In recent times, there has been significant interest in powder metallurgy, driven primarily by the active development of additive manufacturing. Consequently, a pressing task is the development of methods for producing initial metal powders that are cost-effective while meeting high consumer standards. This research is a continuation of studies on titanium powders obtained through SHS hydrogenation and thermal dehydrogenation. The titanium hydride powders, previously obtained using SHS technology, were sieved, resulting in fractions that matched the granulometric composition of titanium powders of PTK, PTS, PTM, and PTOM grades. Subsequently, the titanium hydride powder samples underwent dehydrogenation through vacuum annealing in an electric resistance furnace. Throughout the dehydrogenation process, the kinetics of hydrogen release from the titanium powder were examined as a function of particle size. The macro- and microstructure, chemical composition, and technological properties of the dehydrogenated powders were thoroughly analyzed. It was determined that the titanium powder maintained its original polygonal fragmented shape after dehydrogenation. The average particle size decreased by 5–20 %, and “satellites” were observed on larger particles. Chemical analysis revealed that larger samples contained a higher level of residual hydrogen and gas impurities (Σ 0.77 wt. %) compared to finer powders (Σ 0.26 wt. %). Regarding the study of technological properties, the resulting powders exhibited the necessary characteristics for use in titanium powder metallurgy, with the exception of low flowability due to the particle shape and microstructural heterogeneity). In conclusion, this research has demonstrated the potential of the SHS hydrogenation and thermal dehydrogenation method in producing high-quality titanium powders.

Experimental and analytical studies on gas atomization of the molten beryllium and the production of beryllium granules are presented. The impact of various factors, including the choice of gas (nitrogen or helium), the cooling gas flow rate (ranging from 300 to 650 m/s), melt temperature, and droplet size (<500 µm), on the cooling rate and granule properties, is demonstrated. It has been determined that the solidification of beryllium granules can occur through two distinct mechanisms depending on the atomization process. These mechanisms include crystallization and amorphization (glass transition). When beryllium melt is atomized with nitrogen, granules with diameters less than 100 µm solidify via the amorphization mechanism (glass transition), while those with diameters exceeding 300 µm solidify through crystallization. In such cases, a portion of granules with sizes ranging from 100 to 300 µm undergoes a mixed mechanism solidification. In this process, the surface becomes amorphous, while the central part crystallizes, resulting in the formation of a “shell” on the surface, marking the transition from the glass transition mechanism to the crystallization mechanism. The thickness of this “shell” depends on the granule diameter, measuring 10–15 µm for 300 µm granules and 20–25 µm for 100 µm granules. The findings from this research align well with the hypothesis of a glass-crystalline mechanism of beryllium granule solidification, which leads to their separation at the interfacial boundary. Such solidification through a mixed mechanism results in the creation of a removable “crust” on the granule, which is typically more contaminated with impurities. Understanding this effect opens up possibilities for practical applications in the production of specialized materials from beryllium. The ability to separate the “crust” from the “core” provides the conditions for obtaining specialized sintered beryllium grades suitable for use in nuclear reactors and foil production, where a beryllium microstructure with “clean” boundaries is essential.

This study investigates a two-stage processing approach for a charge of Pb–C composite powder material composed of lead (PS1) and graphite (GISM) powders in a high-energy mill under ambient air conditions. The study aims to determine the influence of graphite content (C_g) and mechanical activation time (τ) on the particle size distribution of the charge. The results indicate that the particle size distribution can be effectively described using the Rosin–Rammler equation. Furthermore, a correlation between the equation's parameters and the quality of the resulting hot compacted materials, as well as an index derived from the generalized desirability function, has been identified. The study delves into the mechanism behind the formation of the Pb–C powder charge during mechanical activation, which involves the creation of loosely bound agglomerates of composite particles. These agglomerates can be easily disrupted during manual processing of the charge in a mortar. Notably, the research reveals that the extremum of the particle size distribution shifts towards smaller average sizes of the Pb–C composite particles that constitute the agglomerates. The size of these formed agglomerates is shown to depend on both the graphite content in the charge and the duration of mechanical processing. Using multicriteria optimization, the study identifies the optimal values for technological factors (τ = 1.8 ks, C_g = 0.15 wt. %) for charge preparation in the two-stage mechanical processing mode. These optimal values result in an enhanced set of physical and mechanical properties for the Pb–C hot-compacted composite material, including shear strength (σ_shear = 6.3 MPa), hardness (HRR = 109), and electrical conductivity (L = 1.812 Ω^–1) of Pb–C. X-ray diffraction analysis conducted during the study reveals the formation of lead oxides during the mechanical activation of the Pb–C charge. Additionally, it indicates an increase in the half-width of the diffraction profile of lines (111) and (222), which subsequently decreases after the hot-compaction process. Comparative data involving the use of lead-based chip waste and lead powder-based composites are also presented in the study. These data suggest that a lower optimum graphite content is required for lead powder PS1 (C_g = 0.15 wt. %) compared to chip waste (C_g = 0.5 wt. %).

The carbon fiber (CF) of UMT 49-12K-ER grade, manufactured by Alabuga-Volokno LLC (Umatex JSC), was the subject of an extensive study. This investigation encompassed an analysis of its physico-chemical properties. The interplanar dimensions and chemical composition of the CF were determined using X-ray diffraction and atomic emission spectroscopy. Surface properties of the CF, including specific surface area and pore size distribution, were investigated through nitrogen adsorption. The BET specific surface area was measured at 0.29 m²/g. The volume of mesopores and their size distribution were calculated using the Barrett, Joyner, and Halenda method. Additionally, an analysis of surface functional groups was conducted through a back titration method. It was observed that there was no presence of carboxyl, phenolic, or carbonyl groups. The diffraction patterns were processed with a two-component profile description model. The results of atomic emission spectral analysis revealed that silicon compounds were the dominant impurities in the chemical composition of the CF. Further investigations determined that, in an inert environment, the epoxy coupling agent used to enhance the performance properties of this CF undergoes thermal decomposition at temperatures of 300–400 °C. The CF itself does not experience weight loss when heated up to 950 °C. It was also discovered that this CF ignites in the presence of oxygen at temperatures exceeding 550 °C, surpassing the thresholds noted in previous publications for carbon fibers without such specialized additives. The results of this research have suggested new methodologies for studying carbon fibers.

This study investigated the hardness of lamella with varying thickness, obtained from a massive, fine-grained cemented carbide comprising WC–6 %Co–0.2 %TaC, characterized by an average grain size of approximately 5 μm. The picoindentation method was employed for this analysis. Picoindentation was carried out using a Berkovich diamond indenter with a radius of curvature around 50 nm, and the experimental data were analyzed using the Oliver–Pharr model. The results revealed a significant correlation between hardness and lamella thickness. The hardness of the electron transparent section (thickness less than 100 nm) of the lamella measured 11.3±2.8 GPa, while the electron nontransparent section (thickness more than 200 nm) exhibited a hardness of 20.8±1.2 GPa. The lower hardness in electron transparent objects (thickness ~100 nm) is likely attributed to a combination of factors, including the potential bending of thin cobalt layers, the presence of edge effect, and closely spaced structural defect dislocations on the lamella surface. In situ TEM studies were conducted to examine structural transformations during the heating of WC–6 %Co–0.2 %TaC lamella, including in the presence of oxide phases (WO_x). Oxide phases on the lamella’s surface were generated by oxidizing the lamella at 200 °C in an air atmosphere. The results indicated that heating up to 500 °C did not bring about significant changes in the structure. However, at 600 °C, there was a notable thinning of cobalt layers due to intense surface diffusion of cobalt. Simultaneously, the formation of nanosized particles of the Co₃W₃C phase, ranging in size from 5 to 20 nm, was observed in the binder.  These particles resulted from a shift in the equilibrium phase composition of the carbide, changing from a two phase region (WC + γ) to a three phase region (WC + γ + Co₃W₃C) as a consequence of the lamella’s oxidation.

It is well-known that chromium in metallic compositions forms dense passivating films that slow down corrosion. The new Fe–Cr–Cu coating was applied on St3 steel through electrospark deposition in an anode mixture consisting of copper and titanium granules, with the addition of chromium powder ranging from 4.85 to 13.26 wt. %. The weight gain of the cathode increased nearly twofold with the addition of chromium powder to the anode mixture. The structure of the coatings was analyzed through X-ray phase analysis, scanning electron microscopy, and energy dispersive spectrometry. The phase composition of the coatings consists of ferrochrome and copper. It is demonstrated that the proposed method of electrospark processing allows for the creation of Fe–Cr–Cu coatings with an average chromium concentration ranging from 55 to 83 at. %. The average copper content in the prepared coatings varied from 5 to 16 at. %. The highest concentration of chromium was observed in the coating prepared with the addition of 13.26 wt. % Cr to the anodic mixture. The corrosion behavior of the coatings was investigated using potentiodynamic polarization and impedance spectroscopy in a 3.5 % NaCl solution. Polarization tests have shown that applying Fe–Cr–Cu coatings to St3 steel can increase its corrosion potential by 12 to 19 % and reduce the corrosion current by 1.5 to 3.4 times. The microhardness of the coating surface ranged from 3.08 to 4.37 GPa, and the coefficient of friction ranged from 0.75 to 0.91. The maximum hardness and the lowest coefficient of friction were observed in the coating with the highest chromium content. It has been demonstrated that Fe–Cr–Cu coatings can enhance the wear resistance of the surface of St3 steel by 1.5 to 3.8 times.

This study considers the formation of an alloyed nickel aluminide structure through automatic electric arc surfacing employing an oscillating electrode composed of composite wire. The arc transversely traverses the weld pool surface at a frequency denoted as f. In comparison to conventional surfacing techniques, this process either displaces the crystallization front alongside the weld pool (at f  = 1.3 Hz) or stabilizes it (at f  ≥ 2 Hz) throughout the cross-sectional area of the coating layer. We have conducted an investigation into the evolution of alloy structures resulting from surfacing. Notably, we have observed that the regions with concentrations of eutectic nickel-aluminum are particularly susceptible to structural alterations. The formation of particle clusters, which is contingent upon heat dissipation conditions near the crystallization front, leads to the development of layered texture regions. Our findings reveal that following 50 thermal cycles (heating to 1100 °C, cooling to 25 °C), the alloy's hardness becomes independent of subsequent thermal cycles, consistently maintaining a level 34–35 HRC. The highest resistance of the surfaced metal to thermal fatigue cracks is achieved when its structure exhibits an optimal  γ-solid solution (relatively ductile) to nickel-aluminum cooling martensite ratio, corresponding to the Ni₂Al phase. The thermal conditions necessary for producing such a structure are elucidated by the gradual cooling of the crystallized metal from elevated temperatures when f  ≥ 2.8 Hz. An analysis of changes in oxidative wear, estimated by mass loss, during thermal fatigue tests conducted at a metal heating temperature of 1100 °C revealed the superiority of the studied alloy over industrial alloys based on nickel and cobalt.

Article for the 90^th anniversary of Academician of the Russian Academy of Sciences Vladimir Nikitovich Antsiferov is dedicated to the stages of development of a scientist, the history of the creation of the largest Scientific Center for Powder Materials Science in Russia, and the achievements of his scientific school. The activities of V.N. Antsiferov as director of the Scientific Center, professor and head of the department of the Perm National Research Polytechnic University is shown, as well as the most important scientific developments of the scientist and the team he leads in the field of powder metallurgy and materials science for the aerospace complex, mechanical and instrument engineering, oil production, medicine and other industries.