电流对Al-4.5%Cu合金定向凝固组织的影响  

Influence of Electric Current on Directional Solidification Structure of Al-4.5%Cu Alloy

作　　者：闫猛[1] 宋长江[1] 张云虎[1] 翟启杰[1] 

机构地区：[1]上海大学上海市现代冶金及材料制备重点实验室,上海200072

出　　处：《铸造》2010年第1期22-25,共4页Foundry

基　　金：国家自然科学基金重点项目(50734008);国家自然科学基金项目(50701030)

摘　　要：为揭示脉冲电流对晶体生长的影响机理,研究了脉冲电流和直流电对Al-4.5%Cu合金定向凝固胞状树枝晶组织的影响。结果表明:脉冲电流和直流电都能消除二次枝晶臂,减小糊状区深度和宽度,使一次枝晶间距减小;比较而言,脉冲电流处理的固-液界面较为平直,而直流电使界面变得凸凹起伏。分析认为电流偏聚所形成的热效应导致胞晶分裂可能是电流影响胞晶一次间距的主要原因,而脉冲电流引起的强制对流使得固-液界面更加平直。To demonstrate the influence mechanism of the electric current on cystal growth, the influences of electric current pulse （ECP） and direct current （DC） on cellular-dendritic structure of Al-4.5%Cu alloy under directional solidification were contrastively studied. The results show that ECP and DC both can eliminate the secondary dendrites, make the mushy zone and the cellular spacing decrease. For the sample treated by ECP, the solid-liquid interface is very planar, while that of samples treated by DC is scraggy. Analysis results suggest that cellular split resulting from Joule heat may be the main reason for decrease of first cellular spacing, and the forced convection caused by ECP make solid-liquid interface more planar.

关 键 词：脉冲电流 直流电 定向凝固 固-液界面 

分 类 号：TG111.4[金属学及工艺—物理冶金]