№11 2022
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1
Microstructure, hardness and tribotechnical characteristics of beryllium-containing steel VNS32-VI were studied after strengthening heat treatment and final ion nitriding. It was found that the microstructure of samples processed according to various methods does not differ, and the thickness of the diffusion layer is 100 μm. The alloying element distribution study showed that the surface was dominated by Cr, Mo and Nb having a high affinity for nitrogen. The best tribotechnical properties were possessed by samples for which the dispersion hardening process was combined with final ion nitriding.
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2
The effect of heat treatment regimes for sheets 2 mm thick of aluminum-lithium alloy V-1469 on the microstructure and microhardness has been studied. Hardening and one- and two-stage artificial aging with various holding times (from 1 to 12 hours) were carried out. Using optical and scanning electron microscopes, the microstructure was studied and a local chemical analysis of the phase components of the alloy was carried out. It is shown that with an increase in the time of one-stage artificial aging, the microhardness increases from 93 to 175 HV, and with an increase in the total exposure during two-stage aging, from 91 to 180 HV, as a result of structural-phase changes and an increase in the proportion of strengthening phases. Inclusions of a regular triangular shape, found after hardening, contain up to 17 % (by mass) of copper and have a size of 1.5–3.0 µm.
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3
Presents the results of studies of the uniformity of the distribution of alloying elements in ingots from economically alloyed casting titanium alloy VT40L. Experimental ingots obtained by double vacuum-arc remelting, for which the main technological parameters of melting calculated. Statistical processing of the results of chemical analysis was carried out using Shewhart control charts, and indicators of process capabilities were also evaluated. Suggestions are made about methods for achieving the best stability indicators.
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4
The trends of modern technologies for the manufacture of magnesium alloys and products from them are considered. The results of research and developed technologies of foreign scientists and world companies in the field of magnesium alloys and magnesium-based materials are presented. Research is focused on selective laser melting (SLM), since it is possible to form high-precision parts of any shape with it help. The fine magnesium or magnesium alloy powders used for SLM are difficult to manufacture due to their rapid oxidation. In connection with this feature, more and more attention is paid to the technology of using wire. The review considers such technologies as laser cladding and gas-dynamic spraying. The presented research and development will expand the scope of application and, in the future, master improved traditional and modern promising additive technologies.
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5
The paper considers self-lubricating antifriction materials reinforced with fabric based on organic fibers. Experimental fabrics of various composition and textile structure were designed and manufactured. Fabrics contain fibers of PTFE and other organic polymers. Samples of fabrics and antifriction organoplastics based on them have been studied, their physical-mechanical and tribological properties have been determined. It is shown that organoplastics based on experimental tissues can be considered as self-lubricating antifriction materials.
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6
The need to manufacture permanent magnets based on rare-earth metals of complex shape and with increased thermal stability of magnetic properties forces the use of heavy rare-earth metal dysprosium and transition metal cobalt in the chemical composition of the alloy. In this regard, the phase composition of the permanent magnet material changes. The study of the magnetic properties of secondary phases and their contribution to the magnetic properties of permanent magnets is necessary to find the optimal composition that allows to obtain permanent magnets with the necessary level of properties.
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7
The article presents the results of changes in the properties of high-temperature carbon fiber reinforced plastic VKU-61 for aviation purposes after testing for fungus resistance, obtained using various test methods. The retention of strength in static bending is 79–92 %, regardless of the method of testing for fungus resistance. For comparison, data on the fungus resistance of carbon plastics based on polymer binders of various chemical nature are given. The results of preservation of the mechanical properties of the considered carbon plastics after 3 months of exposure to heat and humidity conditions, including after exposure to mold fungi, are presented.
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8
Despite the problems currently caused by the pandemic, accidents and sanctions, it is planned to increase the production of structures made of polymer composite materials (PCM) in the aircraft industry. Widespread use of PCM in aircraft structures in 2025–2035. will be accompanied by increased introduction of automated processes, mathematical modeling at the stages of design, manufacture and life cycle of such structures, the use of combinations of thermoplastic and thermosetting matrices and metal elements in their production, as well as the transition to autoclave-free technologies.
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9
In this work the main attention has been given to choice of recipe of inhibitive pigments and fillers, and also definition of their optimum ratio in the polymeric film-forming. For researches the epoxy compositions modified by liquid polysulphide rubber, containing inhibitive pigments and fillers of different structure have been used. For curing of primer compositions organic silicon ammine has been used. For acceleration of process of curing of primer compositions, it was used tertiary amine UP-606/2. As a part of pigmental composition the inhibitive pigments as well as structure-forming fillers, have been investigated.
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10
The paper examines modern directions of development and features of the electroforming method in relation to nickel and its alloys. An overview of the electroforming method is presented, indicating reference sources, features of the method used and various materials. The compositions of electrolytes for nickel electroforming and the physical properties of the coatings obtained from them are presented. The peculiarities of the influence of various additives in electrolytes on the quality and consumer properties of products were considered. Different types of mandrels and materials for their production are described. Their comparison is carried out; the positive and negative aspects of different types of mandrels are considered. Considerable attention is paid to the consideration of the effect of internal stresses on the properties of materials obtained by electroforming.
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11
This work is devoted to the issues of comparison of domestic and foreign standard samples (certified reference materials) of nickel alloys of various grades. Using the method of x-ray fluorescence spectrometry on sets of State standard samples of alloys VZh172 and VZhL21 containing elements such as Al, Co, Cr, Mo, Ti, W, Zr, Fe, Mn, calibration dependences of the mass fraction of elements on the intensity of the signal – the characteristicx-ray radiation. Using statistical techniques, an assessment was made of the possibility of joint use of sets in the construction of general calibration characteristics for the simultaneous determination of Al, Co, Cr, Mo, Nb, Ta, Ti, W, Zr, Fe, Mn in nickel alloys of similar composition.
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12
Because of limited resistance of glass fiber reinforced plastic (GFRP) to influence of climatic factors it is interesting to make natural weathering tests in different climatic conditions. The study of strength and thermomechanical properties changing of GFRP VPS-48/7781 (with or without coating) after 3 year environmental exposure in different climatic zones. It was shown that applying of coating based on VE-69 provides saving strength and thermomechanical properties on the initial level.
