Experimental data on increase of plastic properties in forging from austenitic class steel of 10Х16Н20М2Т grade are given. It is established that the increase of plastic properties practically without change of strength properties is influenced by homogenization annealing carried out at the temperature of 1250°C with 40 hours exposure time, providing dissolution of carbides, carbonitrides and titanium nitrides.

The paper considers the kinetics of formation of coatings based on chromium carbides obtained by the technology of complex chemical thermal treatment (CTT) on steels St3, 40Kh, 40Kh13, 12Kh18N10T. CTT consisted in preliminary cementation in vacuum and subsequent diffusion alloying with chromium in the medium of fusible liquid metal solutions (DALMS). As a result of the research, it was found that the concentration of chromium on the surface of the coated samples, the coating thickness and chromium distribution, the phase composition of the coatings were influenced by the material grade, temperature and duration of DALMS. The coatings consisted of Cr₇C₃ carbides or Cr₇C₃ + Cr₂₃C₆. The release of Cr₂₃C₆ chromium carbides was observed at DALMS temperatures of 1050°C and 1070°C in the range of 180 to 480 minutes.

The patterns of the formation of submicrocrystalline structure of the grain type and copper properties under conditions of intensive plastic deformation and subsequent processing of hydroextrusion with varying degrees of deformation have been studied. It was established that with an increase in the degree of single-stage hydroextrusion to ε = 1.2, the strength level of copper M0b does not increase compared to its strength after equal-channel angular pressing. This indicates the beginning of the return processes and dynamic recrystallization of the material, which is confirmed by structural studies using electron microscopy and radiographic analysis.

A heat treatment regime has been justified and developed that reduces the hardness of the Cr–33Ni– W–V–Ti alloy and improves its machinability by cutting. The influence of the composition of the Cr–50Ni–W– Mo–Ti–Nb–Al alloy on cold plasticity are established. It has been shown that an increase in ductility is achieved with a lower content of elements forming the α-phase with a bcc lattice and the strengthening phases Ni₃Ti and Ni₃Al.

In the macrostructure of products manufactured from powder obtained by the PREP (Plasma Rotating Electrode Process) method, when conducting macrostructure control, it is sometimes possible to observe zones of different etchability. Studying the microstructure in the zone containing both light and dark areas showed that in terms of grain size and shape it is typical for products manufactured by the powder metallurgy method, however, grains from dark areas have clearly defined boundaries due to the increased content of carbides. Additional carbides are formed during the coking of sublimates at the stage of gas-static treatment. The finished product inherits zonal heterogeneity caused by a gradual increase in the amount of sublimates of lubricants in the atmosphere of the spray chamber.

The paper studies properties of a suspension with aluminum oxide powders in a photopolymer composition developed for laser stereolithography. It is shown that the modified photopolymer IPLIT4 is the optimal choice in the manufacture of suspensions for the additive manufacturing of ceramic parts by stereolithography. Pastes with a ceramic filler content of 72% by weight were obtained. The possibilities of terahertz diagnostics of polymer ceramic and ceramic materials at different stages of the production process are demonstrated.

Ti–ZrB₂ coatings on titanium alloy Ti–6Al–4V were prepared by the method of electrospark deposition with a non-localized electrode, using titanium granules and ZrB₂ powder. It was found that the structure of the coatings corresponds to a metal-ceramic material, where α-Ti and β-Ti act as a metal matrix, and ZrB₂ is a reinforcing phase. The concentration of ZrB₂ in coatings was in the range from 38 to 92%. It was shown that with an increase in the concentration of ZrB₂ in coatings, their hardness increased monotonously from 10.79 to 15.86 GPa. With an increase in the ZrB₂ content, the average wear of the coatings was monotonously reduced. This indicates the good wettability of ZrB₂ particles by titanium melt.

The article presents the results of a comprehensive study of the main performance properties of tungsten-containing galvanic coatings Ni–W, Co–W and Ni–P–W, hardened by heat treatment. It is shown that for binary alloys, heat treatment at 600°C is optimal, which allows achieving maximum wear resistance. For the ternary system, it is advisable to use annealing at 350°C. As a result of annealing, all the studied coatings have high adhesion. It is concluded that to ensure wear resistance of machine parts, it is advisable to use Co–W coatings, and for protection against wear and corrosion in salt water, the most acceptable coating is Ni–P–W.

The paper presents a comparative study of the influence of the parameters of electrochemical deposition of Ni–P coatings on their composition and current efficiency when deposited from pyrophosphate and citrate electrolytes. It was shown that both electrolytes are suitable for depositing Ni–P coatings on complex-shaped products. A comparison of the properties of coatings of different compositions obtained from these electrolytes was carried out. To obtain harder coatings, it is advisable to use a pyrophosphate electrolyte; however, due to microcracks development in coatings with a phosphorus content of 12 wt. % or more, it is unsuitable for corrosion protection. For this purpose, it is advisable to use a citrate electrolyte, which ensures porosity of the coatings even with a phosphorus content of 12 wt. %.

The influence of pulsed galvanostatic electrolysis modes (unipolar and reverse) on the corrosion resistance and functional properties of eco-friendly tin-zinc (Sn–Zn) alloy coatings was investigated. An alkaline solution with sodium citrate and sodium lauryl sulfate additives was used as the electrolyte. The unipolar mode (5 ms, 1.5 A/dm²) provided high current efficiency (72%) and microhardness (950–1050 MPa) but increased porosity (7–12%). The reverse mode (5 ms cathodic/anodic phases, 2.0/0,5 A/dm²) demonstrated minimal porosity (2–4%), reduced internal stresses (50–80 MPa), and maximum corrosion resistance (>1200 hours in salt spray). It was established that the anodic phases of the reverse mode level the surface, reducing defects. Pulsed technologies have surpassed stationary electrolysis in wear resistance (2–3 times), microhardness (+15–25%), and solderability (wetting angle 12–18°). The reverse mode is recommended for marine electronics and aviation, while the unipolar mode is suitable for tasks prioritizing microhardness. The results contribute to the development of eco-friendly alternatives to toxic coatings in compliance with RoHS/REACH directives.

The paper studies the effect of halloysite nanotubes of three grades on changes in the physical, mechanical and tribological properties, as well as the structure of polytetrafluoroethylene. Halloysite is a kaolinite rolled into a tube and has the chemical formula Al₂[Si₂O₅](OH)₄. The studied halloysite grades differ in textural characteristics and phase composition. It is shown that composites reinforced with halloysite demonstrate a significant decrease in the wear rate of polytetrafluoroethylene (by 400 times) while maintaining a low friction coefficient (~0.20). With an increase in the halloysite content to 5 wt. %, the elastic modulus of the material increases significantly. It is shown that the introduction of halloysite grade ANT 811 improves the relative elongation by 9 times and wear resistance by 6 times compared to halloysite grade ANT 3810. Changes in wear resistance and

A new method of pressing composites modified with carbon fillers is presented, with additional complex impact of ultrasonic vibrations at 17 kHz and superimposed low-frequency amplitude modulation at 100 Hz. Thus, impact of this kind made it possible to reduce the intensity of mass wear of composite samples under dry friction by 1000 times compared to polytetrafluoroethylene samples and at the same time maintain the friction coefficient of the original polymer. It is shown that ultrasonic vibrations promote disaggregation of nanosized particles, and simultaneously superimposed low-frequency amplitude modulation leads to an ordered distribution of the filler in the polymer matrix. This mode ensures the production of a defect-free structure due to compaction of the composite mixture and helps to eliminate pores and cracks in the volume of the material.

The effect of wollastonite on the properties of polymer composite materials (PCMs) based on polytetrafluoroethylene (PTFE) was investigated. New composite formulations were developed with wollastonite content ranging from 0.1 to 2 wt. %. It was found that the incorporation of wollastonite enhances the mechanical properties of PCMs, resulting in a 35% increase in tensile strength and a 47% improvement in elongation at break. Moreover, the wear resistance of the composites increased by 67-fold compared to pristine PTFE. The investigations were further supported and correlated with thermodynamic and structural analyses. The supramolecular structure of PTFE changes from a ribbon-like to a spherulite-like morphology upon the addition of wollastonite. IR-spectroscopy confirmed the formation of secondary structures derived from oxidized functional groups. Thermodynamic studies revealed that increasing the wollastonite concentration in PCMs led to higher crystallinity and melting enthalpy values.

Microencapsulation of corrosion inhibitors allows increasing the efficiency of modification of polymer composite coatings, increasing their corrosion resistance over a long period. The selection of an inert carrier, which constitutes a solid base of a functional particle, remains an urgent task. The paper considers the features of solid carriers of functional additives, which are used to obtain microcapsules. The kinetics of release of an inhibitory agent was studied by a spectrophotometric method with the construction of a calibration graph. It was found that activated aluminum oxide showed the highest loading of the inhibitory agent and a longer release time among the considered carriers.

The strength properties of unsaturated polyester resin grade PN-609-21M were studied depend-ing on the concentration of two types of silicon dioxide, as well as their influence on the technological prop-erties of the resin.

The effect of polysulfones of the PSF-150 and PSF-180 grades as a thermoplastic modifier on the impact strength of epoxy resin ED-20 in the temperature range from –60 to 20°C was studied. The evolution of the structural and morphological organization of the epoxy composition with an increase in the concentration of polysulfone was studied using scanning electron microscopy. It was shown that at a concentration of 20 phr, a phase structure is formed in which thermoplastic polysulfone becomes a continuous matrix, which provides a significant increase in impact strength in a wide range of temperatures, including extremely low values down to –60°C.

The paper presents the study of the structure of the deposited metal Fe0.09C31Cr8NiN2Mo at different cooling rates. The research was carried out using the EBSD analysis method in the initial state after surfacing. The effect of post weld heat treatment on the resulting percentage of γ/σ phases in the deposited metal, depending on the percentage of γ/σ phases in the before heat treatment state is considered. The ways of improving the performance characteristics of the metal deposited with materials such as Fe0.09C31Cr8NiN2Mo to a temperature of 350–400°C are proposed.

The    paper    presents    results    of    metallographic    examinations,    measurement    of    microhardness    and analysis    of    diffraction    of    back    scattered    electrons    in    a    zone    of    fusing    of    the    anticorrosive    cladding,    which    was executed    in    the    pulse    inert    gas    on    heat    resistant    Cr–Mo–V    steel    by    metal    arc    welding.    Interrelation    of    distri bution    of    values    of    microhardness    on    the    metal    of    underclad    zone    with    its    structure    of    parameters    of    PWHT is    established.

Various types of specimens machined from fuel claddings are   considered and methods of their tests are analyzed. The   disadvantages and advantages of existing methods are  considered from point of view of obtaining adequate   mechanical properties for highly embrittled materials. On the    basis of the performed analysis and calculations the new ring   specimen is proposed and the method of its testing and   processing of experimental data is developed which takes   into account the friction between the loading device and   speci men and allows determining the mechanical properties   and obtaining the true stress-strain curve for fuel clad ding   materials.

The numerical and experimental verification is   performed of the proposed method for determination of standard mechanical properties and   the true stress-strain curve for fuel cladding  material by ring specimens testing and FEM   modeling of their loading (see Part 1 of the   article). The tests results of the proposed ring  specimens are represented for EP823 steel (12Cr-Mo-W-Si-V-Nb-B) in the initial and irradiated states  over a wide temperature range when using various lubricants and without lubrication. Based on the obtained results of these tests, the mechanical properties and true stress-strain curves are  determined for EP823 steel.