№4 2024
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1
The paper presents the results of the application of experimental and computational methods for studying the thermal conditions of the process of directed crystallization of heatresistant alloys, which have found wide application in the production of blades for modern aviation
gas turbine engines made of heat-resistant alloys. Methods for estimating the values of the temperature gradient, the crystallization rate, the size of the liquid-solid zone at the crystallization front, and their effect on the structure and properties of superalloys are proposed and implemented -
2
The segregation defects of ingots of intermetallic titanium alloys based on the ortho-phase (Ti2AlNb), obtained by vacuum-arc melting, are considered. Methods for eliminating similar defects of segregation origin in titanium, nickel and niobium-titanium alloys, the use of which is possible for the smelting of high-quality ingots from intermetallic titanium orthoalloysare presented. Based on the results of a study of the effect of homogenizing heat treatment on the chemical homogeneity of Ti–10V–2Fe–3Al alloy samples, it was concluded that similar work is necessary for ortho-alloy ingots
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3
This paper presents results of study of the microstructure and mechanical properties of welded joints produced by electron beam welding of strip extrusions from high-strength alloy V-1469 of Al–Cu–Li system. The features of the structural and phase state of the material
in various zones of electron beam welding joint are studied by means of scanning and transmission
electron microscopy, thermal analysis and thermodynamic modeling. The influence of welding speed
on the mechanical properties and nature of fracture of welds was studied -
4
A review of research and development related to a class of smart shape memory materials based on epoxy oligomers that can change and recovery a shape in response to various external factors is presented. High-performance shape memory epoxy polymers with high strength, toughness and heat resistance open new possibilities for various applications, offering great prospects for development in many fields of science and technology in the future. The development of the world economy is impossible without the use of new technologies in the aerospace industry, the aviation industry, and the biomedical industry
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5
The formation of several types of nanoformations with a size of 4–80 nm in fluorine rubbers, depending on the history, was detected using XRD. The process of changing the structure of their nanoorganization with the manifestation of phase transitions is also influenced by the chemical structure of junctions in macromolecules, which determines, in particular, the complex and unequal nature of changes in their dynamic viscosity. Titanium dioxide not only facilitates the formation of new types of nano-formations in fluoro-rubbers, but also the polymorphic transition of vinylidene fluoride links from the trans-gosh-trans-gosh conformation to the «flat zigzag» conformation
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6
The article presents the results of the analysis of the design-force diagrams of the main rotor blades of the domestic helicopter equipment and the main stages of the technological process of their repair. According to the results of the analysis the input parameters for the development of the technology of repair of helicopter rotor blades from polymer composite materials in field conditions are revealed and presented. In the process of narration the directions of repair technologies development and main innovations of SIC «Kurchatov Institute» – VIAM are shown.
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7Part 2. Glass fiber-reinforced plastic VPS-68
A comprehensive assessment of the retention of the strength properties of fiberglass VPS-68 for tension, compression, bending, interlayer shear was carried out at test temperatures of –60, +20, +80 and +105 °C in the initial state and after climatic influences in a tropical climate chamber for 1 and 3 months, thermal aging for 500 and 1000 hours, exposure to mycological environments and technical fluids. To confirm viability, samples of VPS-68 fiberglass were tested in tension and compression
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8
Light-absorbing coatings are widely used for the construction of optical instruments and for converting sunlight into thermal energy. This article presents various production methods of light-absorbing coatings. Coatings obtained from both liquid and gas phases are reviewed. Their optical properties are particularly discussed. A comparison of advantages and drawbacks of light-absorbing coatings obtained by different methods, including their corrosion behavior and mechanical properties is conducted
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9
The article presents the results of studies of the effect of corrosion inhibitors of various chemical compositions on the time of crosslinking, the thermal effect and the structural formation of a polysulfide sealant in which they are included. The data on the dependence of the crosslinking rate of a polysulfide sealant with corrosion inhibitors on temperature and relative humidity are presented; the phase transitions and the change in the heat capacity of the sealant samples are determined; the microstructure of the sealant is investigated and its effect on the protective properties of the composition is described
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10
The analysis of test results on stability to gas-abrasive erosion for systems of paint coatings based on the erosion-resistant disperse-reinforced enamel EP-5236 applied on aluminum alloy D16-T and fibreglass VPS-20 at impact angles α = 90° and 15° was carried out. Firmness of coatings was evaluated on changes of weight characteristics of samples. Resistance of paint coatings to gas-droplet erosion on samples from alloy D16-T and also from fibreglass VPS-20 was investigated. It is shown that using of erosion-resistant system of paint coatings based on disperse-reinforced enamel EP-5236 increases resistance to gas-abrasive and gasdroplet erosion
