National University of Science and Technology MISiS, Moscow, Russia¹ ; Moscow Polytechnic University, Moscow, Russia²:

N. V. Letyagin, Lead Research Project Engineer at the Department of Metal Forming¹, Associate Professor of the Scientific Activity Sector², e-mail: n.v.letyagin@gmail.com

National University of Science and Technology MISiS, Moscow, Russia¹ ; Moscow Polytechnic University, Moscow, Russia²:

T. K. Akopyan, Senior Researcher at the Department of Metal Forming¹, Lead Researcher at the Department of Materials Science²

National University of Science and Technology MISiS, Moscow, Russia:
P. A. Palkin, Master’s Degree Student at the Department of Metal Forming

Moscow Polytechnic University, Moscow, Russia:
V. V. Ovchinnikov, Principal Researcher at the Department of Materials Science

Recent years have seen an ever growing interest in hybrid forming technology, with a special focus on aluminium alloys, which conform with the strategy of reduced weight of parts while maintaining high strength. The problem of combining parts made of such materials into a single assembly unit is of relevance today, alongside the development of new high-tech aluminium alloys. This paper examines the applicability of laser welding for butt joining thin hot-rolled sheets of aluminium alloy Al – 5 Zn – 1.3 Mg – 1 Ca (Fe, Mn, Cu, Si) (wt. %). An unhomogenized ingot of the experimental alloy was hot-rolled at the temperature of 450 ^oC down to the thickness of 2 mm (reduction degree of 90%). Two sheets were joined together on a robot laser welding machine in an optimum mode, which ensures a visual quality of the seam with minimum porosity of the weld. Laser power — 2,400 W, laser beam speed — 10 m/sec, focal distance — 217 mm, shielding gas consumption rate — 15 L/min. A study of microstructure and physical and mechanical properties helped evaluate the effect of the selected welding parameters on weld seam formation. It was found that the laser processing helps form a high-quality weld joint with no cracks and with low porosity. The strength of such weld is at the following level: σ_в = 240 MPa, σ_0,2 = 170 MPa, with the elongation of δ = 3%. The ultimate strength of the weld joint is 83 % and the yield point is 92.5% of the strength of the base metal. The obtained results suggest that laser welding can potentially be applicable to joining sheets made of experimental Al – 5 Zn – 1.3 Mg – 1 Ca (Fe, Mn, Cu, Si) (wt. %) alloys, which differ from 7ххх series alloys due to the presence of calcium-containing eutectic that ensures high crack resistance and good casting and welding processability.

Support for this research was provided under Grant No. 22-19-00121 by the Russian Science Foundation, https://rscf.ru/project/22-19-00121/.

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