中文摘要：

利用电磁学理论并结合电脉冲处理细化机制推算出凝固过程中结晶雨产生及激冷层形成时的脉冲电压临界值。对结晶雨出现时等效电流及其影响因素进行模型研究,分析电脉冲作用下合金凝固行为的特点,指出电脉冲处理组织细化时域应处于结晶雨产生与激冷层形成之间。此外,以该条件下Al-5%Cu合金的凝固组织特点对模型进行了验证。

英文摘要：

By using electromagnetism theory combined with the electric pulse modification mechanism,the two critical values of pulse voltage were calculated when the crystal rain and the chill layer were formed during solidification.The equivalent current and its influencing factors were model-based investigated and the solidification behavior was analyzed correspondingly.The model exhibits that the time domain of EPM-induced grain refinement is between the occurrence of crystal rain and the formation of chill layer.Furthermore,the proposed model is validated by the solidification structure changes of Al-5%Cu alloy under this circumstance.