Perm National Research Polytechnic University, Perm, Russia:

Yu. D. Shchitsyn, Professor, Head of the Department of Welding, Metrology and Materials Engineering1, Doctor of Technical Sciences, e-mail: schicin@pstu.ru
Е. А. Krivonosova, Professor at the Department of Welding, Metrology and Materials Engineering1, Doctor of Technical Sciences, e-mail: katerinakkkkk@mail.ru
Т. V. Olshanskaya, Associate Professor at the Department of Welding, Metrology and Materials Engineering1, Doctor of Technical Sciences, e-mail: tvo66@mail.ru
S. D. Neulybin, Engineer at the Department of Welding, Metrology and Materials Engineering1, Candidate of Technical Sciences, e-mail: sn-1991@mail.ru

This paper looks at the structure and properties of the high-strength light Al – Mg – Sc alloy 1580 resultant from the application of plasma welding. It was found that by-layer plasma welding with reverse polarity current ensures the absence of internal defects alongside with high strength, ductility and plasticity in the deposited metal. The authors looked at the strengthening effect produced by by-layer forging and successive by-layer plasma welding. The authors established the effect produced by by-layer forging on the structure and properties of metal in plasma welding. The structural difference is shown between the metal of the lower layers (that are closer to the substrate) and that of the upper layers. It was found that the use of bylayer forging in plasma welding reduces the chances of rapid grain growth triggered by repeated heat cycles and results in grain refinement by 1.5–2 times. It was found that by-layer impacts lead to improved phase composition of the aluminium alloy and a more uniform structure, i.e. prevents the predominant localization of the hardening -phase at the layer boundaries and inhibits coagulation of the intermetallic Al₃(Sc_{1 – х}Zr_х) phases. It was established that the ultimate strength of welded layers is comparable to that of cast aluminium alloy being inferior to that of wrought alloy; the plasticity of welded metal exceeds that of castings by 2–3 times and that of annealed and rolled semi-finished products by 1.5 times.
The research was conducted under financial support of the RF Ministry of Education and Science, within the framework of the basic part of the State Assignment (project No. 9.9697.2017/8/9), Government of Perm territory (Perm krai), Ministry of Education and Science of Perm territory (Perm krai), as a pat of the Agreement C-26/795 dated 21/12/2017.

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