The work covers the effect of niobium, as well as niobium and vanadium together, on mechanical properties of high-strength chromium-nickel-molybdenum steel after thermal improvement (heat treatment). The mechanical properties of steels are determined after applying various tempering temperatures (from 580 to 660°C), durations of tempering (from 1 to 16 hours), and also after quenching from rolling heat and furnace heat with subsequent tempering. It is shown that after quenching and tempering in the temperature range 580– 660°C, simultaneous microalloying by niobium and vanadium, compared to microalloying by niobium alone, increases the yield strength but in significantly decreases toughness and ductility. Quenching from rolling heat increases strength while maintaining high toughness and the increase in strength is most noticeable for steel microalloyed only by niobium.

Processes of dynamic and static recrystallization occurring at different conditions of plastic deformation (reduction modes, deformation temperature) of low-carbon low-alloyed steel are under consideration. Modeling of thermomechanical processing is carried out at Gleeble 3800, followed by complex microstructural analysis. Temperature-deformation conditions leading to formation of uniform dispersed structure are revealed during the investigations. In conclusion the results of implementation in industry of worked out hot rollingmodes are given.

This article deals with structural features and characteristic changes that affect the mechanical characteristics after different service life in real conditions using the example of the blades of the 4th stage of turbine GTE-45-3 with an operating time of 13,000 to 100,000 hours. To study the change in the state of the material under different operating conditions, determine the degree of influence of heat treatment on the regeneration of the microstructure, and restore the mechanical characteristics of the alloy after different periods of operation, non-standard methods were used: relaxation tests on miniature samples to determine the physical yield strength and microplasticity limit and quantitative evaluation of the plasticity coefficient of the material from experimental values of hardness, which allow us to identify the changes occurring in the microvolumes of the material and predict the performance of the product as a whole.

The heterogeneity of the titanium VT41 structural state after hot upset test was investigated by analytical methods of optical and scanning microscopy. Vickers microhardness measurements were performed to estimate the mechanical properties. The analysis of the distribution of deformation and the features of the formation of the structural components of the specimen. Globular grains were deformed by the mechanism of intergranular slipping. β-grains and α-plates made the greatest contribution to plastic deformation. Lamellar grains of α-phase in the zone of localization of deformation undergo recrystallization. The dimensions of the zone in which the recrystallization occurred, coincide with the zone of localization of the deformation, estimated by macrostructure. When tempering the billet, the β-phase in the center of the sample breaks down into α-plates, and in the near-surface areas into smaller grains, probably representing needle-like β-titanium martensite. A decrease in microhardness in the central regions may be due both to recrystallization and to the fact that martensite has been quenched in the surface layers.

The results of studies of the stress-strain state of copper M0b after deformation under different schemes of equal channel angular pressing (ECAP) are presented. The level of macro and micro stresses in copper has been determined in various ECAP modes. It is shown that the strength properties, deformation porosity and parameters of the fine copper structure differ depending on the loading pattern.

The paper studies the structure of cast microwires in glass insulation, obtained at the current density, which leads to melting of the metal core. High melting currents values allow us to recommend cast microwires as low-base fuses against current overloads in electric circuits.

The paper presents results of the development of technology for producing cladded and surfacealloyed powder materials. High-speed mechanosynthesis of matrix powders of FeCrAl and solid nanosized particles of tungsten carbide occurs in a disintegrator in the presence of an active gas phase (nitrogen).

The work deals with topical issues such as development of composite nanostructured powder materials. The results of creating powders based on the system “aluminum–nitride of silicon” are presented. Complex investigations of the composition, structure and properties of powder materials, as well as coatings formed on their basis by supersonic cold gas dynamic spraying, were carried out. It has been found that the high-energy treatment of a powder mixture of aluminum with nanofibers of silicon nitride provides the formation of a composite powder in which a new phase of the Si_(1-х)AlхO_(1-х)N_х type is formed, which additionally increases the hardness in the coatings to be sprayed.

The paper studies the development of a technology for obtaining a wear-resistant functional gradient coating during supersonic cold gas dynamic spraying. The process goes due to the variation of the composition of the gas phase in a heterophase flow. The coating has a high microhardness (up to 12 GPa) on the peripheral layers and wear resistance is 3 times higher than that of coatings obtained by traditional technology.

The features of the process of obtaining a powder composition from an alloy based on the Al–Zn– Sn system are studied. A technology has been developed for obtaining powders of optimal composition, including Al; 6–11% Zn; 6–11% Sn; 2–4% Si; 0.6–0.8% Ce. Functional wear-resistant coatings recommended for practical use in products of precision and power engineering were made by supersonic cold gas dynamic spraying.

The paper presents the results of thermodynamic analysis of oxidation processes occurring during laser treatment of amorphous magnetically sensitive ribbon (71KNSR) in air and in the atmosphere of argon. Kinetic assessment of the rate of chemical reactions is based on the Arrhenius equation. The results of analytical calculations show that the decrease of magnetic properties of the alloy after laser treatment in the air is mostly determined by the formation of iron oxides Fe₂O₃ and Fe₂O₄. Chemical elemental analysis of the composition of the samples after laser configuration in argon shows a significant decrease in their composition of oxygen compared to samples configured in the air. Analysis of samples using scanning electron and magnetic force microscopy confirms the preservation of the magnetic properties after treatment in argon. The developed technology is used for the manufacture of a sensitive element of a fluxgate inclinometer.

The paper treats important problems of domestic engineering, namely, the urgent necessity to increase service life of large-sized turbine blades of the power gas-turbine stations operated on thermal power plants. The heat-resistant coating of the Ni–Co–Cr–Al–Y system with intermetallic phase structure β-(Ni, Me)Al + γ′-(Ni, Me)₃Al has been developed. It was made by high-energy plasma powder spraying and intended for protection of blade surface against high-temperature and erosive gas flow. The article studies microstructure, phase structure and physicomechanical properties of a coating given in an initial state, and after laboratory research of heat resistance and a post-operational state at ~29 000 hours (time of real operation of the gas-turbine engine of the GTE-45-3 power station on thermal power plant). After long-term operation, a decrease in the content of the intermetallic phase of β-(Ni, Ме)Al in the phase composition, an increase in the pore size and a decrease in the hardness of the coating have been established. At the same time, erosion resistance and heat-resistant properties of the coating remain, and, consequently, there is a sufficient resource.

The possibility of creating a wear-resistant dry sliding electrical contact tungsten/steel was studied. It was shown that tungsten caused severe wear of the quenched steel counterbody due to unlimited plastic flow of its surface layer at a current density up to 150 A/cm² . This indicated the impossibility of achieving satisfactory characteristics of such a contact. Low electrical conductivity and wear resistance of the contact tungsten/steel were presented in comparison with the known high copper/steel contact characteristics under the same conditions. X-ray phase analysis data of the steel sliding surfaces made it possible to state that the cause of the unsatisfactory sliding of tungsten was the absence of the necessary concentration of FeO oxide on the sliding surface of the steel.

A simple and environmentally safe method for obtaining stable nanoparticles of metal sulfides nanoparticles – NpAg₂S, NpCdS and NpZnS was developed using different strains of microorganisms in an aqueous solution of metal salts and sulfur sources at the Research Center "Kurchatov Institute" – GosNIIgenetika. The concentration of nanoparticles is 1–4 mg/ml in aqueous suspensions. Using of the methods of electron microscopy, spectrofluorimetry, dynamic light scattering determined the main characteristics of biogenic nanoparticles: shape, size distribution, crystal structure, effective diameter, luminescent spectrum, zeta potential. According to its characteristics, these nanoparticles are referred to quantum dots. It is established that the stability of nanoparticles in aqueous suspensions is due to protein molecules adsorbed on the surface of nanoparticles, which are supplied by cells of microorganisms. Effective immobilization of biogenic nanoparticles on the surface of various polymer supports has been carried out. Biogenic nanoparticles along with nanoparticles obtained by physico-chemical methods can be used as fluorophores for imaging of biological processes, also as photocatalysts, solar cells and for new nanocomposite materials.

Modern mechanical engineering often uses polyurethane elastomers as vibroinsulating material. It is difficult to choose the most perfect structural polyurethane among a large number of proposed materials for manufacturing shock absorbers. The article presents experimental research of vibroinsulating properties using two parameters out of five. Based on preliminary tests, an implicit preference is given to one of the three proposed materials. The energy absorption coefficient and the creep of the elastomer are chosen as criteria for evaluating the vibroinsulation properties of polyurethane elastomers. Final choice of polyurethane elastomer for shock absorbers manufacturing could be made if additional tests are carried out for studying three criteria.

Developing "smart" materials with improved both structural and functional characteristics is one of the promising areas of materials science. Measuring the electrical resistance of CNTs-modified (various mass contents) polymers and in particular, elastomers during performing several tests (compression, stretching, and torsion) at a constant current is relevant in electrical engineering, mechanical engineering, aviation, and space industry. Changes in the elastomer shape under different types of testing lead to the destruction of macromolecules and the structuring of the material as a whole. Therefore, it is important to study the effect of CNTsbased modifying fillers on the elastomer. When compressing, stretching or twisting the nano-modified elastomer, along with the mutual movement of its macromolecular fragments and aggregates, the modifier particles also move, which generally determines the transport of electrons in the resulting structure and affects the physical and mechanical parameters of the composite material. To conduct studies, elastomers containing different amounts of a CNTs-based modifying filler were prepared. To investigate and elucidate relevant dependencies, a measuring system (MS) was constructed, which makes it possible to determine electrical resistance values of the composite material with different CNTs contents in the polymer matrix composition exposed to various mechanical loads. Basing the research results, it was established that the electrical resistance of the elastomer composites modified with 1.0–2.5 wt.% CNTs decreases when compressing from 0 to 100 N, whereas when the compression force ranges from 100 to 350 N, the electrical resistance remains unchanged. When the elastomer composites modified with 2–2.5 wt.% CNTs were stretched by 30–40 %, the electrical resistance was found to increase from 5·10³ to 1.9·10⁷ Ω.

Theoretical studies of the deformation of the carbon fabric structure have been performed. The paper describes investigations that made it possible to obtain functional relationships between the mechanical characteristics of the fabric and the parameters of the structure of carbon fibers, their mechanical characteristics, the parameters of the structure and the technological parameters of the fabric. Based on theoretical studies, mechanical and analytical models of structure deformation of carbon fabric were built.

The review provides an analysis of global trends in current research in the field of carbon fiber composite materials. The paper considers studies conducted in 2018 and identifies four priority areas by assessing the amount of their funding. The mentioned areas include the utilization of carbon composites, optimization of their production process, the use of carbon composites in the aviation and shipbuilding industries. The review may contribute to the determination of high-priority and relevant research that will be conducted in the near future.

The paper treats problems of reducing the cost of welding and improving the quality and productivity of welding parts of cold-resistant steel of great thickness during the construction of oil platforms. The design of tooling structure, and devices for electron-beam welding have been developed such as welding wire feeder, video observation system, software for controlling the workpiece moving and the electron beam gun travel.

The paper presents the results of a study of pitting corrosion of aluminum alloys of seven doping systems after testing by the full-scale accelerated method. The advantages of the method of laser scanning microscopy in the analysis of pitting corrosion are shown, which makes it possible to improve significantly the accuracy of measurements in comparison with the metallographic method. Peculiarities of the kinetics of pitting growth under long-term, accelerated tests were studied, the role of pitting corrosion in the part of characterizing the alloy’s susceptibility to local corrosion failure was shown.