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The particle size distribution significantly affects the material properties of the additively manufactured parts. In this work, the influence of bimodal powder containing nano- and micro-scale particles on microstructure and materials properties is studied. Moreover, to study the effect of the protective atmosphere, the test samples were additively manufactured from 316L stainless steel powder in argon and nitrogen. The samples fabricated from the bimodal powder demonstrate a finer subgrain structure, regardless of protective atmospheres and an increase in the Vickers microhardness, which is in accordance with the Hall-Petch relation. The porosity analysis revealed the deterioration in the quality of as-built parts due to the poor powder flowability. The surface roughness of fabricated samples was the same regardless of the powder feedstock materials used and protective atmospheres. The results suggest that the improvement of mechanical properties is achieved by adding a nano-dispersed fraction, which dramatically increases the total surface area, thereby contributing to the nitrogen absorption by the material.

Electrical explosion of aluminum wires has been shown to be a versatile method for the preparation of bimodal nano/micro powders. The energy input into the wire has been found to determine the relative content of fine and coarse particles in bimodal aluminum powders. The use of aluminum bimodal powders has been shown to be promising for the development of high flowability feedstocks for metal injection molding and material extrusion additive manufacturing.

In this research, Ti-Al powders were produced by electrical explosion of twisted titanium and aluminum wires. The resulting powders were pressed and sintered in a vacuum to obtain bulk composites. Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) studies were performed to analyze synthesized powders and bulk composites. The studies carried out showed the presence of α-Ti, α2-Ti3Al, and γ-TiAl phases, which are formed by coalescence of Ti and Al clusters formed in the process of non-synchronous electrical explosion of twisted wires. Furthermore, an increase in the energy injected into the wires leads to a decrease in the content of micron particles in the powder. During sintering of pressed Ti-Al powder in the range 800–1250 °C, phase transformations occur due to the diffusion of aluminum atoms towards Ti compounds. The research findings can be used to obtain Ti-Al particles and bulk composites with a controllable phase composition.

Magnetic nanoparticles based on iron and its oxides are promising in various biomedical applications. Currently, as a rule, ferromagnetic iron oxide particles with a low specific magnetic moment are used for medical purposes. In the present work, a new method for the synthesis of magnetic nanoparticles based on the electric explosion of a Fe wire is proposed. When wires are dispersed by high current electric pulse in an inert atmosphere containing less than 5% oxygen, nanoparticles with a core-shell structure are formed, where the core is α-Fe and the shell is formed by a mixture of oxides Fe3O4 and FeO. The oxygen concentration in the buffer gas has been found to determine the size of the resulting nanoparticles, their shape, and iron content. The iron oxide shell protects the iron core from the external environment, preventing the rapid dissolution of Fe containing in the nanoparticles, in contrast to nanoparticles obtained in argon atmosphere. The specific magnetic moment of nanoparticles, depending on the content of iron oxides, varies from 90 to 180 emu/g.

In the work, the samples obtained from polymeric feedstock based on bimodal powders of Cronix 70 alloy, obtained by an electric explosion of wire, are investigated. Samples were obtained by the 3D-FDM printing method with the use of micro-extrusion head for a 3D printer. It was found that the density of printed products is at least 95% when sintering parts to 0.9 from the melting point. Despite the discreteness of the obtained parts, the tensile strength and hardness are within the range of standard values for the Cronix 70 alloy.

This work studies the thermal interactions in the system of polylactide (PLA)–calcium phosphates with the addition of glycerol. The obtained composites are based on PLA contain up to 45% calcium phosphates. The impact of glycerol content on the characteristics of composites during thermal extrusion and 3D printing has been thoroughly investigated. It is found that rise in the proportion of calcium phosphates proportionally increases the compressive and flexural strengths. It is shown that the use of glycerol up to 7% is an effective concentration for extrusion and 3D printing.

Titanium alloys are in demand in engineering and medicine due to high specific strength, high corrosion resistance and biocompatibility. Powder injection molding is the most suitable method for producing small batches of complex shaped items. Titanium alloy bimodal powders obtained by electric explosion of wires are promising materials for PIM. The EEW conditions to prepare Ti-6Al-4V alloy bimodal powders with a uniform distribution of nano- and micro- particles have been determined. The load of bimodal powder in feedstock was 93 wt %. The density of the sintered samples reached 98% TD, and the microhardness was 3.1±0.3 GPa. The elemental composition of the sintered samples was close to that of the original wire.

Metal powder composites for powder injection molding (PIM) technology have been studied. Stainless steel 316L bimodal powders consisting of both nano and microparticles and multicomponent binders based on PLA/PMMA (feedstock I), paraffin wax/PE-LD/PMMA (feedstock II) and polyethylene wax (feedstock III) were used to obtain feedstock. The effect of the binder composition on the characteristics of feedstocks and sintered compacts was investigated. The use of PMMA in a binder allows maintaining the strength of the compacts to high temperatures when sintering. The debinding of “green compacts” from feedstock III leads to an almost complete removal of paraffin wax, and the “brown” parts retain their shape only due to the low-temperature sintering of nanoparticles. The use of the paraffin wax as a binder requires an increase in the content of the bimodal metal powder in the feedstock to 95 wt% to increase the strength of the compacts. Feedstocks and molded compacts were characterized by TEM, SEM, DSC-TG methods.

Metal powder composites for Powder injection molding (PIM) technology have been investigated. 316L stainless steel bimodal powder, obtained by electric explosion of the wire and multicomponent binder comprising PMMA, PE-LD and Viscowax were used to obtain feedstocks. The effect of PMMA content in the binder on the properties of feedstocks and sintered parts has been studied. As the PMMA content increases, the molding temperature of the parts rises from 140 to 200°C, the strength of the “green” and “brow” parts increases as well. The optimal PMMA content in the binder has been found to be 15–20 vol %. “Brown” samples sintered in vacuum at 1300°C exhibit shrinkage up to 23% and the samples density reaches 0.98 TD. Samples of feedstocks were characterized by TEM, SEM, DSC-TG methods.

This work studies the new polymer feedstock for the metal injection molding (MIM) process. The proposed feedstock is based on the bimodal powders of steel grade SAE 316L, polymethyl methacrylate (PMMA) and polylactide (PLA). The impact of PMMA content on the molding characteristics, thermal debinding and sintering of samples obtained by pressure casting is thoroughly investigated. It is found that the sintering density of the molded samples increases with the raise of PMMA content. It is shown that implementing the bimodal powder based composites in MIM applications results in samples with sinter density as high as 98%.

In this paper, we study the chemical and mineralogical composition of the Krasnoyarsk Kray clay used in the production of coarse ceramics. It is found that the fire –strength depends of method of preparation of clay paste. It is shown that the forced dissolution of the raw clay material effectively homogenizes clay paste. As a result, strength of the samples increased during firing. It is also justified by the influence of their mineralogical composition and there method of the preparation. It is proved that conditions of preparation and mineralogical composition affect equally.