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Solidification of undercooled molten Cu30Ni70

Published online by Cambridge University Press:  31 January 2011

J. Z. Xiao
Affiliation:
Department of Physics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
H. W. Kui
Affiliation:
Department of Physics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
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Abstract

Recently, it was demonstrated that grain refinement in undercooled Cu30Ni70 is brought about by a remelting of those initially formed dendrites (termed novel dendrites) which are unstable against melting. Also, it was found that in the same transition regime, there is a sharp drop in the specific volume of the undercooled specimens. Before entering into the transition regime, the novel dendrites found in an undercooled specimen are arranged in a regular pattern and the microstructures consist of large dendrites. Voids are found mainly at the dendritic spacings of the large dendrites. On the other hand, near the upper end of the transition regime, the microstructures consist of equiaxed refined grains. Furthermore, each of these grains contains a novel dendrite. Voids have moved to the interdendritic or grain boundaries. Based on these observations, a solidification mechanism of undercooled molten Cu30Ni70 is proposed.

Type
Articles
Copyright
Copyright © Materials Research Society 1999

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References

REFERENCES

1.Walker, J. L., Principles of Solidification, edited by Chalmers, B. (John Wiley, New York, 1964), p. 112.Google Scholar
2.Kattamis, T.Z. and Flemings, M. C., Trans. AIME 236, 1523 (1966).Google Scholar
3.Devaud, G. and Turnbull, D., Acta Metall. 35, 765 (1987).CrossRefGoogle Scholar
4.Lau, C. F. and Kui, H. W., Acta Metall. Mater. 39, 323 (1991).CrossRefGoogle Scholar
5.Chalmers, B., Principles of Solidification (John Wiley, New York, 1964), p. 87.Google Scholar
6.Horvay, G., Int. J. Heat Mass Transfer 8, 195 (1965).CrossRefGoogle Scholar
7.Jackson, K. A., Hunt, J. D., Uhlmann, D. R., and Seward, T. P. III, Trans. Metall. Soc. AIME 236, 149 (1966).Google Scholar
8.Glicksman, M. E., Acta Metall. 13, 1231 (1965).CrossRefGoogle Scholar
9.Schwarz, M., Karma, A., Eckler, K., and Herlach, D. M., Phys. Rev. Lett. 73, 1380 (1994).CrossRefGoogle Scholar
10.Leung, K. K., Chiu, C. P., and Kui, H. W., Scripta Metall. Mater. 32, 1559 (1995).CrossRefGoogle Scholar
11.Xiao, J. Z., Leung, K. K., and Kui, H. W., Appl. Phys. Lett. 67, 3111 (1995).CrossRefGoogle Scholar
12.Xiao, J. Z., Leung, K. K., and Kui, H. W., J. Mater. Res. 12, 873 (1997).CrossRefGoogle Scholar
13.Leung, K. K., Xiao, J. Z., and Kui, H. W., unpublished.Google Scholar
14.Xiao, J. Z. and Kui, H. W., Scripta Mater. 37, 1017 (1997).CrossRefGoogle Scholar
15.Kui, H. W., Greer, A. L., and Turnbull, D., Appl. Phys. Lett. 45, 615 (1984).CrossRefGoogle Scholar
16.Lau, C. F. and Kui, H. W., J. Appl. Phys. 67, 3181 (1990).CrossRefGoogle Scholar
17.Leung, K. K. and Kui, H. W., J. Appl. Phys. 75, 1216 (1994).CrossRefGoogle Scholar
18.Cech, R. E. and Turnbull, D., Trans. AIME 191, 242 (1951).Google Scholar
19.Xiao, J. Z. and Kui, H. W., unpublished.Google Scholar
20.Willnecker, R., Herlach, D. M., and Feuerbacher, B., Appl. Phys. Lett. 56, 324 (1990).CrossRefGoogle Scholar