DSpace Общество: RU:Кафедра "Подвижной состав и пути" <br> EN: Department of Rolling Stock and TrackRU:Кафедра "Подвижной состав и пути" <br> EN: Department of Rolling Stock and Trackhttp://eadnurt.diit.edu.ua/jspui/handle/123456789/6252022-03-20T06:39:14Z2022-03-20T06:39:14ZEffect of Vanadium Nitride Additive on the Structure and Strength Characteristics of Diamond-Containing Composites Based on the Fe–Cu–Ni–Sn Matrix, Formed by Cold Pressing Followed by Vacuum Hot PressingRatov, B. T.Mechnik, V. A.Bondarenko, N. A.Kolodnitskyi, V. M.Kuzin, Nickolai O.Gevorkyan, E. S.Chishkala, V. A.http://eadnurt.diit.edu.ua/jspui/handle/123456789/147792022-03-10T16:10:07Z2021-01-01T00:00:00ZНазвание: Effect of Vanadium Nitride Additive on the Structure and Strength Characteristics of Diamond-Containing Composites Based on the Fe–Cu–Ni–Sn Matrix, Formed by Cold Pressing Followed by Vacuum Hot Pressing
Авторы: Ratov, B. T.; Mechnik, V. A.; Bondarenko, N. A.; Kolodnitskyi, V. M.; Kuzin, Nickolai O.; Gevorkyan, E. S.; Chishkala, V. A.
Краткий осмотр (реферат): ENG: We prepared samples of composite diamond-containing materials 10 mm in diameter and 8 mm in thickness, based on the 51Fe–32Cu–9Ni–8Sn matrix (wt %) with different (0–10 wt %) concentrations of vanadium nitride (VN), the physical the mechanical characteristics of which depend on the composition of the iron matrix. The optimal (cVN = 4%) concentration of vanadium nitride in the matrix of composites sintered in the temperature range of 20–1000°C at a pressure of 30 MPa for 5 min ensures the highest indices of the physicomechanical properties of the composites (Rbm = 1110 MPa and Rcm = 1410 MPa) due to the dispersion mechanism of strengthening and modification of the structure, that is, a decrease in the average grain size, the disappearance of pores, the formation of clusters of the inhibitor phase at the interphase boundaries, and the phase composition of the composites. All sintered samples containing VN powder additives in the charge are characterized by a more uniform distribution of phases and a more dispersed structure compared to a sample without VN additives. The structure of composites containing a VN additive consists of
a solid solution of nitrogen and vanadium in α-iron and a mixture of Fe, Cu, Ni, and Sn phases and primary and secondary dispersed phases of vanadium nitride.
Описание: N. Kuzin: ORCID 0000-0002-6032-45982021-01-01T00:00:00ZInfluence of Diamond–Matrix Transition Zone Structure on Mechanical Properties and wear of Sintered Diamond-Containing Composites Based on Fe–Cu–Ni–Sn Matrix with Varying CrB2 ContentMechnik, V. A.Bondarenko, N. A.Kolodnitskyi, V. M.Zakiev, V. I.Zakiev, I. M.Kuzin, Nickolai O.Gevorkyan, E. S.http://eadnurt.diit.edu.ua/jspui/handle/123456789/147502022-03-05T13:43:16Z2021-01-01T00:00:00ZНазвание: Influence of Diamond–Matrix Transition Zone Structure on Mechanical Properties and wear of Sintered Diamond-Containing Composites Based on Fe–Cu–Ni–Sn Matrix with Varying CrB2 Content
Авторы: Mechnik, V. A.; Bondarenko, N. A.; Kolodnitskyi, V. M.; Zakiev, V. I.; Zakiev, I. M.; Kuzin, Nickolai O.; Gevorkyan, E. S.
Краткий осмотр (реферат): ENG: The influence of CrB2 additive (within the interval ranging from 0 to 8 wt%) on the formation of structure of the diamond–matrix transition zone and the matrix material, microhardness, elastic modulus, retention of diamond grains in Fe–Cu–Ni–Sn matrix material and wear resistance of sintered diamond-containing composites (DCCs) by the powder metallurgy method has been studied. Micro-mechanical and tribological tests were conducted using composite samples 10 mm in diameter and 5 mm thick. It has been established that the transition zone structure significantly depends on the CrB2 content in a composite and is of a different nature than that of the matrix material. The structure of DCCs transition zone based on 51Fe–32Cu–9Ni–8Sn matrix consists of Cu, α-Fe and Ni3Sn phases with graphite inclusions. The structure of DCCs transition zone based on 51Fe–32Cu–9Ni–8Sn matrix with CrB2 additives consists of the α-Fe phase and Fe3C, Cr7C3, Cr3C2 carbide layers without graphite inclusions.
It has been shown that the hardness and the elastic modulus of sintered composite matrix material increase linearly as the concentration of CrB2 in their content increases while the wear rate decreases. The addition of 2 wt% of CrB2 to 51Fe–32Cu–9Ni–8Sn composite contributes to an increase in its hardness from 4.475 to 7.896 GPa and elastic modulus from 86.6 to 107.5 GPa thus
reducing the wear rate from 21.61 × 10−6 to 10.04 × 10−6 mm3 N−1 m−1. The mechanism for enhancing the mechanical properties and wear resistance of DCCs samples containing CrB2 additives consists in refining of matrix phases of iron and copper from 25 μm to 10 μm and binding the carbon released during the graphitization of diamond grains to Fe3C, Cr7C3, Cr3C2 nanoscale carbides. This, in turn, increases the ability of matrix material to keep diamond grains from falling out during DCCs operation. Low values of mechanical properties and wear resistance of the initial (51Fe–32Cu–9Ni–8Sn) composite are attributed to the coarse-grained structure and formation of graphite inclusions in the diamond–matrix transition zone, causing its premature destruction and separation of diamond grains from the DCCs matrix.
Описание: N. Kuzin: ORCID 0000-0002-6032-45982021-01-01T00:00:00ZMicrostructural Features and Mechanical and Tribological Properties of Fe–Cu–Ni–Sn Composites Precipitation-Hardened with CrB2 Additions. Powder Metallurgy and Metal CeramicsMechnik, V. A.Bondarenko, N. A.Kolodnitskyi, V. M.Zakiev, V. I.Zakiev, I. M.Gevorkyan, E. S.Kuzin, Nickolai O.http://eadnurt.diit.edu.ua/jspui/handle/123456789/147492022-03-05T10:52:01Z2021-01-01T00:00:00ZНазвание: Microstructural Features and Mechanical and Tribological Properties of Fe–Cu–Ni–Sn Composites Precipitation-Hardened with CrB2 Additions. Powder Metallurgy and Metal Ceramics
Авторы: Mechnik, V. A.; Bondarenko, N. A.; Kolodnitskyi, V. M.; Zakiev, V. I.; Zakiev, I. M.; Gevorkyan, E. S.; Kuzin, Nickolai O.
Краткий осмотр (реферат): ENG: The structural features, hardness, elastic modulus, and wear resistance of Fe–Cu–Ni–Sn composites with different CrB2 contents, produced by cold pressing and subsequent sintering with additional hot pressing, were studied by X-ray diffraction, scanning electron microscopy, microindentation, and tribological testing. The micromechanical and tribological tests were performed on composite samples 10 mm in diameter and 5 mm thick in dry friction conditions. The test results showed that the mechanical and tribological properties of the composites depended on the CrB2 content. The microhardness and elastic modulus of the samples varied from 1.2 to 9.2 GPa and from 110 to 245 GPa, respectively, depending on their composition, resulting from the uneven distribution of α-Fe, Cu, Cu9NiSn3, NiSn3, and CrB2 phases. The addition of 2 wt.% CrB2 to the 51Fe–32Cu–9Ni– 8Sn composite increased its hardness from 1.2–2.8 GPa to 2.0–4.5 GPa and the elastic modulus from 110–190 GPa to 130–200 GPa and decreased the wear rate from 22.93 ∙ 10–3 to 10.19 × 10–3 mm3 N–1 m–1. The mechanism of increasing the wear resistance of the composite sample containing 2 wt.% CrB2 in comparison with the starting composite was associated with the refinement of iron and copper grains from 5–40 μm to 2–10 μm and the presence of discrete areas of greater hardness and higher elastic modulus. A further increase in the CrB2 content from 2 to 8 wt.% in the composite was accompanied by a simultaneous increase in hardness from 2.0–4.5 GPa to 4.8–9.2 GPa, elastic modulus from 130–200 GPa to 150–245 GPa, and wear rate from 10.19 ×10–3 to 16.68 ∙10–3 mm3 N–1 m–1. The higher wear rate of these composites was due to excessive brittleness caused by excessive CrB2 content.
Описание: N. Kuzin: ORCID 0000-0002-6032-45982021-01-01T00:00:00ZМетодика оцінювання теплових потоків, що діють на сталезалізобетонні мостиОнищенко, Артур МиколайовичКовальчук, Віталій ВолодимировичФедоренко, Олександр ВолодимировичПарнета, Б. З.Рибак, Р. Т.Парнета, М. Б.http://eadnurt.diit.edu.ua/jspui/handle/123456789/147482022-03-04T19:03:36Z2021-01-01T00:00:00ZНазвание: Методика оцінювання теплових потоків, що діють на сталезалізобетонні мости
Авторы: Онищенко, Артур Миколайович; Ковальчук, Віталій Володимирович; Федоренко, Олександр Володимирович; Парнета, Б. З.; Рибак, Р. Т.; Парнета, М. Б.
Краткий осмотр (реферат): UKR: Проведено вимірювання розподілу температури на поверхнях сталезалізобетонних мостів. Наведено методику оцінки теплових потоків, які діють на сталезалізобетонні балки моста при дії змінних перепадів температури навколишнього середовища. Виконано оцінку теплових потоків, що діють на горизонтальну та вертикальну поверхні сталезалізобетонної балки моста. Встановлено, що на розподіл теплових потоків сталезалізобетонною балкою моста впливає температура поверхні та швидкість вітру.; ENG: The temperature distribution on the surfaces of reinforced concrete bridges was measured. The method of estimation of heat fluxes acting on reinforced concrete beams of the bridge under the action of variable differences in ambient temperature is given. The estimation of heat fluxes acting on the horizontal and vertical surfaces of there in forced concrete beam of the bridge is performed. It is established that the surface temperature and wind speed influence the distribution of heat fluxes by a reinforced concrete beam.
Описание: В. Ковальчук: ORCID 0000-0003-4350-1756; А. Онищенко: ORCID 0000-0002-1040-4530, O. Федоренко: ORCID 0000-0002-3464-597X2021-01-01T00:00:00Z