№4-5 2020
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1
The characteristics of structural changes during heat treatment of Mo–Ti–Zr–С powder alloy obtained by spark plasma sintering were studied. The sintering conditions to obtain nearly theoretical density were worked out. The mechanical and physical characteristics like density, bending strength and plasticity were defined. In order to improve mechanical properties of the material and to obtain dispersion-strengthened structure the heat treatment was carried out. After this the material’s structure was investigated using optical and scanning electron microscopy and mechanical tests were carried out.
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2Part 2
The second part paper considers such new and already used in industrial applications reactive type flame retardants for epoxy resins, which can reduce their combustibility without significantly reducing their heat resistance and mechanical properties, as different functionalized phosphazenes, organic compounds based on nitrogen or silicone atoms and rigid aromatic compounds with excellent thermal stability and high resistance to burning. The effects of these additives and their mechanism of action are shown.
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3
The article is devoted to the development of polymer composite materials (PCMs) based on carbon fabrics of sarge weaving and polyester ether ketones. Film and prepreg technologies for production of thermoplastic PCMs based on polyether ether ketones of foreign manufacture have been tested. Requirements for fluidity of polyether ether ketones for obtaining carbon plastic are formulated. In order to assess the potential of obtained sheet carbon plastics as structural materials, studies were carried out on the defect of their structure and determination of strength characteristics of samples from normal and defective areas.
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4
During plane operation on a glider surface often there are defects and damages which at the further operation can lead to breakage, therefore in the conditions of aerodrome carry operative out repairs of such defects, allowing to raise functionability and durability of a design. In activity comparative analysis FSL of the aluminium alloys made of different compositions and glue is presented. Their comparative adhesive characteristics are resulted.
Are resulted their comparative adhesive and прочностные characteristics, and as agency of stoppers from FSL on growth rate of fatigue cracks in aluminium sheetings of an aeronautics.
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5
Properties, processing techniques and possible applications in «hot sections» of gas turbine engine of different structural high-temperature materials with an operating temperature higher than 1200 °С are highlighted. Composites with a multi-layered structure based on «ceramic/carbon», «ceramic/ceramic», «ceramic/metal» systems have demonstrated to be promising materials. Layer widths with low/high Young modules, their ratio and arrangement have a significant impact on the strength parameters. High-temperature composites with a multi-layered structure can have a «graceful failure» mode and higher toughness as compared to particle reinforced ceramic composites.
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6
The surface structure of reaction cured coatings based on a composition of refractory glass in system BaO–Al2O3–SiO2 and silicon tetraboride was studied using atomic force microscopy and scanning electron microscopy depending on the conditions of heat treatment of coatings. Non-significant roughness of the coatings was revealed, the level of which reduces as the result of firing in oxidizing atmosphere. The key structural feature of the reaction cured coatings is the preservation of non-oxidized particles of silicon tetraboride in the glass matrix volume what determines the high level of reaction cured coatings properties.
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7
Рresents researching of the properties of ion-plasma wear-resistant coatings based on multicomponent titanium nitrides deposited on a MAP-3 installation on structural steels. Dependences of wear resistance and heat resistance of coatings on test temperature are established. The effect of alloying elements on the properties of multicomponent titanium nitrides is shown. X-ray structural and metallographic studies of wear-resistant coatings in the initial state and after heat resistance tests were carried out.
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8
In work researches of the plasma electrolytic oxide covering formed with application of silicate and phosphatic electrolit on samples of a sheet semi-finished product from aluminum – a lithium alloy 1441-Т1 are conducted. It is established that thickness of a covering has linear dependence on time in the range from 30 till 165 min. The analysis of a chemical composition and the mechanism of formation of a plasma electrolytic covering is carried out. Research of structure of a covering allowed to establish dependence of properties (microhardness, breakdown resistance) from porosity and other internal defects.
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9
In this article influence of silicate fillers on operational properties of coatings, based on protective polymeric pastes VP-1 and VZP-1 with the lowered content of strontium chromate is studied. It is shown that microwollastonite introduction positively affects the adhesive durability, hardness and water absorption of the received coatings. It is established that partial replacement strontium chromate on microwollastonite as a part of VP-1 paste does not lead to decrease in protective properties of coatings, and in case of VZP-1 paste - allows to increase protective properties of coatings.
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10
Samples of 6 milling cutters from different producers made of WC–Co carbide material were studied. Correlation dependences of hardness and coercive force on the size of grain WC and specific interfacial surface are constructed based on the carried out researches. It is shown that the value of the coercive force can indirectly estimate the grain size WC. The results of the mapping and distribution profiles of the inhibitors over the volume of Co-bundles reveal the nature of this distribution: V is concentrated mainly at the borders of tungsten carbide, while the Cr is uniformly distributed over the volume of Co binder.
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11
Growth of volumes of output of products from nonmetallic materials demands introduction in manufacture of products from them modern highly productive technologies. In this connection in the given work possibility of use of laser radiation for cutting details from organic glasses is considered, are spent comparative strength tests of samples received by means of laser and mechanical cutting. As results of researches on influence of thermal radiation laser beam cutting on residual pressure in plexiglass and in particular on it «silverfirmness» are resulted.
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12
The paper presents the features of the destruction of fibrous metal matrix composites (ММСs) system Ti–SiC under cyclic loads under the review of foreign scientific and technical literature. The main factors affecting the nature of fracture and the fatigue life of fibrous MCMs system Ti–SiC under cyclic loads with different asymmetry coefficients are considered. The stages of destruction of fibrous MCMs system Ti–SiC under the action of mechanical and thermomechanical fatigue are presented. In conclusion of the review, conclusions are drawn and it is shown that in order to achieve high performance characteristics of parts made of MCMs system Ti–SiC, it is necessary to take into account the structural features of the material.
