UDC 539.2.669.0176:669.018
H. S. Oleynyk*, V. M. Volkogon, Yu. A. Fedoran, S. K. Avramchuk, A. V. Kravchuk, A. V. Kotko (Kyiv)
*oleynik@ipms.kiev.ua
The influence of the initial structural state of wurtzite boron nitride on the formation of the grain structure of ego-based materials.I. Structural characteristics of particles of initial powders of BNv
The results of the study of the initial structure of wurtzite BNv particles obtained from graphite-like BN in shock waves with and without water addition, as well as the structure of BNv particles obtained with water addition, after deformation treatment at high (3 GPa) pressure at room temperature and shear rolling, are presented. It is shown that the particles of BNv synthesized with the addition of water always have a larger size in the prismatic section than the particles of BNv synthesized without additives. Treatment at room temperature with high pressure of BN powder obtained with the addition of water contributes to the grinding of particles mainly in the developed (basic) surface. When rolling such a powder, particles are crushed both in the developed surface and in thickness, as well as substructural transformations due to plastic deformation (lattice, rotation, by twinning).
Key words: boron nitride, particle, cutting, deformation, pressure, rolling, substructure, twinning, rotation.
UDC 661.892:544.223.22
C. Z. Fan, J. Li, M. Hu (Qinhuangdao, PR China)
Z. S. Zhao (Washington, USA)
B. Xu, J. L. He (Qinhuangdao, PR China)
A novel layer-structured PtN2: first-principles calculations
Platinum nitride as the first successfully synthesized noble metal nitride shows superior mechanical properties and exotic electronic structure that rival those of conventional transition metal nitrides. In the past, various crystal structures have been proposed to understand its unusual properties. However, very few works pay attention to the dynamic stability of these phases. Here, we examine the potential structures of platinum nitride with a chemical composition of PtN2 by utilizing a widely adopted evolutionary methodology for crystal structure prediction. Except reproducing the previously proposed phases, we also identify a Pmmm symmetric novel layer structure with a low formation enthalpy that is slightly lower than those of marcasite and CoSb2 structures but slightly higher than that of pyrite structure. The elastic constants and the lattice dynamical calculations show that this layer-structured PtN2 is mechanically and dynamically stable. The calculated band structures suggest this new phase together with the simple tetragonal phase are metallic, while other phases are insulators. In addition, it is found that the fluorite structure is dynamically unstable by the phonon spectrum calculations, although it is mechanically stable as suggested by calculated elastic constants.
Keywords: Noble transition metal nitrides, mechanical properties, electronic properties, thermodynamic properties.
UDC 620.178.1
O. G. Lysenko, S. N. Dub*, V. I. Hrushko, E. I. Mytskevich (Kyiv)
G. N. Tolmacheva (Kharkov)
*lz@ism.kiev.ua
Investigation of phase transitions in silicon by methods of scanning tunneling spectroscopy and nanoindentation
The results of experiments on nanoscratching and nanoindentation of the silicon surface using a scanning tunneling microscope equipped with a semiconductor diamond probe are presented. Physical phenomena in silicon that occur at different levels of contact pressure are discussed.
Keywords: silicon, scanning tunneling microscopy, nanoscratching, nanoindentation.
UDC 621.793:539.61:620.1
A. D. Pogrebnyak, I.V. Yakushchenko (Sumy)
G. Abadias, P. Chartier (Poitiers, France)
O. V. Bondar (Sumy)
V. M.Beresnev (Kharkiv)
Y. Takeda (Sakura, Ibaraki, Japan)
O. V. Sobol (Kharkiv)
K. Oyoshi (Sakura, Ibaraki, Japan)
A. A. Andreev (Kharkiv)
B. A.Mukushev (Semei, Republic of Kazakhstan)
Influence of deposition parameters of nitrides of high-entropy alloys (TiZrHfVNb)N on their structure, composition, mechanical and tribological properties
Nitrides of high-entropy alloys (TiZrHfVNb)N, obtained by vacuum-arc evaporation of the cathode, were investigated using scanning electron and atomic force microscopy, energy dispersive analysis, Rutherford ion backscatter analysis, X-ray diffraction analysis, microhardness measurements, and tribological tests. The effect of deposition parameters on the structure, surface morphology, distribution of elements, mechanical and tribological properties of the investigated coatings was found.
Key words: high-entropy alloys, vacuum-arc evaporation of the cathode, phase and elemental composition, microhardness, Young’s modulus, coefficient of friction, wear factor.
UDC 563.421.5:620.22-419
M. Şimşir, K. E. Öksüz (Sivas, Turkey)
Effects of sintering temperature and addition of Fe and B4C on hardness and wear resistance of diamond reinforced metal matrix composites
The effects of sintering temperature and addition of Fe instead of Co into the matrix composition on the mechanical properties of diamond-reinforced MMC’s have been studied. Diamond-reinforced MMC’s based on Fe–Co compositions with and without boron carbide (B4C) have been processed. Three different matrix composites (with different Fe/Co ratios) have been produced with and without B4C at a pressure of 25 MPa and sintered in N2 at various temperatures (800, 900, and 1000°C). After sintering, mechanical properties of the resulting composites have been studied and the results discussed. Addition of B4C has been found to improve the hardness and wear resistance of the composites. Optical microscopy, SEM and EDS have been used to examine the microstructure and surface of the synthesized composites.
Keywords: diamond, powder metallurgy, Fe-based metal matrix composites, hardness, wear.
UDC 621.923
IN. IN. Poltavets*, P. G. Matyuha, V. IN. Gabytov (Donetsk)
- vvardon@mail.ru
Optimization of diamond grinding modes of P6M5F3 steel taking into account non-stationarity of the process
The optimization of the modes of diamond grinding of P6M5F3 steel is considered, taking into account the non-stationarity of the process caused by the change in time of the cutting ability of the working surface of the grinding wheel. For optimization, mortise grinding according to an elastic scheme with a constant force of pressing the workpiece to the working surface of the wheel, the kinematics of which is similar to grinding according to a rigid scheme, was used. The area of possible modes of diamond grinding according to the elastic scheme at the beginning of processing is considered in the coordinate system of the speed of the part and the force of the workpiece. The speed of the part is determined by the given value of the roughness of the machined surface of the product. The clamping force of the workpiece is chosen to be minimal, based on the conditions of ensuring the absence of phase-structural transformations in the surface layer of the processed material, the absence of oxidation of diamonds, and the non-destruction of diamond grains. Nonstationarity of the process was taken into account using equations describing the change during processing of the current limited cutting capacity of the grinding wheel.
Key words: grinding, non-stationarity, optimization, part speed, clamping force, cutting ability, depth of cut.
UDC 621.941:534.141
AT. AND. Gutnychenko*, V. M. Bushlya, J. M. Zhu, Ya.-E. Stoll (Lund, Sweden)
P. Avdovych, U. Simmons (Finspong, Sweden)
*oleksandr.gutnichenko@iprod.lth.se
Dynamic stability of the turning process of nickel superalloys when using a cutter holder obtained by the method of layer-by-layer laser sintering
The results of a comparison of the stability of the tools with standard and experimental tool holders when turning the nickel superalloy Inconel 718 with an oxide ceramic tool reinforced with silicon carbide whiskers are presented. It is shown that the use of an experimental cutter holder with a mesh spatial structure leads to a significant suppression of vibration during processing, as well as stabilization of the cutting process in the range of speeds of 200–500 m/min. It was established that the advantages of the tool with the sintered holder are related to the damping properties of the developed cutter holder.
Keywords: dynamic stability, turning, Inconel 718 alloy, tool wear, wavelet analysis, “0-1” test.
UDC 621.9.025.7:666.3-1
AND. G. Kolmakov, V. I. Antipov (Moscow, Russia)
WITH. AND. Klymenko*, A. WITH. Manokhin, M. Yu.Kopeykina, V. N. Weaver (Kyiv)
M. L. Heifetz (Minsk, Belarus)
L. Tanovic (Belgrade, Serbia)
- klm@ism.kiev.ua
Structure, properties, and application of a ceramic composite obtained from nanostructured powders of the composition ZrO2 + 3% Y2O3
The results of studies of a ceramic composite sintered from powders based on ZrO2, obtained by the method of ultrasonic spray pyrolysis, are presented. Using the methods of sclerometry and microcutting with a single diamond grain, an assessment of the strength and deformation properties of the surface layers of the composite obtained from these powders is given, as well as the possibility of its application in the finishing processes of non-ferrous metals is shown.
Keywords: ceramic composite, cutting tool, deformation, sclerometry, nanostructure.
UDC 666.233
IN. Yu. Dolmatov (St. Petersburg, Russia)
AND. Vehanen, V. Müllumiaki (Vantaa, Finland)
K. AND. Rudometkin (St. Petersburg, Russia)
AND. N. Panova (Kyiv)
K. M. Korolev (St. Petersburg, Russia)
T. AND. Shpadovskaya (Kyiv)
Deep cleaning of detonation nanodiamond material
New variants of chemical purification of detonation nanodiamonds and diamond-containing detonation charge from water-insoluble metal-containing impurities by treatment at high temperature with 0.5–20% (by mass) complex solutions at a ratio of detonation nanodiamond material to complexone are presented. As complexes, you can use sodium 2,3-dimercaptopropanesulfonate, disodium salt of ethylenediaminetetraacetic acid (Trilon), thiourea, potassium rhodanide, dicyandiamide, hexamethylenetetramine. Cleaning of detonation nanomasses can also be carried out under ultrasonic action. The most effective was the combined use of ultrasonic treatment and treatment with solutions of complexes, while the amount of metal-containing impurities was significantly reduced.
Keywords: detonation nanodiamonds, chemical cleaning, complexons, ultrasonic impact.
UDC 661.657:661.636
IN. AND. Mukhanov, P. WITH. Sokolov, Ya. Le Godec, V. L. Solozhenko* (Paris)
*e-mail: vladimir.solozhenko@univ-paris13.fr
Self-propagating high-temperature synthesis of boron phosphide
A new method for obtaining submicron powders of boron phosphide by means of a self-propagating high-temperature reaction between boron phosphate and magnesium in the presence of an inert diluent – sodium chloride – is proposed. By sintering these powders at 7.7 GPa and 2600 K, compact polycrystalline samples of boron phosphide with microhardness HV = 28(2) GPa were obtained.
Keywords: boron phosphide, synthesis, high temperature, high pressure, hardness.