PSI - Issue 20

Fedorov M. V. et al. / Procedia Structural Integrity 20 (2019) 206–211 Fedorov M. V. et al / Structural Integrity Procedia 00 (2019) 000–000

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In specimens of compositions with silicon carbide additives, there is an enlargement in WC grains with an increase in the percentage of additives. Fractures formed on the fracture surface characterized by brittle fracture. Destructions pass along the grain boundary, and have low steps of layers, see Fig. 4c. Also observed are regions of quasi-brittle fracture, as evidenced by the presence of plastic separation ridges. Analysis of the micrographs revealed that, in general, hard alloy tungsten-cobalt materials with ultrafine SiC additives are mainly subject to brittle fracture. The structure clearly shows grain boundaries, which indicate that the more low-melting component is distributed along the grain boundary 3. Conclusions The fracture surfaces of specimens of tungsten-cobalt alloys with ultrafine additions of magnesium spinel and silicon carbide are investigated and, for comparison, specimens with silicon carbide additives are considered. It is shown that the characteristics of the fracture of hard alloy plates significantly depend on the composition of the material: the introduction of ultrafine additives affects the mechanism for removing carbide grains from the working surface. When forming the structure of specimens, ultrafine additives facilitate to reduce the size of tungsten carbide grains. Fractographic studies of microfracture specimens with ultrafine additives MgAl 2 O 4 and SiC found that the fracture character changes depending on the additive content as a result of impact-abrasive operating loads. The fracture of the specimen’s surfaces with additives has the type of intergranular and quasi-brittle, which indicates an increase in the resistance to the destruction of hard alloy materials of experimental drilling plates. Acknowledgements The authors are grateful to the staff of the Institute of the Physical-Technical Problems of the North, SB RAS and the North-Eastern Federal University who helped with the experiments. The research was carried out within the state assignment of the Program of Fundamental Scientific Research of State Academies of Sciences for 2017–2020 (theme III.28.1.2). References Gordeev, Yu.I., Abkaryan, A.K., Binchurov, A.S., Yasinsky, V.B., Karpov, I., V., Lepeshev, A.A., Khasanov, OL, Dvilis, E.S., 2014. Razrabotka effektivnykh putey upravleniya strukturoy i svoystvami tverdosplavnykh kompozitov, modi fi tsirovannykh nanochastitsami. Journal of the Siberian Federal University. Series: Technique and technology 7(3), 270–289. Ho, J. Ryu, Soon H. Hong, Woon H. Baek., 2000. Microstructure and mechanical properties of mechanically alloyed and solid-state sintered tungsten heavy alloys, J. Materials Science & Engineering 291, 91–96. Jose Garcia, Veronica Collado Cipres, Andreas Blomqvist, Bartek Kaplan., 2019. Cemented carbide microstructures: a review. International Journal of Refractory Metals & Hard Materials 80, 40–68. Kosimov, K., Mamadzhanov, P.S., Khidirova, B.T., Mirzaakhmedov, M.M., 2015. Mekhanizm iznosa naplavlennykh pokrytiy iz tverdosplavnykh kompozitsionnykh materialov. Vestnik BGAU 1, 90–92. Kreimer, G.S., 1966. Prochnost’ tverdykh splavov. Moscow, pp. 200. Lebedev, M.P., Vinokurov, G.G., Kychkin, A.K., Vasilyeva, M.I., Makharova, S.N., Sivtseva, A.V., Fedorov, M.V., Dovgal, O.V., 2010. Vliyanie ultradispersnykh dobavok na mikrostrukturu i svoystva volframokobaltovykh splavov rabochikh elementov burovoy tekhniki. Izvestiya Samarskogo nauchnogo tsentra Rossiyskoy akademii nauk 12, 427–421. Multanov, A.S., 2002. Osobokrupnozernistye splavy WC-Co dlya osnashcheniya porodorazrushayushchego instrumenta gornykh mashin. Fizicheskaya mezomekhanika 5, 113–116. Nikolenko, S.V., Verkhoturov, A.D., Janitor, M.I., Vlasova, N.M., Pugachevsky, M.A., Mikhailov, M.M., Krestyanikova, N.S., 2018. Ispolzovanie nanoporoshka Al2O3 v kachestve ingibitora rosta zerna v splave VK8. Voprosy materialovedeniya 2(54), 100–105. Ovcharenko, AG, Kozlyuk, A.Yu., Kurepin, MO, 2010. Povyshenie iznosostoykosti plastin iz tverdogo splava. Obrabotka metallov 2(47), 13–15. Panov, V.S., Chuvilin, A.M., Falkovskii, V.A., 2004. Tekhnologiya i svoystva spechennykh tverdykh splavov i izdeliy iz nikh. Moscow, pp. 464. Rechenko, D.S., Ezhov, A.A., Balova, D.G., Tsarenko, I.A., Kisel, A.G., Kamenov, R.U., 2015. Vidy iznosa tverdosplavnykh plastin pri lezviynoy obrabotke i metody borby s nimi.Omskiy nauchnyy vestnik 3(143), 83–87. Rui-Jun Cao, Chen-Guang Lin, Xing-Cheng Xie, Zhong-Kun Lin., 2018. Microstructure and mechanical properties of WC–Co-based cemented carbide with bimodal WC grain size distribution. J. Rare metals 37, 1–7. Allen, C.,Sheen, M., Williams, J., Pugsley, V. A., 2001. The wear of ultra fi ne WC-Co hard metals. J. Wear 250, 604–610. Armstrong, R. W., 2011. The Hardness and Strength Properties of WC-Co Composites. J. Materials 4, 1287–1308.