Europhys. Lett.
Volume 74, Number 2, April 2006
Page(s) 281 - 286
Section Condensed matter: structural, mechanical and thermal properties
Published online 08 March 2006
Europhys. Lett., 74 (2), pp. 281-286 (2006)
DOI: 10.1209/epl/i2005-10525-0

The transition of alpha-$\chem{Ni}$ phase morphology in highly undercooled eutectic $\chem{Ni_{78.6}Si_{21.4}}$ alloy

Yiping Lu1, Gencang Yang1, Feng Liu1, Haipeng Wang2 and Yaohe Zhou1

1  State Key Laboratory of Solidification Processing Northwestern Polytechnical University - Xi'an 710072, PRC
2  Department of Applied Physics, Northwestern Polytechnical University Xi'an 710072, PRC

received 19 October 2005; accepted in final form 20 February 2006
published online 8 March 2006

High undercooling up to 550$\un{K}$ (0.39 $T_{\ab{E}})$ was achieved in eutectic $\chem{Ni_{78.6}Si_{21.4}}$ melt using glass fluxing combined with the cyclic superheating. According to the microstructure evolution with the initial undercooling, surprisingly, a transition from non-faceted to faceted phase occurs for the as-solidified morphology of the alpha-$\chem{Ni}$ phase at the undercooling of 390$\un{K}$. On the basis of the entropy of fusion criterion and the interface kinetics, this interesting morphology transition at high undercooling is analyzed.

61.82.Bg - Metals and alloys.
68.55.Jk - Structure and morphology; thickness; crystalline orientation and texture.
68.35.Ct - Interface structure and roughness.

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