标题：Refining mechanism of the electric current pulse on the solidification structure of pure aluminum
作者：Liao, Xiliang; Zhai, Qijie; Luo, Jun; Chen, Wenjie; Gong, Yongyong
作者机构：[Liao, XL; Zhai, QJ; Luo, J; Chen, WJ; Gong, YY]Shanghai Univ, Sch Mat Sci & Engn, Shanghai 200072, Peoples R China.;[Liao, XL; Zhai, QJ; 更多
通讯作者地址：[Zhai, QJ]Shanghai Univ, Sch Mat Sci & Engn, 149 Yanchang Rd, Shanghai 200072, Peoples R China.
关键词：pure aluminum; electric current pulse; solidification structure;; refining mechanism
摘要：The refining mechanism of the electric current pulse (ECP) on the solidification structure of pure aluminum is systematically investigated by properly designed experiments. The experiment results show that the solidification structure cannot be refined by exerting an ECP on the high temperature liquid phase, indicating that the ECP has no inoculation effect on the liquid metal. The ECP has also no obvious influence on the solidification structure when it is applied during crystal growth, showing that the ECP cannot cause melting or break off the growing crystal. However, the very fine macrostructure is obtained by applying an ECP during the nucleation of the melt. The reason is that the ECP makes the crystal nuclei formed on the wall of the mould fall off and move freely in the molten metal, promoting the multiplication of crystal nuclei. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.