Amirov A.I. et. al. 2019 Vol. 21 No. 3

OBRABOTKAMETALLOV Vol. 21 No. 3 2019 81 MATERIAL SCIENCE References 1. Mishra R.S., Ma Z.Y. Friction stir welding and processing. Materials Science and Engineering R: Reports , 2005, vol. 50, iss. 1–2, pp. 1–78. DOI: 10.1016/j.mser.2005.07.001. 2. Nandan R., Debroy T., Bhadeshia H. Recent advances in friction-stir welding – Process, weldment structure and properties. Progress in Materials Science , 2008, vol. 53, iss. 6, pp. 980–1023. DOI: 10.1016/j. pmatsci.2008.05.001. 3. FariasA., Batalha G.F., Prados E.F., Magnabosco R., Delijaicov S. Tool wear evaluations in friction stir processing of commercial titanium Ti–6Al–4V. Wear , 2013, vol. 302, iss. 1–2, pp. 1327–1333. DOI: 10.1016/j.wear.2012.10.025. 4. Liu H.J., Zhou L., Liu Q.W. Microstructural evolution mechanism of hydrogenated Ti–6Al–4V in the friction stir welding and post-weld dehydrogenation process. Scripta Materialia , 2009, vol. 61, iss. 11, pp. 1008–1011. DOI: 10.1116/j.scriptamat.2009.08.012. Formation Features of a Welding Joint of Alloy Grade2 by the Friction Stir Welding using Temperature Resistant Tools Alihan Amirov а, * , Veronika Utyaganova b , Vladimir Beloborodov c , Aleksandr Eliseev d Institute of Strength Physics and Materials Science of the Siberian Branch of the RAS, 2/4 pr. Akademicheskii, Tomsk, 634055, Russian Federation а https://orcid.org/0000-0002 - 5143-8235, amirov@ispms.tsc.ru, b https://orcid.org/0000-0002-2303-8015, veronika_ru@ispms.tsc.ru, c https://orcid.org/0000-0003-4609-1617, vabel@ispms.tsc.ru , d https://orcid.org/0000-0001-5273-9729, alan@ispms.tsc.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2019 vol. 21 no. 3 pp. 72–82 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2019-21.3-72-82 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov ARTICLE INFO Article history : Received: 17 May 2019 Revised: 17 June 2019 Accepted: 05 July 2019 Available online: 15 September 2019 Keywords : Friction stir welding Titanium alloy Grade2 Microstructure Welding tool Tool wear Fractography Funding This work was performed within the frame of the Fundamental Research Program of the State Academies of Sciences for 2013-2020, line of research III.23. ABSTRACT Introduction. The technological process of manufacturing products made of titanium is often complicated by the low quality of welded joints during electric arc or gas-flame welding operations due to high residual stresses and strains. An example of a successful resolution of this problem is the development and implementation of such high-tech processes of butt welding of metals, such as friction stir welding, which is not related to fusion bonding methods. Friction stir welding as an advanced technology is used to produce compounds made of “soft” metallic materials, such as aluminum. For “hard” metallic materials, friction stir welding work was limited due to the high demands on the welding tool. Goal of research . The purpose of the work is to compare tools made of various materials used for friction welding with mixing of titanium, as well as to study the welds obtained by friction stir welding in a protective atmosphere of argon. Results and discussion. Optical and scanning electron microscopy results revealed gradient structure, of the weld that is consisted of a thermomechanical impact zone, and a stir zone with a fine-grained structure. When varying the welding parameters, it was shown that the welds defect structure is more influenced by the welding speed, which is caused by a significant difference in the thermal effect on the material. The use of a protective atmosphere of argon during friction stir welding with mixing of a titanium alloy changes the metal structure in the frictional heating zone and eliminates large discontinuities formed without the protective atmosphere of argon at a low welding speed, and there is no oxidation of titanium that occurs during welding. Experimental data show that the use of zirconium diboride tool with silicon carbide additives as a material for friction stir welding tool can lead to excessive occurrence of foreign inclusions in the mixing zone associated with brittle fracture of the tool, which is not observed when using a tungsten carbide tool. For citation: Amirov A.I., Utyaganova V.R., Beloborodov V.A., Eliseev A.A. Formation features of a welding joint of alloy Grade2 by the friction stir welding using temperature resistant tools. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2019, vol. 21, no. 3, pp. 72–82. DOI: 10.17212/1994-6309-2019-21.3-72-82. (In Russian). ______ * Corresponding author Amirov Alihan I., Post-graduate Student Institute of Strength Physics and Materials Science of the Siberian Branch of the RAS 2/4, pr. Akademicheskii, 634055, Tomsk, Russian Federation Tel.: +7 (382) 249–11–60 , e–mail: amirov@ispms.ru