| 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. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 7. |
- 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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| 8. |
- Agmell, M., et al.
(författare)
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Modeling subsurface deformation induced by machining of Inconel 718
- 2017
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Ingår i: Machining Science and Technology. - : Informa UK Limited. - 1091-0344 .- 1532-2483. ; 21:1, s. 103-120
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Tidskriftsartikel (refereegranskat)abstract
- Traditionally, the development and optimization of the machining process with regards to the subsurface deformation are done through experimental method which is often expensive and time consuming. This article presents the development of a finite element model based on an updated Lagrangian formulation. The numerical model is able to predict the depth of subsurface deformation induced in the high- speed machining of Inconel 718 by use of a whisker-reinforced ceramic tool. The effect that the different cutting parameters and tool microgeometries has on subsurface deformation will be investigated both numerically and experimentally. This research article also addresses the temperature distribution in the workpiece and the connection it could have on the wear of the cutting tool. The correlation of the numerical and experimental investigations for the subsurface deformation has been measured by the use of the coefficient of determination, R2. This confirms that the finite element model developed here is able to simulate this type of machining process with sufficient accuracy.
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| 9. |
- Gutnichenko, O., et al.
(författare)
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Improvement of tool utilization when hard turning with cBN tools at varying process parameters
- 2021
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Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 477
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Tidskriftsartikel (refereegranskat)abstract
- Hard turning of helical gear hubs produced from low-carbon alloyed steel with a bulk hardness of HRC 35, and case hardened up to HRC 60–63 with PCBN tools was considered in this study. The workpieces after heat treatment are characterized by a non-uniform thickness of the hardened surface layer which results in a high variation of measured HRC hardness. The deviation of surface microhardness is even greater (HV 314–742) due to the presence of an oxidized layer that should be removed before measurements. When also considering workpiece run-out and deviations in depth-of-cut due to the distribution of the workpiece diameter, all those factors result in a non-uniform development of tool wear that leads to a large deviation in tool life. To uphold quality and avoid scrap, industry uses a fixed conservative tool life (number of parts machined), which leads to many inserts being underutilized, which in turn, means extra expenses considering the price of PCBN tools. The present study addresses the development of different strategies for monitoring of tool wear and prediction of tool life aimed to increase productivity. Laboratory machining tests are performed to optimize the type and number of sensors necessary for data acquisition, to estimate the significance of the data used for the development of prediction model, as well as the efficiency of machine learning algorithms for the selected data and strategies to increase the algorithm's accuracy.
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| 10. |
- Kryzhanivskyy, V, et al.
(författare)
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An inverse problem for retrieving time dependency of heat flux in metal cutting via linear programming
- 2018
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Ingår i: Procedia Manufacturing. - : Elsevier BV. - 2351-9789. ; 25, s. 287-293
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Tidskriftsartikel (refereegranskat)abstract
- The paper addresses the inverse heat transfer problem, in which the dependence of the flux on time is determined on the basis of the measured temperatures in remote points of the tool body. The nonlinear heat equation is considered since the properties of the tool material are temperature-dependent. The machining time interval is divided into subintervals within which the change in the tool material properties is ignored. Therefore, it possible to consider a sequence of linear programming problems, each of which minimizes the maximum deviation of the measured temperatures from the calculated ones.
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