Microstructure Solidification Maps for Al-10 Wt Pct Si Alloys
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Hypo-eutectic Al-Si alloys are widely used in both the automotive and aerospace industries; however, they still have limited usage as structural materials, due to the inherent morphology of the Si phase that forms within the eutectic structure. This non-ideal Si morphology can be modified, via alloy additions and/or rapid solidification (RS), but the underlying mechanism(s) behind this is poorly understood. This work focused on understanding the influence of RS on the eutectic structure, for hypo-eutectic Al-10 wt pct Si alloys produced by Impulse Atomization and Differential Scanning Calorimetry. This study found that the eutectic Si forms into four distinct morphologies: (1) flaky, (2) fibrous, (3) globular + fibrous and (4) globular, depending on the solidification conditions. As a result, two solidification maps of the Si morphology are proposed, one based on local eutectic solidification conditions and another based on a solidification continuous cooling diagram (SCCT). Both maps help identify the required conditions for certain Si morphologies to form. Hardness measurements were also carried out and it was found that the Si morphology would influence the alloy hardness, with the highest value being achieved when the eutectic Si was globular. This result indicates that the Si morphology is an important factor that can alter the mechanical properties of hypo-eutectic Al-Si alloys.
The authors wish to acknowledge funding of this work from a Collaborative Research and Development Grant from the Natural Sciences and Engineering Research Council of Canada, Equispheres Inc., and the European Space Agency (ESA).
- 6.N. Rathod and J. Manghani, International Journal of Emergin Trends in Engineering and Development, 2012, vol. 5, pp. 574-582.Google Scholar
- 18.K. Jackson and J. Hunt, Trans. Am. Inst. Min. Engineers, 1966, vol. 236, p. 1129.Google Scholar
- 22.A. L. Genau, Iowa State University, Ames, Iowa, 2004.Google Scholar
- 23.H. Petersen: Report No. 224, Danish Atomic Energy Commission, Riso, 1970, pp. 6–7.Google Scholar
- 25.K. Oswalt and M. Misra, AFS Transactions, 1980, vol. 88, pp. 845-862.Google Scholar
- 26.P. Anyalebechi, T. Rouns, and R. Sanders: in Light Metals 1991, TMS 1990, pp. 821–50.Google Scholar
- 29.H. Jones: in Rapid Solidification of Metals and Alloys, The Institution of Metallurgists, London, 1983, pp. 40–43.Google Scholar
- 30.P. Anyalebechi, TMS, 2004, pp. 217-33.Google Scholar
- 31.G. Armstrong and H. Jones, Solidification and Casting of Metals, London: Metals Society, 1979.Google Scholar
- 36.Z. Zhang, X. Bian, Y. Wang and X. Liu, Transactions of Nonferrous Metals Society of China, 2001, vol. 11, no. 3, pp. 374-377.Google Scholar
- 38.J. Spinelli, W. Hearn, A.-A. Bogno, and H. Henein: in Light Metals 2018, TMS, 2018, pp. 381–87.Google Scholar
- 39.W. D. Callister Jr. and D. G. Rethwisch, Fundamentals of Materials Science and Engineering: An Integrated Approach, Hoboken: John Wiley & Sons, 2008.Google Scholar