Liquid-phase Separation in Rapid Solidification of Undercooled Fe-Co-Cu Melts

Ning Liu 1,2),Feng Liu 2),Zheng Chen 2,3),Gencang Yang 2),Changlin Yang 2) and Yaohe Zhou 2) 1) School of Metallurgy and Materials Engineering,Jiangsu University of Science and Technology,Zhangjiagang 215600,China 2) State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi an 710072,China 3) School of Materials Science and Engineering,China University of Mining and Technology,Xuzhou 221008,China

摘 要：The homogeneous liquid was separated into two phases,（Fe,Co）-rich L1 and Cu-rich L2,once the melt was undercooled below a liquid-phase separation temperature T sep.If the duration from T sep to T s1（solidification temperature of L1 phase）,termed the liquid-phase separation interval t,exceeded a critical value,an egg-type structure was observed.By utilizing differential thermal analyses（DTA）,the solidification process of the undercooled Fe-Co-Cu alloys was studied.Additionally,an immiscible boundary was obtained,which was a convex parabola with a symmetrical axis of x Cu =0.52.Depending on the relative amounts of L1 and L2,the minor phase was nucleated firstly to form liquid droplets and separated from the original liquids at the beginning of liquid-phase separation.

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