IR spectroscopy, electron microscopy, and X-ray diffraction analysis, including the application of synchrotron radiation, have been used to study the mechanochemical reduction of copper oxide with aluminum at the stoichiometric ratio of the components and in the presence of an excess of oxide-forming metal and aluminum solid solution in copper as well. The possibility is shown of the mechanochemical reduction of copper oxide with aluminum and aluminum solid solution in copper, which is accompanied by the formation of the Сu/Al 2 O 3 composite structure. To modify copper with alumina, using an aluminum solid solution in copper is preferable.

The Center for Collective Use “Siberian Center for Synchrotron and Terahertz Radiation” provides users from various organizations with the opportunity to use modern analytical techniques using synchrotron radiation beams for a wide range of research work. At present, the general direction of the development of new techniques is focused on the development of new original approaches to the use of synchrotron radiation.

An Erratum to this paper has been published: https://doi.org/10.3103/S106287382301001X

Au-Co alloys with limited solubility were synthesized by the high-pressure torsion in boiling nitrogen at various anvil revolutions. Au and Co were initially in the state of a powder mixture in an equiatomic ratio. The obtained alloys were subjected to SEM fractography and XRD analysis in transmission X-ray synchrotron radiation, depending on the amount of strain. It is shown that the morphology of the fracture surfaces of the synthesized alloy depends significantly on strain. It is revealed that the mutual mixing of the components increases with strain. The images of the fracture surfaces of the Au-Co alloys testify that, as the strain and the number of anvil revolutions increase, a transition from ductile fracture, with inclusions of brittle intergranular fracture, to uniformly ductile fracture is observed over the entire thickness of the sample. A further increase in the strain and the number of anvil revolutions corresponds to the transition from the ductile type of the fracture surface to the brittle one. In addition, the fractography of the Au-Co alloys has revealed that the relief of the fracture surface becomes more homogeneous and that the size of the structural elements of the fracture surface decreases with increasing strain.

The paper presents the results of experimental studies on the synthesis of a metal-matrix composite by direct laser deposition, including the assessment of optimum irradiation modes to make such a material free of defects (pores, cracks, etc.). It is shown that in-situ synthesis is provided by laser irradiation of a powder mixture composed of polycrystalline boron and titanium alloy Ti64 in a ratio of 1 : 9 wt %. According to X-ray diffraction analysis with synchrotron radiation, scanning electron microscopy, and nanoindentation, the deposited material contains second phases in the form of TiB and TiB2 ceramics. According to mechanical tests, the elastic modulus and the hardness of the Ti64 metal matrix are E-av = 159.7 GPa and H-av = 7 GPa, and those of synthesized particles (whiskers) are E-av = 321.6 GPa and H-av = 19.7 GPa, respectively.

Diagnostics of the structure of materials is necessary for determining subsequent technological operations in the production of finished products. In the present paper, we propose to use synchrotron radiation for investigating the phase composition of metal-ceramic coatings with a titanium alloy as a matrix and powdered titanium boride as reinforcing elements. A comparison of the results obtained from the diffraction of x-ray tube radiation (Cu) and synchrotron radiation has shown that when it is necessary to determine the phases containing light elements (in the present case B), diffraction of synchrotron radiation makes it possible to unambiguously reveal TiB in the resulting coating, whereas diffraction of x-ray tube radiation could not allow unambiguous interpretation of results. Thus, the advantage of the synchrotron radiation in diffraction studies has been shown.

In the results of this study, the changes in the phase composition of welded joints of the parts made from VT20 titanium alloy and V-1461 aluminum alloy are presented. When laser radiation moves along the joint between the materials, a large number of intermetallic joints, as well as an increase in the size of crystallites, are recorded in the weld. By shifting the projection of the laser radiation focus towards the titanium alloy, it was possible to obtain an intermetallic layer of micron size between the materials being welded, and to increase the strength of the welded joint.

This paper describes the experimental study of strength characteristics and the microstructure of a permanent joint of dissimilar materials (VT20 titanium alloy and V-1461 aluminum alloy), obtained by laser butt welding. Optical and electron microscopy, X-ray spectral and phase analysis, and the transmission diffraction method with the help of synchrotron radiation are all used to investigate the properties of a weld. It is shown that the laser radiation offset relative to the contact surface of dissimilar materials significantly changes the microstructure and phase composition of the intermetallic interlayer formed between the materials welded, thereby affecting the strength of dissimilar welded joints.

The phenomenon of the high-temperature superlocalization of the plastic deformation of single crystals of Ni3Ge alloy, in which plastic deformation is localized in a band with a width of few tens of microns and reaches values of thousands of percent, is considered. Synchrotron radiation is used to study the structural state in the superlocalization band. It is shown that the phenomenon of strain superlocalization is associated with polycrystalline-substructure formation in the initial single crystal. Partial destruction of the long-range atomic order and the formation of an amorphous phase in the superlocalization band are found.

The influence of molecular weight on the optical characteristics (luminescence and luminescence attenuation kinetics) of polymethylmethacrylate obtained by radiation-chemical methods is studied. The luminescence spectra and luminescence kinetics of polymethylmethacrylate do not depend on the method of polymerization, but are determined only by its molecular weight. It was found that the main contribution to radiation is provided by a luminescence band with a maximum at a wavelength of∼0.5 microns and that with the growth of molecular weight, an increase in the luminescence band width is observed, and the luminescence attenuation time decreases according to the logarithmic law. The relationship between the molecular weight of polymethylmethacrylate, the luminescence band width of polymethylmethacrylate and the luminescence attenuation time of polymethylmethacrylate was established for the first time.

A synchrotron radiation study of immiscible Au-Co alloys obtained by consolidating a heterogeneous mixture of components and subsequent severe plastic deformation was performed. Namely, the estimates of the crystal lattice parameter, the average size of the coherent scattering regions and lattice strains in mechanically alloyed supersaturated solid solutions were made using obtained diffraction patterns and diffraction spectra. The effect of the temperature regime of deformation processing on the listed characteristics is shown, when the transition from cold deformation to cryogenic is carried out.

Самым тугоплавким из известных на сегодняшний день материалов является карбид гафния. Были проведены исследования возможности получения изделий из расплавленного карбида гафния методом разогрева механокомпозита гафний/углерод высокоинтенсивным лазерным излучением.

The structural features of Cu–Ag alloys mechanically synthesized by means of severe plastic deformation at a room and cryogenic temperature are revealed using X-ray diffractometry and electron microscopy and via in situ measurement of structure-sensitive characteristics such as shear stress depending on the deformation level. The effect of cryogenic strain temperature consists in a special character of change in the structure and shear stress of the formed alloys, which, in turn, affects the composition of the solid solution and the kinetics of structural transformations, as well as the mechanical properties.

The proportion of products manufactured by additive methods is constantly growing in modern technology. The use of radiation technologies makes it possible to obtain materials that combine the best characteristics of metals, oxides, carbides, borides, and so on. It attracts the interest of developers of new technology. Tungsten boride is a promising material for enhancing the protective properties of containers in which radioactive materials are stored. The possibility of synthesizing borides by electron beam processing is studied.

A study is performed on the possibility of obtaining products from molten hafnium carbide, the most refractory material known so far, by heating a hafnium/carbon mechanocomposite with high-intensity laser radiation.

The paper studies the high-temperature plastic deformation in Ni 3 Ge alloy single crystals localizing in a band a few tens of microns wide that reaches the shear strain of thousands of percent. The electron backscatter diffraction and synchrotron radiation techniques allow investigating the structure of the single crystal in the band of super-localized plastic deformation. It is shown that super-localization of plastic deformation occurs due to the formation of polycrystalline multi-level substructure in the initial single crystal. The grain size and grain misorientation bimodal distributions are determined in the polycrystalline substructure. Also, regions of amorphous state are observed in the super-localization band at high homologous temperature Т > 0.5T m . A partial destruction of the far atomic order is detected.