中文摘要：

采用超导强磁场装置研究了磁场强度对有、无细化剂颗粒Al-7％Si（质量分数）合金凝固组织的作用效果。研究发现，施加强磁场使无细化剂颗粒合金中的初生α-Al枝晶转变为发达枝晶形貌，二次枝晶生长充分，三次枝晶分支明显，枝晶尖端清晰可见；晶粒细化，且枝晶主轴与磁场方向呈30°规则排列。施加强磁场后初生α-Al枝晶数量和Si在α-Al中的溶解度都有少量增加。强磁场抑制添加细化剂合金熔体中的对流，加剧了Ti的重力偏析，使初生α-Al相出现明显枝晶化趋势，方向性增强，枝晶臂粗化明显。

英文摘要：

The effects of high magnetic fields on the solidification behavior of refined and non-refined Al-7wt% Si alloys with superconducting magnetic fields device were investigated. The results indicate that the α-Al dendrites transform into developed dendrites, secondary dendrites arms grow fully, teriary dendritic branches are obvious by imposing high magnetic fields; grains are refining and the dendrites principal axis with the magnetic fields direction angle at a 30 degrees. The number of α-Al dendrites and the solubility of Si in α-Al dendrites obtained a small increase by imposing high magnetic fields. Strong magnetic fields suppress the refined alloy melt convection, intensify Ti gravity segregation, and the α-Al of specimens refined appears obviously dendritic trend by imposing high magnetic fields, and shows a strong directional, dendrite arms coarsening obviously.