Факультет технічних систем і енергоефективних технологій (ТеСЕТ)
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Item Technological Features for Controlling Steel Part Quality Parameters by the Method of Electrospark Alloying Using Carburezer Containing Nitrogen—Carbon Components(MDPI, 2022) Гапонова, Оксана Петрівна; Гапонова, Оксана Петровна; Haponova, Oksana Petrivna; Tarelnyk, V.B.; Antoszewski, B.; Radek, N.; Tarelnyk, N.V.; Kurp, P.; Myslyvchenko, O.M.; Hoffman, J.A new method of surface modification based on the method of electrospark alloying (ESA) using carburizer containing nitrogen—carbon components for producing coatings is considered. New processes have been proposed that include the step of applying saturating media in the form of paste-like nitrogenous and nitrogenous-carbon components, respectively, onto the surface without waiting for those media to dry, conducting the ESA process with the use of a steel electrode-tool, as well as with a graphite electrode-tool. Before applying the saturating media, an aluminium layer is applied onto the surface with the use of the ESA method at a discharge energy of Wp = 0.13–6.80 J. A saturating medium in the form of a paste was applied to the surfaces of specimens of steel C22 and steel C40. During nitriding, nitrocarburizing and carburization by ESA (CESA) processes, with an increase in the discharge energy (Wp), the thickness, micro hardness and continuity of the “white layer” coatings, as well as the magnitude of the surface roughness, increase due to saturation of the steel surface with nitrogen and/or carbon, high cooling rates, formation of non-equilibrium structures, formation of special phases, etc. In the course of nitriding, nitrocarburizing and CESA processing of steels C22 and C40, preliminary processing with the use of the ESA method by aluminum increases the thickness, microhardness and continuity of the “white layer”, while the roughness changes insignificantly. Analysis of the phase composition indicates that the presence of the aluminum sublayer leads to the formation of the aluminum-containing phases, resulting in a significant increase in the hardness and, in addition, in an increase in the thickness and quality of the surface layers. The proposed methods can be used to strengthen the surface layers of the critical parts and their elements for compressor and pumping equipment.Item Solidus Temperatures and Hot Hardness of Ti–Nb–Mo Alloys(G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, 2022) Myslyvchenko, O.M.; Bondar, A.A.; Voblikov, V.М.; Tsyganenko, N.I.; Silinska, T.A.; Гапонова, Оксана Петрівна; Гапонова, Оксана Петровна; Haponova, Oksana PetrivnaEight alloys of the Ti–Nb–Mo system are synthesized by the arc remelting method. As shown, they have dendritic microstructures typical of casting. The phase composition and lattice periods of the formed phases are determined. Using the method of differential thermal analysis (DTA), phase transformations in the solid state are investigated, and the temperatures of the onset of melting and crystallization are determined. For alloys, the solidus temperature of which is above 2000°C, together with DTA, the Pirani–Althermum pyrometric method is also used. Based on the experimental data, the temperature dependences of the hardness of the alloys are constructed and the activation energies of deformation of the material under the indenter are calculated. The analysis of the curves of the dependence of the hardness of the alloys is carried out and the temperature of the sharp softening of the material is determined. As shown, that the α→β transition in titanium alloys with an unstable β-phase does not lead to a significant change in hardness.Item Modeling of Polymer Composite Materials Chaotically Reinforced with Spherical and Cylindrical Inclusions(MDPI, 2022) Берладір, Христина Володимирівна; Берладир, Кристина Владимировна; Berladir, Khrystyna Volodymyrivna; Жигилій, Дмитро Олексійович; Жигилий, Дмитрий Алексеевич; Zhyhylii, Dmytro Oleksiiovych; Гапонова, Оксана Петрівна; Гапонова, Оксана Петровна; Haponova, Oksana Petrivna; Krmela, J.; Krmelova, V.; Артюхов, Артем Євгенович; Артюхов, Артем Евгеньевич; Artiukhov, Artem YevhenovychThe technical and economic efficiency of new PCMs depends on the ability to predict their performance. The problem of predicting the properties of PCMs can be solved by computer simulation by the finite element method. In this work, an experimental determination of the physical and mechanical properties of PTFE PCMs depending on the concentration of fibrous and dispersed filler was carried out. A finite element model in ANSYS APDL was built to simulate the strength and load-bearing capacity of the material with the analysis of damage accumulation. Verification of the developed computer model to predict the mechanical properties of composite materials was performed by comparing the results obtained during field and model experiments. It was found that the finite element model predicts the strength of chaotically reinforced spherical inclusions of composite materials. This is due to the smoothness of the filler surfaces and the lack of filler dissection in the model. Instead, the prediction of the strength of a finite element model of chaotically reinforced cylindrical inclusions of composite materials requires additional analysis. The matrix and the fibrous filler obviously have stress concentrators and are both subject to the difficulties of creating a reliable structural model.Item Electric-Spark Alloying of Metal Surfaces with Graphite(G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, 2022) Tarelnyk, V. B.; Гапонова, Оксана Петрівна; Гапонова, Оксана Петровна; Haponova, Oksana Petrivna; Konoplianchenko, Ye.V.The article reviews and analyses the current scientific research in the field of surface treatment of metal surfaces with concentrated energy fluxes (CEF) — the electric-spark (in the literature, known also as electrospark) alloying (ESA), which makes it possible to obtain surface structures with unique physical, mechanical and tribological properties at the nanoscale. The ESA method with a graphite electrode (electrospark carburizing — EC) is based on the process of diffusion (saturation of the surface layer of a part with carbon), and it is not accompanied by an increase in the size of the part. In this article, the influence of the EC parameters on the quality of the carburized layer is investigated. The microstructural analysis shows that the three characteristic zones could be distinguished in the structure: the carburized (‘white’) layer, the finely dispersed transition zone with fine grain, and the base metal zone. The analysis of the results of the durometric studies of the coatings is carried out. To achieve the required parameters of dimensional accuracy and roughness of the working surface of the part after the EC process, it is necessary to use the method of non-abrasive ultrasonic finishing (NAUF). In addition, because of applying the NAUF method, the surface roughness is decreased, the tensile stresses are changed to the compressive ones, and the fatigue strength is increased too. In addition, to reduce the roughness of the treated surface, it is proposed to apply the EC technology in stages, reducing the energy of the spark discharge at each subsequent stage. In order to increase the quality of the carburized layer obtained by the EC process, it is proposed to use a graphite powder, which is applied to the treated surface before alloying. The comparative analysis shows that, after the traditional EC process at Wp = 4.6 J, the surface roughness of steel 20 is Ra = 8.3–9.0 μm, and after the proposed technology, Ra = 3.2–4.8 μm. In this case, the continuity of the alloyed layer increases up to 100%; there increases the depth of the diffusion zone of carbon up to 80 μm as well as the microhardness of the ‘white’ layer and its thickness, which increase up to 9932 MPa and up to 230 μm, respectively. The local micro-x-ray spectral analysis of the obtained coatings shows that, at the EC process carried out in a traditional way, the applying Wp = 0.9, 2.6, 4.6 J provides the formation of the surface layers with high-carbon content depths of 70, 100, 120 μm, respectively, and with the use of a graphite powder, they are of 80, 120, 170 μm. While deepening, the amount of carbon is decreasing from 0.72–0.86% to the carbon content in the base metal — 0.17–0.24%. In the near-surface layer formed with the use of the new technology, the pores are filled with free graphite, which could be used as a solid lubricant to improve the operating characteristics of the friction-pairs parts processed thereby.Item Комбіновані електроіскрові припрацювальні покриття бронзових деталей. Частина 2. Розподіл елементів у поверхневому шарі(Інститут металофізики ім. Г. В. Курдюмова НÀН України, 2021) Гапонова, Оксана Петрівна; Гапонова, Оксана Петровна; Haponova, Oksana Petrivna; Тарельник, В`ячеслав Борисович; Тарельник, Вячеслав Борисович; Tarelnyk, Viacheslav Borysovych; Марцинковський, В.С.; Коноплянченко, Є.В.; Мельник, В.І.; Власовець, В.М.; Тарельник, Н.В.; Герасименко, В.О.; Бондарев, С.Г.; Баталова, А.Б.; Кирик, Г.В.; Поливаний, А.Д.; Семирненко, Ю.І.; Рясна, О.В.У статті представлено результати локального мікрорентґеноспектрального аналізу припрацювальних сульфідованих комбінованих електроіскрових покриттів (КЕІП) бронзових деталей. Досліджені покриття одержано в послідовностях S + Ag → Pb → S + Ag і S + Ag → Sn → S + Ag. Встановлено, що для КЕІП характерна наявність елементів металів, що входять до складу електродів-інструментів (Ag, Pb і Sn). У покриттях, до складу яких входить оливо, зі збільшенням енергії розряду, за леґування як сріблом, так і оливом, збільшується дифузійна зона сірки до відповідно 90, 135 і 200 мкм. Сірка по глибині шару розподіляється нерівномірно; її вміст становить 1,59–3,3%. Після формування КЕІП на зразку з покриттям S + Ag → Pb → S + Ag його товщина складає 700 мкм. Сірку виявлено на поверхні і на глибині до 50 мкм, а також у перехідній зоні на відстані ≅650 мкм від поверхні. У разі збільшення енергії розряду в зразках з покриттям S + Ag → Sn → S + Ag товщина нанесеного КЕІП досягає 1,05 і 1,310 мм. Сірку виявлено на поверхні, її дифузійна зона простягається на 200 мкм від поверхні, а в перехідній зоні — на ≅100 мкм.Item Комбіновані електроіскрові припрацювальні покриття бронзових деталей. Частина 3. Трибологічні властивості(Інститут металофізики ім. Г. В. Курдюмова НАН України, 2021) Гапонова, Оксана Петрівна; Гапонова, Оксана Петровна; Haponova, Oksana Petrivna; Тарельник, В`ячеслав Борисович; Тарельник, Вячеслав Борисович; Tarelnyk, Viacheslav Borysovych; Марцинковський, В.С.; Коноплянченко, Є.В.; Мельник, В.І.; Власовець, В.М.; Кирик, Г.В.; Тарельник, Н.В.; Мікуліна, М.О.; Кутах, А.А.; Поливаний, А.Д.; Майфат, М.М.; Калнагуз, О.М.У статті в результаті проведених досліджень вдосконалена технологія нанесення на бронзу БрО10С10 припрацювальних комбінованих електроіскрових покриттів (КЕІП), сформованих у послідовності: S+Ag → Pb → S+Ag і S+Ag → Sn → S+Ag. Покриття, одержані за запропонованою технологією, містять сірку, що знижує схоплювання контактувальних поверхонь, мають достатню для подальшої механічної обробки товщину 0,19–1,31 мм. Трибологічними дослідженнями на тестері Т-01М за схемою «кулька-диск» встановлено, що зі збільшенням товщини КЕІП зростає сила тертя. У зразків з КЕІП (S+Ag → Pb → S+Ag), товщина яких залежно від енергії розряду дорівнює 0,19; 0,26 і 1,01 мм, сила тертя становить 1,454; 1,762 і 2,543 Н відповідно, а у зразків з КЕІП (S+Ag → Sn → S+Ag) товщиною 0,89; 1,05 і 1,31 мм відповідно 0,934; 1,904 і 2,152 Н. Сірка в КЕІП знижує силу тертя сталевої кульки по поверхні бронзових зразків на 19%. Для практичного застосування можна рекомендувати КЕІП (S+Ag → Pb → S+Ag) і (S+Ag → Sn → S+Ag), одержані за енергії розряду відповідно 0,52 → 0,13 → 0,05 і 4,6 → 0,36 → 0,36 Дж, які забезпечують зниження сили тертя у порівнянні з зразками без покриття відповідно у 1,90 і 1,22 раза.Item Analysis of the Quality of Sulfomolybdenum Coatings Obtained by Electrospark Alloying Methods(MDPI, 2021) Гапонова, Оксана Петрівна; Гапонова, Оксана Петровна; Haponova, Oksana Petrivna; Antoszewski, B.; Tarelnyk, V.B.; Kurp, P.; Myslyvchenko, O.M.; Tarelnyk, N.V.The authors of this paper have attempted to improve the quality of surface layers applied to steel elements of machine parts constituting friction couples. The main goal of the research was to investigate an electrospark alloying method process for obtaining abrasion-resistant tribological coatings containing molybdenum disulfide on a steel surface. A substance in the form of sulfur ointment with a sulfur content of 33.3% was applied on the surfaces of C22 and C40 steel specimens. In order to determine the influence of the energy parameters of ESA equipment on the quality parameters of coatings, the ESA process was carried out using a molybdenum electrode with discharge energies Wp = 0.13; Wp = 0.55; Wp = 3.4 J. The following tests were carried out on specimens with such coatings: metallographic analysis, microhardness tests, surface roughness, and local X-ray diffraction microanalysis. The experiments revealed that sulfomolybdenum coatings consist of four zones with different mechanical properties. Depending on the discharge energy and the substrate material, the hardness of these zones varies from approx. 1100 to over 10,000 MPa. Differences in the distribution of, among others, sulfur and molybdenum in the obtained coatings, as well as differences in the microstructure of the observed coatings, were observed.Item Assessment of Technological Capabilities for Forming Al-C-B System Coatings on Steel Surfaces by Electrospark Alloying Method(MDPI, 2021) Antoszewski, B.; Гапонова, Оксана Петрівна; Гапонова, Оксана Петровна; Haponova, Oksana Petrivna; Tarelnyk, V.B.; Myslyvchenko, O.M.; Kurp, P.; Zhylenko, T.I.; Konoplianchenko, I.In this paper, the possibility of applying the electrospark alloying (ESA) method to obtain boron-containing coatings characterised by increased hardness and wear resistance is considered. A new method for producing such coatings is proposed. The method consists in applying grease containing aluminium powder and amorphous boron to the surface to be treated and subsequently processing the obtained surface using the ESA method by a graphite electrode. The microstructural analysis of the Al-C-B coatings on steel C40 showed that the surface layer consists of several zones, the number and parameters of which are determined by the energy conditions of the ESA process. Durametric studies showed that with an increase in the discharge energy influence, the microhardness values of both the upper strengthened layer and the diffusion zone increased to Wp = 0.13 J, Hµ = 6487 MPa, and Wp = 4.9 J, Hµ = 12350 MPa, respectively. The results of X-ray diffraction analysis indicate that at the discharge energies of 0.13 and 0.55 J, the phase composition of the coating is represented by solid solutions of body-centred cubic lattice (BCC) and face-centred cubic lattice (FCC). The coatings obtained at Wp = 4.9 J were characterised by the presence of intermetallics Fe4Al13 and borocementite Fe3 (CB) in addition to the solid solutions. The X-ray spectral analysis of the obtained coatings indicated that during the electrospark alloying process, the surface layers were saturated with aluminium, boron, and carbon. With increasing discharge energy, the diffusion zone increases; during the ESA process with the use of the discharge energy of 0.13 J for steel C40, the diffusion zone is 10–15 µm. When replacing a substrate made of steel C40 with the same one material but of steel C22, an increase in the thickness of the surface layer accompanied by a slight decrease in microhardness is observed as a result of processing with the use of the ESA method. There were simulated phase portraits of the Al-C-B coatings. It is shown that near the stationary points in the phase portraits, one can see either a slowing down of the evolution or a spiral twisting of the diffusion-process particle.