不同条件下脉冲电流对纯铝凝固组织的细化

在金属凝固的过程中施加脉冲电流是一种有效的细化凝固组织的方法。围绕脉冲电流细化晶粒的机制提出了多种理论。利用纯铝作为研究材料，在脉冲电流参数、浇注温度等工艺参数不变的情况下，设计了两组铸型条件不同的试验，发现不同条件下得到的铸锭凝固组织的特征有所不同。结合结晶雨机制讨论了这些特征的形成原因，指出了熔体的流动情况对脉冲电流细化效果有重大的影响。

Refinement of solidification structure of pure aluminum by #br# pulsed current under different conditions

 It is an effective method to refine the solidification structure by applying pulsed current during the solidification process of metals. Many theories have been put forward to reveal the mechanism of grain refinement by the pulsed current. Taking pure aluminum as the studied material, under the condition that the process parameters such as the pulsed current parameters and pouring temperature were unchanged, two groups of experiments with different mold conditions were designed and conducted. It was found that the solidification structures of ingots changed with the mold conditions. Based on the mechanism of crystal rain, the formation process of solidification structure characteristics was discussed. Finally, it was pointed out that the melt flow had a great influence on the grain refinement by the pulsed current.