloy(Elsevier, 2022) Wu, L.; Харченко, Василь Олегович; Харченко, Василий Олегович; Kharchenko, Vasyl Olehovych; Kong, X.; Харченко, Д.О.The energetic properties of ternary Zr–Nb–Sn Zirconium-based alloy with concentration of dissolved alloying elements - 1,5 % are studied by using density functional theory. The possibility of alloying additions separated by different distances to dissolve/segregate in a host matrix is analyzed with the help of mixing energy and solute–solute binding energy. The ability of solutes to trap single vacancy is discussed by studying formation energy of a vacancy, located on a different distances from both solute atoms and the corresponding solute–solute–vacancy binding. This study provides an insight into the details of vacancy energetics in Zirconium-based alloys exploited in nuclear-power plants.Item Effect of Energy Factors on the Structure and Substructure Characteristics of Hafnium Diboride Films Deposited by RF Magnetron Sputtering(G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, 2020) Гончаров, Максим Миколайович; Гончаров, Максим Николаевич; Honcharov, Maksym Mykolaiovych; Zykov, A.V.; Юнда, Андрій Миколайович; Юнда, Андрей Николаевич; Yunda, Andrii Mykolaiovych; Шелест, Ігор Владиславович; Шелест, Игорь Владиславович; Shelest, Ihor Vladyslavovych; Буранич, Володимир Володимирович; Буранич, Владимир Владимирович; Buranych, Volodymyr VolodymyrovychIn this paper, the influence of energy factors, such as the bias potential, current density, deposition rate, on the formation of the structure and substructure of hafnium diboride films deposited using RF magnetron sputtering is analysed. As shown, the structural changes from a quasi-amorphous to a nanocrystalline state with a growth texture occur due to changes in energy factors.Item Gas Flow Simulation in the Working Gap of Impulse Gas-Barrier Face Seal(Sciendo, 2020) Кузнєцов, Едуард Геннадійович; Кузнецов, Эдуард Геннадьевич; Kuznietsov, Eduard Hennadiiovych; Нагорний, Володимир В`ячеславович; Нагорный, Владимир Вячеславович; Nahornyi, Volodymyr Viacheslavovych; Krenicky, T.Numerical simulation method of the working process of a centrifugal unit contactless face impulse seal is proposed. A seal functioning physical model was created. Its operation key aspects that are not taken into account in the traditional methods of calculating contactless impulse seals are identified. A numerical simulation of seal working process based on the Reynolds equation solution for the medium vortex-free motion in the gap between moving surfaces is proposed. Hypothesis that simplify the equation’s numerical solution for the face impulse seal is formulated. The numerical solution is obtained using the boundary element method. Based on the obtained numerical solution, the distribution of the working medium pressure field in the seal gap is simulated.Item The cathodic electrolytic plasma hardening of the 20Cr2Ni4A chromium-nickel steel(Elsevier, 2020) Rakhadilov, B.K.; Буранич, Володимир Володимирович; Буранич, Владимир Владимирович; Buranych, Volodymyr Volodymyrovych; Satbayeva, Z.A.; Sagdoldina, Z.B.; Kozhanova, R.S.; Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr DmytrovychIn order to obtain the modified surface structure of the 20Cr2Ni4A steel plasma electrolytic hardening (PEH) method was used. The surface hardening process was conducted in the aqueous electrolyte solution of 20% sodium carbonate and 20% urea. The sample consists of a ferritic-pearlitic structure, i.e. the part retains its viscous core, and the surface layer contains carbide particles. Hardening process induces martensite transformation and creation of carbide particles in the surface layer. The presence of carbide particles in the surface layers has a positive effect on the tribo-mechanical performance. Hardened structure 600 m long was obtained with hardness increase up to 520 HV and 2.5 times higher wear resistance. Tribological test results showed the difference of the coefficient of friction as a function of surface roughness determined by plasma-electrolytic hardening process.Item Effect of the PEN/C surface layer modification on the microstructure, mechanical and tribological properties of the 30CrMnSiA mild-carbon steel(Elsevier, 2020) Zhurerova, L.G.; Rakhadilov, B.K.; Popova, N.A.; Kylyshkanov, M.K.; Буранич, Володимир Володимирович; Буранич, Владимир Владимирович; Buranych, Volodymyr Volodymyrovych; Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr DmytrovychAs a result of plasma-electrolytic nitrocarburizing 30CrMnSiA carbon steel (ferrite-perlite grade), there was a change in the elemental and phase composition, as well as the surface layer microstructure (40 ÷ 45 microns thick from the surface). A formation of Me23(CN)6 carbonitrides, FeN nitrides, Fe3C - (Fe, Cr)3C carbides and an increase in dislocation density within –phase (tempered martensite crystallites), high-temperature lamellar martensite were observed. As a result of PEN / C exposure for 7min. At 750 ◦C there is a reduction of friction coefficient and wear rate, what is connected with finely dispersed secondary phases FeN, (Fe, Cr)3C, Me23(C, N)6 formation. Thus, there is an 2,5 ÷ 3,3 times increase in hardness of 30CrMnSiA carbon steel samples.