Dual solidification mechanisms of liquid ternary Fe-Cu-Sn alloy

作     者：WeiLi Wang XiaoMei Zhang LiuHui Li BingBo Wei 

作者机构：Northwestern Polytech Univ Dept Appl Phys Xian 710072 Peoples R China 

出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学：物理学、力学、天文学（英文版）)

年 卷 期：2012年第55卷第3期

页      面：450-459页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 081304[工学-建筑技术科学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0802[工学-机械工程] 0813[工学-建筑学] 080201[工学-机械制造及其自动化] 

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 51101123 and 50971105) the Fundamental Research Fund of Northwestern Polytechnical University (GrantNo. JC201050) 

主　　题：peritectic solidification phase separation macrosegregation undercooling dendritic growth 

摘      要：Liquid ternary Fe47.5Cu47.5Sn5 alloy displayed dual solidification mechanisms when it was undercooled by up to 329 K （0.19TL）. Below a critical undercooling of about 196 K, it solidified just like a normal peritectic alloy, even though metastable phase separation occurred to a microscopic extent. Once bulk undercooling exceeds 196 K, macroscopic segregation played a domi- nant role in solidification. In both cases, the solidification process was always characterized by two successive peritectic trans- formations： firstly primary yFe dendrites reacted with liquid phase to form （Cu） phase, and subsequently the （Cu） phase reacted with residual liquid phase to yield β-Cu5.6Sn intermetallic compound. The primary yFe dendrites achieved a maximum growth velocity of 400 mm/s and experienced a growth kinetics transition as a result of macrosegregation. Since the （Cu） phase was both the product phase of the first peritectic transformation and also the reactant phase for the second peritectic transformation, it appeared as two layers in solidification microstructures due to the microsegregation of Sn solute. The boundary continuity between the macroscopically separated Fe-rich and Cu-ricb zones was enhanced with the increase of undercooling.