A two-phase powder alloy based on substitutional solid solutions with BCC and FCC lattices was obtained by highintensity mechanical treatment (HMT) of a multicomponent Fe–Cr–Co–Ni–Ti powder mixture. Sample sections and particles of mixtures obtained were studied using an ultra high resolution field emission scanning electron microscope by scanning electron microscopy. XRD patterns of mixtures were recorded on the DRON 3 diffractometer with FeK_α and CuK_α radiation. It was found that after 10 minutes of HMT one intense superposition reflection remains on the XRD pattern with the angular position corresponding to Reflections 111 and 110 of phases with FCC and BCC lattices, respectively. A spark plasma sintering (SPS) method was used to obtain compact high-entropy material samples from the mixture after 90 minutes of HMT at 800 and 1000 °C. Their specific electrical resistance and density as well as the dependence of these properties on the sintering temperature were determined. It was demonstrated that the substitutional solid solution with the BCC lattice is probably enriched with titanium during the powder alloy SPS process.

Two variants of the self-propagating high-temperature synthesis process, namely SHS from elements and SHS metallurgy, were combined to obtain cast materials based on the MAX phases of Cr₂AlC and (Cr_0,7Ti_0,3)₂AlC. Experiments involved mixtures with compositions calculated according to the chemical scheme 70%(Cr₂O₃ + 3Al + C)/(2Ti + Al + C) + + 30%(3CaO₂ + 2Al). Synthesis was carried out in a 3 l reactor at an argon pressure of 5 MPa. The structure and phase composition of the reaction product were studied by X-ray diffraction and scanning electron microscopy. It was found during the research that the ratio of original reagents has a significant effect on the synthesis parameters and phase composition of desired products. The possibility of obtaining a cast material based on the titanium-doped Cr₂AlC phase was shown. It was found that the resulting product is a composite material based on the (Cr_1–хTi_х)₂AlC (х = 0,18÷0,28) phase, and the content of this phase is 43–62 wt.% depending on the original ratio of reagents. The material microstructure features by the presence of laminate layers with carbide grain inclusions. The end product contains carbide (Ti_0,9Cr_0,1C, Cr₇C₃, Cr₃С₂)and intermetallic (Al₈Cr₅, AlTi₃)  impurities due to the insufficient life time of a melt formed in the combustion wave.

Polyimide coatings currently provide the highest performance properties of quartz fibers. The purpose of this research is to determine the strength, hardness, dynamic fatigue, performance period and crack resistance of optical fibers with polyimide coatings. The strength limit of fibers determined by the method of axial stretching over the distance between capstans of 500 mm was 4.8–6.0 GPa at a loading speed of 10–500 mm/min. W. Weibull distribution curves were plotted in coordinates that relate the probability of failure to the strength, fiber length, and parameter describing the ultimate strength. The dynamic fatigue parameter n was found, which in physical sense corresponds to the slope tgα equal to 1/(1+n) in double logarithmic coordinates. Hardness and crack resistance values of quartz fibers were measured by indentation. Crack resistance K1c was calculated using the A. Niihara semi-empirical dependence, which connects the indentation size, radial crack length, and crack resistance. The initial crack length was calculated and the size of the characteristic defect was determined using scanning electron microscopy. Thermogravimetric analysis demonstrated that polyimide coated fibers maintain thermal stability up to 450 °С. The service life of optical fibers was determined based on the dynamic fatigue data, and it amounted to at least 25 years at a load of 0.2 GPa. The greater the difference between the lower strength level and the upper one in the stretch tests of fiber segments, the higher the distribution parameter m describing the ultimate strength of optical fibers. The values of this parameter are determined by the fiber quality: m = 50÷100 for coated fibers and m = 1÷5 for uncoated ones.

The powder metallurgy method including mechanical activation of powders in a planetary mill and spark plasma sintering at 1470 °C in an inert atmosphere was used to obtain NiAl–45vol.%Al₂O₃ cermet samples with the addition of nanoparticles of magnesium aluminum spinel in an amount of 0.05 vol.%. The features of their microstructure were investigated. Spinel nanoparticles are located at the boundaries between the grains of composite components. The results of X-ray phase analysis at t = 25 and 800 °C were obtained. The main components of the material at t = 20 °C are α-Al₂O₃ and NiAl. The dependence of internal friction on temperature in the range of 20–900 °C was studied, and the influence of magnesium aluminum spinel nanoparticles on the nature of its change was established. The internal friction curve shows that vibration damping occurs up to 600 °C. Dependences of the ultimate bending strength of cermets at t = 20÷750 °C were determined. The positive effect of introducing a small amount of magnesium aluminum spinel on the elastic properties of composites was established. The best mechanical properties were demonstrated for NiAl–42vol.%Al2O3–0.05vol.%MgAl₂O₄ samples. On average, the ultimate bending strength of this material was 8–15 % higher compared to samples without nanoparticles. The materials obtained in this research had an ultimate bending strength under normal conditions of 460–490 MPa. A summarizing analysis of NiAl–Al₂O₃ cermet researches was carried out to determine the nature of the ultimate bending strength dependence on the ratio of components. It was found that it has an extreme nature: the maximum is observed when using the ratio of aluminum oxide to aluminum nickel equal to 0.5.

The study covers the process of carbon-graphite – lead composite formation by impregnating a porous AG-1500 scaffold with a lead melt containing 2.0 at.% Cu. The paper describes the kinetics of filling the carbon-graphite open porosity with molten metal with the continuously heated furnace and impregnating device. A feature of this method is the volumetric expansion of the lead alloy impregnating porous carbon-graphite. It is placed in a sealed steel container filled with lead by 2/3 of its volume with further vacuuming, melt adding and sealing. Then the device is placed in the furnace so that the lead-copper alloy, already having a temperature below the liquidus temperature by 20–30 °C when heated in the furnace to 900 °C, impregnates the carbon-graphite scaffold with further expansion at constant heating. Porous scaffold capillaries are filled as the melt temperature continuously increases. Once graphite-carbon impregnated with lead alloy is taken out, it was investigated using X-ray spectral and energy-dispersive analysis. It was found that the elements of the impregnating alloy were redistributed at the carbon-graphite scaffold/Pb alloy interface depending on its initial composition. During the carbon-graphite scaffold impregnation with the Pb–2%Сu alloy under a pressure of up to 5 MPa, copper redistribution occurs on its inner pore surface and the boundary with the alloy, which leads to the formation of an interphase layer containing 70 % Cu. The conducted research made it possible to obtain a composite with a copper content of 1.85 at.% in the impregnating Pb alloy at the interface with carbon graphite.

The paper studies methods for obtaining a multilevel gradient porous material by the layer-by-layer sintering of distributed α-Fe₂O₃ nanopowders and submicron powders. Nanopowders with an average particle size of 12 nm were obtained by the coprecipitation method, and submicron powders, which are hollow spheres, were obtained using the spray pyrolysis method. Powders were consolidated by sintering in a muffle furnace, hot pressing, and spark plasma sintering (SPS) at various temperatures, loads, and holding times. It was shown that muffle furnace sintering and hot pressing methods cannot provide a compact of enough strength due to the different activity of nanopowders and submicron powders. Powder materials were obtained by spark plasma sintering when holding at 700, 750, 800, and 900 °С for 3 min. It was found that a series of samples obtained by SPS at 750 °С has sufficient strength and open porosity of 20 % with a total porosity of 37 %. Rising temperature in this method leads to an increase in the particle size in the nanopowder volume to a micron size and partial destruction of hollow submicron spheres. It was found during the study that the phase composition of samples obtained is identical to the phase composition of initial powders. However, for a series of samples obtained by hot pressing and SPS in the nanopowder volume, there is a directed growth of crystals towards the highest electrical and thermal conductivity [001] along the punch axis. This is due to the temperature gradient between the powder volume and punches and the lowest value of the plane surface energy (110), which includes direction [001].

Pulsed magnetron sputtering of a TaSi2 ceramic target 120 mm in diameter was used to deposit coatings on model silicon substrates at a gas flow rate ratio of Ar/N₂ = 1/2 and frequencies of 5, 50, and 350 kHz. The structure and composition of coatings were investigated using scanning electron microscopy, energy dispersive analysis and glow discharge optical emission spectroscopy. The phase composition was determined by X-ray diffraction analysis using CuKα radiation. Mechanical properties were measured by the nanoindentation method using a Nano Hardness Tester equipped with a Berkovich indenter at a load of 4 mN. The heat resistance of coatings was evaluated by isothermal annealing in the air in a muffle furnace at 1200 °С, and oxidation resistance was estimated by the structure and thickness of the oxide layer. The results of structure studies have shown that the coatings are X-ray amorphous and have a dense homogeneous structure. Increasing the frequency from 5 to 350 kHz led to a decrease in the thickness and growth rate of the coatings. Samples deposited at 5 and 50 kHz showed high mechanical performance: hardness at the level of 23–24 GPa, elastic modulus of 211–214 GPa, and elastic recovery of 75–77 %. The coating obtained at the maximum frequency had a hardness of 15 GPa, elastic modulus of 138 GPa, and elastic recovery of 65 %. Annealing led to the formation of protective SiO₂, Ta₂O₅, TaO₂ oxide layers. A pronounced crystallization of the TaSi2 phase was observed, which is confirmed by the X-ray diffraction analysis data. Samples deposited at 5 and 50 kHz showed a small oxide layer thickness of 0.9 and 1.1 μm, which indicates the good heat resistance of coatings at 1200 °С.

The study covers the influence of bipolar pulsed regime parameters of titanium plasma electrolytic oxidation (PEO): voltage (U), pulse duration (t) and pause duration between pulses on the structure and morphology of TiO2 coatings doped with Ca and P. Threshold values of voltage (U1) and positive pulse duration (t1), which led to pore-free coating formation, were determined. It was shown that an increase in U1 leads to an increase in pore size and Ca and P concentration in the TiO2 coating. A relationship between rutile content in the coating and Ca and P concentrations was identified. It was found that the size and distribution of pores depend ont1. A structure with fine pores evenly distributed over the sample area is formed during a short positive pulse. An increase in t1 leads to the formation of a structure with unevenly distributed large pores. An increase in the values of U2 and t2 leads to a decrease in Ca and P concentrations and rutile content in the coating. It was shown that the surface of PEO TiO2 coatings ensures the growth of crystallites of (Ca, P)-containing phases when kept in a simulated body fluid solution. It was found that the amount of an apatite-like layer depends on the content of Ca and P in the TiO2 layer, as well as the size and distribution of pores.