|郭學(xué)鋒2， 楊根倉(cāng)3， 李建國(guó)1
(1. 上海交通大學(xué) 材料科學(xué)與工程學(xué)院， 上海 200030；
2. 西安理工大學(xué) 材料科學(xué)與工程學(xué)院， 西安 710048；
3. 西北工業(yè)大學(xué) 凝固技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室， 西安 710072)
摘 要: 采用熔融玻璃凈化和循環(huán)過(guò)熱相結(jié)合的方法研究了Ni-31.44%Pb偏晶合金寬過(guò)冷區(qū)間的凝固組織演化規(guī)律；從形核熱力學(xué)和動(dòng)力學(xué)兩方面分析過(guò)冷熔體中穩(wěn)定相（α）和亞穩(wěn)相（L2）兩相的競(jìng)爭(zhēng)形核規(guī)律。 研究結(jié)果表明： 過(guò)冷Ni-31.44%Pb偏晶合金在快速凝固階段本質(zhì)上是以枝晶方式生長(zhǎng)， 首先形成/α/枝晶骨架， 再輝重熔后分布于枝晶間的殘余液相按照正常凝固模式進(jìn)行分相/偏晶等后續(xù)反應(yīng)。
關(guān)鍵字: 深過(guò)冷；Ni-Pb偏晶合金；形核理論；枝晶生長(zhǎng)
GUO Xue-feng2, YANG Gen-cang3, LI Jian-guo1
（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
