Abstract
The results of experiments are reported in which air bubbles were held for varying lengths of time in melts of three different Al alloys, (commercially pure Al, Al-7Si-0.3Mg, (2L99), and Al-5Mg alloy), with the air bubbles acting as analogs for the behavior of the interior atmosphere of double oxide film defects. After solidification a Pore Gas Analyser was used to measure the contents of the bubble, to determine how their oxygen, nitrogen and hydrogen content varied over time in the different alloys. The results showed that, firstly, oxygen should be consumed by reaction with the surrounding melt to form an oxide, followed by nitrogen, forming a nitride, probably AlN. Simultaneously, hydrogen dissolved in the melt passed in to the air bubble. At the end of the 40 minute holding period the air bubbles, and by analogy the interior atmosphere of a double oxide film defect, largely consisted of a nitrogen/hydrogen atmosphere. The reaction rates obtained from these experiments were used to estimate the time taken for the interior atmosphere of a typical double oxide film defect to be consumed, which was found to vary with alloy type, and to be about 25 minutes in the case of a defect in the Al-7Si-0.3 Mg alloy.
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References
J. Campbell, Castings, Butterworth-Heineman, Oxford, 2003.
N. R. Green and J. Campbell, Influence of oxide film filling defects on the strength of Al-7Si-Mg alloy castings, AFS Trans., 102 (1994) 341–347.
W. D. Griffiths and N-W Lai, Double oxide film defects in cast magnesium alloy, Met. and Mat. Trans. A, 38A, (2007) 190–196.
J. Mi, R. A. Harding, M. Wickins and J. Campbell, J., Entrained oxide films in TiAl castings, Intermetallics, 11 (2003) 377–385.
C. Nyahumwa, N. R. Green, and J. Campbell, J., AFS Trans., 58 (1998) 215–223.
R. Raeiszadeh and W. D. Griffiths, A method to study the history of a double oxide film defect in liquid aluminium alloys, Met. Mat. Trans. B, 37B (2006) 865–871.
El-Sayed, M.A., Salem, H.A.G., Kandeil, A.Y., and Griffiths, W.D., Oxide Film Defects in Al Alloy Castings, 22nd International Conference on Computer-Aided Production Engineering, (2011) Edinburgh, Scotland.
El-Sayed, M.A., Salem, H.A.G., Kandeil, A.Y., and Griffiths, W.D., Effect of Holding Time Before Solidification on DoubleOxide Film Defects and Mechanical Properties of Aluminum Alloys, Met. Mat. Trans. B 42B (2011) 1104–1109.
R. Raeiszadeh and W. D. Griffiths, A semi-empirical mathematical model to estimate the duration of the atmosphere within a double oxide film defect in pure Al alloy, 39B, Met. Mat. Trans. B, 39B (2008) 298–303.
J. M. Park, Behaviour of bifilms in A356 alloy during solidification: developing observation techniques with 3-D micro x-ray tomography, MRes thesis, University of Birmingham, 2010.
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© 2013 TMS (The Minerals, Metals & Materials Society)
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Griffiths, W.D., Caden, A.J., El-Sayed, M.A. (2013). The Behaviour of Entrainment Defects in Aluminium Alloy Castings. In: Krane, M.J.M., Jardy, A., Williamson, R.L., Beaman, J.J. (eds) Proceedings of the 2013 International Symposium on Liquid Metal Processing & Casting. Springer, Cham. https://doi.org/10.1007/978-3-319-48102-9_28
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DOI: https://doi.org/10.1007/978-3-319-48102-9_28
Publisher Name: Springer, Cham
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