UDC 621.921.34:666.233
N. V. Novikov, G. P. Bogatyreva (Kyiv)
Nanodiamonds of static and detonation synthesis and prospects for their application
The main physical, physicomechanical, physicochemical characteristics of diamond nanopowders of detonation and static synthesis and carbon composites based on them are considered. It is shown that these properties are determined by the composition of the feedstock, thermobaric conditions of nanopowder synthesis, and methods of their isolation from the synthesis products. The most promising areas of nanodiamond application are given.
Keywords: nanodiamonds, static synthesis, detonation synthesis, physicochemical, energetic, adsorption-structural characteristics, application of nanodiamonds.
UDC 539.3:539.89
S. B. Polotnyak (Kyiv)
Methodology of numerical modeling of martensitic phase transformation processes in small volumes of materials during deformation on diamond anvils
A model, algorithm and software for finite element modeling of martensitic phase transformation in a small volume of sample material during deformation under quasi-hydrostatic conditions (in a gasket without a pressure-transmitting medium) on diamond anvils of an ultra-high-pressure apparatus have been developed, which are based on the thermomechanical theory of phase transformations in inelastic materials developed by prof. V. I. Levitas. An algorithm for modeling the kinetics of the phase transformation process is proposed, consisting of a cyclic solution of a contact elastic-plastic problem, an assessment of the possibility of a phase transformation and a repeated solution of the problem taking into account the phase deformation.
Keywords: diamond anvils, martensitic phase transitions, computer modeling, finite element method.
UDC 62-987:666.233
A. I. Prikhna (Kyiv)
Diamond Synthesis Apparatus
A high-pressure apparatus is presented, the cavity of which is formed by the mouths of two oppositely located clamps, covered by an annular body. The parameters are determined at which the pressure created in the cavity is maintained by friction forces without the participation of the press. A scheme of the installation for servicing a group of apparatuses with one press is proposed.
Keywords: apparatus, punch, container, diamond.
UDC 544.3:621.762.
A. F. Lisovsky (Kyiv)
Thermodynamics of liquid phase migration in a three-phase disperse system with one dissolving solid phase
An expression is obtained that describes the change in the Gibbs potential during liquid phase migration in a three-phase disperse system with one dissolving solid phase. The conditions are determined under which structures can be formed without changing the initial skeletal structure of the refractory phase, as well as as a result of complete or partial deconsolidation of the skeletal structure.
Keywords: thermodynamics, mass transfer, liquid.
UDC 666.11.01:621.921-419
A.E. Shilo, S.A. Kukharenko, N.G. Klimenko, V.N. Tkach, A.G. Gontar, E.F. Kuzmenko (Kyiv)
The influence of diffusion processes on interaction in multicomponent silicate systems
The main results of the study of diffusion processes in silicate multicomponent systems, which are widely used as binders for composite materials of various functional purposes, are presented and summarized. It is shown that the effective diffusion coefficients of alkali and alkaline earth cations in a diffusion pair are not an unambiguous function of the ionic radius of the cation, but depend on structural factors and the energy of binding with other ions of the melt.
Keywords: multicomponent silicate systems, diffusion, migration processes, alkali silicate glasses, effective diffusion coefficient, interaction, alkali and alkaline earth cations, diffusion activation energy.
UDC 621.9.01:621.793.7
S. A. Klimenko, Yu. A. Melniychuk (Kyiv), G. V. Vstovsky (Moscow)
Interrelationship between the parameters of the structure, mechanical properties of sprayed materials and tool life during their cutting
The results of fractal studies of the structure and properties of sprayed amorphous-crystalline coatings are presented. A close correlation between the fractal parameters of the structure and the set of mechanical properties of the coating materials is shown. It is established that the durability of cutting tools during the cutting of coatings is largely determined by the homogeneity of the structure and the stability of the mechanical properties of the materials being processed.
Keywords: material structure, wear-resistant coatings, fractals, fractal dimension, tool life.
UDC 621.923
N. V. Azarova, P. G. Matyukha, V. V. Poltavets (Donetsk)
Specific cost of the process of flat grinding of vanadium high-speed steel with wheels made of superhard materials
Using the criterion of the minimum specific cost of grinding, a comparison was made of the process of grinding P6M5F3 steel with cubonite and diamond wheels dressed by the electrical discharge method. It was shown that the specific cost of grinding with the compared wheels is almost the same, which gives the right to equally use in grinding anii steel R6M5F3 circles from comparable superhard materials.
Keywords: specific grinding cost, stainless steel, diamond, cubonite circles.
UDC 622.24.051:536.2:004.942
V. A. Dutka (Kyiv)
Computer-based formation of the temperature field of a hard alloy cutter for its induction brazing and hardening
The results of numerical experiments on the formation of the temperature field of the surface of the hard alloy cutter holder for its induction brazing and subsequent hardening are presented. In this case, a previously developed computer model of the temperature field of a hard alloy cutter during its induction brazing was used. It is shown that the entire time interval of soldering can be divided into two stages according to the heating rate: the first stage is rapid heating, which lasts from the beginning until the magnetic transformation temperature is reached, and the second stage is slow heating, which lasts for the rest of the soldering time. At the first stage, the heating rate of the cutter holder surface is 5-6 times higher than at the second stage. According to the results of the calculations, a parameter surface was constructed in the three-dimensional time-frequency-current coordinate space in the inductor, which can be used to select induction soldering modes.
Keywords: temperature field, numerical modeling, carbide cutter, induction soldering, quenching.
UDC 621.793
V. S. Antonyuk, E. B. Soroka, V. I. Kalynychenko (Kyiv)
Ensuring adhesion strength in the base-coating system under contact loading conditions
Ways of determining the geometric parameters of a discrete-type coating from the point of view of observing the adhesive strength of the base-coating composition are considered. When calculating the stress-strain state, an element of a carbide tool with a vacuum-plasma coating was used under the conditions of contact loading, taking into account frictional forces.
Key words: coatings, contact loads, adhesive contact surface, adhesive strength.
UDC 621.921
IN. I. Lavrynenko, V. N. Tkach, B. IN. Sytnyk, O. AT. Pasichny (Kyiv)
Technological aspects of changing the structural orientation of the working layer of STM circles
The issue of the importance of taking into account the structural orientation of the working layer of grinding wheels made of superhard materials is considered. Technological techniques used in pressing and sintering of the working layer of circles are shown, in which it is possible to change the structural orientation of such a layer.
Keywords: structure of the working layer, structural orientation of the working layer, regularity of the structure, Fourier analysis of the surface image, change of the orientation angle of the structure.