脉冲电流作用下LY12铝合金的微观结构和合金元素分布

研究了在凝固过程中施加脉冲电流对LY12铝合金微观结构和合金元素分布的影响.实验结果表明,在脉冲电流作用下,LY12合金的微观结构发生了明显变化,聚集在晶界和枝晶网的共晶组织大大减少,网络变得不连续,在晶内和晶界附近存在弥散的近似球状的共晶质点.另外,脉冲电流能有效地改善合金中Cu和Mg的成分偏析,其中对Cu在Al合金中的负偏析现象的改善更为显著,使Cu较均匀地分布于整个试样. 关键词： LY12铝合金 脉冲电流 显微结构 偏析

MICROSTRUCTURES AND DISTRIBUTION OF ALLOYING ELEMENTS OF LY12 Al-ALLOY MODIFIED BY A PULSED CURRENT

The effect of pulsed current on the microstructures and distribution of alloying elements of LY12 Al alloy during solidification process was studied. The experimental result showed that the microstructures of a LY12 Al alloy was evidently changed by pulsed current treatment, the eutectic structure which aggregated at grain boundary and dendrite net, was greatly reduced. The net became discontinuous, the dispersive and approximately spherical eutectic particles were formed inside the grains and near the boundary. The pulsed current can effectively reduce the segregation of Cu and Mg in the alloy, especially for Cu, and can remarkably improve the negative segregation phenomena of Cu in Al alloy, make Cu element more uniformly distributed in the whole sample.