Abstract
The possibility of the bonding of the two layers of a double oxide film defect when held in liquid A356 Al alloy was investigated. The defect was modelled experimentally by maintaining two aluminium oxide layers in contact with each other and the atmosphere trapped between them in the A356 liquid alloy for varying lengths of time of between 30 s and 48 h. Any changes in the composition and morphology of these layers were studied by SEM, EDX and XRD. The results showed that the two layers of a double oxide film defect might bond to each other by two different mechanisms, one during the transformation of Al2O3 to MgAl2O4 spinel in relatively short holding times, which would cause the layers to bond at several points and the other during the gradual transformation of spinel to MgO in longer times, which would cause strong bonding between the layers. It was shown that any bonding can take place essentially only after the oxygen and nitrogen of the atmosphere within the defect are consumed.
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Acknowledgement
The authors would like to gratefully thank the “International Center for Science, High Technology and Environmental Sciences”, Mahan, Kerman, Iran, who supported this project under the Contract No. 1/1864, and Dr. W. D. Griffiths from the University of Birmingham for helpful discussions.
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This article is dedicated to the founder of Kerman University, Mr. Alireza Afzalipour, on the occasion of the centenary of his birth.
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Aryafar, M., Raiszadeh, R. & Shalbafzadeh, A. Healing of double oxide film defects in A356 aluminium melt. J Mater Sci 45, 3041–3051 (2010). https://doi.org/10.1007/s10853-010-4308-8
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DOI: https://doi.org/10.1007/s10853-010-4308-8