Al-Si共晶合金中频磁场下初生硅相析出机制研究  

Investigation on Primary Silicon Precipitation Mechanism in Al-Si Eutectic Alloy under Electromagnetic Field

作　　者：Zhang Zhiqing 1 , Li Qiulin 2 , Chen Dandan 1 , Liu Wei 3 , Liu Qing 1 (1. Chongqing University, Chongqing 400045, China) (2. Graduate School of Shenzhen, Tsinghua University, Shenzhen 518055, China) (3. Tsinghua University, Beijing 100084, China) 

机构地区：[1]重庆大学 [2]李丘林 [3]清华大学(深圳研究生院) [4]陈丹丹 [5]刘伟 [6]刘庆

出　　处：《稀有金属材料与工程》2011年第S2期322-328,共7页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50474048);中央高校基本科研业务费资助(CDJRC10130008)

摘　　要：通过对Al-12.5Si(质量分数,%)共晶合金施加一定频率电磁场,采用光学显微镜、扫描电镜(SEM)研究有/无电磁场条件下连续铸造Al-Si共晶合金组织特点,发现电磁场条件下共晶合金发生初生硅相、初生铝相共存(晕圈)的异常现象,并且随磁场强度的增加,初生硅相的含量及尺寸逐渐减少,逐渐等轴化。通过对凝固组织中初生硅相与其周围初生铝相晶体学关系的分析认为两者独立形核长大,并认为由于电磁场下Al-Al原子团簇所受Lorntz力大于Si-Si原子团簇所受Lorntz力,因此熔体中出现Al-Al及Si-Si原子团簇偏聚,从而使得初生硅相自发形核长大。Microstructures of a eutectic Al-Si alloy in continuous casting either with or without an EMF were investigated using optical microscopy (OM), and scanning electron microscopy (SEM) techniques. Primary silicon and primary aluminum was found coexisted under an EMF. The volume faction and size of primary silicon are decreased, while change from long bar into short equiaxed particles with increasing EMF power. Based on crystallographic orientation analysis using electron backscatter diffraction (EBSD), it is found that primary Si and surround primary Al share no crystallography relationship. Because the Lorntz force Al-Al clusters suffered is larger than that on Al-Al clusters, so Si-Si clusters are segregated in the melt and then nucleate independently.

关 键 词：AL-SI共晶合金 微观观组织 电磁场 共晶转变 

分 类 号：TG146.21[一般工业技术—材料科学与工程]