Inorganic Materials: Applied Research最新文献

The electroplastic effect in aluminum and its alloys is reviewed. The electroplastic effect is a phenomenon of a decrease in the strain resistance of a metal and an increase in its ductility under the action of a high-density electric current. The main methods of electroplastic processing are described, including the use of pulsed currents and external heating. The factors governing the kinetics of electroplastic strain and various physical effects influencing this process are discussed. The results of the molecular dynamics modeling and fractographic analysis are considered, which confirm the important role of the stress-induced grain growth in plastic straining of nanocrystalline metals and alloys.

This paper presents the results of dynamic testing of nine gas pipeline steel samples (09Mn2Si, 13KhFA, Х65, and others) exposed to the corrosive effects of CO₂ present in the extracted and transported media. Simulation tests on two developed corrosion stands simulating conditions of alternating wetting and fluid circulation in the presence of CO₂ made it possible to evaluate the influence of microstructure on the resistance of the studied steel samples to local carbon dioxide corrosion. The composition of corrosion products formed on steels, the adhesion of which to the metal surface affects their resistance to dynamic conditions of fluid flow transport through the gas pipeline, has been studied.

This study assessed the influence of the orientation of printed layers (90°, 45°, and 0°) in 12Kh18N10T alloy specimens relative to the direction of uniaxial deformation on the microstructure, physical and mechanical properties, and nondestructive testing parameters. It was found that deformation of specimens results in the intensive formation of structural defects, which significantly impact the strength properties of material (increasing the yield strength and microhardness), as well as the nondestructive testing diagnostic parameters. These results of research can be used to assess the condition of structures made of stainless chromium-nickel steels using the DMD method.

The structure and hybridized forms of carbon in primary particles of diamond nanopowders obtained by grinding of natural diamond and detonation synthesis followed by modifying heat treatment have been studied by solid-state nuclear magnetic resonance spectroscopy. Differences in the composition of non-diamond carbon in the shell surrounding the diamond core of natural and synthetic nanodiamonds before and after heat treatment have been found, demonstrating the potential of the heat treatment for controlling the nanodiamond surface chemistry

The results of experimental studies of one-sided friction stir welding of 10-mm-thick plates made of aluminum alloys 6082T6 (pressed profile) and 1565chM (the sheet positioned upstream of the working tool) are presented. Welded butt joints without internal defects are obtained. The tensile strength of the joints averages 210.9 MPa, which is 0.69 of the strength obtained for alloy 6082T6. The fracture of welds during the tensile test develops in the heat-affected zone on the side of alloy 6082T6. The tensile strength of the metal of the mixing zone is higher than that of alloy 6082T6. It is almost the same as for alloy 1565chM. The microstructure of the mixing zone consists of areas featuring a chemical composition corresponding to the chemical composition of the alloys to be welded or to the areas having partial mixing of alloys to be joined. At the same time, the metal of the mixing zone is resistant to intercrystalline corrosion. The heat-affected zone on the side of the 6082T6 alloy is the most susceptible to intercrystalline corrosion.

The microstructure, microhardness distribution, and phase composition were studied, and wear tests were conducted on samples of VNS32-VI beryllium-containing steel after various types of thermochemical treatment followed by strengthening heat treatment. It was found that combined thermochemical treatment reduces the wear rate of samples by 8–16.5 times depending on the treatment mode.

A combined treatment was performed on the surface layer formed on 30KhGSA steel by plasma cladding in a nitrogen atmosphere with an M10‑based high‑entropy high‑speed steel. The combined treatment consisted of two cycles of high‑temperature tempering of the cladded layer followed by irradiation with a pulsed electron beam of submillisecond duration (30 J/cm², 50 μs, 0.3 s^–1, 10 pulses). It was found that the combined treatment of the cladding–substrate system is accompanied by an increase in the microhardness of the cladded metal to 8.4 GPa, which is 2.8 times higher than the microhardness of the substrate (30KhGSA steel). It was shown that the microhardness of the surface layer obtained by plasma cladding and subjected to the combined treatment is practically independent of the distance from the substrate. Irradiation of the cladded metal with a pulsed electron beam resulted in formation of a hardened surface layer approximately 100 μm thick. It is suggested that the creation of the hardened surface layer is due to the development of a polycrystalline structure with grain sizes of 4–6 μm, within which a martensitic substructure is observed.

Results of a study of the physical and mechanical properties of crystal structures from the human gallbladder (density, speed of sound, heat capacity, etc.) are presented. These parameters are required for the development of methods for fracturing crystalline structures during lithotripsy, execution of computing modeling of the process of fracturing, and selection of the characteristics of an energy unit.

The possibility of formation of composites of PTFE with 5–40% Al₂O₃ by explosive pressing of powder mixtures is shown. Special attention is paid to the investigation of the morphology, crystal structure, thermal deformation, and other properties of the composites obtained. Regularities of the change in the structure upon compaction of composite mixtures by a shock wave are found, which results in intensification of the adhesion of the filler to the polymer and improvement of the properties of the materials being created.

The possible accuracy of determining the period of the crystal lattice of α-Fe-based solid solutions by X-ray diffractometry is discussed from a point of view that differs from the view of the Kurdyumov’s and other scholar school concerning the role of residual stresses of the 3-d kind in the formation of crystal lattice distortions of undeformed solid solutions.