Hardening of Al-Mg-Si Alloys and Effect of Particle Structure

Abstract:

In the present study, several Al-Mg-Si alloys have been studied with respect to microstructure characteristics, i.e. particle statistics, and resulting mechanical properties. The alloys and tempers represents a wide range of type of hardening particles stretching from pre-β’’, via β’’, to post-β’’ particles such as β’, U1, U2 and B’, and various sizes, number densities and volume fractions of these particles. The correlation between volume fraction of hardening precipitates and mechanical strength is strong within alloys with pre-β’’ and β’’ as the main hardening precipitates, but this correlation does not fit for alloys with post-β’’ precipitates. However, a strong correlation between mechanical strength and both number density and cross-section area of the hardening precipitates is found, independent of type of precipitate. The consequences of these correlations are discussed with respect to proposed hardening models found in the literature.

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 283-288
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.283
• Online since: January 2012
• Authors: Sverre Gulbrandsen-Dahl, Calin D. Marioara, Ketill Olav Pedersen, Knut Marthinsen
• Keywords: Al-Mg-Si Alloy, Artificial Aging, Mechanical Property, Precipitation

References

[1] I. Polemar: Light Alloys, 4th ed (Butterworth-Heinemann), (2006), pp.29-96.

[2] L.M. Brown, R.K. Ham, In: Strengthning methods in crystals, edited by A. Kelly, R.B. Nicholson/Elsiver Publishing Company, p.12 (1971).

[3] G. Liu, G.J. Zhang, X.D. Ding, J. Sun, K.H. Chen, Mater. Sci. Eng. A Vol. 344 (2003), pp.113-124.

[4] P.M. Kelly, Scripta Metall., 6 (1972), pp.647-656.

[5] O.R. Myhr, Ø. Grong, S.J. Andersen, Acta Mater. Vol. 49 (2001), pp.65-75.

[6] A.W. Zhu, E.A. Starke Jr., Acta Mater. Vol. 47 (1999), pp.3263-3269.

[7] S.P. Yuan, R.H. Wang, G. Liu, R. Li, J.M. Park, J. Sun, K. -H. Chen, Mater. Sci. Eng. A Vol. 527 (2010), p.7369–7381.

[8] C.D. Marioara, S.J. Andersen, J. Jansen, H.W. Zandbergen, Acta Mater. Vol. 51 (2003), pp.789-796.

[9] S.J. Andersen, Metall. Mater. Trans. Vol. 26A (1995), p.1931-(1937).

[10] C. D. Marioara, S. J. Andersen, T. N. Stene, H. Hasting, J. Walmsley, A.T.J. van Helvoort and R. Holmestad, Phil. Mag. Vol. 87 (2003), pp.3385-3413.

DOI: 10.1080/14786430701287377

[11] C.D. Marioara, H. Nordmark, S.J. Andersen, R. Holmestad, J. Mat, Sci. Vol. 41 (2006), pp.471-478.

[12] S. Gulbrandsen-Dahl, K.O. Pedersen, C. Marioara, M. Kolar and K. Marthinsen, in: Aluminium Alloys, edited by J. Hirsch, B. Skrotzki and G. Gottstein/Wiley-VCH, Germany (2008), pp.1634-1639.