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Transmission electron microscopy and differential scanning calorimetry studies on the precipitation sequence in an Al–Mg–Si alloy: AA6022

Published online by Cambridge University Press:  03 March 2011

Reza S. Yassar ,
David P. Field  and
Hasso Weiland
Reza S. Yassar*
Affiliation:
School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920
David P. Field
Affiliation:
School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920
Hasso Weiland
Affiliation:
Alcoa Technical Center, Alcoa Center, Pennsylvania 15069
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

The precipitate sequence in a 6022 aluminum alloy was investigated by means of differential scanning calorimetry (DSC), transmission electron microscopy, and Vickers hardness measurements. The solution-treated samples were quenched and then immediately subjected to DSC and isothermal aging experiments. It was observed that in the early stages of aging there are some unknown small precipitates that form prior to the formation of β″ precipitates. Studies on isothermally aged and DSC heated samples suggest that some of the β″ needles transform during growth to lath-shaped precipitates. An alternative precipitation sequence for AA6022 is proposed.

Keywords

AgingSecond phasesTransmission electron microscopy (TEM)
Type
Articles
Information
Journal of Materials Research , Volume 20 , Issue 10 , October 2005 , pp. 2705 - 2711
Copyright
Copyright © Materials Research Society 2005

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References

REFERENCES

1Miao, W.F. and Laughlin, D.E.: Effects of Cu content and pre-aging on precipitation characteristics in aluminum alloys 6022. Metall. Mater. Trans. A 31, 361 (2000).CrossRefGoogle Scholar
2Miao, W.F. and Laughlin, D.E.: Precipitation hardening in aluminum alloy 6022. Scripta Mater. 40, 873 (1999).CrossRefGoogle Scholar
3Edwards, G.A., Stiller, K., Dunlop, G.L. and Couper, M.J.: The precipitation sequence in Al–Mg–Si alloys. Acta Mater. 46, 3893 (1998).CrossRefGoogle Scholar
4Murayama, M. and Hono, K.: Pre-precipitate clusters and precipitation processes in Al–Mg–Si alloys. Acta Mater. 47, 1537 (1999).CrossRefGoogle Scholar
5Dutta, I. and Allen, S.M.: J. Mater. Sci. Lett. 10, 323 (1991).CrossRefGoogle Scholar
6Andersen, S.J., Zandbergen, H.W., Jansen, J., TrÆholt, C., Tundal, U. and Reiso, O.: Crystal structure of the β′ phase in Al–Mg–Si alloys. Acta Mater. 46, 3283 (1998).CrossRefGoogle Scholar
7Matsuda, K., Naoi, T., Uetani, Y., Sato, T., Kamio, A. and Ikeno, S.: High resolution energy-filtering transmission electron microscopy for equilibrium β-phase in an Al–Mg–Si alloy. Scripta Mater. 41, 379 (1999).CrossRefGoogle Scholar
8Chakrabarti, D.J. and Laughlin, E.: Phase relations and precipitation in Al–Mg–Si alloys with Cu additions. Prog. Mater. Sci. 49, 389 (2004).CrossRefGoogle Scholar
9Wolverton, C.: Crystal structure and stability of complex precipitate phases in Al–Cu–Mg–(Si) and Al–Mg–Si alloys. Acta Mater. 49, 3129 (2001).CrossRefGoogle Scholar
10Bryant, J.D.: The effect of preageing treatments on ageing kinetics and mechanical properties in AA6111 aluminum autobody sheet. Metall. Mater. Trans. A 30, 1999 (1999).CrossRefGoogle Scholar
11Zhen, L. and Kang, S.B.: DSC analyses of the precipitation behavior of two Al–Mg–Si alloys naturally aged for different times. Mater. Lett. 37, 349 (1998).CrossRefGoogle Scholar
12Jacobs, M.H.: The structure of the metastable precipitates formed during ageing of an Al–Mg–Si alloy. Philos. Mag. 26, 1 (1972).CrossRefGoogle Scholar
13Sagalowicz, L., Hug, G., Bechet, D., Sainfort, P. and Lapasset, G. Study of the structural precipitation in the Al-Mg-Si-Cu system, in Intl. Conf. of Al Alloys 4 (Trans Tech, Switzerland, 1994), p. 636.Google Scholar
14Cayron, C., Sagalowicz, L., Beffort, O. and Buffat, P.A.: Structural phase transition in Al–Cu–Mg–Si alloys by transmission-electron-microscopy study on an Al–4 wt% Cu–1 wt% Mg–Ag alloy reinforced by SiC particles. Philos. Mag. 79, 2833 (1999).CrossRefGoogle Scholar
15Westengen, H. and Ryum, N.: Precipitation reactions in an aluminium 1 wt% Mg2Si alloy. Z. Metallkde. 70, 528 (1979).Google Scholar