UDC 541.16
A. L. Ivanovsky (Yekaterinburg, Russia)
Search for new superhard and incompressible materials based on higher borides of s, p, d-metals
A brief overview of the current state of the search for new superhard and (or) incompressible materials based on higher borides of s, p, and d-metals is presented. Information on experimental and theoretical studies of the following groups of borides is presented: diborides of heavy 4d, 5d-metals (Tc, Ru, Rh, Re, Os, and Ir), hexagonal tetraborides with a WB4-type structure, and АМВ14 borides (where A, M are s, p-metals), as well as a number of related systems.
Keywords: higher borides of s, p, and d-metals, elastic moduli, hardness, atomic structure, synthesis, modeling.
UDC 621.762.4.045
Qing-hua Zou (Wuhan, Hubei, China)
Densification of hot-pressed composite materials for diamond tools
A set of compaction equations suitable for final stage of hot-press forming and sintering is deduced, all physical parameters are analyzed, the analysis results are consistent with a part of empirical formulas. Composites for diamond tools are taken as the subject of the investigation. Under the conditions of hot-forming sintering, the priority is given to the research of the relation between heat capacity Cp at constant pressure. By combining analysis of the set of compaction equations, we performed differential thermal analysis (DTA) in the differential scanning calorimetry (DSC) mode of heat capacity at constant pressure of pure Co powder, composite powder that consists of 663Cu and 35‰ Fe-based powder, analyzed the relationship between Cp and composite densification, and modified Cp of matrix composites containing 35‰ Fe-based composite powder for diamond tools in the mode of mixing a rare earth to make it as similar to Cp of pure Co as possible. Such modified powder is used in practical hot pressing of diamond tool composites and guides it with a set of compaction dynamical equations to radically improve the stability of practical performance (bending strength, hardness, impact ductility, porosity) of powder metallurgy composites and compaction of diamond tool composites.
Keywords: densification, hot-press forming, powder metallurgy, heat capacity, critical nucleation power, thermodynamic parameter, composite for diamond tool.
UDC 621.762.5.:921.43-49
Y. O. Podoba, V. P. Pereyaslov, V. M. Serdyuk, L. M. Bologova (Kiev)
The infusion of technological parameters of intense electrospinning on the performance of inserts made from composite diamond mixed materials on a cobalt bond
We describe the development of devices and express methods for studying the performance characteristics of composite diamond-containing materials on cobalt bonding. In minds similar to the real minds of the robotic tool, an experimental investigation was carried out to determine the usefulness of materials under the regime of intense electrical spiking. Correlations between technological parameters of the process, microstructure, physical and mechanical properties and operational characteristics of composite diamonds and instrumental materials have been established. The ranges of changes and combinations of technological parameters that are most promising from the point of view of the content of the materials have been identified. On the basis of these data, a detailed technology for the production of segments from composite diamond-mixed materials for stone cutting with improved performance characteristics is detailed.
Keywords: composite diamond material, electrosplicing of composites, wear, productivity.
UDC 666.11.01:621.921-419
S. A. Kukharenko, A. E. Shilo, A. M. Kutsay, P. P. Itsenko (Kiev)
Study of interaction of silicate multicomponent systems with aluminum oxide by spectroscopic methods
The main results of the study of interaction of glass melts with aluminum oxide are presented and summarized. It is shown that aluminum oxide partially dissolves in sodium borosilicate glass. By incorporating into the silicon-oxygen framework of glass, it isomorphically replaces the silicon cation, increases the rigidity of the framework and increases its strength.
Keywords: sodium borosilicate glass, aluminum oxide, interaction, dissolution, silicon-oxygen framework of glass, IR absorption spectra.
UDC 536.421.5
Yu. D. Serdyuk, O. A. Semizhon (Mariupol) N. M. Prokopiv, G. A. Petasyuk, O. V. Kharchenko, T. V. Omelchuk (Kiev)
The influence of thermocompression treatment parameters on the quality characteristics and wear mechanisms of cutting inserts made of T5K10 alloy during rough turning
The article presents the results of a study of the influence patterns of the parameters (argon pressure, temperature and isothermal holding time) of the thermocompression treatment process under pressure up to 4.5 MPa on the quality indicators and wear mechanisms of replaceable cutting inserts of the SNMM 250724 form made of T5K10 alloy manufactured by the Pobedit plant during rough turning of rolled blanks for railway car axles.
Key words: hard alloy, thermocompression treatment, wear mechanisms, types of wear, microporosity, durability, variation coefficient.
UDC 621.941
N. E. Stakhniv, L. N. Devin (Kyiv)
Study of wear of cutters with CBN-based composite and its influence on cutting forces during finish turning of hardened steels
The article presents the results of a study of the process of finish turning of hardened KhVG steel with a tool equipped with a round cutting plate made of a composite based on cubic boron nitride (cBN–Si3N4 system). The patterns of change in cutter wear during the processing time, as well as its influence on the components and resultant of the cutting force, are established.
Keywords: turning of hardened steels, cutting forces, round cutting plate, CBN-based composite, correlation and spectral analysis.
UDC 548.736.15:666.233:546.26-162
G. P. Bogatyreva, I. I. Timofeeva, G. A. Petasyuk, G. A. Bazaliy, M. A. Vasilkovskaya (Kyiv)
Determination of non-diamond carbon in detonation synthesis nanodiamonds
The article presents the method of determination and the results of the study of the amount of non-diamond carbon in nanosized diamond powders and in various intermediate products. The method is based on the quantitative analysis of X-ray diffraction patterns of the samples under study using the mathematical apparatus of cubic splines.
Keywords: detonation synthesis nanodiamonds, characteristics, quality, non-diamond carbon, reflection lines, intensity, peak area, cubic splines.
UDC 548
A. V. Lysenko (Kyiv)
On the structure of amorphous 3D networks of diamond-like carbon
A developed molecular-chemical model of diamond-like carbon is presented, in which 2D layers of non-graphitized carbon are partially cross-linked by cross-links localized in the region of structural defects that arose due to the formation of network nanopores.
Keywords: carbon, diamond-like forms, high-molecular, structure.
UDC 669.018.29
A. F. Lisovsky (Kyiv)
Features of mesostructure formation in WC–Co hard alloys
The process of cobalt melt migration occurring during the liquid-phase formation of the WC–Co mesocomposition structure between mesoelements and the hard-alloy matrix is described. The driving force of the process is the pressure gradient of migration. During the migration of the cobalt melt, the volumes of mesoelements and the matrix change, which affects the redistribution of the cobalt melt.
Keywords: sintered hard alloys, mesostructure.