This study presents a comparative investigation of the density, phase composition, magnetic, and mechanical properties of isotropic powder metallurgy alloys Fe–28Cr–15Co and Fe–32Cr–22Co doped with 2 wt. % titanium introduced either as conventional titanium powder (PTS-1 grade) or as titanium hydride powder. The sample fabrication process included powder blend prepa­ration, compaction, vacuum sintering, quenching, and heat treatment aimed at developing magnetic properties. The use of titanium hydride powder resulted in an increase in residual porosity from 2 to 4 %. A significant difference in the phase composition of the alloys after sintering was observed: the structure of the Fe–28Cr–15Co–2Ti alloy consisted of a BCC α-phase solid solution and tetragonal σ-phase inclusions, while Fe–32Cr–22Co–2Ti exhibited a σ-phase solid solution matrix with FCC γ-phase inclusions. After heat treatment, all alloys deve­loped a BCC α-phase solid solution structure. In the samples containing titanium hydride, minor traces of an impurity phase – most likely a hydride of a titanium–chromium intermetallic compound – were also detected. Samples prepared using PTS-1 titanium powder exhi­bited higher residual induction values (B_r up to 0.84 and 0.82 T for Fe–28Cr–15Co–2Ti and Fe–32Cr–22Co–2Ti, respectively) compared to those containing titanium hydride (up to 0.80 and 0.79 T, respectively), which is attributed to diffe­rences in residual porosity. On the other hand, samples with titanium hydride powder showed higher coercivity values (H_c up to 41.1 and 57.2 kA/m for Fe–28Cr–15Co–2Ti and Fe–32Cr–22Co–2Ti, respectively) compared to those with titanium powder (up to 38.4 and 49.2 kA/m, respectively). The maximum energy product ((BH)_max) reached 11.0–11.5 kJ/m³ for Fe–28Cr–15Co–2Ti and 14.0–14.5 kJ/m³ for Fe–32Cr–22Co–2Ti, with virtually no dependence on the titanium source. The compression stress–strain curves for alloys with different titanium sources were nearly identical. Alloys of the Fe–32Cr–22Co–2Ti composition exhibited higher yield strength values (σ_0.2 = 1200–1400 MPa) compared to Fe–28Cr–15Co–2Ti alloys (σ_0.2 = 1000 MPa). All materials studied in this work demonstrated ductility.

This study presents the results of research on optimizing powder mixing parameters for the Al–15Sn–5Pb (vol. %) system for application in selective laser melting technology. The primary focus is on ensuring the uniform distribution of soft-phase particles (Sn and Pb), which is essential for obtaining products with a homogeneous structure and improved tribological properties. The initial materials used in the study were aluminum (ASD-1), tin (PO-1), and lead (PS-1) powders. Before mixing, the powders were sieved using mesh sizes ranging from 50 to 25 µm. The sieved powders had a nearly spherical shape and good flowability characteristics (less than 25 s / 50 g). The effect of mixing time on the homogeneity of the powder mixture was studied using the discrete element method and a modified Hertz–Mindlin model. The obtained mixtures were analyzed using X-ray phase analysis, micro-X-ray spectral analysis, and graphical analysis methods. Subsequent experimental validation confirmed the reliability of numerical calculations and enabled the assessment of optimal mixing parameters. It was established that the optimal mixing time for achieving a uniform distribution of the initial powder particles falls within the range of 60 to 120 min. It was also found that the complex motion pattern of a Turbula-type mixer reduces the impact of gravitational segregation, thereby improving the uniform distribution of soft-phase particles (Sn + Pb). The proposed approach can be used for developing new powder preparation methods for additive manufacturing technologies and for creating composite materials with enhanced performance characteristics.

The addition of graphite particles to aluminum improves its tribological properties due to the self-lubricating effect, while reinforcement of such aluminum matrix composites (Al–C) with the ceramic phase of titanium carbide (TiC), known for its high hardness and strength, results in Al–TiC–C hybrid composites with enhanced physical and mechanical properties and improved wear resistance. This study explores a novel energy-efficient approach to fabricating Al–TiC–C composites by combining self-propagating high-temperature synthesis (SHS) of porous TiC–C composite frameworks with subsequent spontaneous infiltration using molten aluminum. The titanium carbide was synthesized from a stoichiometric powder mixture of titanium and graphite (Ti + C). To introduce free carbon, additional graphite powders with particle sizes of 10–15 and 100–1000 µm, as well as chopped carbon fibers with a diameter of 7 µm and a length of 3 mm, were added to the stoichiometric mixture. The microstructure and composition of the resulting composites were examined using scanning electron microscopy with energy-dispersive spectroscopy and X-ray diffraction analysis. Density was measured by hydrostatic weighing, while Brinell hardness, compressive strength, and tribological properties were evaluated using a pin-on-disk tribometer. It was found that fine graphite particles (10–15 µm) dissolved almost completely in molten aluminum, whereas coarse graphite (100–1000 µm) and carbon fibers remained intact. The compressive strength of the carbon-containing aluminum matrix composites ranged from 203 to 233 MPa. Under dry sliding conditions, abrasive wear was the predominant wear mechanism, accompanied by a high coefficient of friction (0.88–0.98); however, the wear rate of the composite containing coarse graphite was three times lower.

Composite materials based on aluminum alloys reinforced with a highly dispersed titanium carbide phase demonstrate enhanced antifriction properties, allowing them to be classified as promising tribotechnical materials. One of the most accessible and efficient methods for producing such composites is Self-Propagating High-Temperature Synthesis (SHS), which relies on the exothermic reaction between titanium and carbon precursors directly in the aluminum melt. This process enables the synthesis of a carbide phase with particle sizes ranging from 100 nm to 2 μm. The present study investigates the set of performance and processing characteristics of composites obtained via SHS of titanium carbide in melts of the industrial piston alloys AM4.5Kd and AK10M2N, aiming to assess their potential application as antifriction materials for manufacturing engine pistons. A comparative analysis was conducted on both the base alloys and the composite materials produced from them, after heat treatment including quenching and artificial aging under heat treatment conditions ensuring maximum hardness. The results demonstrated that in the AM4.5Kd–10 % TiC composite, the wear rate decreased by a factor of 2.4, the friction coefficient decreased by a factor of 2.7, and scuff resistance improved by a factor of 1.7 compared to the matrix alloy. In the AK10M2N–10 % TiC composite, the wear rate decreased by a factor of 17 and the friction coefficient decreased by a factor of 4, while maintaining the same level of scuff resistance as the matrix alloy. Both materials exhibited thermal self-heating during friction, a thermal linear expansion coefficient at 300 °C, heat resistance at 250 °C, fluidity, and linear shrinkage comparable to those of the matrix alloys (with variations within 10 %). The obtained data support the recommendation of these composites for use in the production of cast engine pistons as replacements for the original alloys.

This study investigates the dependencies between contiguity and hardness in nanostructured and ultrafine-grained tungsten-cobalt cemented carbides and tungsten carbide samples fabricated using spark plasma sintering (SPS) and liquid phase sintering (LPS). The main microstructural parameters were determined: average WC grain size, grain contiguity, and mean free path in cobalt. The average WC grain size in tungsten-cobalt cemented carbides produced by spark plasma sintering does not exceed 0.2 µm, classifying them as nanostructured materials. In cemented carbides obtained by liquid phase sintering and tungsten carbide fabricated using spark plasma sintering, the average WC grain size ranges from 0.2 to 0.5 µm, which corresponds to ultrafine-grained materials. The applicability of existing models developed for medium- and fine-grained cemented carbides was analyzed to describe the dependencies of contiguity on the cobalt volume fraction in the obtained ultrafine-grained and nanostructured materials. It was found that an exponential dependence adequately describes this relationship for the samples sintered in this study. The applicability of the theoretical hardness dependence on key microstructural parameters was also analyzed. The hardness of the obtained alloys was lower than predicted by the theoretical dependence based on the Hall–Petch law. The highest hardness (HV = 2260 ± 30) among all the samples was observed in the nanostructured WC–5Co–0.4VC–0.4Cr₃C₂ alloy produced by spark plasma sintering. The hardness of ultrafine-grained sintered tungsten carbide was slightly lower (HV = 2250 ± 20).

Research on novel metalloceramic coatings that combine high-temperature oxidation resistance and wear resistance remains a relevant topic. Ni–Al–Fe coatings reinforced with varying amounts of tungsten carbide were synthesized for the first time using electric spark deposition on 35 steel. Their structure was analyzed using X-ray phase analysis and scanning electron microscopy. The average thickness of the WC/Ni–Al–Fe coatings ranged from 23 to 33 μm. The identified phases included AlNi, (Fe, Ni), α-WC, and W₂C. The coating microstructure exhibited reinforcing tungsten carbide inclusions with diameters ranging from 1.49 to 10.12 μm. The corrosion behavior of coated samples was studied using potentiodynamic polarization and impedance spectroscopy in a 3.5 % NaCl solution. The coatings’ high-temperature oxidation resistance was evaluated at 700 °C for 110 h under natural aeration conditions. Wear testing was conducted under dry friction conditions at loads of 25 and 50 N. The results demonstrate that the application of WC/Ni–Al–Fe-coatings can reduce the specific wear of the steel surface by a factor of 11 to 24 and enhances resistance to high-temperature oxidation by a factor of 10.5 to 49.9.