JSC Arсonic SMZ, Moscow, Russia

А. М. Drits, Director for Business Development and New Technologies, Candidate of Technical Sciences, Associate Professor, e-mail: dritsam@gmail.com

Moscow Polytechnic University, Moscow, Russia

V. V. Ovchinnikov, Head of the Department of Materials Science, Doctor of Technical Sciences, Professor, e-mail: vikov1956@mail.ru
R. B. Reztsov, Postgraduate Student of the Department of Materials Science, e-mail: anikron_91@mail.ru

CJSC Cheboksary Enterprise “Sespel”, Cheboksary, Russia

V. А. Bakshaev, General Director, e-mail: zaosespel@yandex.ru

Comparative studies results of the structure of mechanical and corrosion properties of butt joints of a pressed profile with a thickness of 20 mm made of aluminum alloy 6082T6, which have been obtained by double-sided friction stir welding (FSW) in air and in water, are presented. It is shown that an increase in the cooling intensity of the metal of the stir zone and the heat-affected zone of the joint has practically no effect on the temporary resistance of welded joints. At the same time, the strength coefficient of the joints is at the level of 0.73–0.74. The use of FSW on a plate made of 6082T6 alloy in water ensures the formation of a stir zone with an average grain size of 4.3–4.7 microns, and with FSW in air, the average grain size in the joint is 6.5–6.8 microns. Both in the case of FSW in air and in the case of FSW of a pressed plate made of 6082T6 alloy in water, the fracture site of the welded joint during tensile tests originates along the thermo-mechanical impact zone (TMIZ) and then develops in the heat-affected zone. When performing FSW in water, the length of the heat-affected zone decreases by about 1.4–1.8 times compared to FSW in the air. The hardness of the stir zone, both after FSW in air and after FSW of alloy 6082T6 in water, is lower than the hardness of the base metal (108 HV). At the same time, the hardness of the stir zone during FSW in water is 90–95 HV, and during FSW in air is 80-83 HV. The fracture of the metal of the stir zone during tensile testing both after welding in air and in water, and after additional ageing at 170 ^oC for 12 hours, has a pronounced viscous nature with the presence of specific pits on the surface.

1. Weglowski M. S. Friction stir processing – State of the art. Archives of Civil and Mechanical Engineering. 2018. Vol. 18, Iss. 1. pp. 114–129.
2. Xie G. M. et al. Development of a fine-grained microstructure and the properties of a nugget zone in friction stir welded pure copper. Scripta Materialia. 2007. Vol. 57, Iss. 2. pp. 73–76.
3. Patel V. V. et al. Influence of friction stir processed parameters on superplasticity of Al – Zn – Mg – Cu alloy. Materials and Manufacturing Processes. 2016. Vol. 31, Iss. 12. pp. 1573–1582.
4. V. A. Bakshaev, A. M. Drits, V. V. Ovchinnikov, M. V. Grigoriev. The method of friction welding with mixing of butt joints of aluminum alloys. Patent RF, No. 2686494. Patent bulletin No. 13. Applied: 12.10.2018. Published: 29.04.2019.
5. Srinivaza Rao T., Koteswara Rao S. R., Madhusudhan Reddy G. Microstructure and fracture features of aluminum alloy AA7075-T651 cooled during friction welding with stirring. Metallovedeniye i termicheskaya obrabotka metallov. 2019. No. 6. pp.48–55.
6. Lukin V. I., Betsofen S. Ya., Panteleev M. D., Dolgova M. I. Influence of the thermal deformation cycle of FSW on the formation of the structure of the welded joint of alloy B-1469. Svarochnoye proizvodstvo. 2017. No. 7. pp. 17–24.
7. Kumar K. S. A., Yogesha K. B. Experimental investigations to find the effect of post weld heat treatment (PWHT) on the microstructure and mechanical properties of FSW dissimilar joints of AA2024-T351 and AA7075-T651. Materials Today: Proceedings. 2021. Vol. 49. pp. 243–249.
8. Vasiliev P. A., Shvedov M. A., Grigoriev V. S., Malov I. A. Friction welding with stirring of aluminum alloy 6082 in an aqueous medium. Svarshchik v Rossii. 2020. No. 2. pp. 6–7.
9. Drits A. M., Ovchinnikov V. V., Bakshaev V. A., Reztsov R. B. The effect of additional cooling during friction-stir welding on the structure and properties of aluminum alloy compounds. Zagotovitelnye proizvodstva v mashinostroenii. 2024. Vol. 22, No. 7. pp. 296–305.
10. Drits A. M., Ovchinnikov V. V., Solovieva I. V., Bakshaev V. A. The effect of forced cooling during friction stir welding on the structure and properties of 1565ChN116 aluminium alloy joints. Tsvetnye Metally. 2021. No. 8. pp. 50–57.
11. Drits A. M., Ovchinnikov V. V., Solovieva I. V., Bakshaev V. A. Properties and structure of joints of alloy 1151 of the Al – Cu – Mg system, obtained by friction stir welding with forced cooling of the seam. Tsvetnye Metally. 2020. No. 11. pp. 70–76.
12. Snyder B., Strauss A. M. In-process cooling of friction stir extruded joints for increased weld performance via compressed air, water, granu lated dry ice, and liquid nitrogen. J. Manuf. Process. 2021. Vol. 68. pp. 1004–1017.
13. Wahid M. A. et al. Analysis of process parameters effects on underwater friction stir welding of aluminum alloy 6082-T6. Proc. Inst. Mech. Eng. Part B. J. Eng. Manuf. 2019. Vol. 233, Iss. 6. pp. 1700–1710.
14. Shanavas S., Edwin Raja Dhas J., Murugan N. Weldability of marine grade AA 5052 aluminum alloy by underwater friction stir welding. Int. J. Adv. Manuf. Technol. 2018. Vol. 95. pp. 4535–4546.
15. Liu H. J., Zhang H. J., Yu L. Effect of welding speed on microstructures and mechanical properties of underwater friction stir welded 2219 aluminum alloy. Mater. Des. 2011. Vol. 32, Iss. 3. pp 1548–1553.
16. Dong J., Zhang D., Zhang W., Zhang W., Qiu C. Microstructure and properties of underwater friction stir-welded 7003-T4/6060-T4 aluminum alloys. J. Mater. Sci. 2019. Vol. 54, Iss. 16. pp. 11254–11262.
17. Zhang H. J., Liu H. J., Yu L. Microstructure and mechanical properties as a function of rotation speed in underwater friction stir welded aluminum alloy joints. Mater. Des. 2011. Vol. 32, Iss. 8-9. pp. 4402–4407.
18. Rouzbehani R., Kokabi A. H., Sabet H., Paidar M., Ojo O. O. Metallurgical and mechanical properties of underwater friction stir welds of Al7075 aluminum alloy. J. Mater. Process. Technol. 2018. Vol. 262. pp. 239–256.
19. Wahid M. A. et al. Friction stir welding of AA-5754 in water and air: a comparative study. Mater. Res. Express. 2018. Vol. 6, Iss. 1. 16545.
20. Nelson T. W., Steel R. J., Arbegast W. J. In situ thermal studies and postweld mechanical properties of friction stir welds in age hardenable aluminium alloys. Science and Technology of Welding and Joining. 2003. Vol. 8, Iss. 4. pp. 283–288.
21. GOST 6996-66. Welded joints. Methods of mechanical properties determination. Introduced: 01.01.1967.
22. GOST 6507-1-2007. Metals and alloys. Vickers hardness test. Part 1. Test method. Introduced: 01.08.2008.
23. GOST 9.021–74. Unified system of corrosion and ageing protection. Aluminium and aluminium alloys. Accelerated test methods for intercrystalline corrosion. Introduced: 01.01.1975.
24. Humphreys F. J. Quantitative metallography by electron backscattered diffraction. Journal of microscopy. 1999. Vol. 195, Iss. 3. pp. 170–185.
25. Vysotskiy I., Malopheyev S., Mironov S., Kaibyshev R. Effect of prestrain path on suppression of abnormal grain growth in friction-stir welded 6061 aluminum alloy. Materials Science and Engineering: A. 2019. Vol. 760. pp. 206–213.
26. Sun G. et al. Study on small fatigue crack initiation and growth for friction stir welded joints. Materials Science and Engineering: A. 2019. Vol. 739. pp. 71–85.