Inorganic Materials: Applied Research最新文献

Abstract—This work presents the results of the studied selective laser melted samples of a mixture of 1CP and copper powders at varying scanning angle. The initial powder material was formed by mixing 1CP iron alloy powder and 10 wt % pure copper powder. The composite samples were prepared with a selective laser melting unit at a varying scanning angle. Data on the macrostructure, phase composition, and degree of amorphization of the samples were obtained by optical microscopy, X-ray diffraction analysis, and differential scanning calorimetry. The results of this study can be used for further research and development of the technology for manufacturing soft-magnetic composites via selective laser melting.

The results of experimental studies are given for specific formation of the structure of 1565chM alloy in the zone of intersection of welds. The welds are made using friction stir welding (FSW). It is found that the area where two welds intersect features a decrease in the average grain size from 5.2 to 3.3 μm. The measurements made for the moving force of the tool show that, upon moving from the welding section of 1565 chM alloy to the section of intersection with a preliminarily made weld, this value decreases from 11.75 to 3.8 kN. The metal in the area of intersection of two FSW welds has better strength properties. At the same time, the relative elongation is slightly lower here compared to the metal in the single weld stir zone. The static tensile tests reveal the highest strength properties in samples having longitudinal weld orientation relative to the direction of applying the load. Samples with intersecting welds are about 10–15% less strong.

Abstract—For rails of increased wear resistance and contact endurance of the DH400RK category made of E–0.9C–Cr–V–Fe hypereutectoid steel, after a tonnage of 187 million tons, the fine structure in the railhead along the central axis at distances of 0, 2, and 10 mm was analyzed using transmission electron microscopy for the four morphological components of pearlite from the rolling surface. The nonmonotonic change in scalar and excess dislocation density, fragment size, cementite particles, and internal long-range stress fields in the railhead section was analyzed.

A sample found by geologists in 2002 in a forest near the village of Chelmuzhi (Medvezhyegorsky district of the Republic of Karelia) was examined. Unlike regional rocks, the sample had high hardness and strength, electrical conductivity, and weak magnetic properties. During its detailed study, Widmanstätten structure, chondrules, and iron-chromium-nickel alloy of matrix consisting mainly of taenite and cohenite, the grains of metals, their oxides, refractory perovskite, periclase, rutile, pyrochlore, corundum, and Ca, Al, and C inclusions were discovered. High contents of carbon and low content or complete absence of oxygen were recorded in some components of the sample. The hypotheses of the meteoritic and mantle origin of the sample are discussed.

Abstract—Metal and glass samples discovered in 2019 in the vicinity of Tallinn are described. Their structure, composition, and properties are analyzed. In terms of structural and chemical parameters, the samples belong to the same parent body and differ from representatives of known groups of iron meteorites, technogenic ferroalloys, and industrial and natural glasses. Analogs of the material composition of samples are protvanites. The possible cosmic origin of samples is confirmed by surface regmaglypts, fullerenes, other carbon phases, and cohenite.

Abstract—Using high-temperature X-ray diffraction, the thermal expansion coefficient was determined in VNS9Sh steel, Mg-8Li-1Al alloy, and Si+SiC multilayer coating layer. The TCLE value of the γ phase significantly exceeds the TCLE of the α phase, which corresponds to the data for austenitic and martensitic steels, while the TCLE values of each phase depend on the composition of phases. The TCLE value in the β phase of a magnesium alloy exceeds the TCLE value for the α phase, and this difference increases with an increase in temperature. The TCLE value of the α phase in the direction of the “c” axis (α_c) is higher than in the basal plane (α_a). It is shown that the advantage of the high-temperature X-ray diffraction method for assessing the TCLE is the ability to measure them in thin surface layers, as well as the ability to evaluate the TCLE of individual phases and their anisotropy in multiphase, textured objects.

Abstract—The influence of various technological conditions of crystallization melting of corundum with cerium on its electrical conductivity and electroluminescence has been studied. The relation between the electrical conductivity of the samples and Ce⁴⁺ ions in the crystal lattice is discussed. The relation between electroluminescence of the samples and Ce³⁺ ions in electrically conducting samples is considered.

Abstract—The mechanical properties of polyether ether ketone that has a partially crystalline structure are studied using low-speed uniaxial compression. Compression diagrams are measured, by which the elastic and elastoplastic properties of the material are characterized. Compression experiments are applicable for choosing the mode of cold gas dynamic spraying of solid polymer materials.

Abstract—In this investigation, thin films of copper oxides obtained by arc deposition at low pressure on borosilicate glass are studied. The phase composition, structural characteristics, and chemical state of the samples are confirmed by X-ray diffraction and X-ray photoelectron spectroscopy. Hall measurements using the van der Pauw method show that films of both Cu₂O and CuO phase compositions have hole conductivity (p-type). The concentration of charge carriers, mobility, and resistivity of the samples are determined. The formation of a heterojunction with a significant decrease in the concentration of charge carriers due to the recombination of electron–hole pairs is observed in a thin film of mixed composition (Cu₂O/CuO). From UV-visible spectroscopy measurements, the absorption/transmission characteristics of the films are determined and the optical band gap is calculated. It is shown that change in the phase composition of the oxide from Cu₂O to CuO leads to a decrease in the band gap from 1.90 to 1.34 eV.

This paper presents the results of a study of the dependence of the impact strength of impregnated 3D printed samples on the type of used hardener (PEPA and TETA) and the curing mode after impregnation for samples with different directions of plastic laying during the printing process.