Chair of Technology of Foundry Processes, National University of Science and Technology “MISiS”, Moscow, Russia:

N. A. Belov, Professor, Director of Engineering Center “Innovation foundry technologies and materials”, e-mail: nikolay-belov@yandex.ru
A. N. Alabin, Head of Department of Engineering Center “Innovation foundry technologies and materials”
R. A. Biktagirov, Candidate for a Master's Degree

Subsidiary of “RUSAL” JSC, IP LTD, Moscow, Russia:

I. A. Matveeva, Head of a Project

“Plant of aluminium alloys” JSC, Moscow Oblast, Russia:

A. G. Tsydenov, Chief Executive Officer

There was researched the influence of 0.3–0.4% of zirconium additive on durability of cold rolled sheets of aluminum can alloys (AA3104 grade), annealed at the temperatures of up to 450 ^оC, inclusively. The sheets with 1 mm thickness, obtained by cold rolling from flat ingots with 15 mm thickness, were the objects of this research. The structure was studied by methods of light and electronic microscopy (scanning and transmission). Mechanical properties of sheets were estimated, according to the results of hardness and tension tests. All alloys, obtained from the can scrap, had identical structure in as-cast condition: Fe-containing phase streaks (basically, Al₁₅(Fe, Mn)₃Si₂), situated on the boundaries of dendrite cells. The whole amount of zirconium was contained in aluminum solid solution, because the primary crystals of Al3Zr phase were not found. Even during the foil obtaining, presence of zirconium in aluminium solid solution had no influence on the processability during the cold rolling. Zirconium has inconsiderable influence on hardness in cold-worked condition, because the solid solution hardening of this additive is insignificant. However, zirconium leads to essential increase of resistance to softening after annealing, starting from the temperature of 350 ^оC. This effect can be explained by formation of the Al3Zr (Ll2) phase nanoparticles, which are efficient anti-recrystallizers. The movement of dislocations is mostly hindered by Al₃Zr nanoparticles, despite their smaller volume fraction (in comparison with Al₆Mn)_, which is connected with smaller distance between particles. Addition of 0,4% of Zr in AA3104 alloy made it possible to raise the yield strength after annealing at 400 oC by 3 times (from 70 MPa to 210 MPa). During the comparison of properties of 6ххх grade and AA3104 + Zr grade alloys, the increased heat resistance of alloys appeared at lower temperatures. In particular, AD33 (AA6061) alloy is strongly softened at the temperature of 300 ^oC, and AD31 (AA6063) alloy is softened at the temperature of 200 ^oC. It is shown that addition of zirconium in 3ххх grade alloys is prospective, because it makes possible to increase the durability of this group of alloys, saving their basic advantages (in particular, high technological efficiency and corrosion resistance).

1. Makarov G. S. Slitki iz alyuminievykh splavov s magniem i kremniem dlya pressovaniya. Osnovy proizvodstva (Ingots, made of aluminium alloys with magnesium and silicon for pressing. Basis of production). Moscow : Intermet Engineering, 2011. 528 p.
2. Alyuminiy. Svoystva i fizicheskoe metallovedenie : spravochnik (Aluminum. Properties and physical metallurgy). Edited by John E. Hatch. Moscow : Metalurgiya, 1989.
3. Promyshlennye alyuminievye splavy : spravochnik (Industrial aluminium alloys : reference book). Edited by F. I. Kvasov and I. N. Fridlyander. Moscow : Metallurgiya, 1984.
4. GOST 4784–97. Alyuminiy i splavy alyuminievye deformiruemye. Marki (State Standard 4784–97. Aluminium and aluminium wrought alloys. Grades). Introduced : 2000–07–01. Moscow : Publishing House of Standards, 2009.
5. Fukui K., Takeda M., Endo T. Morphology and thermal stability of metastable precipitates formed in an Al – Mg – Si ternary alloy aged at 403 K to 483 K. Materials Letters. 2005. Vol. 59. pp. 1444–1448.
6. Sushanta Kumar Panigrahi, R. Jayaganthan. A study on the mechanical properties of cryorolled Al – Mg – Si alloy. Materials Science and Engineering A. 2008. Vol. 480. pp. 299–305.
7. Mori K., Maki S., Ishiguro M. Improvement of product strength and formability in stamping of Al – Mg – Si alloy sheets having bake hardenability by resistance heat and artificial aging treatments. International Journal of Machine Tools & Manufacture. 2006. Vol. 46. pp. 1966–1971.
8. Majed M. R. Jaradeh, Torbjorn Carlberg. Solidification Studies of 3003 Aluminium Alloys with Cu and Zr Additions. Journal of Materials Science and Technology. 2011. Vol. 27, Iss. 7. pp. 615–627.
9. Vlach M., Stulikova I., Smola B., Piesova J., Cisarova H., Danis S., Plasek J., Gemma R., Tanprayoon D., Neuber V. Effect of cold rolling on precipitation processes in Al – Mn – Sc – Zr alloy. Materials Science and Engineering A. 2012. Vol. 548. pp. 27–32.
10. Forbord B., Hallem H., Marthinsen K. The Effect of Alloying Elements on Precipitation and Recrystallisation in Al – Zr. Materials Science Forum. 2004. pp. 1179–1184.
11. Fuller Christian B., Seidman David N. Temporal evolution of the nanostructure of Al(Sc,Zr) alloys. Part II. Coarsening of Al₃(Sc_1–xZr_x) precipitates. Acta Materialia. 2005. Vol. 53. pp. 5415–5428.
12. Clouet E., Barbu A., Lae L., Martin G. Precipitation kinetics of Al₃Zr and Al₃Sc in aluminum alloys modeled with cluster dynamics. Acta Materialia. 2005. Vol. 53. pp. 2313–2325.
13. Knych T., Piwowarska M., Uliasz P. Studies on process of heat treatment of conductive Al – Zr alloys obtained in various productive processes. Archives of Metallurgy and materials. 2011. Vol. 56. pp. 985–692.
14. GOST 2999–75. Metally i splavy. Metod izmereniya tverdosti po Vikkersu (State Standard 2999–75. Metals and alloys. Vickers hardness test method). Introduced: 1976–06–01. Moscow : Publishing House of Standards, 1986.
15. GOST 1496–84. Metally. Metody ispytaniy na rastyazhenie (State Standard 1496–84. Metals. Tensile test methods). Introduced : 1986–01–01. Moscow : Publishing House of Standards, 2008.
16. Lai J., Zhang Z., Chen X.-G. The thermal stability of mechanical properties of Al – B₄C composites alloyed with Sc and Zr at elevated temperatures. Materials Science and Engineering A. 2012 Vol. 532. pp. 462–470.