№6 2022
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1
A wrought heat-resistant superalloy VZh179-ID has been developed for blades of the last stages of a high-pressure compressor with an operating temperature up to 800 °С of high-thrust gas turbine engines. To achieve the required indicators for mechanical properties structural studies have been carried out, the results of which are used in determining the models of alloy’s heat treatment. According to the complex of mechanical properties the developed alloy has significant quotes of superiority both in comparison with EP718-ID alloy and the most heat-resistant wrought alloy for blades EP220.
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2
The article considers the effect of the martensitic structure dispersion degree on the tribotechnical characteristic of high carbon complex-alloyed steel. After hardening heat treatment of samples with a various degree of deformation there have been obtained samples with a structure from fine- to large-needle martensite. According to the results of the wear test under conditions of dry sliding friction it has been found that samples with a structure of fine-needle martensite have a wear rate lower by 50 and 70 % compared to medium- and large-needle martensitic structures.
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3
The article presents the results of a complex of studies: analysis of the microstructure, determination of mechanical properties under the influence of breaking loads at break, shear, as well as determination of fatigue characteristics at room temperature of fasteners made of VT47 pseudo-β-titanium alloy. A comparative analysis of the obtained research results was carried out, showing the dependence of the mechanical properties of fasteners on the structure. The relevance of the use of VT47 pseudo-β-titanium alloy as material of fasteners is shown.
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4
It is shown that the use of EP-0234 epoxy primer, used as an adhesive sublayer under VK-36 epoxy-polysulfone adhesive leads to an increase in the holding time between the process of chemical oxidation in chromic acid (An.Ox.chrome) of the glued surfaces of aluminum alloys and the start of technological bonding work for up to 30 days (instead of 2 days for anodized surfaces without primer) without deterioration of the glued samples, and in some cases – to their improvement.
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5
A comparison of the technological properties of prepregs produced by online and offline technologies and the physical and mechanical properties of carbon fiber plastics based on a molten epoxy highly deformative binder is carried out. The advantages and disadvantages of the considered prepreg manufacturing technologies and their influence on the properties of carbon fiber plastics are evaluated. It is shown that the difference in the technology of obtaining semi-finished products (prepregs) does not affect the obtaining of the final properties of carbon fiber plastics obtained by autoclave molding.
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6Part 1
Currently, polymer composite materials (PCM) are widely used instead of such traditional materials as steel or wood. For large-sized PCM parts, the infusion process is becoming the most popular and frequently used. This technology is used to manufacture ship hulls, wind turbine blades, aircraft wings. The purpose of this review is to consider various types of infusion, their advantages, disadvantages and prospects for use.
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7
This review considers the biological damage of thermoplastic and thermoset reinforced polymer composite materials, carbon and glass fibers and resins by microorganisms and fungi. It is shown that biodegradation affects the structural integrity of the material, physical and mechanical properties. The conditions for the favorable development of microorganisms, the mechanism of biodegradation, some types of bacteria and fungi that affect polymer composite materials and the mechanisms of biofilm formation are considered.
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8
The article presents an overview of scientific and technical information in the field of technological features of the process of obtaining high-temperature carbon plastics based on thermosetting polyimide binders. The parameters of molding are given and their comparative analysis, areas of application and recommended operating temperatures of high-temperature polyimide carbon-fiber reinforced plastics, developed and produced by foreign companies, whose products have been successfully implemented in practice in structural elements of aerospace engineering products, are presented.
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9
In the current trends towards saving and increasing the efficiency of electricity use, magnetic materials of the Nd–Fe–B system are widely used in the production of fully electric vehicles: cars (Tesla), aircraft, as well as new energy sources – for example, wind turbines. Considers various methods of applying protective coatings to magnetic materials of the Nd–Fe–B system, surface preparation modes and evaluates the effect of the technology of applying anticorrosive coatings on their protective ability, the magnitude of residual induction and coercive force on the magnetization of magnetic materials.
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10
Results of practical researches of corrosion resistance of the metal materials used in designs of domestic aviation engineering, for the long-term period are stated. In work the chronology of researches and development of anticorrosive protection is observed. Problem questions regarding climatic and biological firmness of materials are stated. Standard corrosion destructions of metal materials because of corrosion cracking, application of technical liquids and fuels, and also contact of diverse materials are given. Technological decisions on the anticorrosive protection, its developments accepted at different stages which are actual and now are provided.
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11
In this work, the principal possibility of quantifying the heat transfer coefficient of the material using a stand was tested, as well as the selection of experimental parameters to increase the reliability of the assessment of the thermal conductivity coefficient of the layered material. It is possible to use one part of the data array within one test to estimate the heat transfer coefficient of the material on its hot side, and when processing another part of the experimental data, to use the heat transfer coefficient to estimate the heat absorbed by the sample. The proposed estimation method is much simpler in terms of hardware compared to the classical calorimetric method.
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12Part 3. Corrosion cracking of aluminum alloys
Based on reviews of the corrosion-mechanical destruction of metals (in parts 1 and 2), the impact of the corrosive environment and mechanical loads on aluminum alloys is considered. The main theories and practical results of determining changes in the mechanical characteristics of aluminum alloys are presented. The values of the tensile velocity must correspond to the investigated metal-medium system and ensure that the mechanism of destruction of the tested material in the experiment on samples corresponds to the mechanism of destruction of real structures under operating conditions.
