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在7A04铝合金的凝固过程中施加矩形波磁场,分析了不同频率对7A04铝合金凝固组织、晶粒大小及凝固冷却曲线的影响。结果表明,在矩形波磁场作用下,7A04铝合金的凝固组织、晶粒大小和冷却曲线均发生了明显变化。在频率为40Hz时,铸锭组织的晶粒细化效果最佳。与未经磁场处理的相比,不仅增加了过冷度,提高了硬度,其晶粒尺寸也减小了37.1%。
A square wave magnetic field was applied during the solidification of 7A04 aluminum alloy. The effects of different frequencies on the solidification structure, grain size and solidification cooling curve of 7A04 aluminum alloy were analyzed. The results show that the solidification structure, grain size and cooling curve of 7A04 aluminum alloy all change obviously under the action of rectangular magnetic field. The ingot microstructure has the best grain refinement at a frequency of 40 Hz. Compared with no magnetic field treatment, not only increased the degree of undercooling, increased hardness, the grain size is also reduced by 37.1%.