University of Science and Technology MISIS, Moscow, Russia

N. A. Belov, Chief Researcher, Doctor of Engineering Sciences, Professor, Dept. of Metal Forming, e-mail: nikolay-belov@yandex.ru
S. O. Cherkasov, Research Project Engineer, Dept. of Metal Forming, e-mail: cherkasov.so@misis.ru
A. I. Khabibullina, Research Project Engineer, Dept. of Metal Forming, e-mail: alinochka_khabibulina@mail.ru

Siberian Federal University, Krasnoyarsk, Russia

M. M. Motkov, Senior Researcher, Candidate of Engineering Sciences, Dept. of Electrical Engineering and Electrotechnology, e-mail: mikhail145@mail.ru

Using computational methods (Thermo-Calc software) and experimental approaches such as scanning electron microscopy, microanalysis, and transmission electron microscopy, the microstructural changes in an aluminum alloy of the Al – Zn – Mg – Ni – Fe – Zr – Sc system containing 7.4% Zn, 2.8% Mg, 1.3% Ni, 0.9% Fe, 0.2% Zr, and 0.1 % Sc have been studied. The alloy was cast in an electromagnetic crystallizer (EMC) using ElmaCast™ technology at the production facilities of Research and Production Center of Magnetohydrodynamics, as a cast rod stock with a diameter of 12 mm. Workpieces cut from cast articles underwent complex deformation and heat treatment, resulting in various semi-finished products such as strips, rods, and wire. Hot-rolled strips with a thickness of 2 mm were produced on a two-high mill at MISIS, while cold-rolled sheets with a thickness of 1 mm were formed using VEM 3M electromechanical rolls. Rods with a diameter of 3.7 mm were produced using the Conform method, and then wire with a diameter of 1.3 mm was produced using calibrated rolling on manual rollers. The results showed that casting using the ElmaCast™ technology (crystallization rate over 1000 K/s) produces a highly dispersed cast structure, with the average dendritic cell size of the aluminum matrix being approximately 5 μm. The iron is completely incorporated into submicron eutectic inclusions of the Al9FeNi phase. The highly homogeneous cast structure of the EMC workpieces ensures the necessary ductility for deformation, enabling the production of various semi-finished products. During deformation, a composite-like structure is formed, in which submicron globular particles of the Al9FeNi phase are uniformly distributed within the aluminum matrix. The optimal combination of high hardness, achieved after quenching and aging, and preserved deformation ductility contributes to a significant improvement in mechanical properties. Given the significant presence of the eutectic phase in the experimental alloy, it can be concluded that it has potential for use in additive manufacturing.
This work was supported by the Russian Science Foundation grant No. 22-19-00128 (https://rscf.ru/project/22-19-00128/).

1. GOST 4784–2019. Aluminium and wrought aluminium alloys. Grades. Introduced: 01.09.2019.
2. Polmear I., StJohn D., Nie J.F., Qian M. Physical metallurgy of aluminium alloys. Light Alloys. 5th ed. London : Elsevier, 2017. pp. 31–107.
3. Zhang M., Liu T., He C., Ding J., Liu E., Shi C., Li J., Zhao N. Evolution of microstructure and properties of Al – Zn – Mg – Cu – Sc – Zr alloy during aging treatment. Journal of Alloys and Compounds. 2016. Vol. 658. pp. 946–951.
4. Yang W., Ji S., Zhang Q., Wang M. Investigation of mechanical and corrosion properties of an Al – Zn – Mg – Cu alloy under various ageing conditions and interface analysis of η′ precipitate. Materials and Design. 2015. Vol. 85. pp. 752–761.
5. Zhu Q., Cao L., Wu X., Zou Y., Couper M. J. Effect of Ag on age-hardening response of Al – Zn – Mg – Cu alloys. Materials Science and Engineering A. 2019. Vol. 754. pp. 265–268.
6. Ghosh A., Ghosh M., Kalsar R. Influence of homogenization time on evolution of eutectic phases, dispersoid behaviour and crystallographic texture for Al – Zn – Mg – Cu – Ag alloy. Journal of Alloys and Compounds. 2019. Vol. 802. pp. 276–289.
7. Ohira T., Kishi T. Effect of iron content on fracture toughness and cracking processes in high strength Al – Zn – Mg – Cu alloy. Materials Science and Engineering A. 1986. Vol. 78, Iss. 1. pp. 9–19.
8. Dobatkin V. I., Elagin V. I., Fedorov V. M. Rapidly crystallized aluminum alloys. Moscow : VILS, 1995. 341 p.
9. Avdulov A. A., Usynina G. P., Sergeev N. V., Gudkov I. S. Distinctive features of the structure and characteristics of long-length light gauge ingots from aluminium alloys cast into electromagnetic crystallizer. Tsvetnye Metally. 2017. No. 7. pp. 73–77.
10. Sidelnikov S. B., Voroshilov D. S., Motkov M. M., Timofeev V. N. et al. Investigation structure and properties of wire from the alloy of AL-REM system obtained with the application of casting in the electromagnetic mold, combined rolling-extruding, and drawing. The International Journal of Advanced Manufacturing Technology. 2021. Vol. 114. pp. 2633–2649.
11. Timofeev V. N., Pervukhin M. V., Sergeev N. V. etc. Method for continuous casting of an ingot and a melting and casting installation for its implementation. Patent RF, No. 2745520. Applied: 23.03.2020. Published: 25.03.2021.
12. Korotkova N. O., Belov N. A., Timofeev V. N., Motkov M. M., Cherkasov S. O. Influence of heat treatment mode on the structure and properties of conductive aluminium alloy Al – 7% REE obtained by casting into an electromagnetic crystallizer. Fizika metallov i metallovedenie. 2020. Vol. 121. No. 2. pp. 200–206.
13. Belov N. A., Korotkova N. O., Akopyan T. K., Timofeev V. N. Structure and properties of Al – 0.6% Zr – 0.4% Fe – 0.4% Si (wt.%) wire alloy manufactured by electromagnetic casting. JOM. 2020. Vol. 72, Iss. 4. pp. 1561–1570.
15. GOST 11069–74. Primary aluminium. Grades. Introduced: 01.01.1975.
16. GOST 3640–79. Zinc. Specifications. Introduced: 01.01.1980.
17. GOST 804–93. Primary magnesium ingots. Specifications. Introduced: 01.01.1997.
18. GOST 2999–75. Metals and alloys. Vickers hardness test by diamond pyramid. Introduced: 01.07.1976.
19. GOST 27333–87. Nondestructive testing. Measurement of electrical conductivity of non-ferrous metals by eddy current method. Introduced: 01.07.1988.
19. Belov N. A. Sparingly alloyed high-strength aluminum alloys: Principles of phase composition optimization. Metallovedenie i termicheskaya obrabotka metallov. 2011. Vol. 53. No. 9–10. pp. 420–427.
20. Akopyan T. K., Belov N. A. Approaches to the design of the new highstrength casting aluminum alloys of 7xxx series with high iron content. Non-ferrous Metals. 2016. No. 1. pp. 20–27.
21. Akopyan T.K., Belov N.A., Alabin A.N., Zlobin G.S. Calculation and experimental study of aging of cast high-strength aluminum alloys of the Al – Zn – Mg – (Cu) – Ni – Fe system. Metals. 2014. No. 1. pp. 70–76.
22. Belov N. A., Alabin A. N., Matveeva I. A. Optimization of phase composition of Al – Cu – Mn – Zr – Sc alloys for rolled products without requirement for solution treatment and quenching. Journal of Alloys and Compounds. 2014. Vol. 583. pp. 206–213.
23. Knipling K. E., Karnesky R. A., Lee C. P., Dunand D. C., Seidman D. N. Precipitation evolution in Al – 0.1 Sc, Al – 0.1 Zr and Al – 0.1 Sc – 0.1 Zr (at.%) alloys during isochronal aging. Acta Materialia. 2010. Vol. 58. pp. 5184–5195.
24. Mukherjee T., Zuback J. S., De A., DebRoy T. Printability of alloys for additive manufacturing. Scientific Reports. 2016. Vol. 6. 9717.
25. Konkevich V. Yu., Timofeev V. N., Usynina G. P., Belotserkovets V. V. Structure formation during WAAM and L-DED processes using wire produced from ingots of Al – Mg alloys with transition metals by electromagnetic crystallization. Tsvetnye Metally. 2023. No. 7. pp. 47–55.