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

Published online by Cambridge University Press:  12 March 2013

George Vander Voort ,
Beatriz Suárez-Peña  and
Juan Asensio-Lozano
George Vander Voort
Affiliation:
Struers Inc., 2887 N. Southern Hills Drive, Wadsworth, IL 60083-9293, USA
Beatriz Suárez-Peña
Affiliation:
Materials Science and Metallurgical Engineering Department, The University of Oviedo, Gijón Polytechnic School of Engineering, Viesques University, Gijón, Asturias 33203, Spain
Juan Asensio-Lozano*
Affiliation:
Materials Science and Metallurgical Engineering Department, The University of Oviedo, The School of Mines, Oviedo, Asturias 33004, Spain
*
*Corresponding author. E-mail: jasensio@uniovi.es
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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.

Keywords

light optical microscopyscanning electron microscopyquantitative metallographic characterization6063 aluminum alloysprecipitationstreak formation
Type
Materials Applications
Information
Microscopy and Microanalysis , Volume 19 , Issue 2 , April 2013 , pp. 276 - 284
Copyright
Copyright © Microscopy Society of America 2013

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References

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. 803–807. Warrendale, PA: Minerals, Metals, and Materials Society.Google Scholar
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, 1819–1823.Google Scholar
ASM Specialty Handbook (2002). Properties of wrought aluminum alloys. In ASM Aluminum and Aluminum Alloys, Davis, J.R., Davis & Associates (Eds.), pp. 686–687. Materials Park, OH: ASM International.Google Scholar
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. Google Scholar
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, 58–61.Google Scholar
Callister, W.D. (2000). Development of microstructure-nonequilibrium cooling. In Materials Science and Engineering: An Introduction, Anderson, W. (Ed.), pp. 253–255. New York: John Wiley and Sons Inc. Google Scholar
Chakrabarti, D.J. & Laughlin, S.D. (2004). Phase relations and precipitation in Al-Mg-Si alloys with Cu additions. Prog Mater Sci 49, 389–410.Google Scholar
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, 263–268.Google Scholar
Dieter, G.E. (1988). Fundamentals of metalworking. In Mechanical Metallurgy, pp. 524–526. London: McGraw Hill Book Co. Google Scholar
Edwards, G.A., Stilloer, K., Dunlop, G.L. & Couper, M.J. (1998). The precipitation sequence in Al-Mg-Si alloys. Acta Mater 46, 3893–3904.Google Scholar
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, 751–763.Google Scholar
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, 149–155.Google Scholar
Gavgali, M. & Aksakal, B. (1998). Effects of various homogenization treatments on the hot workability of ingot aluminum alloy AA2014. Mater Sci Eng A 254, 189–199.Google Scholar
Gruzlesky, J.E. (2000). Segregation phenomena. In Microstructure Development during Metalcasting, AFS (Ed.), pp. 117–131. Des Plaines, IL: American Foundrymen's Society Inc. Google Scholar
Gruzlesky, J.E. & Closset, B.M. (1999). Grain refinement. In The Treatment of Liquid Aluminum-Silicon Alloys, AFS (Ed.), pp. 127–142. Des Plaines, IL: American Foundrymen's Society Inc. Google Scholar
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, 140–146.Google Scholar
Higginson, R.L. & Sellars, C.M. (2003). Worked Examples in Quantitative Metallography. London: Institute of Metals, Maney Publishing.Google Scholar
Jackson, A. & Sheppard, T. (1997). Extrusion limit diagrams: Effect of homogenizing conditions and extension to productivity analysis. Mater Sci Tech-Lond 13, 61–68.Google Scholar
Lassance, D., Fabregue, D., Delannay, F. & Pardoen, T. (2007). Micromechanics temperature fracture in 6xxx Al alloys. Prog Mater Sci 52, 62–129.Google Scholar
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, 278–283.Google Scholar
Mrowka-Nowotnik, G. (2010). Influence of chemical composition variation and heat properties of 6xxx alloys. Arch Mater Sci Eng 46, 98–107.Google Scholar
Muirhead, J., Cawley, J. & Strang, A. (2000). Quantitative aspects of grain size measurement. Mater Sci Tech-Lond 16, 1160–1166.Google Scholar
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, 929–936.Google Scholar
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, 15–23.Google Scholar
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, 2632–2638.Google Scholar
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, 53–59.Google Scholar
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, 4621–4631.Google Scholar
Vander Voort, G.F. (1984). Metallography: Principles and Practice. New York: McGraw-Hill.Google Scholar
Vander Voort, G.F. (1994). Precision and reproducibility of quantitative measurements. In Quantitative Microscopy and Image Analysis, Diaz, D.J. (Ed.), pp. 21–34. Materials Park, OH: ASM International.Google Scholar
Vander Voort, G.F. (2000). Specimen preparation for image analysis. In Practical Guide to Image Analysis, ASM (Ed.), pp. 35–74. Materials Park, OH: ASM International.Google Scholar
Vander Voort, G.F. (2004). Metallographic techniques for aluminum and its alloys. In Metallography and Microstructures, vol. 9, Vander Voort, G.F. (Ed.), pp. 711–751. Materials Park, OH: ASM International.Google Scholar
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, 13–32.CrossRefGoogle Scholar
Zhang, J., Fan, Z., Wang, Y.Q. & Zhou, B.L. (2001). Equilibrium pseudobinary Al-Mg2Si phase diagram. Mater Sci Tech 17, 494–496.Google Scholar
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, 66–71.CrossRefGoogle Scholar
Zhu, H., Zhang, X., Couper, M.J. & Dahle, A.K. (2009). Effect of initial microstructure of anodized aluminum extrusions. Metall Mater Trans A 40, 3264–3275.Google Scholar
Zhu, H., Zhang, X., Couper, M.J. & Dahle, A.K. (2010). The formation of streak defects on anodized aluminum extrusions. JOM 62, 46–51.CrossRefGoogle Scholar