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

N. A. Belov, Professor of a Chair of Casting Technologies and Art Material Processing, e-mail: nikolay-belov@yandex.ru

V. V. Doroshenko, Post-Graduate Student, Engineer of a Chair of Metal Forming

N. E. Bauman Moscow State Technical University, Moscow, Russia:
E. A. Naumova, Leading Engineer of a Chair of Metal Forming

Moscow Polytechnic University, Moscow, Russia:
V. D. Ilyukhin, Assistant Professor of a Chair of Mechanics and Control

The experimental alloy Al6Ca1Fe is an example of substantiated principal possibility of alloy using on the basis of aluminium-calcium eutectic for foundry goods obtaining by die casting. The alloys were made in resistor furnace in graphite-chamotte cup on the basis of aluminium A85. Pure calcium and iron as master alloy Al – 10% Fe were introduced. Casting was carried out with the temperature of 730–740 ^оС, obtaining various foundry goods. Microstructure of cast samples was studied with optical microscope Olympus GX51 and scanning electron microscope TESCAN VEGA 3. Primary crystals of aluminium solid solution contain almost no calcium and iron. These elements are found in eutectic, containing ~7.4% Ca and 0.9% Fe. Besides, aluminium solid solution can be in equilibrium not only with the double system phases (Al₄Ca and Al₃Fe), but also with triple compound Al₁₀CaFe₂. According to this, the general form of the phase diagram Al – Ca – Fe in the rich-aluminium area is shown. In particular, the structure of liquidus surface is offered, two triple-phase areas (Al) + Al₄Ca + Al₁₀CaFe₂ and (Al) + Al₁₀CaFe₂ + Al₃Fe were found, and two non-variant reactions were set (the eutectic one L → (Al) + Al₄Ca + Al₁₀CaFe₂ and the peritectic one L + Al₃Fe → (Al) + Al₁₀CaFe₂). Comparison of experimental alloy Al6Ca1Fe and АК12 silumine showed that aluminium-calcium eutectic is much finer than aluminium-silicon one. The size of dendrite cells of solid aliminium solution is ~7 μm, and thickness of dendrite branches of aliminides, included in eutectic, is lesser than 0.5 μm. Casting properties of alloy Al6Ca1Fe (particularly, hot-shortness), are the same as of eutectic silumines. The samples for investigation of structure and properties were obtained from alloy Al6Ca1Fe by die casting on unit А71108 with locking device 250 t. Definition of mechanical properties on especially cast tensile samples (thickness from 1.9 to 6.5 mm) showed their characteristics by high stability. At the same time, the ultimate resistance is higher than 200 MPa.
This paper was written within the subsidiary agreement No. 14.578.21.0220 (unique identifier ПНИЭР RFMEFI57816X0178) of the Ministry of Education and Science of Russian Federation within the realization of the Federal Target Program “Investigations and developments on priority ways of development of scientific-technological complex of Russia for 2014–2020”.

1. Kaufman J. G., Rooy E. L. Aluminum alloy castings: properties, processes and applications. Materials Park: ASM International, 2004. 340 p.

2. Zolotorevskiy V. S., Belov N. A. Metal science of cast aluminium alloys. Moscow : MISiS, 2005. 376 p.
3. Belov N. A., Savchenko S. V., Belov V. D. Atlas of microstructures of industrial silumines. Moscow : Izdatelskiy Dom “MISiS”, 2009. 204 p.
4. State Standard GOST 1583–93. Aluminium casting alloys. Specifications. Introduced: 1997–01–01.
5. Mohamed A. M. A., Samuel F. H., Samuel A. M., Doty H. W. Influence of additives on the impact toughness of Al – 10.8 % Si near-eutectic cast alloys. Materials and Design. 2009. Vol. 30. pp. 4218–4229.
6. Hosch T., Napolitano R. E. The effect of the flake to fiber transition in silicon morphology on the tensile properties of Al – Si eutectic alloys. Materials Science and Engineering A. 2010. Vol. 528. pp. 226–232.
7. Bao Li, Hongwei Wang, Jinchuan Jie, Zunjie Wei. Effects of yttrium and heat treatment on the microstructure and tensile properties of Al – 7.5Si – 0.5Mg alloy. Materials and Design. 2011. Vol. 32. pp. 1617–1622.
8. Puga H., Costa S., Barbosa J., Ribeiro S., Prokic M. Influence of ultrasonic melt treatment on microstructure and mechanical properties of AlSi₉Cu₃ alloy. Journal of Materials Processing Technology. 2011. Vol. 211. pp. 1729–1735.
9. Hosch T., Napolitano R. E. The effect of the flake to fiber transition in silicon morphology on the tensile properties of Al – Si eutectic alloys. Materials Science and Engineering A. 2010. Vol. 528. pp. 226–232.
10. Milligan J., Vintila R., Brochu M. Nanocrystalline eutectic Al–Si alloy produced by cryomilling. Materials Science and Engineering A. 2009. Vol. 508. pp. 43–49.
11. Böyük U., Engin S., Maral N. Microstructural characterization of unidirectional solidified eutectic Al – Si – Ni alloy. Materials characterization. 2011. Vol. 62. pp. 844–851.
12. Wu Shu-sen, Zhong Gu, An Ping, Wan Li, H. Nakae. Microstructural characteristics of Al – 20Si – 2Cu – 0.4Mg – 1Ni alloy formed by rheo-squeeze casting after ultrasonic vibration treatment. Transactions of Nonferrous Metals Society of China. 2012. Vol. 22. pp. 2863–2870.
13. Moustafa M. A., Samuel F. H., Doty H. W. Effect of solution heat treatment and additives on the microstructure of Al – Si (A413.1) automotive alloys. Journal of materials science. 2003. Vol. 38. pp. 4507–4522.
14. Mondolfo L. F. Structure and Properties of Aluminum Alloys. Translated from English. Moscow : Metallurgiya, 1979. 640 p.
15. Kevorkov D., Schmid-Fetzer R. The Al – Ca system. Part 1: experimental investigation of phase equilibria and crystal structures. Z. Metallkd. 2001. Vol. 92 (8). pp. 946–952.
16. Belov N. A., Naumova E. A., Alabin A. N., Matveeva I. A. Effect of scandium on structure and hardening of Al – Ca eutectic alloys. Journal of Alloys and Compounds. 2015. Vol. 646. pp. 741–747.
17. Novikov I. I. Hot-shortness of non-ferrous metals and alloys. Moscow : Nauka, 1966. 299 p.
18. Eskin D. G., Katgerman L. Mechanical properties in the semi-solid state and hot tearing of aluminium alloys. Progress in Materials Science. 2004. Vol. 49. pp. 629–711.
19. State Standard GOST 11069–2001. Primary aluminium. Grades. Introduced: 2003–01–01.
20. State Standard GOST 1497–84. Metals. Methods of tension test. Introduced: 1986–01–01.
21. State Standard GOST 9.021–74. Unified system of corrosion and aging protection. Aluminium and aluminium alloys. Accelerated test methods for intercrystalline corrosion. Introduced: 1975–01–01.
22. Bäckerud L., Chai G., Tamminen J. Solidification characteristics of aluminum alloys. Vol. 2: Foundry Alloys, Des Plaines: AFS. SkanAluminium, 1990. 136 p.
23. Belov N. A. Phase composition of industrial and prospective aluminium alloys. Moscow : Izdatelskiy Dom “MISiS”, 2010. 511 p.