Solidification of Immiscible Alloys and Convective Effect

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Abstract:

A model describing the microstructure formation in a directionally solidified immiscible alloy under the convective effect is presented. The microstructure evolution in a directionally solidified Al-Pb alloy is investigated. It is demonstrated that convective flows have great effects on the solidification of immiscible alloys. A convective flow against the solidification direction causes an increase in the nucleation rate while a convective flow along the solidification direction causes a decrease in the nucleation rate. The convective flows lead to a more uneven distribution of the minority phase droplets in the melt. It causes an increase in the size of the largest minority phase droplets and is against the obtaining of the immiscible alloys with a well dispersed microstructure.

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Materials Science Forum (Volumes 783-786)

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2231-2236

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May 2014

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© 2014 Trans Tech Publications Ltd. All Rights Reserved

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[1] J. R. Rogers, R. H. Davis, Modeling of collision and coalescence of droplets during microgravity processing of Zn-Bi immiscible alloys, Metall. Trans. A 21 (1990) 59-68.

DOI: 10.1007/bf02656424

Google Scholar

[2] T. Carlberg, H. Fredriksson, The influence of microgravity on the solidification of Zn-Bi immiscible alloys, Metall. Trans. A 11 (1980) 1665-1676.

DOI: 10.1007/bf02660521

Google Scholar

[3] J. Z. Zhao, L. Ratke, A model describing the microstructure evolution during a cooling of immiscible alloys in the miscibility gap, Scripta Mater. 50 (2004) 543-546.

DOI: 10.1016/j.scriptamat.2003.10.024

Google Scholar

[4] R. H. Davis, M. A. Hassen, Spreading of the interface at the top of a slightly polydisperse sedimenting suspension, J. Fluid. Mech. 196 (1988) 107-134.

DOI: 10.1017/s0022112088002630

Google Scholar

[5] J. Z. Zhao, L. Ratke, B. Feuerbacher, Microstructure evolution of immiscible alloys during cooling through the miscibility gap, Modelling Simul. Mater. Sci. Eng. 6 (1998) 123-139.

DOI: 10.1088/0965-0393/6/2/003

Google Scholar

[6] J. Z. Zhao, Formation of the minor phase shell on the surface of hypermonotectic alloy powders, Scripta Mater. 54 (2006) 247-250.

DOI: 10.1016/j.scriptamat.2005.09.038

Google Scholar

[7] J. J. Guo, Y. Liu, J. Jia, Y. Q. Su, H. S. Ding, Coarsening process of minority phase droplets during rapidly cooling an immiscible alloy through the miscibility gap, Acta Metall. Sin. 37 (2001) 363-368.

Google Scholar

[8] H. L. Li, J. Z. Zhao, Convective effect on the microstructure evolution during a liquid-liquid decomposition, Appl. Phys. Lett. 92 (2008) 241902.

DOI: 10.1063/1.2945634

Google Scholar

[9] M. H. Wu, A. Ludwig, L. Ratke, Modeling of Marangoni-induced droplet motion and melt convection during solidification of hypermonotectic alloys, Metall. Mater. Trans. A 34 (2003) 3009-3019.

DOI: 10.1007/s11661-003-0200-3

Google Scholar