Competitive Nucleation and Rapid Growth of Co-Si Intermetallic Compounds during Eutectic Solidification under Containerless Processing Condition

作     者：Wenjing Yao Zipeng Ye Nan Wang Xiujun Han Jianyuan Wang Xixing Wen 

作者机构：Department of Applied Physics Northwestern Polyteehnical University Xi＇an 710072 China School of Materials Science Shanghai Jiaotong University Shanghai 200240 China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2011年第27卷第11期

页      面：1077-1082页

核心收录：

学科分类：08[工学] 

基　　金：supported by the National Natural Science Foundations of China (Grant Nos. 50871090, 50971104 and 50901060) the NPU Foundations for Fundamental Research (JC20110279) the financial support from the National Aerospace Science Foundation of China (Grant Nos. 2008ZF53052 and 2010ZF53059) 

主　　题：Liquid-solid transition Competitive nucleation Intermetallic compound Undercooling 

摘      要：The liquid-solid transitions of （Co2Si＋CoSi） and （CoSi＋CoSi2） eutectic alloys were realized in drop tube and the rapid eutectic growth mechanism of intermetallic compounds was examined. The experimental and calculated results indicate that with increasing Co content, the intermetallic compound prefers nucleating primarily. The eutectic microstructures experience the transitions of ＇lamellar-anomalous-divorced＇ eutectic with undercooling. In undercooled state, the growth of CoSi intermetallic compound always lags behind others, and no matter how large the undercooling is, this intermetallic compound grows under the solutal diffusion control The calculated coupled zone demonstrates that （Co2Si＋CoSi） eutectic can form within certain undercooling regime, when the composition is in the range from 23.6% to 25.4% Si. And the calculated coupled zone of （CoSi＋CoSi2） covers a composition range from 40.8% to 43.8% Si.