Establishment of Graded Hybrid Microstructure Through Centrifugal ‎Casting ‎of a Hypereutectic Al-Mg2Si Alloy‎

Document Type : Original Research Article

Authors

1 M.Sc. Student, Faculty of Materials Engineering, Sahand University of Technology, Tabriz, Iran

2 Associate Professor, Faculty of Materials Engineering, Sahand University of Technology, Tabriz, Iran.

10.22034/frj.2018.134151.1042

Abstract

In this study, centrifugal casting method was used to produce a hyper-eutectic composite Al-Mg2Si ‎with hybrid microstructure and graded hardness. For this purpose, two cylinders with a chemical ‎composition of Al-20Si and Al-20Si-9Mg (weight percent) were cast using a vertical centrifugal ‎casting machine. Then the microstructure and hardness of the cast cylinders were studied along the ‎radial direction by optical and scanning electron microscopes and brinell method, respectively. The ‎results show that in Al-20Si cast cylinder; in contrary to the outer layer which shows only a binary ‎eutectic Al-Si microstructure, the inner layer contains a high volume fraction of in situ segregated ‎primary silicon particles inside the eutectic matrix. By addition of 9% Mg to Al-20Si alloy, the inner ‎layer of the cast cylinder form a hybrid microstructure containing of both Si and Mg2Si particles ‎inside the eutectic matrix, while the outer layer shows only a ternary eutectic Al-Si-Mg2Si ‎microstructure. As a result of these microstructure changes along the radial direction of the ‎cylinders, not only the hardness of both cylinders are smoothly increased from the outer towards the ‎inner layers, but also all radial sections of the Al-20Si-9Mg cylinder in compared with the other one, ‎indicate higher hardness (about 18 brinell).

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Main Subjects


[1] Yan-Bo Z., Chang-Ming L., Kai W., Mao-Hua Z., Yong X., Characteristics of two Al-based functionally ‎gradient composites reinforced by primary Si particles and Si/ in situ Mg2Si particles in centrifugal ‎casting, Transactions of Nonferrous Metals Society of China, (2010), 20, 361-370.‎
‎[2] Yamagiwa K., Wantanabe Y., Fukui Y., Kapranos P., Novel recycling of aluminium and iron ‎wastes in-situ Al-Al3Fe functionally graded material manufactured by a centrifugal method, Materials ‎Transaction, (2003), 44, 2461-2467.‎
‎[3] Rasheedat M.M., Akinlabi E. T., Functionally graded materials, Springer, (2017).‎
‎[4] Erdemer F., Canakcl A., Varol T., Microstructural characterization and mechanical properties of ‎functionally graded Al 2024/SiC composites prepared by powder metallurgy techniques, Trans. ‎Nonferrous Met. Soc. China, (2015), 25, 3569–3577.‎
‎[5] Jiupeng S., Yang Y., Zhigang Zh., Youyun L., Yang Q., Preparation of W–Cu functionally graded ‎material coated with CVD–W for plasma-facing components, Journal of Nuclear Materials, (2013), 442, ‎S208– S213.‎
‎[6] Dbrzanski L.A., Zukowska L.W., Kula J.M., Golombek K., Structure and mechanical properties of ‎gradient PVD coatings, J. Mater. Proc. Tech., (2008), 201, 310–314.‎
‎[7] Pan C., Xu X., New functionally graded thermal barrier coating system based on LaMgAl11O19/YSZ ‎prepared by air plasma spraying, Surf. Coat. Tech., (2012), 206, 2265–2274.‎
‎[8] Ogawa T., Watanabe Y., Sato H., Kim I., Fukui Y., Theoretical study on fabrication of functionally ‎graded material with density gradient by a centrifugal solid-particle method, Composites: Part A, ‎‎(2006), 37, 2194–2200.‎
‎[9] Wang K., Zhang Z.M., Yu T., Zhu Z.Z., The transfer behavior in centrifugal casting of SiCp/Al ‎composites, Journal of Materials Processing Technology, (2017), 242, 60-67. ‎
‎[10] Jayakumar E., Jibin C.J., Rajan T.P.D., Joseph M.A., Pai B.C., Processing and characterization ‎of functionally graded aluminum (A319)-SiCp metallic composites by centrifugal casting technique, ‎Metallurgical and Materials Transactions A, (2016), 47, 4306-4315.‎
‏[11] صمدی ا.، غایب لو م.، آزادی آ.، تاثیر افزودن آهن بر ریزساختار درجه‌بندی شده کامپوزیت ‏Al-13.8‎wt.%Mg2Si‏ در ریخته‌گری‏ گریز از مرکز، مهندسی متالورژی، (1394)، 57، 53-45.‏
‎[12] Valhinho A., Botas J.D., Ariza E., Gomes J.R., Rocha L.A., Tribocorrosion studies in centrifugally ‎cast Al-matrix SiC-reinforced functionally graded composites, Materials Science Forum, ‎‎(2004), 455-456, 871-875.‎
‎[13] Rajan T.P.D., Pillai R.M., Pai B.C., Characterization of centrifugal cast functionally graded ‎aluminum-silicon carbide metal matrix composites, Materials Characterization, (2010), 61, 923-928.‎
‎[14] Radhika N., Mechanical properties and abrasive wear behavior of functionally graded Al-‎Si12Cu/Al2O3 metal matrix composite, Trans. Indian Inst. Met., IIM, (2016), DOI 10.1007/s12666-016-0870-‎‎3.‎
‎[15] El-Hadad Sh., Sato H., Watanabe Y., Wear of Al/Al3Zr functionally graded materials fabricated by ‎centrifugal solid-particle method, Journal of Materials Processing Technology, (2010), 210, 2245-2251.‎
‎[16] Matsuda K., Watanabe Y., Fukui Y., Particle size distributions in in situ Al–Al3Ni FGMs fabricated ‎by centrifugal in situ method, Ceramic Trans, (2001),114, 1–8.‎
‎[17] El-Hadad Sh., Sato H., Miura-Fujiwara E., Watanabe Y., Fabrication of Al-Al3Ti/Ti3Al functionally graded materials ‎under a centrifugal force, Materials, (2010), 3(9), 4639-4656.‎
‏ [18] آقازاده س.، صمدی ا.، آقازاده ا.، تأثیر مقدار سیلیسیم بر درجه‌بندی ریزساختار آلیاژهای ‏Al-Si‏ ریخته‌ شده به ‏روش گریز از مرکز، پژوهش‌نامه ریخته‌گری‏، (1396)، 1(2)، 97-89.‏
‏‎[19] Zhang J., Fan Z., Wang Y.Q., Zhou B.L., Hypereutectic aluminium alloy tubes with graded ‎distribution of Mg2Si particles prepared by centrifugal casting , Materials & Design, (2000), 21(3),149-‎‎153.‎
‎[20] Samadi A., Shahbazkhani H.R., Effect of pouring temperature and casting thickness on distribution ‎gradient of in situ formed Al2Cu particles during centrifugal casting of hypereutectic Al–Cu alloy, ‎International Journal of Cast Metals Research, (2014), 27, 129-134.‎
‎[21] Wang Q., Wei Y., Chen W., Zhu Y., Ma C., Ding W., In situ surface composites of (Mg2Si+Si)/ZA27 ‎fabricated by centrifugal casting, Materials Letters, (2003), 57, 3851– 3858.‎
‎[22] Zhang J., Fan Z., Wang Y.Q., Zhou B.L., Microstructure and mechanical properties of in-situ Al-‎Mg2Si composites, Materials Science and Technology, (2000), 16, 913-918.‎
‎[23] Emamy A., Emami A.R., Khorshidi R., The effect of Fe-rich intermetallics on the microstructure, ‎hardness and tensile properties of Al-Mg2Si die-cast composite, Materials and Design, (2013), 46, 881-‎‎888.‎