A Homogeneous Solidification Criterion for Undercooled Ni-20at%Pb Hypermonotectic Melts
The kinetic process of liquid-liquid phase separation in the undercooled Ni-20at%Pb hypermonotectic alloy melts was analyzed theoretically. The results showed that liquid-liquid separation could not be inhibited due to smaller nucleation barrier and bigger nucleation rate of Pb-rich droplets. In the course of liquid-liquid phase separation, the volume fraction of Pb-rich droplets was thought as a function of time or temperature. At a certain cooling rate, the volume fraction was mainly controlled by the undercooling of Ni-Pb hypermonotectic melts. Based on the above results, a homogeneous solidification criterion for the undercooled Ni-20at%Pb hypermonotectic alloy melts was developed. Such a criterion predicted that the homogeneous microstructure could be obtained at the undercooling 263K, and the experimental results accorded with the predicting ones on the whole.
Hyungsun Kim, Jian Feng Yang, Chuleol Hee Han, Somchai Thongtem and Soo Wohn Lee
H. Xie et al., "A Homogeneous Solidification Criterion for Undercooled Ni-20at%Pb Hypermonotectic Melts", Materials Science Forum, Vol. 695, pp. 340-343, 2011