Andrey A. Nepapushev

AlSi10Mg-based aluminum matrix composites (AMCs) with additives of Cu, CuNi, and multicomponent CuNiFeCo alloy additives were fabricated by selective laser melting. The additives were prepared by solution combustion synthesis, and the composite powder mixtures were produced by mechanical processing in a planetary ball mill. The study examined the powder morphology, phase composition, and properties of compact samples with particular focus on their thermophysical and electrical behavior. The Cu-containing alloy additives markedly improved the functional performance of the materials: thermal conductivity increased by up to 55 %, and heat capacity increased by up to 15 % compared with the base AlSi10Mg alloy. Electrical conductivity decreased of up to 65 %, with the strongest effect observed for the multicomponent CuNiFeCo additive. The resulting AMCs combine enhanced thermophysical properties with reduced electrical conductivity, making them suitable for heat-dissipating and heat-resistant components in electronics and aerospace applications. Lower electrical conductivity may also be beneficial in radio-frequency modules, inductive components, and shielded electronic systems, where parasitic currents and eddy-current losses should be minimized. Because they compatible with selective laser melting, these materials are promising for the additive manufacturing of complex-shaped functional components, including heat-dissipating housing, heat sinks, and weight-optimized parts.

Metal matrix composites based on an aluminum (Al‐MMC) with W₂B₅ particles are prepared by the laser powder bed fusion (LPBF) method. The feedstock material is obtained by pretreatment of the AlSi10Mg alloy with the W₂B₅ functional additive in a planetary ball mill under conditions that ensured the preservation of the good flowability of the resulting powder and the distribution of ceramic particles on its surface. The resulting powders have a composite structure and are suitable for subsequent 3D printing. As a result of the optimization of the LPBF process parameters, dense Al‐MMC with 5, 10, and 15 wt% of W₂B₅ is obtained for the first time. Microstructure investigations supported by X‐Ray phase diffraction reveal the presence of the WB phase as well as initial W₂B₅ particles and the AlSi10Mg matrix in the resulting materials. The thermodynamic calculations support the observed formation of the WB phase due to the W₂B₅ decomposition under the influence of the LPBF process conditions. All fabricated samples exhibit a high level of mechanical properties. A sample with 10 wt% of W₂B₅ demonstrates the highest values of ultimate tensile strength and elongation (394.9 ± 3.1 MPa and 4.8% ± 0.5%, respectively) among the investigated composites.

In this study, the possibility of employing ZrN/AlSi10Mg composite powders with 10, 20, and 30 wt% ZrN and a low‐pressure cold spraying (CS) unit to enhance the surface properties of AlSi10Mg obtained through laser powder bed fusion (LPBF) is investigated for the first time. A high‐energy ball mill is used to produce composite powders from AlSi10Mg and ZrN powders. ZrN/AlSi10Mg powders are sprayed onto the surface of LPBFed AlSi10Mg at a pressure of 0.7 MPa and a temperature of 400 °C. It is demonstrated that the utilization of composite powders facilitates a uniform distribution of ceramic particles in the coating and reduces the share of their losses during the CS process to 2%. It is found that the microhardness and elastic modulus of composite coatings increase with increasing mass fractions of ZrN, while the wear rate (WR) decreases. A change in the wear mechanism from adhesive to abrasive is observed. It is possible to increase the microhardness and elastic modulus of the LPBFed AlSi10Mg surface with a coating containing 30 wt% ZrN by 43% (193 ± 5 HV_0.1) and 62% (105 ± 9 GPa), respectively, and reduce the WR by 25% (8.26 ± 0.09) × 10⁻⁴ mm³ m⁻¹.

In this research, we combined mechanical activation (MA), self-propagating high-temperature synthesis (SHS), and spark plasma sintering (SPS) methods to obtain a dense high-entropy (Hf,Ta,Nb)(C,N) carbonitride and studied its properties. To implement the SHS process, a mixture of initial metals and carbon was subjected to pre-treatment in a planetary mill in the low-energy mode, in which the jar rotation speed reached 350 rpm. We studied the evolution of microstructure and phase composition during the MA process. It has been established that after 60 min of treatment, Hf/Ta/Nb/C layered composite particles consisting of Hf, Ta, Nb and C submicron layers, with an average size of about 15 μm, were formed. However, according to the X-ray diffraction analysis, the components in the jar did not interact. SHS of Hf/Ta/Nb/C reactive mixtures was performed in a nitrogen atmosphere (P = 0.8 MPa); after synthesis, two isomorphic (Hf,Ta,Nb)(C,N) phases of the Fm-3m (225) space group with lattice parameters of a = 0.4476 nm (71 wt. %) and a = 0.4469 nm (22 wt. %) were revealed in the powder. After SHS, the average size of agglomerates was 10 μm and their morphology resembled that of composite particles after MA. The agglomerates formed during SHS consisted of pores and round-shaped particles ranging in size from 0.5 to 2 μm, which was caused by the melting of metal components in the combustion zone and rapid crystallization of product grains from the melt, followed by subsequent recrystallization. Spark plasma sintering at a temperature of 2000 °C, a pressure of 50 MPa and a holding time of 20 min enabled to obtain a single-phase high-entropy (Hf_0.33Ta_0.33Nb_0.33)C_0.5N_0.3 material with a lattice parameter of 0.4482 nm characterized by a high relative density of 98 %, a hardness of 21.5 ± 0.4 GPa, a Young’s modulus of 458 ± 10 GPa, and a fracture toughness value of 3.7 ± 0.3 MPa∙m^1/2.

Nanostructured single-phase hafnium-zirconium carbonitride powders were synthesized using a simple and fast mechanochemical synthesis approach. The critical milling duration, after which a (Hf,Zr)(C,N) solid solution formation inside a jar occurred via mechanically induced self-sustained reaction (MSR), was 10 min. After 30 min of treatment, a solid-gas reaction was completed, and as a result, a homogeneous (Hf,Zr)(C,N) powder consisting of 10–500 nm submicron particles was obtained. The phase and structure evolution of the powders after different treatment durations allowed for the establishment of possible reaction mechanisms, which included the formation of Hf/Zr/C-layered composite particles, their interaction via MSR, and further grinding and nitridization. Spark plasma sintering (SPS) was used to produce bulk hafnium-zirconium carbonitride ceramics from nanostructured powder. The sample had higher values of relative density, hardness, and fracture toughness than those for binary compounds of a similar composition.