Abstract
Microstructural observation and thermal analysis of Al-21 wt % Si alloys with different rare earth metals were performed to examine the effect of rare earth metal on the refinement of primary silicon phase. Simultaneous refinement of both primary and eutectic silicon morphology is achieved with the addition of rare earth and its effect increases with the amount of rare earth addition and cooling rate. Depression of 12–17 °C in primary reaction temperature and 2–7 °C in eutectic temperature is measured with the addition of rare earth. Rare earth bearing compounds were not believed to act as a nucleation agent of primary silicon phase. Some rare earth bearing compounds determined to AlCe were around primary silicon in the matrix. The twin density of eutectic silicon remains same regardless of the addition of rare earth. The refinement of silicon in rare earth treated hypereutectic Al-Si alloys is supposed to be due to the suppression of the nucleation temperature of silicon phase.
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References
I. J. Polmear, “Light Alloys, Metallurgy of the Light Metals” 2nd edition (Edward Arnold, London, 1989) p. 147.
J. E. Gruzleski and B. M. Closset, “The Treatment of Liquid Aluminum-Silicon Alloys” (American Foundrymen's Society, Inc. Des Plaines, Illinois, U.S.A. 1990) p. 19.
B. J. Ye, C. R. Loper, D. Y. Lu and C. S. Kang, AFS Trans. 30 (1985) 533.
M. Ravi, U. T. S. Pillai, B. C. Pai, A. D. Damodran and E. S. Dwarakadasa, Metal. Trans. 27A (1996) 1283.
J. C. Weiss, C. R. Loper. Jr, AFS Trans. 32 (1987) 51.
T. Kowata, H. Horie, S. Hiratsuka and A. Chida, Imono 66 (1994) 803.
S. Ghosh and W. J. Mott, Mordern Casting (1964) 721.
H. P. Shingu and J. I. Takamura, Metal. Trans. (1970) 2339.
Shu-Zu Lu and A. Hellawell, Metal. Trans. 18A (1987) 1721.
MOST Research Report, Development of High Strength Al-Alloys by a P/M Process(I), UCN1255-5523-1, Korea, (1995) p. 64.
C. R. Ho and B. Cantor, Acta Metal. Mater. 43 (1995) 3231.
R. Sharan and T. R. Anantharaman, Current Sci. 5 (1967) 568.
C. B. Kim and R. W. Hrine, J. Inst. Met. 92 (1963-1964) 367.
B. J. Ye, Ph.D. thesis, University of Wisconsin-Madison, 1985.
J. Cisse, G. F. Bolling and K. W. Kerr, Metal. Trans. B (1975) 195.
G. Thomas and M. J. Goringe “Transmission Electron Microscopy of Materials” (John Wiley & Sons, New York, 1979) p. 94.
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Chang, J., Moon, I. & Choi, C. Refinement of Cast Microstructure of Hypereutectic Al-Si Alloys Through the Addition of Rare Earth Metals. Journal of Materials Science 33, 5015–5023 (1998). https://doi.org/10.1023/A:1004463125340
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DOI: https://doi.org/10.1023/A:1004463125340