Radio-absorbing materials for electromagnetic compatibility and reduction of electromagnetic wave reflections are used in radio electronic equipment. In the practical application of materials in the form of coatings and gaskets, it is important to take into account the mechanical properties due to possible joint changes in microwave and mechanical characteristics. The effect of the introduction of silicon dioxide (tarkosil) nanopowder on the microwave characteristics and rheological properties of a highly filled composite based on the silicone binder SilcoTin 25 and microparticles of carbonyl iron grade P-10 has been studied. The samples were made according to the method of obtaining highly filled composites with a content of 80 wt. % of micro-powder P10, previously tested for various grades of carbonyl iron. Microwave measurements were performed using the transmission/reflection method in a coaxial cell using S-parameters with the calculation of reflection, transmission, and absorption coefficients in the "lumen" mode of a 2 mm thick layer without a metal substrate. The frequency measurement range is 0.5 ‒ 18.0 GHz. It has been shown that the administration of tarkosil (1 ‒ 3 wt. %) in a composite with micro-powder P10 leads to an ambiguous restructuring of the balance of absorption, reflection and transmission. With a moderate change in absorption, an increase in reflection is observed. The dielectric and magnetic tangents of the loss angle, as well as the modulus of the normalized impedance, are calculated from the frequency dependences of the complex values of the dielectric ε* and magnetic μ* permittivity. It is shown that the increase in reflection is mainly associated with a deterioration in impedance matching while maintaining significant magnetic losses. 

The thermal motion of molecules and the forces of intermolecular interaction are the fundamental causes that determine the frequency of vibrations in liquids. In contrast to the crystal structure of solids, where atoms or molecules are fixed in lattice sites and vibrate around these positions, in liquids, particles vibrate near volatile centers of equilibrium. These fluctuations are accompanied by periodic "jumps" of molecules to new, also temporary, positions, which characterizes the dynamic nature of the liquid state. The link between the microscopic movement of molecules and macroscopic viscosity is the sedentary lifetime, the time during which a molecule oscillates around one equilibrium position before making a "leap." The longer the molecule oscillates near the equilibrium point, the rarer the displacement acts occur and the higher the viscosity. The concept describing the theory under consideration was developed by J.I. Frenkel. On the other hand, A.E. Bachinsky found that the viscosity of liquids is related to the "free" volume, which already depends on temperature. The oscillation frequency, sedentary life time, activation energy, and free volume of various liquids have been studied. To determine the free volume, data on vapor densities and enthalpies at various temperatures were used, which were calculated using linear extrapolation and the Watson formula. Using the viscosity theories of G. Eyring and J.I. Frenkel, the values of oscillation frequencies and sedentary life time for more than twenty different liquids were obtained. The calculations showed that near the boiling point, the proportion of free volume increases to 7 ‒ 9 % (excluding formic acid). A.E. Bachinsky found that with a fixed volume, the viscosity of a liquid remains almost unchanged, despite variations in pressure and temperature. 

The effect of the test temperature on the kinetics of localized plasticity fronts in an aluminum-magnesium alloy with structural heterogeneity in the form of a weld is investigated. The relevance of the study is due to the widespread use of welded structures made of Al ‒ Mg alloys in combination with the inherent tendency of these materials to the Portevin effect. ‒ Le Chatelier (instability of plastic flow, manifested as an abrupt change in stress and localization of deformation). The studies were carried out in the temperature range from ‒20 to 30 °C at a deformation rate of 1 mm/min. The fields of local deformations and the kinetics of propagation of deformation fronts are analyzed by the method of digital image correlation. It has been found that at all temperatures, the deformation curves exhibit a yield point and intermittent flow, while the values of yield strength and strength remain unchanged. At the yield point, the fronts of the Luders bands monotonously propagate from the boundaries of the mixing zone of the weld, representing autowaves of switching localized plasticity. When stresses exceeding the yield point are reached, localized deformation fronts, which are self-excitation waves, begin to propagate through the sample. Moreover, an increase in temperature to 30 °C shifts the critical deformation of the beginning of the Portevin effect ‒ Le Chatelier enters the area of higher stresses and reduces the duration of the yield point by half. At all temperatures, the weld area with hardened boundaries contributes to the delocalization of deformation: the accumulated deformation in the seam area is almost two times lower than in the base metal.

The results of a study of the features of the formation of fusion boundaries of bimetallic samples obtained by the method of wire electron beam additive manufacturing are presented. Austenitic stainless steel (06X18H9T), ferrite-pearlite steel (08G2C) and wear-resistant steel (40X9X2) were used as the studied materials. The microstructure, distribution of chemical elements, and strength characteristics of transition zones were studied using scanning electron microscopy, energy dispersion spectral analysis, and mechanical tests for uniaxial static stretching. It was found that the selected technological parameters (wire feed rate 745 ‒ 1911 mm/min; number of wires per layer 323 ‒ 828 mm; electron beam current 69.9 ‒ 26.0 mA) ensure the formation of bimetallic transition zones that do not contain macroscopic defects (cracks or delaminations). A pronounced structural and chemical asymmetry has been revealed, which directly depends on the sequence of application of the layers. When 08G2C grade steel is deposited on top of 06X18N9T or 40X9C2 grade steel, a sharp jump in chemical composition and minimal mutual diffusion of alloying elements are observed (the diffusion zone does not exceed 10 microns). On the contrary, during the formation of austenitic or wear-resistant steel on top of ferrite-pearlite, significant mutual mixing of melts and a smooth, gradient change in the concentration of basic chemical elements are recorded. Mechanical tests of samples cut across the boundary of the structural transition showed that the fracture occurs in the bulk of the base metal of the least durable component (steel grade 08G2C), bypassing the fusion boundary itself, which indicates the high strength of the bimetallic compound. In longitudinal tests, the strength parameters of the boundary zone occupy an intermediate position between the properties of the starting materials. 

The structure of the Ti ‒ 43.7Al ‒ 3.4Nb ‒ 1.1Mo alloy (at. %) was studied, the temperatures of the phase transformations and their sequence during heating and heat treatment aimed at activating the cellular reaction were determined. The latter consists in the formation of new large-plate (λ₂) in nanoplatellar (λ₁) colonies (λ₂ >> λ₁). The temperature of the eutectoid (α₂ → γ) transformation (1137 °C (calculated temperature 1071 °C)) and the temperature of the dissolution of the γ-phase (1273 °C (calculated temperature 1262 °C)) were theoretically and experimentally determined using differential scanning calorimetry during heating, and the dependence of phase fractions on temperature is modeled. A metastable α₂-grain structure with β-phase interlayers was obtained by quenching from the two-phase (α + β)-phase region. As a result of subsequent aging, a heterogeneous structure formed during the cellular reaction was obtained. After aging at a temperature of 800 °C for a duration of 6 hours, the heterogeneous structure consisted of nanoplatellar (α₂ + γ) colonies with an interplate distance of 0.01 microns and large-plate (α₂/β + γ) colonies with an interplate distance of 0.3 microns and a volume fraction of 5 %. An increase in the aging temperature to 850 ° C led to an increase in the interplate distance of large-plate colonies to 0.5 microns and the absence of changes in the volume fraction of 5 %. The obtained states were subjected to subsequent annealing at a temperature of 1050 ° C, which led to an increase in the interplate spacing of nanoplatellar colonies to 0.5 microns and large-plate colonies to 3.2 microns, as well as an increase in their proportion to 23 vol. % in case of aging at 800 °C. As a result of annealing after aging at a temperature of 850 ° C, the interplate distance in nanoplatellar colonies was 0.7 microns, and in large-plate colonies 4.2 microns, the volume fraction of which reached 22 %. During annealing at 1050 °C, an active α → β transformation was observed, leading to the transformation of large-plate (α₂/β + γ) colonies into (β + γ) colonies, and nanoplate (α₂ + γ) colonies into (α₂/β + γ) colonies.

The effect of controlled heat treatment at temperatures below the start of crystallization on the complex of mechanical properties of an amorphous cobalt-based alloy has been studied. The object of the study was an amorphous ribbon of the composition 83.7 % Co + 3.7 % Fe + 3.2 % Cr + 9.4 % Si, obtained by rapid quenching from a melt. The patterns of changes in the strength and deformation characteristics of the alloy depending on the temperature and exposure time of annealing after quenching have been established, and temperature ranges in which the most significant structural changes occur have been identified. The heat treatment was carried out in an air environment at temperatures of 150 – 350 °C with an exposure time of 15 – 60 min. It is shown that heat treatment has a pronounced effect on the nature of deformation curves and the ratio of strength and ductility. In the temperature range of 200-250 °C, there is an increase in relative elongation and the appearance of a stage of plastic flow, which is probably a consequence of relaxation of internal stresses, redistribution of free volume, and the formation of locally ordered clusters that prevent the unstable development of shear bands. An increase in the annealing temperature above 250 ° C and a holding time of more than 15 minutes leads to a decrease in plasticity, an increase in the tendency to embrittlement and degradation of mechanical properties due to intense structural relaxation and compaction of the amorphous matrix. The results obtained can be used to optimize the mechanical properties of cobalt-based amorphous tapes.

Kinetic estimates of the predominant formation of Cu₅Zn₈ γ-brass nanoparticles among intermetallic phases during evaporation of copper and zinc by a continuous beam of high-energy electrons followed by rapid vapor condensation in a stream of inert argon gas have been carried out. The calculated dependence of the change in the free energy of the mixing of zinc and copper components in the binary system, taking into account the addition to the formation of a new surface during crushing into nanoparticles, on the composition and particle size has a minimum that overlaps the concentration range on the Cu ‒ Zn phase diagram corresponding to γ- and β-brass; There is a vertical shift in the graph of the dependence of the free energy of mixing towards smaller (modulo) values with a decrease in the size of nanoparticles from 126 to 5 nm due to an increase in the surface contribution. It is shown that the dependence of the change in free energy on the composition of the Cu ‒ Zn mixture reflects the thermodynamics of mixing and does not determine the choice of the crystalline phase. The classical theory of nucleation is used to explain the phase composition, taking into account the interphase surface energy at the solid-embryo‒supercooled liquid-cluster interface. Calculations of the change in the free energy of crystal nucleation were carried out with the introduction of effective interphase energy for β-brass, additionally taking into account the energy costs of establishing a long-range subcutaneous order and the contribution of antiphase boundaries. The critical radii and energy nucleation barriers for γ-and β-brass nanoparticles are calculated and it is determined that with increasing supercooling of the cluster at the moment of crystallization, the critical radii and barriers decrease, and the nucleation barrier for γ-brass is significantly lower than for β-brass, due to lower energy costs for formation structure and absence of the need to establish a long-range sublattice order. The estimates obtained are in qualitative agreement with experimental data and explain the predominant formation of the γ-phase among the intermetallic phases of brass under conditions of rapid condensation.

Important aspects of the choice of material for the manufacture of equipment operated in caustic solutions at various temperatures are considered. The basic object of the study was the Nickel 201 alloy, from which the equipment of a number of enterprises specializing in the production of caustic soda was made. Due to its resistance to alkaline media, the material in question is ideally suited for use in sodium hydroxide solutions. However, the alloy has a low hardness, which significantly reduces its wear resistance. One of the significant limitations of the high-tonnage consumption of Nickel 201 alloy is its high cost. Samples of three corrosion-resistant materials (Nickel 201 alloy, high-alloy steel grades 10X23H18 and 06KHN28MDT) were tested at different temperatures (20, 80 and 100 °C) in solutions of sodium hydroxide of various concentrations (50, 60, 70 and 80 %). A special feature of these steels is the significant chromium and nickel content, which provides them with increased resistance to contact with caustic substances, as well as an acceptable cost in comparison with a nickel alloy. It was found that steel grade 10X23H18 has the highest corrosion resistance among the three materials at room temperature. This alloy can be recommended for the manufacture of equipment used in the early stages of caustic soda production at low temperatures. In hot alkaline solutions, Nickel 201 alloy is more resistant. For each material in the Statgraphics shell, an equation has been obtained that makes it possible to make a calculated prediction of their corrosion rate, including at elevated temperatures typical of caustic soda production processes. The use of this approach is designed to ensure not only a significant increase in the durability of metal equipment, but also significant savings in the material resources of the industry.

Transition metal carbides have a combination of refractory, high hardness, chemical inertia and electrical conductivity, which makes them indispensable materials for modern industry and high-tech technologies. Vanadium carbides occupy a special place among them, being a key component of wear-resistant coatings of cutting tools and alloying additives for high-strength steels. Despite the variety of synthesis methods, processes based on the reduction of oxides with active metals (Mg, Ca) remain the most promising for large-scale production. The use of metallothermy makes it possible to realize the reaction in gorenje mode, providing a significant reduction in energy consumption and synthesis time. The results of single-stage synthesis of vanadium carbide by self-propagating high-temperature synthesis in the V₂O₅ ‒ C ‒Ca system are presented. Direct measurements of gorenje temperatures have been carried out, confirming the high exothermicity of the process. The effectiveness of acid purification of synthesis products is shown, which made it possible to isolate a single-phase vanadium carbide powder V₆C₅. Using the methods of X-ray phase analysis and ultrasonic laser diffraction, the phase composition and dispersion characteristics of the obtained powders were determined. A pattern has been revealed according to which the content of impurity oxygen correlates with an increase in the size of powder particles. The results obtained prove the possibility of forming a vanadium carbide phase in one stage, which opens up broad prospects for their use in functional materials and energy devices.

A study was conducted on the modification of polymer-mineral composites based on secondary polyolefins from landfills and the addition of sand in the form of metallurgical waste. The possibility of using blast furnace sludge and dried blast furnace sludge as a partial and complete replacement for sand with a fixed ratio of polymer matrix and mineral filler was considered. A mixture of high- and low-pressure polyethylene was used as the polymer matrix. The features of the processing technology, including the stages of plasticization, granulation, re-homogenization and subsequent pressing, are considered. This ensured a more uniform distribution of the mineral phase in the volume of the composite. The effect of the ratio of sand and slag-slurry mixture on the compressive strength of the samples was evaluated. It was found that with an increase in the proportion of metallurgical components in the filler, the maximum compressive stress increases from 25.21 to 28.87 MPa. The obtained result indicates the positive effect of the slag-slurry mixture on the strength properties of the composite under the studied conditions. It is shown that blast furnace slag and sludge can be considered not only as a substitute for a part of natural mineral raw materials, but also as a functional mineral phase in the composition of polymer-mineral composites. The data obtained allow us to consider the joint use of secondary polyolefins and metallurgical waste as one of the promising areas for the disposal of industrial and household waste. The results confirm the expediency of further studies of such composites in relation to the production of oil- and gasoline-resistant plates and road surface elements that do not carry structural loads.

The structure, phase composition, and dislocation substructure of pearlite colonies of lamellar morphology of metal chips of rails of the DT400IK category made of hypereutectoid steel at a depth of 10 mm from the rolling surface after passing a tonnage of 175.9 million tons on the East Siberian Railway has been studied. The structure analysis was performed at several structural-scale levels (macro-, micro-, submicro- and nanoscale levels). It is shown that perlite colonies are bent at the macroscopic level, the presence of perlite colonies with destroyed cementite plates in steel was revealed at the microlevel, the phenomenon of fragmentation of ferrite plates of pearlite colonies was noted at the submicroscopic level, and fragmentation of cementite plates at the nanoscale level. Nanoscale (10 ‒ 15 nm) cementite particles are observed in the volume of ferrite plates, which should be attributed to tertiary cementite formed during the decomposition of a solid solution based on α-iron. They are located on the dislocation lines. It is noted that the dislocation substructure is observed only in ferrite plates. It is represented by chaotically distributed dislocations, dislocations forming clusters, and a mesh dislocation substructure. It is shown that the steel under study is characterized by the presence of internal stress fields having a purely elastic character. The sources of stress fields are intra- and interphase boundaries (boundaries between colonies of perlite and a certain set of plates within one colony, boundaries between plates of ferrite and cementite). The identified sources of internal stress fields will lead to the formation of microcracks, which in turn contribute to the premature destruction of the rail metal during operation.

The main technological features of converter melting when used for purging two-tier hydrogen tuyeres are considered. The reasons for the formation of metal slag deposits on the tuyere trunk during upper purging of the melt in heavy-duty converters are analyzed, depending on the specifics of the organization of the blast regime and the different level of foamed slag-metal emulsion in the working space of the unit. A conjugated three-dimensional mathematical model of hydrodynamic and mass transfer processes in the slag and metal phases of the converter is proposed, which can be used to study the patterns of formation and direction of melt circulation flows in a bath at the positions of a two-tier tuyere, the number of nozzles in the lower and upper tiers, the angles of inclination of the nozzles, oxygen consumption through the tiers of nozzles and other design and technological parameters. A physical model is formulated and numerical simulation of the metal purging process in a 350 ton converter is performed using a two-tiered tuyere with four Laval nozzles in the lower tip and twelve nozzles in the upper tier. The presented data make it possible to obtain reliable information about the nature of the movement of the metal and slag phases during purging in the converter and the mechanism of formation of slag-metal deposits on the tuyere trunk.

A metallographic study of the depth distribution of the visible decarbonized layer along the perimeter of R65 railway rails made from continuously cast billets with a cross section of 300 × 360 mm made of 76XF steel on a universal rail rolling mill has been carried out. It was found that the depth of the visible decarbonized layer along the perimeter of the rail profile is unevenly distributed, is in the range of 45 ‒ 184 microns and actually varies by 6 times. In the area of the rolling surface of the rail head, the depth of the decarbonized layer is only 170 microns. The lowest depth of the decarbonized layer is typical for the cutouts connecting the sole and neck of the rail profile (sections 12 and 24). The maximum depth of the decarbonized layer of 184 microns corresponds to the area 20 located in the area of the feathers of the sole of the rail profile. A comparative analysis of the data obtained with the results of previously performed work for rails obtained from continuously cast billets (steel grade E76F) shows that significant progress has been made in reducing the visible decarbonized layer in rail products of the West Siberian Metallurgical Combine branch of PJSC EVRAZ. The technical re-equipment of the enterprise ensured a reduction in the maximum depth of the visible decarbonized layer along the cross-section of the rail profile from 1000 to 184 microns, while its arithmetic mean value according to the results of measurements at 32 points along the perimeter of the profile was reduced from 346 to 123 microns, that is, 2.8 times. The unevenness of the depth distribution of the decarbonized layer was reduced from 33 to 6 (5.5 times).

The current state and development of converter steel production is largely associated with the use of various energy fuels. Based on theoretical and experimental studies, the issues of the possibility of regulating the oxidizing ability of oxygen-gas flares when purging carbon and alloy steel with varying degrees of dilution of the flare with natural gas are considered. It has been found that as the dissociation of combustion products increases, the amount of heat transferred from the purge zone to the metal volume decreases, and when purging alloy steel, the process proceeds more intensively due to the reaction of formation of chromium, molybdenum oxides and other chemical elements, which are more endothermic than the oxidation of iron to FeO. Gorenje When purging carbon steel, the average value of the degree of chemical interaction of CO₂ and H₂O with the elements of the melt is 0.69, while for alloy steel, primarily due to the presence of chromium, it shifts closer to unity (0.74), which helps to reduce the amount of heat released in the reaction zone. Adding fuel to oxygen jets and implementing oxygen gas purging is an effective way to reduce dust formation in converter melting, provides opportunities to improve the thermal balance of melting, reduces the temperature of the reaction zone and, accordingly, the development of the smoke emission process, changes the nature of oxidation and condensation of atomized metal droplets, contributing to particle coagulation and their return to the bath. To further improve the efficiency of the gas purification system, it is necessary to reduce the dust content in the exhaust gases everywhere and use various technological methods to reduce dust emission during the purge process.