Ukrainian Journal of Mechanical Engineering and Materials Science

Permanent URI for this communityhttps://ena.lpnu.ua/handle/ntb/31565

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Influence of diamond component based on wurtzite boron nitride on wear resistance of cutting tool
(Lviv Politechnic Publishing House, 2020) Volkogon, Volodymyr; Avramchuk, Svitlana; Fedoran, Yuriy; Kravchuk, Andrii; Pavlychuk, Tetiana; Antonyuk, Viktor; Avramchuk, Kateryna; I. M. Frantsevich Institute for Problems of Materials Science of the National Academy of Sciences of Ukraine; National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”
The article is devoted to the study of the influence of the diamond component in a composite superhard material based on wurtzite boron nitride on the stability of the tool during turning of hardened steels in the mode of smooth turning and when processing intermittent surfaces. The aim of the work is to study the influence of the content of the diamond component in the composite superhard material based on wurtzite boron nitride on the stability of the tool. Based on the analysis of the main patterns of changes in the coefficient of friction depending on various factors, the evaluation of composites containing diamonds of different dispersion in comparison with other materials of this class. The results of the study of the technical level of composite polycrystalline superhard materials based on wurtzite boron nitride of different composition and determination of the efficiency of their use as a cutting tool in the machining of hardened steels are presented. The intensity of wear of composites in the cutting tool during processing of hardened steels is experimentally determined. It is established that the presence of a diamond component in the composite significantly affects the stability of the tool in the conditions of smooth turning due to heat dissipation in contact with the processed material. In the processing of hardened steels with the presence of shock loads, the phase state of the matrix component of the composite plays a decisive role. The obtained research results make it possible to determine the optimal composition and conditions for obtaining a composite material of the system “boron nitride – diamond”, which provides the most effective application of the cutting tool in practice.
Research of volt-ampere characteristics of the wire pierce electron gun at electron-beam microprocessing of dielectrics
(Lviv Politechnic Publishing House, 2018-01-29) Bondarenko, Maksym; Antonyuk, Viktor; Kovalenko, Yurii; Rud, Maksym; Haidash, Roman; Cherkasy State Technological University; National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”
The article considers the basic energy characteristics of a wire Pierce electron-beam gun, which used for microprocessing of dielectric materials in vacuo. The aim of the work is to determine the optimal regimes of electron-beam microprocessing of dielectric materials by studying the volt-ampere characteristics of the wire Pierce electron-beam gun. In the methodical part of the scientific work, a technological experiment with electron-beam microprocessing of dielectric surfaces is proposed, and also identified and studied the operating modes of the Pierce electron-beam gun in depending on their energy characteristics. As a result, the analysis of the obtained results of electron-beam microprocessing of surfaces of dielectric materials makes it possible to increase the reproducibility of the results of such treatment in terms of purity and residual nanorelief by 18–25 %. The comparison of the results of experimental electron-beam microprocessing of dielectrics with the results of their laser processing made it possible to establish a decrease in the residual microroughness of the surface of the optical glass K8 by 17...27 times with electron-beam microprocessing and by 12–14 times with surface laser treatment. Wherein, surface laser processing does not allow to eliminate the undulation of the surface, which is related to the specificity of the interaction of the laser beam with the surface of the optical material, whereas, when processing by the ribbon-shaped electronic stream such undulation does not appear. Conclusions and analyzed data obtained in the article based on the results of experimental studies can be used to optimize the technological regimes of electron-beam microprocessing in the production of micro-optics products, integrated optics, microelectrooptics, nanoelectronics, etc.