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Phase field modeling for the entire formation process of the
self-organized core-shell microstructure in Cu-Fe alloys
Shi Rongpei
a,b
, Liu Xingjun
a
, Wang Cuiping
a,*
, Wang Yunzhi
b
a) Department of Materials Science and Engineering, College of Materials, and Research Center of
Materials Design and Applications, Xiamen University, Xiamen 361005, People’s republic of China
b) Department of Materials Science and Engineering, The Ohio State University, 2041 College Road,
Columbus, Ohio 43210, USA
* Corresponding author (E-mail:
wangcp@xmu.edu.cn)
Abstract
Entire formation process of self-organized core-shell microstructures in liquid immiscible Cu-Fe alloys
was investigated by phase field method. The model simultaneously accounts for liquid decomposition,
convection induced by chemical potential gradient during spinodal decomposition, collision and
coalescence between liquid droplets, and Marangoni motion caused by the temperature dependence of
the interfacial energy. The simulation results show the entire formation process of the egg-type
microstructure and are in good agreement with experimental observations.
Keywords: Marangoni convection; Liquid spinodal decomposition; Cu-Fe, Phase filed; Core-Shell
1 Introduction
Recently, Wang et al.[1] have successfully produced interesting self-organized core-shell
composite powders, where one alloy encase another alloy, from liquid immiscible Cu-Fe base alloys by
conventional gas atomization under gravity condition. The typical core-shell microstructure with
Fe-Core and Cu-Shell is shown in Figure.1.
Composite powders with this kind of core-shell microstructure have good combinations of high
strength and corrosion resistance (Fe-rich phase) and high electric and thermal conductivities (Cu-rich
phase), they thus have great potential for many advanced applications in electronic devices[1].
Therefore, it is highly desirable to develop a fundamental understanding of the formation mechanisms
and processing parameters that control the formation kinetics, which will be of great help for us to
improve our control level for the processing.
The formation of the core-shell microstructures is governed by, at least, four intimately coupled
processes taking place simultaneously in liquid state[1, 2]: spinodal decomposition, convection
induced by chemical potential gradient during the spinodal decomposition, coagulations between
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