Shear enhanced heterogeneous nucleation in some Mg- and Al-alloys
Shear enhanced heterogeneous nucleation in some Mg- and Al-alloys
复制标题
某些镁合金和铝合金中的剪切增强异质形核
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
G. Scamans
中科院分区：
文献类型：
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作者：
Zhongyun Fan;Y. Wang;Z. Zhang;M. Xia;H. Li;J. Xu;László Gránásy;G. Scamans
摘要采用双螺杆机构对合金熔体在高于液相线的温度下进行强剪切。然后将剪切的熔体浇铸到TP 1模具中进行显微结构检查。使用N-Tech Ltd开发的Prefil技术对有或无剪切的合金熔体进行过滤，以分析氧化物和其他第二相颗粒。实验结果表明，通过增强异质形核，晶粒细化显着。强烈的熔体剪切将氧化物膜和团聚体转化为具有窄尺寸分布的分散良好的细颗粒。据证实，细氧化物颗粒可以作为有效的网站，在剪切熔体的凝固过程中的形核。本文介绍了镁、铝合金凝固过程中剪切增强异质形核的实验结果和理论分析。提出并讨论了多步异质形核机制。
Abstract Intensive shearing was applied to alloy melts at temperatures above their liquidus by using a twin-screw mechanism. The sheared melt was then cast into a TP1 mould for microstructural examination. Alloy melts with or without shearing were also filtered using the Prefil technique developed by N-Tech Ltd in order to analyse oxides and other second phase particles. The experimental results showed a significant grain refinement through enhancement of heterogeneous nucleation. The intensive melt shearing converted oxide films and agglomerates into well dispersed fine particles with a narrow size distribution. It was confirmed that the fine oxide particles can act as potent sites for nucleation during the solidification of the sheared melt. This paper presents the experimental results and theoretical analysis of shear enhanced heterogeneous nucleation during solidification of Mg- and Al-alloys. A multi-step heterogeneous nucleation mechanism has been proposed and discussed.