Formation of feathery grains with the application of a static magnetic field during direct chill casting of Al-9.8wt%Zn alloy
Formation of feathery grains with the application of a static magnetic field during direct chill casting of Al-9.8wt%Zn alloy
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DOI：
10.1007/s10853-008-3158-0
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发表时间：
2009-01
影响因子：
4.5
通讯作者：
Lei Li;Yudong Zhang;C. Esling;Zhi-hao Zhao;Y. Zuo;Haitao Zhang;J. Cui
中科院分区：
文献类型：
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作者：
Lei Li;Yudong Zhang;C. Esling;Zhi-hao Zhao;Y. Zuo;Haitao Zhang;J. Cui
研究了0.2T静磁场对直接冷铸Al-9.8wt%Zn合金板坯组织的影响。在静磁场作用下，显微组织由等轴晶和柱状晶的混合体转变为孪晶片状羽状晶，初生臂和二次臂沿~lt；110>；方向生长。静磁场的施加，通过对对流的抑制作用，延缓了熔体向固体的转变，从而降低了放热量和溶质混合量，并要求通过减小过冷度损失的界面面积来降低液/固界面能。延迟和请求是生长方向改变和片层形成的原因。Al原子半径和锌原子半径的差异以及相关的入射流动促进了孪晶的形成。
Effect of a 0.2-T static magnetic field on the microstructure of a direct chill cast Al-9.8wt%Zn alloy slab was investigated. The static magnetic field transferred the microstructure from a mixture of equiaxed and columnar grains with the primary trunks growing in <100> directions to twinned lamellar feathery grains with the primary and secondary arms growing in <110> directions. The application of the static magnetic field results in the reduction of the heat discharge and solute mixing capacity through a damping effect on convection and thus a delay of the melt transformation to solid and a request to reduce the liquid/solid interface energy through reducing the interface area due to the loss of undercooling. The delay and the request account for the growth direction change and the formation of lamellas. The difference between the Al and Zn atomic radii and the related incoming flow facilitate the formation of the twins.