电磁振荡对半连铸7075Al合金的宏观偏析的抑制作用  

Effects of Electromagnetic Vibration on the Macro-segregation of 7075Al Alloy by Semi-continuous Casting

作　　者：张勤[1] 崔建忠[1] 路贵民[1] 

机构地区：[1]东北大学材料电磁过程教育部重点试验室,辽宁沈阳110006

出　　处：《铸造》2003年第3期171-175,共5页Foundry

基　　金：国家重大基础发展规划项目"973"(编号:G199906490501)。

摘　　要：研究了电磁振荡作用下半连铸7075Al合金铸锭微观组织及溶质元素在截面上的宏观分布规律,结果表明:在适当的电磁频率范围内(10～30Hz),随着交变磁场感应线圈电流强度增加,铸坯中近球形组织增多,蔷薇型组织减少,晶粒整体尺寸变得更加细小和均匀,铸锭表面质量明显提高,宏观偏析现象在很大程度上得到了抑制和消除。从电磁振荡使得初凝壳高度降低、液穴深度变浅、温度场和浓度场趋于均匀、非枝晶化程度提高、溶质元素平衡分配系数增大,结晶区间变小等因素出发,首次尝试性地对电磁振荡的宏观偏析抑制作用进行了解释和说明。The microstructure and solute distribution in the crosssection of 7075 alloy ingot produced by semicontinuous casting under the electromagnetic vibration were studied. The results show that in the suitable range of electromagnetic frequency (10～30Hz), with the increase of intensity of alternating magnetic field, the quantity of spheroidshaped grain increase, rosetteshaped grains decrease, the microstructure of ingot becomes more fine and uniform, surface quality of ingot is improved and the macrosegregation is restrained in a great degree. It is explained that the suppressing effects of macrosegregation under the electromagnetic vibration is resulted from the decrease in primary solidified shell height and sump height; uniform of temperature and solute concentration fields; the increase in nondendritic structure degree and solute equilibrium partition coefficient ; decrease in solidification interval under electromagnetic vibration.

关 键 词：电磁振荡 半连铸 铝合金 微观组织 宏观偏析 

分 类 号：TG292[金属学及工艺—铸造]