Effect of abruptly changing withdrawal rate on solidification microstructure in directionally solidified Al-4.5wt%Cu alloy

作     者：Yang Luyan Li Shuangming Zhong Hong Ren Ruohua Fu Hengzhi 

作者机构：State Key Laboratory of Solidif ication Processing Northwestern Polytechnical University 

出 版 物：《China Foundry》 (中国铸造（英文版）)

年 卷 期：2014年第11卷第1期

页      面：8-13页

核心收录：

学科分类：0806[工学-冶金工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0702[理学-物理学] 

基　　金：financially supported by the National Natural Science Foundation of China(No.50971101) the Specialized Research Fund for the Doctoral Program of Higher Education(No.20136102110014) 

主　　题：directional solidification abrupt change of withdrawal rate primary dendrite arm spacing liquid-solute distribution Al-4.5wt.%Cu alloy 

摘      要：Al-4.5wt.%Cu alloy has been directionally solidified at constant and abruptly changing withdrawal rates, respectively. The effects of the withdrawal rate on solidification microstructure, primary dendrite arm spacing(PDAS) and liquid solute distribution in front of the solid-liquid interface were investigated. The experimental results for the PDAS at a constant withdrawal rate agree well with the values calculated by the Hunt, Trivedi and Hunt-Lu models. At an abrupt change in the withdrawal rate, the maximum to minimum ratio of the PDAS at a given solidification parameter, i.e. λ1max/λ1min, is more than 2, and the PDAS values are remarkably history-dependent. Further, the liquid-solute distribution curve based on theoretical calculation shows that the larger the initial withdrawal rate is, the smaller the minimum of liquid solute concentration in front of the solid-liquid interface is after the abrupt change in withdrawal rate.