(1. 上海交通大学 材料科学与工程学院， 上海 200030；
2. 西安理工大学 材料科学与工程学院， 西安 710048；
3. 西北工业大学 凝固技术国家重点实验室， 西安 710072)
摘 要: 采用熔融玻璃净化和循环过热相结合的方法研究了Ni-31.44%Pb偏晶合金宽过冷区间的凝固组织演化规律；从形核热力学和动力学两方面分析过冷熔体中稳定相（α）和亚稳相（L2）两相的竞争形核规律。 研究结果表明： 过冷Ni-31.44%Pb偏晶合金在快速凝固阶段本质上是以枝晶方式生长， 首先形成/α/枝晶骨架， 再辉重熔后分布于枝晶间的残余液相按照正常凝固模式进行分相/偏晶等后续反应。
关键字: 深过冷；Ni-Pb偏晶合金；形核理论；枝晶生长
（1. School of Materials Science and Engineering,
Shanghai Jiaotong University, Shanghai 200030, China;
2. School of Materials Science and Engineering,
Xi＇an University of Technology, Xi＇an 710048, China;
3. State Key Laboratory of Solidification Processing,
Northwestern Polytechnical University, Xi＇an 710072, China）
Abstract:By using the method of molten glass denucleating combined with superheating cycle, structural evolution of undercooled Ni-31.44%Pb monotectic alloy was systematically investigated within the achieved undercooling range from 10 to 286K. The phase selection of high temperature melts was calculated by adopting steady state and transient state nucleation theories, respectively. The calculation results of nucleation theories show that the undercooled Ni-31.44%Pb monotectic alloy melts solidify in the same mode of the undercooled single-phase alloy melts, i.e., undercooled Ni-31.44%Pb monotectic alloy solidifies in the form of dendrite essentially during the stage of rapid solidification and after recalescence, the interdendritic residual melts solidify in the equilibrium mode.
Key words: high undercooling; Ni-Pb monotectic alloy; nucleation theory; dendritic growth
