Title of the article |
OPTIMIZATION OF VOLUME DAMAGEABILITY OF THE HALF-SPACE LOADED BY ELLIPTICALLY DISTRIBUTED CONTACT PRESSURE AND NON-CONTACT STRESSES |
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Authors |
SHERBAKOV Sergei S., D. Sc. in Phys. and Math., Assoc. Prof., Vice-Chairman (State Committee on Science and Technology of the Republic of Belarus, Minsk, Republic of Belarus), Professor of the Department of Theoretical and Applied Mechanics (Belarusian State University, Minsk, Republic of Belarus), This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. |
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In the section | TRIBO-FATIGUE SYSTEMS MECHANICS | ||||
Year | 2018 | Issue | 4 | Pages | 96–100 |
Type of article | RAR | Index UDK | 539.3 | Index BBK | |
Abstract |
The paper considers numerical and analytical modeling of the stress-strain state and the state of volume damageability of a half-space under its simultaneous loading by elliptically distributed load directed along the normal to the surface axis and non-contact extension/compression along one of the coordinate axes parallel to the surface. The dependence of the values of dangerous volumes and integral damageability on the number of boundary elements on the surface of a half-space and on the number of elementary volumes in the three-dimensional computational domain is shown. The ratios of maximum contact pressure and non-contact stresses are obtained at which the values of dangerous volumes are minimal. |
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Keywords |
tribo-fatigue, boundary element method, numerical and analytical modeling, stress-strain state, volume damageability |
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Title of the article |
OPTIMIZATION OF CONTENT OF RUNNING-IN COMPOSITION AND REGIMES OF TRIBOMECHANICAL PROCESSING OF GAS-THERMAL STEEL COATINGS |
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Authors |
ZHORNIK Viktor I., D. Sc. in Eng., Assoc. Prof., Head of the Laboratory of Nanostructured and Superhard Materials, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. BELOTSERKOVSKY Marat A., D. Sc. in Eng., Assoc. Prof., Head of the Laboratory of Gas-Thermal Methods of Machine Components Hardening, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. PARNITSKY Alexander M., Junior Researcher of the Laboratory of Nanostructured and Superhard Materials, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus YALOVIK Alexander P., Director General, JSC “Neftezavodmontazh”, Novopolotsk, Republic of Belarus |
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In the section | MATERIALS SCIENCE IN MECHANICAL ENGINEERING | ||||
Year | 2018 | Issue | 4 | Pages | 86–95 |
Type of article | RAR | Index UDK | 669.018.95 | Index BBK | |
Abstract |
The mathematical model of the process of tribomechanical modification of gas-thermal steel coatings is developed with the use of the method of computational and experimental modeling. This model makes it possible to choose the optimal running-in regimes depending on the given frictional surface parameters after the tribomechanical processing. In this case the optimization parameters are the concentration of the nanosized additive in the running-in composition, the tribocontact pressure and the slip velocity. And the optimization criteria are the friction coefficient, the surface hardness and the friction path in the running-in. It is shown that, for example, with the aim of tribomechanical modification of gas-thermal spray composite coatings produced by the simultaneous spraying of wires from austenitic steels with a nickel content of not less than СNi = 10 % and the martensitic steel grade with a carbon content of more than CC = 0.4 % with the ratio of the diameters of the wires dmart.st./daust.st. = 1.12–1.20, it is necessary to use the running-in composition with a penetration number of N = 265–340 units at a concentration of diamond-graphite charge in it СShA-A = 0.25–0.35 wt.% having a particle size within dp = 10–50 nm, and the running-in process must be carried out at a specific load P = 40–50 MPa and a sliding velocity Vsl = 0.20–0.30 m/s. |
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Keywords |
gas-thermal coatings, steels of austenitic and martensitic grades, tribomechanical modification, running-in composition, optimization of running-in regimes, concentration of diamond-graphite charge, specific load, sliding velocity |
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Title of the article |
MECHANICAL ACTIVATION OF THE POWDER MIXTURE OF “ULTRA-HIGH MOLECULAR WEIGHT POLYETHYLENE — COMPOSITE B4C/W” |
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Authors |
KOVALEVA Svetlana A., Senior Researcher of the Laboratory of Nanostructured and Superhard Materials, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. ZHORNIK Viktor I., D. Sc. in Eng., Assoc. Prof., Head of the Laboratory of Nanostructured and Superhard Materials, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. GRIGORIEVA Tatyana F., D. Sc. in Chem., Leading Researcher of the Laboratory of Chemical Materials Science, Solid State Chemistry and Mechanochemistry of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia |
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In the section | MATERIALS SCIENCE IN MECHANICAL ENGINEERING | ||||
Year | 2018 | Issue | 4 | Pages | 65–71 |
Type of article | RAR | Index UDK | 621.762.2 | Index BBK | |
Abstract |
The article presents the results of the experimental studies of the structural transformations of a powder mixture of ultra-high molecular weight polyethylene and 80 wt.% (45 vol.%) of the nanostructured composite B4C/W treated in a high-energy ball planetary mill that are studied by the methods of X-ray diffraction, scanning electron microscopy and Fourier-IR spectroscopy. It is shown that the polymer composite particles of a flaky shape and the size of 160–400 μm with a uniform distribution in them of boron carbide and tungsten particles with the size of 1–5 μm and 0.1–0.2 μm respectively are formed during the process of mechanical activation (MA), while the oxidative destruction of polymer is not detected. The main results of the interaction of the polymer matrix and dispersed filler powders with MA are the processes of breaking of intramolecular bonds, cross-linking of polymer molecules, as well as mechanical dispersion of particles. |
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Keywords |
mechanical activation, microstructure, composites, ultra-high molecular weight polyethylene, boron carbide, tungsten |
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Title of the article |
PECULIARITIES OF CENTRIFUGAL INDUCTION MELTING OF TIN BRONZE WITH NANOSCALE ADDITIONS |
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Authors |
BELOTSERKOVSKY Marat A., D. Sc. in Eng., Assoc. Prof., Head of the Laboratory of Gas-Thermal, Methods of Machine Components Hardening, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. KURILYONOK Artem A., Junior Researcher, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. ALEXANDROVA Vera S., Researcher, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. |
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In the section | MATERIALS SCIENCE IN MECHANICAL ENGINEERING | ||||
Year | 2018 | Issue | 4 | Pages | 79–85 |
Type of article | RAR | Index UDK | 621.79:536.2 | Index BBK | |
Abstract |
The article presents the physico-mathematical modeling of the dynamic effect of the melt on a nanoscale particle during the formation of coatings by induction centrifugal surfacing. The forces acting on the particle in the liquid melt during the isothermal holding under induction prismatic welding are determined. A dependence is obtained that determines the rate of displacement of nano-sized particles from the initial position in the liquid melt during surfacing of the coating. A method for the formation of coatings with nano-sized additives is developed by induction centrifugal surfacing, including preliminary preparation of the bronze charge. It is shown that the introduced nanoscale additive in an amount of 4 wt.% to the powdered charge of tin bronze, according to the proposed method, leads to its phase-structural transformations, which allows achieving higher anti-frictional properties of bronze, since a uniform distribution of the solid structural component throughout the whole coating is ensured. The detected factors lead to an increase in the tribotechnical properties of coatings — a reduction in the coefficient of friction with simultaneous increase in wear resistance and micro-hardening of coatings. |
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Keywords |
induction surfacing, induction heating, bronze charge, nanoscale additives, dynamic action, antifriction coatings |
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Title of the article |
PECULIARITIES OF THE STRUCTURE FORMATION AND PROPERTIES OF SILUMIN AlSi7 UNDER THE INFLUENCE OF THE NANOFILLER TiC-Al2O3 |
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Authors |
KOMAROV Alexander I., Ph. D. in Eng., Head of the Laboratory of Modification Technologies of Engineering Materials, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. ORDA Dmitriy V., Junior Researcher of the Laboratory of Modification Technologies of Engineering Materials, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus ISKANDAROVA Donata O., Junior Researcher of the Laboratory of Modification Technologies of Engineering Materials, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus |
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In the section | TECHNOLOGICAL MECHANICS | ||||
Year | 2018 | Issue | 4 | Pages | 65–71 |
Type of article | RAR | Index UDK | 669.715 | Index BBK | |
Abstract |
The article deals with the structural-phase transformations of the pre-eutectic alloy AlSi7, occurring during its modification by nanoscale composition TiC–α-Al2O3, introduced together with micro powders of aluminum or copper. It is shown that the use of micro powders of different nature and morphology has a direct impact on the degree of transformation of the alloy structure. In this case, the introduction of a nanofiller is most effective together with copper powder, the particles of which are represented by dendrites with a developed surface. It is shown that the modification of the alloy by small fractions (0.5 wt.%) of nanofiller leads to dispersion of the structure (reduction of aluminum solid solution dendrites and iron-containing inclusions by 2 and 3 times, respectively), as well as changes in the morphology of intermetallic inclusions. The formation of the modified structure reduces the friction coefficient, increases wear resistance and extends the range of loads. It is shown that the introduction of nanoscale composition TiC–α-Al2O3 in the amount of 0.5 wt.% together with the micro powder of copper or aluminum leads to a decrease in the coefficient of friction in 1.8–2 times at loads up to 20 MPa, and the additional introduction of CNT provides an intensive reduction in the coefficient of friction at 30 MPa to values 0.016–0.018. It was found that the use of aluminum micro powders with the introduction of the modifier provides an increase in wear resistance by 1.4–1.6 times, and the use of copper or copper with CNT provides a multiple increase in wear resistance (weight loss on the samples is not fixed), whereas for the initial alloy it is 8.73∙10–5 mg/m. |
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Keywords |
nanofiller, titanium carbide, corundum, structure formation, alloy AlSi7, friction coefficient, wear resistance |
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