UDC 662.24.051.4:669.018.25
A. F. Lisovsky
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
lisovsky@ism.kiev.ua
The role of materials science in increasing the performance of rock-breaking tools equipped with WC–Co hard alloy inserts. Review (pp. 3–27)
A concept for increasing the performance of rock-breaking tools is proposed. The concept uses the principles of thermodynamics of open systems. Based on the proposed concept, the following promising directions for increasing the performance of rock-breaking tools are identified: doping of the Co phase, creation of gradient strictures in the volume of the rock-breaking element, formation of mesostructures in sintered hard alloys.
Keywords: rock, tool, sintered hard alloys, gradient structures, mesostructures.
UDC 666.233
V. Yu. Dolmatov
Federal State Unitary Enterprise “Special Design and Technological Bureau “Technologist”, St. Petersburg, Russia
*diamondcentre@mail.ru
On the possibility of obtaining detonation nanodiamonds that do not contain nitrogen. The influence of covalently bound nitrogen in explosive molecules on the yield of nanodiamonds (pp. 28–34)
The possibility of obtaining nitrogen-free detonation nanodiamonds from industrially produced explosives has been investigated, and the low probability of their obtaining has been shown. The dependence of the yield of detonation nanodiamonds on the content of covalently bound nitrogen C–N in explosive molecules has been established, and the optimal (23–28% (by mass)) range of nitrogen content has been determined.
Keywords: detonation nanodiamonds, nitrogen-free nanodiamond, covalently bound nitrogen–carbon, individual explosives, mixed carbon-containing explosives, detonation synthesis, mechanism of formation of detonation nanodiamonds, explosive charges.
UDC 539.89
K. V. Slipchenko1,3 *, D. A. Stratiychuk1, V. Z. Turkevich1, N. M. Bilyavyna2, V. M. Bushlya3, Ya.-E. Shtol3
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
3Lund University, Lund, Sweden
*kateslipchenko@gmail.com
High-pressure and high-temperature sintering of cBN-based composites with ZrC and Al (pp. 35–42)
High-pressure and high-temperature sintering of cerammatrix materials based on cubic boron nitride with zirconium carbide and aluminum was carried out. The study revealed that at sintering temperatures above 1750 °C under conditions of applying a pressure of 7.7 GPa, the interaction of the charge components occurs with the formation of a new phase – zirconium diboride (ZrB2). Further increase in the sintering temperature leads to an increase in the volume content of ZrB2 and a decrease in the microhardness and crack resistance of the studied materials. The wear of the samples on the back surface under the conditions of processing AISI316L stainless steel (vc = 300 m/min, t = 300 s) increases with increasing sintering temperature, reaching a critical value of VB = 325 μm in the case of using a sample manufactured at a sintering temperature of 2300 °C, and a value of VB = 200 μm for a sample manufactured at a sintering temperature of 1750 °C.
Keywords: zirconium carbide, cubic boron nitride, zirconium diboride, microhardness, high pressure.
UDC 66.045.34+621.763
O. O. Shulzhenko1, *, O. M. Sokolov1, L. Yavorska2, V. G. Gargin1, L. O. Romanko1, E. F. Kuzmenko1, E. M. Lutsak1
1V.M. Bakul Institute of Superhard Materials, National Academy of Sciences of Ukraine, Kyiv, Ukraine
2AGH University of Science and Technology. Non-Ferrous Metals Faculty, Krakow, Poland
*kybor@ism.kiev.ua
Structure and properties of the copper–n-layer graphene composite depending on the method of mixing the components (pp. 43–48)
The structure and properties of the copper–n-layer graphene composite obtained under HPNT conditions were investigated, depending on the method of mixing the components of the charge – using a Pulverisette 6 classic line ball mill, EXAKT three-roll mill, manual mixing. It was found that regardless of the method of mixing the components, the addition of n-layer graphene contributes to an increase in the thermal conductivity of the composite compared to pure copper. The highest (559 W×m–1·K–1) thermal conductivity was observed in the composite sintered from the charge obtained by manual mixing, due to ensuring a uniform distribution of components in the charge and minimizing plastic deformation of copper particles during mixing.
Keywords: n-layer graphene, copper, sintering, high pressure, density, thermal conductivity, electrical conductivity.
UDC 622.24.051:536.2
V. A. Dutka*, A. L. Maistrenko, O. I. Borymsky, V. G. Kulych, T. O. Kosenchuk
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*vadutka@ukr.net
Modeling the temperature field in a high-pressure apparatus during sintering of large-sized products based on boron carbide (pp. 49–61)
Based on the finite element method, a computer model of the temperature field in the working cell of a high-pressure apparatus during the sintering of large-sized products from boron carbide at a pressure of 0.5–1.0 GPa and temperatures of 1700–1750 °C was developed. The dependence of the thermophysical The dependence of the physical properties of the sample on porosity and temperature during the sintering process. It is shown that by choosing the geometric parameters of the structural elements of the working cell of the high-pressure apparatus, it is possible to find such a design, when using which it is possible to ensure a practically uniform temperature field in a large-sized sample during the sintering process and uniformity of the density and physical and mechanical properties of the sintered sample.
Keywords: boron carbide, sintering, high pressure, temperature field, computer modeling.
UDC 620.22-621.921.34
V. A. Mechnyk1, *, M. O. Bondarenko1, V. M. Kolodnitsky1, **, V. I. Zakiyev2, I. M. Zakiyev2, S. R. Ignatovych2, S. S. Yutskevich2
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2National Aviation University, Kyiv, Ukraine
*vlad.me4nik@ukr.net
**stmj@ism.kiev.ua
Mechanical and tribological properties of Fe-Cu-Ni-Sn materials with different CrB2 contents used as matrices for diamond-containing composites (pp. 62–77)
The effect of the CrB2 additive content (in the range from 0 to 8% (by weight)) on the microstructure, microhardness, elastic modulus, friction coefficient and wear resistance of the matrix material of the Fe–Cu–N–Sn composite material formed by cold pressing and subsequent sintering with hot post-pressing was studied. It was found that an increase in the CrB2 concentration in the composite is accompanied by an increase in its hardness and elastic modulus. At the same time, the friction coefficient and wear rate, as well as the parameters H/E and H3/E2, which describe the resistance of the matrix material of the composite material to elastic deformation and its resistance to plastic deformation, respectively, decrease at a CrB2 content of 2% (by mass), and increase with an increase in the additive concentration. A significant increase in wear resistance in the sample containing 2% (by mass) CrB2, compared to the original sample, is due to the formation of a fine-grained microstructure and an optimal combination of hardness and elastic modulus. Tribological tests of sintered samples in the finger-disk and ball-grind testing modes indicate a significant expansion of the functional capabilities of the developed composite containing 2% CrB2.
Keywords: composite, concentration, structure, dispersion, hardness, elastic modulus, friction coefficient, wear resistance.
UDC 621.9.025.77:615.46:616.728
E. O. Pashchenko1, S. V. Sokhan1, *, G. V. Sorochenko2, D. A. Savchenko1, O. V. Lazhevska1, S. V. Skorokhod1, O. A. Mykyshchenko1
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2O. O. Bogomolets National Medical University, Kyiv, Ukraine Kyiv, Ukraine
*svsokh@gmail.com
The influence of the porosity of the tool composite on the efficiency of profile diamond grinding of sapphire and zirconium dioxide (pp. 78–92)
The efficiency of diamond grinding of the spherical surface of sapphire and polycrystalline zirconium dioxide with a tool on a metal bond with a reduced size distribution of porous inclusions of the bond was studied. Polyethylene glycol modified with adamantane derivatives was used to seal the tool composite, which increased the nonlinearity of the wetting agent flow at the briquetting stage. It was shown that under the friction conditions of such a composite, the amplitude of the friction coefficient oscillations decreases, and when friction is on zirconium dioxide, it is 3 times more intense compared to sapphire. In addition, unlike grinding zirconium dioxide, pitting was observed on the polished surface of sapphire, to eliminate which it is advisable to ensure the structure of the porous space of the composite not only with a certain distribution of porous inclusions by size, but also with a reduced most probable value. The indicators of relative productivity, wear of a diamond tool during fine grinding of sapphire, zirconium dioxide differ by 2 or 3 times depending on the grain size of the diamond tool. The surface roughness of polycrystalline zirconium dioxide during its fine grinding is generally 4–5 times lower than that of sapphire.
Keywords: tool composite, distribution of porous inclusions, sapphire, polycrystalline zirconium dioxide, spherical surface, diamond grinding, surface roughness.
UDC 621.919
S. E. Sheikin1, *, I. Yu. Rostotsky1, **, V. T. Protsyshyn2, V. V. Melnychenko1, S. F. Studenets1, D. V. Efrosinin1, Ya. V. Melnychenko1
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2State Enterprise “Ukrainian Research Institute of Oil Refining Industry “MASMA”
*sheykin2003@ukr.net
**dokarost@gmail.com
Improving the performance of hard alloy deforming broaches by using modified technological lubricants (pp. 93–100)
The performance of hard alloy deforming broaches when machining shaped holes in parts made of 38Kh2MYUA steel by deforming broaches was increased, which was achieved by using the developed effective technological lubricant and antifriction coating of titanium nitride on the working surfaces of the tool, which led to a decrease in axial broaches forces and obtaining low roughness values. Experience The developed approach allows for processing without setting under normal contact pressures up to 4 GPa.
Keywords: technological lubricant, deforming drawing, setting, operational properties.
UDC 620.22:669.018.25
S. A. Davydenko
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
snesha@ism.kiev.ua
On the formation of metal layers in the diamond–(Ti,W)C–WC–Co composite (pp. 101–104)
The conditions for the stable existence of metal layers at the diamond/(Ti,W)C–WC–Co matrix interface are substantiated, and the values of the critical layer size depending on the composition and structure of the composite are obtained. The research results allow developing a technology that ensures the existence of metal layers at the diamond/(Ti,W)C–WC–Co interface, which allows relaxing the stress between diamond particles and the matrix, ensuring strong retention of diamond particles by the matrix, and increasing the service life of products made from the diamond–(Ti,W)C–WC–Co composite.
Keywords: diamond–(Ti,W)C–WC–Co composite, metal layer, interface, structure, diamond retention.