Effect of Multi-Scale Thermoelectric Magnetic Convection on Solidification Microstructure in Directionally Solidified Al-Si Alloys Under a Transverse Magnetic Field
Effect of Multi-Scale Thermoelectric Magnetic Convection on Solidification Microstructure in Directionally Solidified Al-Si Alloys Under a Transverse Magnetic Field
复制标题
横向磁场下多尺度热电磁对流对定向凝固铝硅合金凝固组织的影响
DOI：
10.1007/s11661-014-2496-6
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发表时间：
2014-11-01
影响因子：
2.8
通讯作者：
Moreau, Rene
中科院分区：
文献类型：
--
作者：
Li, Xi;Du, Dafan;Moreau, Rene
研究了横向磁场（B < 1 T）对定向凝固Al-Si合金凝固组织的影响。实验结果表明，磁场对Al-7 wt - pct Si合金和Al-7 wt - pct Si-1 wt - pct Fe合金的宏观偏析、枝晶细化和糊状区长度的减小都有促进作用。此外，磁场的应用能够分离出Al-7 wt - pct Si-1 wt - pct Fe合金中的富铁金属间相。对Al-Si合金定向凝固过程进行了热电磁力对流（TEMC）数值模拟。结果表明，当磁场强度达到临界磁场强度时，TEMC增大到最大值（），随着磁场强度的进一步增大，TEMC减小。TEMC表现出多尺度效应，在不同尺度上和值不同，随尺度的减小而减小和增大。磁场作用下凝固组织的改变应归因于样品和枝晶尺度上的TEMC。
The influence of a transverse magnetic field (B < 1 T) on the solidification structure in directionally solidified Al-Si alloys was investigated. Experimental results indicate that the magnetic field caused macrosegregation, dendrite refinement, and a decrease in the length of the mushy zone in both Al-7 wt pct Si alloy and Al-7 wt pct Si-1 wt pct Fe alloys. Moreover, the application of the magnetic field is capable of separating the Fe-rich intermetallic phases from Al-7 wt pct Si-1 wt pct Fe alloy. Thermoelectric magnetic convection (TEMC) was numerically simulated during the directional solidification of Al-Si alloys. The results reveal that the TEMC increases to a maximum () when the magnetic field reaches a critical magnetic field strength (), and then decreases as the magnetic field strength increases further. The TEMC exhibits the multi-scales effects: the and values are different at various scales, with decreasing and increasing as the scale decreases. The modification of the solidification structure under the magnetic field should be attributed to the TEMC on the sample and dendrite scales.