电磁铸造镁合金大规格板坯的宏观偏析与宏观组织  

Macrosegregation and Macrostructure of Large Scale Magnesium Slab by LFEC Process

作　　者：胡文义 乐启炽[1] 刘轩[1] 张志强[1] 宝磊[1] 崔建忠[1] 

机构地区：[1]东北大学材料电磁过程研究教育部重点实验室,辽宁沈阳110819

出　　处：《稀有金属材料与工程》2016年第9期2434-2438,共5页Rare Metal Materials and Engineering

基　　金：国家重点基础研究发展计划("973"计划)(2013CB632203);辽宁省自然科学基金(201202072;2014028027);辽宁省高等学校优秀人才支持计划(LJQ2012023);中央高校基本科研业务费专项资金(N120509002)

摘　　要：研究了不同铸造速度下截面尺寸为300 mm×800 mm的AZ31镁合金大规格板坯的宏观偏析及宏观组织。结果表明,偏析区域出现在距离板坯表面20～30 mm范围内,板坯心部偏析小。宏观组织可分为表面激冷区,粗大柱状晶区和内部等轴晶区。低速铸造可减轻宏观偏析,随铸造速度增加,整体晶粒尺寸先增大后减小,表面柱状晶区宽度减小。高速铸造时晶粒尺寸小,但不均匀。合理的铸造速度为32 mm/min。The low frequency electromagnetic casting（LFEC） process was used to cast the large scale AZ31 magnesium slabs with the cross section of 300 mm×800 mm, and the macrostructure and macrosegregation were investigated at different casting velocities. The result shows that the segregation is slight in the centre of the slab and becomes serious in the region about 20～30 mm from the slab surface. There exist three zones in the AZ31 magnesium alloy slab, i.e. a surface chill zone, a columnar crystal zone, an internal equiaxed crystal zone. The low velocity casting can weaken the macrosegregation. With the casting velocity increasing, the size of grains increases first and then decreases, the width of columnar crystal zone decreases drastically as well as the macrosegregation. At high casting velocity, the grain size is finer, but more uneven. Thus, the appropriate casting velocity in this process is 32 mm/min.

关 键 词：大规格镁合金板坯 铸造速度 宏观偏析 宏观组织 

分 类 号：TG292[金属学及工艺—铸造]