结晶器材料对低频电磁铸造超高强铝合金铸态组织的影响

EFFECT OF MOULD MATERIALS ON THE AS-CAST MICROSTRUCTURES OF A SUPER-HIGH STRENGTH Al ALLOY CAST BY LOW FREQUENCY ELECTROMAGNETIC CASTING

数值模拟了结晶器材料对低频电磁铸造超高强铝合金过程中铸锭内磁场的影响,空载测定了不同材料结晶器内部的磁场,采用实验进行验证,结果表明,选用高电阻率钛合金材料制作低频电磁铸造结晶器,能够大幅度地减小电磁场在结晶器中的涡流损耗,提高有效功率。在相同条件下,高电阻率钛合金结晶器的铸锭组织细小、均匀,铸锭边部和中部平均晶粒直径分别为24和27μm;而低电阻率铝合金结晶器的铸锭中间和边部的微观组织均为粗大的蔷薇型枝晶,晶粒平均直径分别为38和45μm材料电阻率高的结晶器有利于溶质元素溶入晶内。

The effect of mould materials on the magnetic intensity in ingots was numerically simulated, then the magnetic intensities without ingots were measured, and some experiments were conducted to study these effects. The results show that during low frequency electromagnetic casting the mould with high electrical resistivity such as titanium alloy can greatly reduce eddy loss of mould, thus increase useful power. At the same condition, when the ingot was cast by titanium alloy mould (high electrical resistivity), the microstructures is uniform and fine, the average grain sizes at the border and center of the ingot are 24 mum and 27 mum respectively, but when the ingot was cast by aluminum alloy mould (low electrical resistivity), the microstructures of both the border and center of the ingot are coarse, their average sizes are 38 mum and 45 mum. Furthermore, the mould with higher electrical resistivity can increase the content of solute elements within grains.