| 1. |
- Rumiantseva, Yu Yu, et al.
(författare)
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Electrical Characteristics of Thermobarically Sintered cBN–NbN Composite
- 2020
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Ingår i: Journal of Superhard Materials. - 1063-4576. ; 42:2, s. 126-128
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Tidskriftsartikel (refereegranskat)abstract
- The structure, phase composition, and temperature dependence of electrical resistivity of the thermobarically sintered cBN–NbN composite are presented. The semiconductor character of the change in resistivity from 2.5 to 1.8 Ohm cm in the range of 300–700 K is revealed.
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| 2. |
- Dub, S. N., et al.
(författare)
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Theoretical shear strength and the onset of plasticity in nanodeformation of cubic boron nitride
- 2017
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Ingår i: Journal of Superhard Materials. - 1063-4576. ; 39:2, s. 88-98
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Tidskriftsartikel (refereegranskat)abstract
- The nanoindentation in the continuous stiffness measurement mode was used to investigate the onset of plasticity at the nanodeformation of cubic boron nitride (cBN). This technique allows us to reveal an elastic-plastic transition in the contact and to measure the yield strength of cBN at the nanoscale. An abrupt elastoplastic transition (a pop-in) was observed in the (111) cBN single crystal as a result of a homogeneous or heterogeneous nucleation of dislocations in the previously dislocations-free region under the contact. The analysis of the data obtained at the homogeneous nucleation of dislocations in the contact region made it possible to experimentally estimate the theoretical shear strength of cBN and its ideal (elastic) hardness. In a sample of the fine-grained cBN with a nanotwinned substructure a smooth elastoplastic transition was observed in consequence of the propagation and multiplication of already existing dislocations in the contact region.
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| 3. |
- Rumiantseva, Yu, et al.
(författare)
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Influence of cBN content, Al2O3 and Si3N4 additives and their morphology on microstructure, properties, and wear of PCBN with NbN binder
- 2020
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Ingår i: Ceramics International. - : Elsevier BV. - 0272-8842. ; 46:14, s. 22230-22238
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Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline cubic boron nitride (PCBN) tool materials with NbN binder without additives and PCBN with Al2O3 or Si3N4 micropowder and whisker additives were manufactured and compared. PCBN materials with Si3N4 whisker reinforcement have the best mechanical properties of all the evaluated materials. Composites reinforced with Al2O3 whiskers have the lowest fracture toughness. However, Al2O3 whisker-reinforced tools outperform both commercial and Si3N4 reinforced tools when machining hardened steel. Thus Al2O3 whisker-reinforced PCBN materials are promising for industrial applications, likely due to their higher resistance to oxidation and diffusional wear mechanisms during cutting operations.
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| 4. |
- Rumiantseva, Yu Yu, et al.
(författare)
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The Role of Microfibers and Liquid Aluminum in the Reaction between Boron Nitride and Tantalum Nitride
- 2024
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Ingår i: Journal of Superhard Materials. - 1063-4576. ; 45:6, s. 415-417
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Tidskriftsartikel (refereegranskat)abstract
- The results of thermodynamic modeling of superhard materials based on cubic boron nitride (cBN) with a tantalum nitride (TaN) binder and additions of aluminum, as well as microfibers of various physicochemical nature (oxide (Al2O3, Mg2B2O5) and non-oxide (SiC, Si3N4)), are presented. The theoretically calculated chemical interactions between the components of superhard composite materials are experimentally verified. The chemical nature of the microfibers significantly affects the reaction interaction between the cBN matrix material and TaN binder in the presence of liquid aluminum, resulting in the formation of tantalum boride.
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| 5. |
- Serdiuk, Iryna Vitaliivna, et al.
(författare)
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Machining of Titanium Alloys with a Cemented Carbide Cutting Tools with Tungsten-Based Vacuum-Arc Nitride Coatings
- 2023
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Ingår i: Metallofizika i Noveishie Tekhnologii. - 1024-1809. ; 45:8, s. 993-1014
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Tidskriftsartikel (refereegranskat)abstract
- Finding the right coatings for cutting tools is essential in order to increase the tool wear resistance and, thus, to get better surface roughness for the machined workpieces, and to improve productivity. A coating requirements are not only its mechanical and strength properties, but also its response to a given load and a given wear exposure. To expand ideas about the phenomena and mechanisms of wear of tungsten-based vacuum-arc coatings on the cemented carbides-based cutting tools during mechanical processing of titanium alloy Ti–6Al–4V, vacuum-arc W–N, W–Zr–N, W–Nb–N, W–Cr–N, W– Mo–N, W–TiSi–N, W–TiAlYCr–N coatings are obtained, investigated and tested on the CNC turning machine SMT 500 Swedturn with use of 8%-oil– water emulsion under pressure of 10 bars. Several main wear mechanisms and their influence on the geometry of vacuum-arc coatings are established, and factors influencing on the improvement of the operational properties of the tool are investigated.
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| 6. |
- Slipchenko, K. V., et al.
(författare)
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Sintering of BN Based Composites with ZrC and Al under High Temperatures and Pressures
- 2020
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Ingår i: Journal of Superhard Materials. - 1063-4576. ; 42:4, s. 229-234
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: The sintering of cubic boron nitride (cBN) based ceramic matrix materials with zirconium carbide and aluminum has been carried out under high pressures and temperatures. The performed study has revealed that the interaction between mixture components with the formation of a new phase, namely, zirconium diboride (ZrB2) occurs at sintering temperatures above 1750°C and an applied pressure of 7.7 GPa. A further increase in the sintering temperature leads to a growth in the volume ZrB2 content and reduces the microhardness and crack toughness of the studied materials. The flank wear of specimens under the conditions used for the processing of AISI316L stainless steel (vc = 300 m/min, t = 300 s) grows with an increase in the sintering temperature to attain the critical value VB = 325 µm, when the specimen sintered at temperature of 2300°C is used, and VB = 200 µm for the specimen sintered at 1750°C.
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| 7. |
- Slipchenko, K. V., et al.
(författare)
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Sintering of cBN Based Materials with a TaC Binder for Cutting Tool Application
- 2020
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Ingår i: Journal of Superhard Materials. - 1063-4576. ; 42:2, s. 51-57
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Ceramic matrix composites based on cubic boron nitride with a TaC binder phase are sintered under conditions of high pressure and high temperature. The sintering is carried out in a high-pressure apparatus of the toroid type in the temperature range of 1450–2450°C. It is shown that a chemical reaction between components of the mixture with the formation of TaB2 takes place at a sintering temperature above 2150°C. The microhardness of the composites increases with an increase in the sintering temperature and reaches a maximum value (34 GPa) at 2150°C. The composites show high resistance to mechanochemical wear when used for high-speed machining of nickel-based alloy Inconel 718.
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| 8. |
- Slipchenko, K. V., et al.
(författare)
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Особливості формування структури та фазового складу в процесі реакційного спікання кубічного нітриду бору зі сполуками Ti, Cr, V
- 2018
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Ingår i: Metallofizika i Noveishie Tekhnologii. - : National Academy of Sciences of Ukraine (Co. LTD Ukrinformnauka). - 1024-1809. ; 40:8, s. 1081-1091
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Tidskriftsartikel (refereegranskat)abstract
- Influence of sintering temperature on both phase composition and structure of ceramic matrix composites based on cubic boron nitride with binders in a form of Al and the Ti, Cr, V carbides are investigated by methods of physical materials science. As the object of study, three cBN–TiC–Al, cBN–Cr3C2–Al, cBN–VC–Al compositions containing 60% vol. cBN are selected. The composites are obtained by high-pressure high-temperature (HPHT) sintering in high-pressure apparatus AVTT-30 in the temperature range of 1600– 2450°C under pressure of 7.7 GPa. In the process of HPHT sintering of composites in the cBN–TiC–Al and cBN–Cr3C2–Al systems, the formation of titanium and chromium diborides is found at the temperatures of sintering Тsint ≥ 1850°С and Тsint ≥ 2150°С, respectively, simultaneously with the formation of alu-minium nitride.
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| 9. |
- Stratiіchuk, D. A., et al.
(författare)
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Sintering of Superhard cBN-Based Materials with Ti4WC5
- 2020
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Ingår i: Journal of Superhard Materials. - 1063-4576. ; 42:6, s. 371-376
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: The physicomechanical properties and structure of superhard cBN–Ti4WC5–Al materials were studied. The materials were sintered under a pressure of 7.7 GPa within a broad range of temperatures (1600–2450°C). The formation of a dense material with high physicomechanical properties was found at a sintetring temperature of 1800°C. A further increase in the sintering temperature had a negligible effect on the properties of sintered materials. The formation of titanium diboride and a slight increase in the unit cell parameters of Ti4WC5 were revealed at sintering temperatures above 2000°C. According to X-ray diffraction analysis, this might be due to the diffusion of Al into the Ti4WC5 lattice. Cutting performance in the longitudinal turning of stainless steel AISI 316L correlated with the sintering temperature, and the average tool wear was ranged within 60–82 µm.
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| 10. |
- Bushlya, V., et al.
(författare)
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On chemical and diffusional interactions between PCBN and superalloy Inconel 718 : Imitational experiments
- 2019
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Ingår i: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219. ; 39:8, s. 2658-2665
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Tidskriftsartikel (refereegranskat)abstract
- During a metal cutting process, chemical wear can become the dominant mechanism of tool degradation under the high temperatures and contact pressures that arise between the tool and the metal workpiece. This study focuses on the chemical and diffusional interactions between superalloy Inconel 718 and cubic boron nitride (cBN) tool material with and without TiC binder. It covers thermodynamic modeling and experimental tests in the pressure range of 0.1 Pa to 2.5 GPa at temperatures up to 1600 °C. The methods used include diffusion couples under both vacuum and high pressure, transmission electron microscopy (TEM) analysis and in-situ synchrotron observations. It is shown that cBN is prone to diffusional dissolution in the metal and to reactions with niobium, molybdenum, and chromium from Inconel 718. Adding TiC binder changes the overall degradation process because it is less susceptible to these interaction mechanisms.
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