Al-3.46Cu-5.70Si合金变截面铸件定向凝固宏观偏析研究  

Investigation of Macrosegregation of Ternary Al-3.46Cu-5.70Si Alloy Casting with Variable Cross-Section in Directional Solidification

作　　者：赵光伟[1] 石增敏[1] 叶喜葱[1] 徐达鸣[2] 

机构地区：[1]三峡大学机械与材料学院,湖北宜昌443002 [2]哈尔滨工业大学材料科学与工程学院,黑龙江哈尔滨150001

出　　处：《铸造》2013年第12期1176-1180,共5页Foundry

基　　金：三峡大学科学基金(KJ2011B032);国家自然科学基金(51201093)

摘　　要：选取成分为Al-3.46Cu-5.70Si的三元Al合金,设计垂直定向凝固实验,得到了变截面工字型铸锭。采用扫描电镜、成分分析等手段研究了定向凝固铸锭不同部位的凝固组织、二次枝晶间距、宏观偏析等。结果表明,变截面工字型铸锭不同凝固部位由于凝固速率不同,凝固组织晶粒尺寸与枝晶间距随着与结晶器距离的增加呈明显增大趋势。Cu和Si元素均产生了明显的宏观偏析现象,靠近结晶器的位置出现正偏析,而在下变截面位置处纵向出现负偏析,横向出现正偏析,并发现Cu元素的偏析程度要大于Si元素。The directional solidification experiment was carried out on ternary alloy of Al-3.46Cu-5.70Si （in wt.%） and an I-shaped variable cross-section ingot was obtained. The solidifieation structure, secondary dendrite arm spacing and macrosegregation at different positions of the ingot were investigated by scanning electron microscopy and component analysis, The results show that the grain size and the second dendrite arm space of the ingot increase with the increasing of the distance from the crystallizer to the position, because of the differences in solidification rate, Obviously macrosegregation of element Cu and Si was observed. Near the crystallizer of the ingot positive macrosegregation appears, and negative macrosegregation in vertical direction and positive macrosegregation in the lateral direction at the variable section position of ingot are observed. And the experiment results show that the degree ofmacrosegregation of Cu is larger than Si.

关 键 词：变截面 定向凝固 宏观偏析 Al合金铸件 

分 类 号：TG146.21[一般工业技术—材料科学与工程]