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Microstructure Investigations of Streak Formation in 6063 Aluminum Extrusions by Optical Metallographic Techniques

  • George Vander Voort (a1), Beatriz Suárez-Peña (a2) and Juan Asensio-Lozano (a3)

Abstract

The present study investigates the effect of the solidification strategy for AA 6063 alloy on the surface appearance of anodized extrusions. The microstructure of the samples was analyzed using both light optical microscopy and scanning electron microscopy. Results show that if heavy segregation occurs from rapid solidification, coarse Mg2Si particles form, thus reducing the potential for precipitation strengthening by the finer β-Mg2Si developed in the solid state. Differentially-strained regions formed during hot extrusion induce differences in particle size for magnesium silicide (Mg2Si) precipitates. Anodizing generates surface roughness due to Mg2Si particle dissolution and AlFeSi decohesion, which is related to both particle size and deformation. During anodizing, an oxide layer forms on the surface of the extruded products, which can lead to streak formation, usually a subject of rejection due to unacceptable heterogeneous reflectivity.

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* Corresponding author. E-mail: jasensio@uniovi.es

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Ali, A.H.A., Hassan, J.M.G., Martin, G. & Ghosh, K. (2011). Development of alba high speed alloy. Light Metals 2011: Proceedings of the TMS 2011 Annual Meeting & Exhibition, San Diego, CA, Feburary 27–March 3, 2011, Lindsay, S.J. (Ed.), pp. 803807. Warrendale, PA: Minerals, Metals, and Materials Society.
Al-Marahleh, G. (2006). Effect of heat treatment on distribution parameters and volume fraction of Mg2Si in structural Al alloy 6063. Am J Appl Sci 3, 18191823.
ASM Specialty Handbook (2002). Properties of wrought aluminum alloys. In ASM Aluminum and Aluminum Alloys, Davis, J.R., Davis & Associates (Eds.), pp. 686687. Materials Park, OH: ASM International.
ASTM Standard E562-11 (2011). “Standard test method for determining volume fraction by systematic manual point count.” West Conshohocken, PA: ASTM International. doi:10.1520/EO562-11.
Cai, M. & Cheng, G.J. (2007). Microstructure-properties relationship in Al-Mg-Si alloys subject to a combined process of extrusion and ageing. JOM 59, 5861.
Callister, W.D. (2000). Development of microstructure-nonequilibrium cooling. In Materials Science and Engineering: An Introduction, Anderson, W. (Ed.), pp. 253255. New York: John Wiley and Sons Inc.
Chakrabarti, D.J. & Laughlin, S.D. (2004). Phase relations and precipitation in Al-Mg-Si alloys with Cu additions. Prog Mater Sci 49, 389410.
Couto, K.S., Claves, S.R., Van Geertruyden, W.H., Misiolek, W.Z. & Goncalves, M. (2005). Treatment effects of homogenization on microstructure and hot ductility of aluminum alloy 6063. Mater Sci Tech 21, 263268.
Dieter, G.E. (1988). Fundamentals of metalworking. In Mechanical Metallurgy, pp. 524526. London: McGraw Hill Book Co.
Edwards, G.A., Stilloer, K., Dunlop, G.L. & Couper, M.J. (1998). The precipitation sequence in Al-Mg-Si alloys. Acta Mater 46, 38933904.
Esmaeili, S., Wang, X., Lloyd, D.J. & Poole, W.J. (2003). On the precipitation-hardening behavior of the Al-Mg-Si-Cu alloy AA6111. Metall Mater Trans A 34, 751763.
Gaber, A., Mossad, A., Matsuda, A.K., Kawabata, T., Yamazaki, T. & Ikeno, S. (2007). Study of the developed precipitates in Al-0.63Mg-0.37Si-0.5Cu (wt%) alloy by using DSC and TEM techniques. J Alloy Compd 432, 149155.
Gavgali, M. & Aksakal, B. (1998). Effects of various homogenization treatments on the hot workability of ingot aluminum alloy AA2014. Mater Sci Eng A 254, 189199.
Gruzlesky, J.E. (2000). Segregation phenomena. In Microstructure Development during Metalcasting, AFS (Ed.), pp. 117131. Des Plaines, IL: American Foundrymen's Society Inc.
Gruzlesky, J.E. & Closset, B.M. (1999). Grain refinement. In The Treatment of Liquid Aluminum-Silicon Alloys, AFS (Ed.), pp. 127142. Des Plaines, IL: American Foundrymen's Society Inc.
Gupta, A.K., Lloyd, D.J. & Court, S.A. (2001). Precipitation hardening in an Al processes 0.4% Mg-1.3% Si-0.25% Fe aluminum alloy. Mater Sci Eng A 301, 140146.
Higginson, R.L. & Sellars, C.M. (2003). Worked Examples in Quantitative Metallography. London: Institute of Metals, Maney Publishing.
Jackson, A. & Sheppard, T. (1997). Extrusion limit diagrams: Effect of homogenizing conditions and extension to productivity analysis. Mater Sci Tech-Lond 13, 6168.
Lassance, D., Fabregue, D., Delannay, F. & Pardoen, T. (2007). Micromechanics temperature fracture in 6xxx Al alloys. Prog Mater Sci 52, 62129.
Meyveci, A., Karacan, I., Caligülü, U. & Durmus, H. (2010). Pin-on-disc characterization of 2xxx and 6xxx aluminum alloys aged by precipitation age and hardening. J Alloy Compd 491, 278283.
Mrowka-Nowotnik, G. (2010). Influence of chemical composition variation and heat properties of 6xxx alloys. Arch Mater Sci Eng 46, 98107.
Muirhead, J., Cawley, J. & Strang, A. (2000). Quantitative aspects of grain size measurement. Mater Sci Tech-Lond 16, 11601166.
Mulazimoglu, M.H., Zaluska, A., Gurzleski, J.E. & Paray, F. (1996). Electron Al-Fe-Si intermetallics in 6201 aluminum alloy. Metall Mater Trans A 27, 929936.
Rivas, A.L., Muñoz, P., Camero, S. & Quintero-Sayago, O. (1999). Effect of the microstructure on the mechanical properties and surface finish of an extruded AA-6063 aluminum alloy. Adv Mat Sci Tech 2, 1523.
Tabrizian, N., Hansen, H.N., Hansen, P.E., Ambat, R. & Moller, P. (2010). Influence of annealing and deformation on optical properties of ultra precision diamond turned and anodized 6060 aluminum alloy. Surf Coat Technol 204, 26322638.
Tokit, Y., Gavgali, M., Salender, R. & Kaymaz, I. (2004). The effect of the microstructural difference between surface and center of the workability of AA6063 homogenized ingot. J Adv Mater 36, 5359.
Tsao, C.S., Chen, C.Y., Jeng, U.S. & Kuo, T.Y. (2006). Precipitation kinetics and transformation of metaestable phases in Al-Mg-Si alloys. Acta Mater 54, 46214631.
Vander Voort, G.F. (1984). Metallography: Principles and Practice. New York: McGraw-Hill.
Vander Voort, G.F. (1994). Precision and reproducibility of quantitative measurements. In Quantitative Microscopy and Image Analysis, Diaz, D.J. (Ed.), pp. 2134. Materials Park, OH: ASM International.
Vander Voort, G.F. (2000). Specimen preparation for image analysis. In Practical Guide to Image Analysis, ASM (Ed.), pp. 3574. Materials Park, OH: ASM International.
Vander Voort, G.F. (2004). Metallographic techniques for aluminum and its alloys. In Metallography and Microstructures, vol. 9, Vander Voort, G.F. (Ed.), pp. 711751. Materials Park, OH: ASM International.
Vermolen, F., Vuik, K. & Van Der Zwaag, S. (1998). A mathematical model for the dissolution kinetics of Mg2Si phases in Al-Mg-Si alloys during homogenization under industrial conditions. Mater Sci Eng A 254, 1332.
Zhang, J., Fan, Z., Wang, Y.Q. & Zhou, B.L. (2001). Equilibrium pseudobinary Al-Mg2Si phase diagram. Mater Sci Tech 17, 494496.
Zhu, H., Couper, M.J. & Dahle, A.K. (2011). Effect of process variables on Mg-Si particles and extrudability of 6xxx series aluminum extrusions. JOM 63, 6671.
Zhu, H., Zhang, X., Couper, M.J. & Dahle, A.K. (2009). Effect of initial microstructure of anodized aluminum extrusions. Metall Mater Trans A 40, 32643275.
Zhu, H., Zhang, X., Couper, M.J. & Dahle, A.K. (2010). The formation of streak defects on anodized aluminum extrusions. JOM 62, 4651.

Keywords

Microstructure Investigations of Streak Formation in 6063 Aluminum Extrusions by Optical Metallographic Techniques

  • George Vander Voort (a1), Beatriz Suárez-Peña (a2) and Juan Asensio-Lozano (a3)

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