Microstructures and evolution mechanism of highly undercooled Ni-Pb hypermonotectic alloy

来源期刊：中国有色金属学报(英文版)2004年第3期

论文作者：谢辉 杨根仓 郝维新 樊建锋 朱耀产 许丽君

文章页码：417 - 420

Key words：high undercooling; Ni-Pb hypermonotectic alloy; structural evolution; dendrites remelting; recrystallization

Abstract: The microstructures and evolution mechanism of the undercooled Ni-20%Pb(molar fraction) alloy were investigated systematically by high undercooling solidification technique. The experiment results indicate that the morphology of α-Ni phase and the distribution of Pb element in undercooled Ni-20%Pb alloys change with the increase of undercooling. The main evolution mechanisms of α-Ni are dendrite remelting and recrystallization. Pb phase in the microstructure of Ni-20%Pb hypermonotectic alloy originates from L₂ phase separated from the parent melt during the cooling process through immiscible gap and L′₂ phase formed at the temperature of monotectic transformation. The solubility of Pb element in α-Ni phase under high undercooling condition is up to 5.83% which is obviously higher than that under equilibrium solidification condition. The real reason that causes the solubility difference is distinct solute trapping.

基金信息：the National Natural Science Foundation of China