脉冲电流作用下LY12铝合金凝固组织变化

Variation of Solidification Structures of LY12 Al Alloy Solidified Under Pulse Current

在LY12铝合金凝固过程施加脉冲电流,研究了脉冲电流的不同放电电压对宏观凝固组织及溶质元素晶内含量的影响。脉冲电流的放电工艺为:固定脉冲电容器的电容为80μF,放电电压在3～7kV之间变化。通过试验发现,与未施加脉冲电流的试样相比,不同放电电压的脉冲电流作用可以使试样的宏观组织得到不同程度的细化,细化效果并非随放电电压的增加而越来越明显,而是存在一个最佳电压值,当放电电压为5kV时,细化效果最显著。经过脉冲电流处理后,LY12铝合金中Cu元素的晶内含量得到显著提高。初步阐明了脉冲电流的作用机制。

The pulse current was applied to the solidification process of LY12 Al alloy. The effect of discharging voltage of pulse current on the macrostructures and solute content inside the grain was studied. The discharge process was as follow： the capacitance of the capacitor is 80 IJF and the discharge voltage varied from 3 kV to 7 kV. The experiment results show that comparing with the sample solidified without pulse current, the macrostructures of samples solidified under pulse current with different discharging voltage were refined in different degree. The refinement was not enhanced with the increasing of the discharge voltage but there is an optimal voltage. The optimal refinement can be obtained when the discharging voltage was 5 kV. Meanwhile, after treated with pulse current, the Cu content inside the grain of LY12 AI alloy was obviously increased. The action mechanism of pulse current was discussed in this paper.