Effect of mechanical activation of WC-based powder on the properties of sintered alloys

OBRABOTKAMETALLOV Vol. 23 No. 1 2021 76 MATERIAL SCIENCE Effect of mechanical activation of WC-based powder on the properties of sintered alloys Ekaterina Abdulmenova 1, a, * , Sergey Kulkov 1, 2, b 1 Institute of Strength Physics and Materials Science of Siberian Branch of Russian Academy of Sciences, 2/4 pr. Akademicheskii, Tomsk, 634055, Russian Federation 2 National Research Tomsk State University, 36 Lenin Avenue, Tomsk, 634050, Russian Federation a https://orcid.org/0000-0002-9594-5706, Ekaterina.V.Abdulmenova@yandex.ru, b https://orcid.org/0000-0002-4635-6569, kulkov@ispms.ru . Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2021 vol. 23 no. 1 pp. 68–78 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2021-23.1-68-78 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov ARTICLE INFO Article history : Received: 09 October 2020 Revised: 23 October 2020 Accepted: 14 December 2020 Available online: 15 March 2021 Keywords : Wolfram carbide Mechanical activation Phase composition Quasi-amorphous state Coherently diffracting domain Microdistortion Lattice parameter Porosity Hardness Funding The results were obtained in the framework of the Integrated Project “Establishment of import-substituting high-tech full-cycle production of complex-shaped indexable carbide cutting inserts for priority industries” (Agreement No. 075-11-2019-036 dated November 27, 2019) implemented by the ISPMS SB RAS at the fi nancial support of the Ministry of Education and Science of the Russian Federation as part of Decree of the Government of the Russian Federation No. 218 dated April 09, 2010. Acknowledgements The authors express their gratitude to the staff of the Laboratory of Physics of Nano- structured Functional Materials (LPNFM) for their help in preparing hard-alloy sam- ples and help in preparation of sintered samples for further research. ABSTRACT Introduction. For the manufacture of wearproof tools and machine elements, the method of powder metallurgy is widely used. The preliminary high- intensity mechanical activation of the powder is used to improve the structure and properties of the alloy obtained by the method of powder metallurgy. The mechanical activation can result in formation of nanostructures with subsequent amorphization of the material, can bring phase transformations, it can certainly affect the properties of the material. However, mechanical treatment does not always lead to a positive result. Therefore, the study of the effect of mechanical activation of WC-based powder on the properties of sintered alloys is important. Purpose of the work: to study the effect of high-intensity mechanical activation of WC-based powder on the structure and properties of sintered samples. The work investigates alloys obtained by the method of powder metallurgy, using mechanically activated powders for 10 to 300 seconds in a planetary ball mill. Materials and methods. The alloys are obtained by cold one-sided pressing followed by sintering at a temperature of 1400 °C in a vacuum furnace. Particle morphology of powder and structure of alloys is analyzed by scanning electron microscopy method. The metallographic analysis of the alloys is carried out by optical microscopy. Phase analysis and the parameters of the crystal structure are performed by X-ray diffraction. The hardness of the sintered samples is measured by hardness tester. Results and its discussion . It is shown that after sintering of powders alloys with WC and Co phases are formed. The lattice parameter of the WC-phase correlates well with values in literature. A second carbide phase, Co 3 W 3 C, is formed in the samples upon mechanical activation for more than 100 sec. The minimum porosity of sintered sample is 7.8 ± 1 % that corresponds of sample with preliminary mechanical treatment for 30 seconds. It is shown that the hardness depends on grain size, porosity and second carbide content. Thus, mechanical activation can be effective for increasing the physical and mechanical properties and inhibiting grain growth, but in this case, it is necessary to carry out mechanical processing in the mechanical treatment time range 60-100 sec. For citation: Abdulmenova E.V., Kulkov S.N. Effect of mechanical activation of WC-based powder on the properties of sintered alloys . Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2021, vol. 23, no. 1, pp. 68–78. DOI:10.17212/1994-6309-2021-23.1-68-78. (In Russian). ______ * Corresponding author Abdulmenova Ekaterina V. , Postgraduate student Institute of Strength Physics and Materials, Science of Siberian Branch of Russian Academy of Sciences, 2/4 pr. Akademicheskii, 634055, Tomsk, Russian Federation Tel .: 8 (3822) 286-988, e-mail : Ekaterina.V.Abdulmenova@ispms.ru