不同磁场条件对双流铸造7075铝合金组织的影响

成功研制了双流低频电磁半连续铸造铝合金的设备,使用该设备实现7075铝合金连续稳定的铸造,为工业实现多流低频电磁半连续铸造提供实验基础.利用此铸造设备,对比研究双流铸造中不同磁场条件对7075铝合金组织的影响.研究发现:相邻线圈电流方向相反时铸锭宏观组织略微好于线圈电流方向相同时;随着电流强度的增大,晶粒逐渐得到细化,当电流强度大于160 A后,磁场作用基本达到最佳效果;励磁电流频率小于等于10 Hz或者大于等于30 Hz均无法改善合金组织,当励磁电流频率为20 Hz的时候,铸锭晶粒相对细小,分布均匀,且宏观偏析得到了显著抑制.

Effect of Different Electromagnetic Fields on the Structure of Dual-Ingot Casted 7075 Aluminum Alloy

Equipment for dual-ingot LFEC casting of 7075 aluminum alloy was developed utilizing a low frequency electromagnetic casting(LFEC) method.The equipment was used to achieve continuous and stable casting of the 7075 aluminum alloy,thus providing an experimental basis for muti-ingot LFEC in industrial production.The effects of different magnetic fields on the structure of 7075 aluminum alloy were compared using dual-ingot LFEC.When the current direction of adjacent coils was opposite,ingot macrostructure was better than with current oriented in the same direction;and grains were gradually refined as current increased.The best magnetic effect was achieved when current intensity was greater than 160 A.Alloy microstructure was not improved when current frequency was less than or equal to 10 Hz,or greater than or equal to 30 Hz.At a current frequency of 20 Hz,grains were relatively small and homogenous,while macrosegregation was significantly inhibited.