(西北工业大学 凝固技术国家重点实验室, 西安 710072)
摘 要: 采用惰性形核涂层型壳和氩气保护下循环过热的方法, 使Al72Ni12Co16合金获得200K的大过冷度, 在此基础上从实验和理论两方面研究了深过冷Al72Ni12Co16合金熔体中的相选择规律。 实验和理论计算表明： 熔体过冷度是决定Al72Ni12Co16合金中准晶相与晶体相竞争形核的主要因素, 且存在一临界过冷度, 其值约为60K, 当Al72Ni12Co16合金的初始过冷度大于临界过冷度时, 十面体准晶相将作为初生相从熔体中析出；反之, 当Al72-Ni12Co16合金的初始过冷度小于临界过冷度时, 熔体初生相为β晶体相。
关键字: 准晶； 深过冷；相选择
（State Key Laboratory of Solidification Processing,
Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:A large undercooling of 200K was obtained in Al72Ni12Co16 melt by the method of the nucleation-inhibitive coating mold and recycle superheating under Ar atmosphere, on the basis of which, the theoretical and experimental results on phase selection in Al72Ni12Co16 melt were reviewed. The primary undercooling of Al72Ni12Co16 alloy is the chief factor that determines the type of primary phase. While the primary undercooling of Al72Ni12Co16 alloy is more than about 60K, quasicrystal phase will precipitate from the undercooled melt as primary phase; otherwise, the crystal β phase will be the primary phase.
Key words: quasicrystal; undercooling; phase selection
