UDC 661.65:661.55
V. I. Kushch, S. N. Dub (Kyiv)
Evaluation of elastic-plastic properties of materials based on nanoindentation data and computer modeling. 1. State of the art (literature review)
A review and critical analysis of existing methods and approaches to determining elastic-plastic properties of materials based on nanoindentation data is provided. The problems that remain open to date are formulated and the main areas of efforts to solve them are indicated. They consist of improving nanoindentation techniques; involving other instrumentation to obtain additional information that, in combination with nanoindentation data, provides an unambiguous assessment of the mechanical properties of the material; further development of model concepts of contact interaction in the indenter-sample system and patterns of material deformation in nanovolumes and at high pressures.
Keywords: nanoindentation, elastic modulus, yield strength, finite element method.
UDC 666.233-49.2; 658.012.122;621.921
L. O. Tavares, W. S. Vianna, G. S. Bobrovnitchii, A. L. D. Skury, J. J. A. Rangel (Campos, RJ, Brazil)
Possibility of application of the computational intelligence in the production of superhard materials. Report 1
A new system to control DO138B model 630-ton and DO044 model 2500-ton presses (Russia) has been developed. The system not only controls the basic parameters of superhard materials synthesis and sintering, but also records a total of 11 parameters. The studies have been performed using high-pressure apparatuses of anvil with cavities. The features of behavior and the effect of individual parameters and their totalities on the superhard materials production have been discussed and the possibility to use these factors both for the process optimization and for the development of a future computational intelligence has been considered.
Keywords: high pressure, superhard materials, synthesis, sintering, press, high-pressure apparatus, command.
UDC 621.921.34:621.921.34–413:621.923.4:662.23.05
A. N. Sokolov, A. A. Shulzhenko, V. G. Gargin, M. G. Loshak, L. I. Aleksandrova, A. S. Nikolenko, V. V. Strelchuk, A. N. Katrushka, A. M. Kutsai (Kiev)
Structure and hardness of single crystals of natural diamond of octahedral habit depending on barothermal treatment conditions
The evolution of the structure of single crystals of natural diamond of octahedral habit depending on barothermal treatment conditions was studied using Raman scattering and infrared spectroscopy. It was found that the formation of a polycrystalline diamond shell around a single crystal at p = 8 GPa and T = 1500 °C leads to the creation of a complex structurally stressed state in it due to its plastic deformation, the manifestation of which, in particular, is a significant (more than twofold) broadening of the characteristic diamond line (1332 cm–1) in the Raman spectrum and an increase in the hardness of the single crystal from 105 to 120 GPa.
Keywords: diamond, barothermal treatment, plastic deformation, hardness.
UDC 536.631,722:546.26
V. B. Muratov, O. O. Vasiliev, L. M. Kulikov, V. V. Garbuz, Yu. V. Nesterenko, T. I. Duda (m. Kiev)
Thermodynamic power of rich-walled carbon nanotubes
An experimental study of the thermal capacity of bulk-thick carbon nanotubes under a steel pressure was carried out in the temperature range of 60–300 K. It was shown that the temperature range of the thermal capacity For graphite, explanations are provided to highlight the peculiarities of the phonon spectra of these materials. Based on the experimental results and reliable literature data, standard values of the main thermodynamic functions of rich carbon carbon nanotubes – enthalpy, entropy and reduced Gibbs energy – have been determined.
Key words: carbon nanotubes, thermodynamic functions, heat capacity, enthalpy.
UDC 621.921.34-666-233
V. E. Orel, A. D. Shevchenko, G. P. Bogatyreva, O. V. Leshchenko, A. V. Romanov, A. Yu. Rykhal’skiy, I. I. Dzyatkovskaya, N. A. Nikolov, N. N. Dzyatkovskaya, I. B. Shchepotin (Kyiv)
Magnetic characteristics and antitumor activity of a nanocomplex consisting of detonation nanodiamond and doxorubicin
A nanocomplex with magnetic properties of a soft ferromagnet was obtained using detonation nanodiamonds and the antitumor drug doxorubicin by mechanomagnetic-chemical synthesis. The combined effect of the synthesized nanocomplex and local radiofrequency hyperthermia initiates a tendency to increase the growth inhibition of Walker-256 carcinosarcoma compared to the monoeffects of the nanocomplex and official doxorubicin.
Keywords: detonation nanodiamond, doxorubicin, magnetic properties, antitumor activity, mechanomagnetochemical synthesis.
UDC 691.327:666.973.6
M. A. Tsysar (Kyiv)
Use of a scanning tunneling microscope with a diamond tip to study the structural features of ta-C film
Conducted The paper presents the physical and mathematical modeling of the surface of a diamond-like carbon (ta-C) film for the sp2/sp3 phase transition region and presents the results of its study using scanning tunneling microscopy using a tip made of a semiconductor single crystal of diamond doped with boron. It is shown that the height difference in the boundary layer of sp2/sp3 phases is not associated with the functional features of the tunneling microscope. Using three independent methods, a fractal analysis of the surface, contour and profile of the section is carried out, and on this basis the fact that the surface belongs to the fractal Brownian ones is confirmed. It is shown that the area of the real surface under study can significantly exceed the area of the visible contact window.
Keywords: diamond-like carbon film, physical and mathematical model, scanning tunneling microscope, tip made of a semiconductor single crystal of diamond.
UDC 621.941
N. E. Stakhniv, L. N. Devin (Kyiv)
Study of the effect of cutter wear equipped with a CBN composite plate on its vibration during finish turning of hardened steels
The effect of cutter wear equipped with a round cutting plate made of CBN composite on its vibration during finish turning of hardened steels of different hardness was established. The effect of vibration on the roughness of the machined surface was studied.
Keywords: hardened steel turning, vibrations, round cutting plate, CBN composite, spectral analysis.
UDC 621.921.34:666.233.08374
G. A. Petasyuk, Yu. V. Sirota (Kyiv)
Analytical determination of the number of grains in one carat of diamond powder based on the extrapolation-affine 3D grain model
A new method for analytical determination of the number of grains in one carat of diamond powder has been developed, based on the proposed extrapolation-affine 3D grain model. The results of testing the method on synthetic diamond grinding powders are presented. The average value of the relative error on 11 test powders was 1.34%, the maximum was 3%.
Keywords: synthetic diamond powders, 3D grain model, number of grains in one carat, analytical determination, testing, relative error
UDC 539.89+546.185:661.63+541.128.13
V. V. Lesnyak, V. V. Safonova, D. A. Stratiychuk, O. Yu. Boldyreva (Kiev)
Production of diphosphates МР2О7 (M = Nb, Ta, Re, Mo, W) under high pressure conditions and catalytic activity of Pt(Pd)/MP2O7 systems in the reaction of hydrogen oxidation
The paper reports on the production of diphosphates МР2О7 (M = W, Mo, Nb, Ta, Re) as initial matrices for catalytic hydrogen-oxidizing Pt(Pd)/MP2O7 systems.
Keywords: diphosphates, high pressure, hydrogen oxidation, catalysts.
UDC 661.665.3; 536.421.1:53.092
V. A. Mukhanov, P. S. Sokolov, V. L. Solozhenko (Paris)
On the melting of boron carbide B4C under pressure
The baric dependences of the melting temperatures of boron carbide and the B4C–carbon eutectic at pressures up to 8 GPa were studied and it was found that in both cases the melting curves have a negative slope (–13±6 K/GPa), indicating a higher melt density compared to the solid phase.
Keywords: boron carbide, melting, high pressure, B–C system.