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Title: DRILLING INSERTS OF THE WC-Co-CrB2 SYSTEM WITH INCREASED MECHANICAL PROPERTIES
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DRILLING INSERTS OF THE WC-Co-CrB2 SYSTEM WITH INCREASED MECHANICAL PROPERTIES
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1314-2704
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English
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21
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1.1
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• Prof. DSc. Oleksandr Trofymchuk, UKRAINE
• Prof. Dr. hab. oec. Baiba Rivza, LATVIA |
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A comprehensive study of composites using traditional methods of testing mechanical
properties in combination with methods of digital optical and scanning atomic force microscopy made it possible to establish stable correlations between the content of chromium diboride CrB2 additive with an average grain size WC, microstructure parameters, hardness, fracture toughness, ultimate strength at bending and compression. The optimal ratios of the components of the WC–Co-CrB2 system have been established, at which a finely dispersed structure is formed with a simultaneous improvement in physical and mechanical properties. It is shown that the introduction of CrB2 (in concentration CrB2 C = 4% (% by mass)) leads to a twofold increase in fracture toughness (from KIc = 4.4 MPa • m1/2 to KIc = 9.8 MPa • m1/2) with a slight decrease hardness (from H = 15.1 to 13.9 GPa), as well as to an increase in the ultimate strength in bending (from ? = 2000 to 2500 MPa) and compression (from ? = 5300 to 6000 MPa) of sintered specimens. Creation of WC–Co- CrB2 composite materials with enhanced mechanical properties is essential for optimizing the designs of drilling tools for various technological purposes, increasing their reliability and improving operational properties. The properties of the materials under consideration are determined by the composition, structure, and morphology, which, in turn, depend on the properties of their constituents, methods and technological modes of sintering. 1. Established that the particles of CrB2 powder in the initial state have an irregular shape, their size varies from 2 to 8 ?m. During the briquetting process, the CrB2 particles did not change their shape and size. 2. For composites WC – 6% Co (% by mass), a coarse-grained structure with an average size of a carbide grain of 5.6 ?m is observed. 3. It is shown that the presence of CrB2 in the composition of the initial charge in the required amount prevents the processes of Oswald ripening (absorption of small grains by large grains) and acts as a growth inhibitor, providing a decrease in the grain of tungsten carbide from 5.6 ?m to 3.4 ?m at a content of 10% ... 4. It is shown that the introduction of CrB2 (concentration = 4%) leads to a twofold increase in fracture toughness (from KIc = 4.4 MPa • m1/2 to KIc = 9.8 MPa • m1/2) with a slight decrease in hardness (from H = 15.1 to 13.9 GPa), as well as to an increase in the ultimate strength in bending (from ? = 2000 to 2500 MPa) and compression (from ? = 5300 to 6000 MPa) of sintered specimens. With a further increase in the content from 4 to 10% CrB2 in the composite, a gradual decrease in hardness and fracture toughness is observed. Creation of WC – Co - CrB2 composite materials with improved mechanical and operational properties is essential for optimizing the designs of drilling tools for various technological purposes, increasing their reliability, energy saving, and improving operational properties.? |
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conference
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21st International Multidisciplinary Scientific GeoConference SGEM 2021
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21st International Multidisciplinary Scientific GeoConference SGEM 2021, 16 - 22 August, 2021
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Proceedings Paper
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STEF92 Technology
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SGEM International Multidisciplinary Scientific GeoConference
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SWS Scholarly Society; Acad Sci Czech Republ; Latvian Acad Sci; Polish Acad Sci; Serbian Acad Sci & Arts; Natl Acad Sci Ukraine; Natl Acad Sci Armenia; Sci Council Japan; European Acad Sci, Arts & Letters; Acad Fine Arts Zagreb Croatia; Croatian Acad Sci
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617-626
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16 - 22 August, 2021
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website
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cdrom
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7838
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composite; composition; concentration; structure; properties
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