Studying the structure and phase composition of high-speed steel R2M9 surfacing of medium-carbon steel 30KhGSA, transmission and scanning electron microscopy, X-ray phase and X-ray structural analysis were used. Heat treatment included three-fold high-temperature tempering with subsequent irradiation with pulsed electron beams. The solid solution based on α-iron is the main phase in the initial state and after heat treatment; the γ-phase is present in a small amount (3–5 mas.%). The lattice parameter of both phases decreases after tempering. Irradiation of the deposited layer with electron beams is accompanied by an increase in the crystal lattice parameter of the α-phase and its decrease for the γ-phase. The paper discusses reasons of the observed patterns. It has been established that the deposited layer is characterized by the presence of a carbide frame containing carbides of complex composition MeC, Me₆C, Me₂₃C₆, Me₇C₃, which is not destroyed after tempering and electron beam treatment. Carbide of composition Me₆C is the main phase forming the frame, and MeC is formed after tempering and electron beam treatment. The martensitic structure formed during surfacing contains nanosized inclusions of the second phase of the composition MoC, Mo₂C, Me₆C with a size of 20–45 nm, located in the martensite plates’ volume and along the boundaries. Their volume fraction decreases to 19 mas.% after tempering and additional irradiation with electron beams.

The paper investigates ways of increasing the strength of the experimental high-alloy titanium alloy having a thermally unstable β-phase in the structure at room temperature. It is shown that solid solution and structural strengthening leads to a change in the phase and intrastructural state of the material under study, which, in turn, ensures an increase in strength characteristics. At the same time, depending on the annealing mode, an increase in the conditional yield strength from 1000 to 1200 MPa is ensured without a significant decrease of viscoplastic properties.

At present, aluminum and its alloys are successfully replacing metals and alloys traditionally used in a number of areas. One of the promising areas of aluminum use is the electrical engineering industry. Thus, the conductive aluminum alloy of the E-AlMgSi (Aldrey) type is characterized by high strength and good ductility. With appropriate heat treatment, this alloy acquires high electrical conductivity. Wires made from it are used almost exclusively for overhead power lines. The article presents the results of a study of the temperature dependence of the heat capacity, heat transfer coefficient and thermodynamic functions of the aluminum alloy E-AlMgSi (Aldrey) with thallium. The studies were carried out in the “cooling” mode. It is shown that with increasing temperature, the values of the heat capacity, heat transfer coefficient, enthalpy and entropy of the E-AlMgSi (Aldrey) alloy with thallium increase, and the value of the Gibbs energy decreases. With the addition of thallium up to 1 wt. % decreases the heat capacity, heat transfer coefficient, enthalpy and entropy of the initial alloy and increases the Gibbs energy.

A thermoelectric alloy containing the Mn₅ (Si_2.5Al_0.5) phase was obtained for the first time using self-propagating high-temperature synthesis combined with pressing. The microstructure of the alloy is represented by grains up to 10 μm in size. X-ray phase analysis showed the presence of the following phases in the synthesized sample: Mn₅ (Si_2.5Al_0.5), TiC and SiO₂. The presence of the TiC and SiO₂ phases is due to the specific features of the sample synthesis using the SHS pressing method. A study of the thermoelectric characteristics of the material was conducted. The value of the Seebeck coefficient (S) at room temperature is about 8 μV/K and reaches a wide maximum of 9–10 μV/K at T = 360 K, and the maximum value of specific electrical resistance of 1.5∙10^-2 Ohm∙cm is achieved at room temperature.

The article presents the results of the study of the structure and magnetic characteristics of powders of Co–Ni–Al alloys of the compositions Co₃₇Ni₃₆Al₂₇ and Co₃₂Ni₃₉Al₂₉ obtained by mechanical alloying in a planetary mill. The influence of alloying technological modes on the elemental composition of powders, their saturation magnetization and coercive force, is studied. The mechanical alloying efficiency for obtaining new hard magnetic alloys based on the Co–Ni–Al system is shown.

A series of samples were manufactured using the additive technology of direct laser deposition (DLD) from 08Kh14NDL steel powder at different process parameters (radiation power, scanning speed and powder feed rate). The macroand microstructure, density and hardness of the samples were studied. The structural features of the steel manufactured by DLD were studied in comparison with casting, non-metallic inclusions were identified, and the size of the structural components was determined. It was shown that the structure, density and hardness of the steel can be varied by changing the DLD modes, which is promising for the development of industrial additive technologies.

The possibility of using nanosized copper particles as a filler for polyetheretherketone (PEEK) in order to create a tribotechnically effective composite has been investigated. Based on the physical wear model, the calculated concentration dependences of the relative intensity of linear wear of the composite with respect to the matrix have been constructed for four sizes of dispersed filler from the nanoand micro-sized range. As a result, the ranges of effective filler concentrations have been determined when introducing nanocopper into PEEK. The molecular dynamics method has been used to study the causes of increased wear resistance of the nanocomposite when introducing dispersed copper particles. It has been found that in the presence of a nanofiller, the energy of intermolecular bonds increases significantly, differences in the density of polymer molecules in the contact area before and after shear, as well as differences in the energies of intermolecular interaction between the contacting surfaces depending on the shear time have been revealed.

A technology for producing a gradient of a binder in carbon fiber reinforced plastic by powder spraying has been developed. The plastic based on benzoxazine-phthalonitrile binder has been obtained. The binder in the upper layers of the carbon fiber reinforced plastic contains mainly phthalonitrile, the binder in the center of the plate contains mainly benzoxazine. The binder composition changes smoothly from the surface to the center of the sample, i.e. there is a gradient of the matrix composition. To improve impact resistance, a high-temperature thermoplastic is introduced into the binder composition, the concentration of which also changes over the thickness of the sample. Compared with a homogeneous carbon fiber reinforced plastic with the same content of components in the binder, the gradient carbon fiber reinforced plastic has shown higher heat resistance and impact strength without loss of rigidity.

Microstructural and FT-IR-spectroscopic investigation of heat-resistant carbon-fiber-reinforced plastic the VKU-61 brands on the basis of thermosetting polyimide binding and carbon full-strength fabrics after laboratory simulated and controlled operational factors – elevated temperature and humidity influences were performed. On the basis of the analysis and ordering of the received results, the general consistent patterns and features of structural changes in composite material in the conditions of controlled external factors were determined.

This article discusses the influence of multipass welding with several electrodes of different brands on the chemical composition and microstructure of the seam. The objects of study were samples of pipe section made of stainless steel grade 12X18H10T. As a result of the conducted research, the values of the effective thermal power of the heating source were established, ensuring a uniform distribution of elements in the deposited metal, an austenitic structure, a minimum content of the ferritic phase and a uniform distribution of microhardness over the seam section.

The character of the stress condition, physical-mechanical and structural properties of mild steel welded joints made in cold ambient conditions were studied. Welded samples were obtained by MMA using electrodes UONI-13/MOROZ, KHOBEX-K-54, LB-52TRU. The studies were conducted within the framework of full-scale climatic tests under natural cold conditions of welding equipment and materials. It is shown that when welded under cold conditions, the level of tensile residual welding stresses increases by an average of 40–50% compared to welding at room temperature. Welding in cold ambient conditions revealed features of structure and mechanical properties. Methods of climatic test of welding materials and equipment in cold ambient conditions have been developed.

The corrosion resistance in carbon dioxide environments of a number of structural steels used for pipelines of gas fields has been studied. The aggressive conditions of gas facilities are characterized by the fact that most of the internal space of pipelines is filled with the gas phase. Corrosion effects on steel, when only a small gas pipeline is filled with a liquid phase, have previously been practically unstudied. During the research, a corrosion stand specially designed for this purpose was used, on which some of the most aggressive conditions of alternating wetting of the gas pipeline wall with water were reproduced. The corrosive activity of such conditions is associated with the destruction of films of corrosion products. In places where they crack and peel, local corrosion damage forms on the steel. The corrosion behavior of pipe steels from different gas pipelines under conditions of variable wetting with water was studied. A comparative assessment of the resistance of pipe steels 09Mn2Si and 13KhFA in carbon dioxide environments under conditions of variable wetting and moisture condensation, the main effects of internal corrosion, was carried out. It was determined that the main type of destruction is local corrosion of the steel surface of the pipes. The influence of the microstructure of steels and their chromium content on their corrosion resistance under conditions of transport of CO2-containing gas through pipelines has been assessed.

This work is devoted to the research of high-strength medium-alloy martensitic and bainite-martensitic steels in various structural states. The critical values of the J-integral were determined and their stable correlation with the results of tensile test of cylindrical samples with the circumferential deep grooves was obtained. To confirm this correlation, the statistical formulation of the local criterion for brittle fracture proposed in previous works was used as an energy condition for the propagation of microcracks crossing through grain boundaries with large-angle misorientation of the crystal lattice. The analysis of the relationship between parameters used in the proposed local criterion and the structural characteristics of the material was performed. The predictive ability of the proposed model to determine the temperature dependence of fracture toughness was also analyzed.

For geometrically complex designs of nuclear power plants, the justification of cyclic strength based on modern approaches is a time-consuming and resource-intensive process. From a practical point of view, the regulatory documents on the justification of the strength of nuclear power structures suggest the most simplified approach. The article numerically substantiates the inapplicability of such an approach for the case of non-isothermal cyclic loading. In this regard, a new effective methodology has been developed for assessing the fatigue of structures under isothermal or non-isothermal cyclic loads. Based on numerical elastic-plastic calculations of classical problems of deformation of cylindrical rods with deep annular incisions of various sharpness, the effectiveness of the developed technique has been confirmed.

The article presents information on the study of porosity of control samples cast from silumin alloy using X-ray computed tomography (CT). The theoretical calculations and experiments had a goal: to develop an X-ray tomographic scale of gas porosity that would be absolutely adequate to the results of metallography. Currently, a radiographic porosity scale is widely used by the operator who compares the sample radiograph with a radiograph of the test object. Such an assessment of the quality of non-destructive testing is subjective, and it is determined by the experience, physical health of the operator performing the control, and the quality of radiographic images. X-ray tomography of reference porosity samples provides quantitative indicators of porosity and completely eliminates the subjective factor.

The usage of special complex alloying and deoxidizing systems, combining various alloying components, micro-alloying components, deoxidizing and modifying elements that cannot be added into metal cored wires is the main aspect in the development of chemical compositions of welding consumables for high-strength steel welding. The optimal amount of acicular ferrite in the microstructure of the weld metal, as well as its high mechanical properties can be achieved by controlled introduction of titanium or titanium with boron. To ensure the best strength and ductility characteristics during complex micro-alloying of flux-cored wires, the titanium content should be about 0.04%, and boron – 0.003%

The paper presents the results of the study of the structural organization and properties of bimetallic specimens of the system copper – stainless steel obtained by the wire-feed electron beam additive technology. Peculiarities of the formation of heterogeneous material joints are revealed. Inhomogeneities of copper and steel distribution at the interface with formation of local areas of mechanical mixture due to interfusion of components in liquid state have been found. The shape of the copper particles in the area of mechanical mixing is free, close to spherical. The homogeneous and defect-free structure of the transition zone between the components of the specimen contributes to its sufficiently high mechanical properties, which are intermediate between the properties of copper and steel, corresponding to the properties of similar materials in the cast state.

The paper considers the correlation of the physical and acoustic characteristics of fiberglass manufactured using various reinforcing materials and molding methods. An adjusted technique for monitoring and calculating the correlation coefficients of ultrasound velocity with density and elasticity modules on various types of fiberglass is being worked out.