National University of Science and Technology MISiS, Moscow, Russia:

N. A. Belov, Professor, Principal Researcher at the Department of Metal Forming, Doctor of Technical Sciences, e-mail: nikolay-belov@yandex.ru
Т. К. Akopyan, Research Fellow at the Department of Metal Forming, Candidate of Technical Sciences, e-mail: nemiroffandtor@yandex.ru
S. S. Mishurov, Lead Engineer at the Department of Metal Forming, e-mail: mishurovs@mail.ru
А. А. Sokorev, Senior Lecturer, Department of Casting and Material Working, e-mail: RCstuff@yandex.ru

Through thermodynamic analysis of the phase diagram Al – Ca – Fe – Si in Thermo-Calc (database: TTAL5), the concentrations of calcium, iron and silicon have been confirmed for the new aluminium matrix composite with the following composition, wt %: Al – 4Ca – 1Fe – 0.6Si, based on quaternary eutectic L  (Al) + Al₄Ca + Al₁₀CaFe₂ + Al₂CaSi₂. Small portions of transition metals Zr and Sc (i.e. 0.2 and 0.1 wt %, correspondingly) were used for additional doping of the selected alloy. The design characteristics of such alloy indicate that the total content of calcium phases exceeds 18 vol %, and the nanoparticles of the L1₂ phase, which form after disintegration of the supersaturated (Al), should amount to approximately 0.5 vol %. A continuous casting machine was used to produce a quality round ingot with the diameter of 150 mm and the length of 800 mm from the selected alloy. Structural studies by optical microscopy, scanning electron microscopy and electron microprobe analysis showed that the cast structure of the alloy contains primary (Al) crystals and a high dispersion eutectic. According to the spectral analysis, the primary (Al) crystals only contain zirconium and scandium, whereas almost all of the calcium, iron and silicon make a part of the eutectic. Subjected to radial-displacement rolling at the temperature not exceeding 450 ^oC, the obtained alloy demonstrated high processability (~99% of total reduction), and a 9 mm rod was produced with no visible defects. Due to high structural dispersion observed after deformation, further deformation was applied at ambient temperature. Thus, rolling of a 11 mm square section to final size (~98% reduction) and the following drawing operation produced wire rod with the minimum diameter of 0.26 mm (~94% reduction). Analysis of the mechanical properties of the wire rod showed that the obtained aluminium-calcium alloy can be considered a material operating at higher temperatures. In particular, after 1 h of heat treatment at 400 ^oC the ultimate tensile strength was 260 MPa, and the yield strength was 220 MPa. This means that the alloy in view significantly outperforms the most heat resistant wrought alloys of 2ххх series (2024, 2019 and others) subjected to the same regime of heat treatment.
The research was conducted under support of the Assignment No. 11.2072.2017/4.6 for implementation of the project on the theme "Development of fabrication technology for deformed semiproducts made of aluminium matrix eutectic composites, strengthened by L12 phase nano-particles without quenching".

1. Polmear I. J. Light Metals: From Traditional Alloys to Nanocrystals. 4th edition. Elsevier, 2005. 421 p.
2. Hatch J. E. Aluminum: properties and physical metallurgy. ASM International. Ohio. 1984. 422 p.
3. Adem O., Hatem A., Fevzi Y. Production and characterisation of silicon carbide particulate reinforced aluminium-copper alloy matrix composites by direct squeeze casting method. Journal of Alloys and Compounds. 2007. Vol. 36. pp. 375–382.
4. Abdoli H., Saebnouri E., Sadrnezhaad S. K., Ghanbari M., Shahrabi T. Processing and surface properties of Al – AlN composites produced from nanostructured milled powders. Journal of Alloys and Compounds. 2010. Vol. 490. pp. 624–630.
5. Gulevskiy V. A., Vlasov S. E., Kidalov N. A., Antipov V. I., Kolmakov A. G., Vinogradov L. V. Method for producing composite materials. Patent RF, No. 2539528S1. Applied: 04.07.2013. Published: 20.01.2015. Bulletin No. 2.
6. Belov N. A., Alabin A. N., Eskin D. G. Improving the Properties of Cold Rolled Al – 6 % Ni sheets by alloying and heat treatment. Scripta Materialia. 2004. Vol. 50, Iss. 1. pp. 89–94.
7. Ratke L., Alkemper J. Ordering of the fibrous eutectic microstructure of Al ± Al₃Ni due to accelerated solidification conditions. Acta Materialia. 2000. Vol. 48, Iss. 8. pp. 1939–1948.
8. Xi Li, Yves Fautrelle, Zhongming Ren, Yudong Zhang, Claude Esling. Effect of a high magnetic field on the Al – Al₃Ni fiber eutectic during directional solidification. Acta Materialia. 2010. Vol. 58, Iss. 7. pp. 2430–2441.
9. Belov N. A., Naumova E. A., Akopyan T. K. Aluminium-based eutectic alloys: New doping systems. Moscow : “Ore and Metals” Publishing House, 2016. 256 p.
10. Belov N. A., Naumova E. A., Doroshenko V. V., Avxentieva N. N. Combined Effect of Calcium and Silicon on the Phase Composition and Structure of Al – 10 % Mg Alloy. Russian Journal of Non-Ferrous Metals. 2018. Vol. 59, No. 1. pp. 67–75.
11. Belov N. A., Akopyan T. K., Mishurov S. S., Korotkova N. O. Effect of Fe and Si on the microstructure and phase composition of the aluminium – calcium eutectic alloys. Non-Ferrous Metals. 2017. No 2. pp. 32–37.
12. 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 (t.%) alloys during isochronal ageing. Acta Materialia. 2010. Vol. 58. pp. 5184–5195.
13. Lefebvre W., Danoix F., Hallem H., Forbord B., A. Bostel B, Marthinsen K. Precipitation kinetic of Al₃(Sc,Zr) dispersoids in aluminum. Journal of Alloys and Compounds. 2009. Vol. 470, Iss. 1–2. pp. 107–110.
14. Thermo–Cals Software. Available at: www.thermocalc.com (Accessed: 29.01.2020).
15. Belov N. A., Naumova E. A., Ilyukhin V. D., Doroshenko V. V. Structure and mechanical properties of Al – 6% Ca – 1% Fe alloy foundry goods, obtained by die casting. Tsvetnye Metally. 2017. No. 3. pp. 69–75.
16. Zolotorevskiy V. S., Belov N. A. Technology of cast aluminium alloys. Moscow : MISiS, 2005. 376 p.
17. Belov N. A., Alabin A. N., Eskin D. G., Istomin-Kastrovskiy V. V. Optimization of Hardening of Al – Zr – Sc Casting Alloys. Journal of Material Science. 2006. Vol. 41. pp. 5890–5899.
18. GOST 11069–2001. Primary aluminium. Introduced: 01.01.2003. 19. TU 083.5.314–94. Calcium metal.
20. GOST 1583–93. Aluminium casting alloys. Specifications. Introduced: 01.01.1997.
21. GOST 53777–2010. Master alloys of aluminium. Specifications. Introduced: 01.07.2010.
22. Galkin S. P. Radial Shear Rolling as an Optimal Technology for Lean Production. Steel in Translation. 2014. Vol. 44, No. 1. pp. 61–64.
23. GOST 10446–80. Wire. Tensile test method (incl. Revisions 1, 2). Introduced: 01.07.1982.
24. Belov N. A., Naumova E. A., Doroshenko V. V. Casting aluminumcalcium alloy. Patent RF, No. 2660492. Applied: 03.11.2017. Published: 06.07.2018. Bulletin No. 19.
25. Dobatkin V. I., Elagin V. I., Fedorov V. M. Rapidly solidified aluminium alloys. Moscow : VILS, 1995. 341 p.