PSI - Issue 20

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Procedia Structural Integrity 20 (2019) 206–211

1st International Conference on Integrity and Lifetime in Extreme Environment (ILEE-2019) Fracture analysis of hard-alloy tungsten-cobalt plates with ultrafine powder additives Fedorov M. V. a, *, Vasilyeva M. I. b , Danzanova E. V. c a Federal Research Centre “Yakut Science Centre of SB RAS”, 2, Petrovskogo str., Yakutsk, 677000, Russia b V. P. Larionov Institute of Physical-Technical Problems of the North of Siberian Branch of Russian Academy of Sciences, 1, Oktyabrskaya str., Yakutsk, 677891, Russia c Institute of Oil and Gas problems of the Siberian Branch of Russian Academy of Sciences, 20, Avtodorojnaya str., Yakutsk, 677007, Russia Abstract The article presents a fracture surface analysis of hard-alloy tungsten-cobalt plates of a group WC8 with ultrafine additives in impact-abrasive wear. When testing on impact-abrasive wear, a wearing surface repeatedly hits the abrasive layer. Magnesium spinel powders (MgAl 2 O 4 ) are used as ultrafine additives, and for comparison, silicon carbide (SiC) additives are considered. A percentage of additives is varied in composition test specimens. The geometric parameters of test specimens without additives and with ultrafine additives are the same. This analysis of fracture surface contributes to a risk prediction of studied material premature destruction and failure. The insertion of ultrafine additives of magnesium spinel and silicon carbide into tungsten cobalt alloys supports to reduce the WC grain size and increase the hardness values of the samples than the sample without additives. Based on the macroanalysis of the fracture surface of the specimens it is identified that the character of fracture are depending on the composition of the material. Prevailing wear type is a chipping WC particles. In the studied specimens with the additives of magnesium spinel (MgAl 2 O 4 ) and silicon carbide (SiC), areas with small elements of ductile fracture are detected. A change of the fracture character is detected when ultrafine additives are added to the composition of tungsten-cobalt alloys: the fracture of the specimen without additives is brittle, but the fracture of specimens with the ultrafine powder additives of magnesium spinel and silicon carbide is intergranular, quasi-brittle. 1st International Conference on Integrity and Lifetime in Extreme Environment (ILEE-2019) Fracture analysis of hard-alloy tungsten-cobalt plates with ultrafine powder additives Fedorov M. V. a, *, Vasilyeva M. I. b , Danzanova E. V. c a Fed ral Research Centre “Yakut Science C ntre of SB RAS”, 2, Petrovskogo tr., Yakutsk, 677000, Russia b V. P. Larionov Institute of Physical-Technical Problems of the North of Siberian Branch of Russian Academy of Sciences, 1, Oktyabrskaya str., Yakut k, 677891, Russia c Institute of Oil and Gas problems of the Siberian Branch of Russian Academy of Sciences, 20, Avtodorojnaya str., Yakutsk, 677007, Russia Abstract The article presents a fracture surface analysis of hard-alloy tungsten-cobalt plates of a group WC8 with ultr fine additives in impact-abrasive wear. When testing on impact-abrasi e wear, a wearing surface repeatedly hits the brasive layer. Magnesium spin l powders (MgAl 2 O 4 ) are used as ultrafine additives, and for comparison, silicon carbide (SiC) additives are c nsidered. A percentage of additives is varied in co position test specimens. The geometric parameters of test specimens without additives and with ultrafine additives are the same. This analysis of fr cture surface co tributes to a risk prediction of studied material premature destruction and failure. The insertion of ultrafi e additiv s of magnesi m spinel and silicon carbide into tungsten cobalt alloys supports to reduce the WC grain size and in rease the hardn ss values of th samples than the sample without additives. Based on the macroanalysis of the fracture surface of the specime s it is identified that the character of fracture ar depending on the composition of the material. Prevailing wear type is a chipping WC particles. In the studied sp cimens with the additives of magnesium spinel (MgAl 2 O 4 ) and silicon carbide (SiC), areas with small ele ents of ductile fracture are detected. A change of the fracture character is detected when ultrafine additives ar added to the composition of tu gsten-cobalt alloys: the fracture of the specimen without additiv s is brittle, but the fracture of specimens with the ultrafine powder additives of magnesium spinel and silicon carbide is intergranular, quasi-brittle.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers © 2019 The Author(s).Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers © 2019 The Author(s).Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers

Keywords: hard-alloy; ultrafine powder additive; magnesium spinel; silicon carbide; impact-abrasive wear; chipping; fracture Keywords: hard-alloy; ultrafine powder additive; magnesium spinel; silicon carbide; impact-abrasive wear; chipping; fracture

2452-3216© 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers 2452 3216© 2019 The Author(s). Publis ed by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers * Correspon ing auth . Tel.: +7-924-175-8136; fax: +7-411-233-6665. E-mail address: fedorov.83@mail.ru * Corresponding author. Tel.: +7-924-175-8136; fax: +7-411-233-6665. E-mail address: fedorov.83@mail.ru

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers 10.1016/j.prostr.2019.12.140