凝固压力对A357合金凝固组织及含Fe相的影响  

Effect of Solidification Pressure on Microstructure and Iron-Bearing Phase of A357 Alloy

作　　者：陈忠伟[1] 江雅民[1] 柴艳[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《铸造》2009年第9期887-890,共4页Foundry

基　　金：陕西省自然科学基金资助(SJ08-ZT05)

摘　　要：研究了不同凝固压力作用下A357合金的反重力铸造凝固过程,分析了凝固压力和冷却速率对合金凝固组织二次枝晶间距λ2和含Fe相的影响。结果表明,由试样中心到边缘,随着冷却速率的增加,λ2减小,合金微观组织α-Al枝晶细化;凝固压力从1.55kPa增加到30.90kPa时,λ2减小,同时,冷却速率愈大,α-Al枝晶细化愈明显。增大凝固压力也使合金组织中含Fe相由针状转变为骨骼状。The investigation was carried out to study the effects of solidification pressure and cooling rate on microstructure of A357 alloy during counter-gravity casting solidification process. The results show that, from the center to the edge of samples, the secondary dendrite spacing λ2 reduced and microstructure was refined with the cooling rate increasing; as the solidification pressure increased from 1.55 kPa to 30.90 kPa, λ2 decreased and the morphology of iron-bearing phase changed from needle-like to skeleton shape; the microstructure was refined more remarkable with the increase of solidification pressure and cooling rate.

关 键 词：A357合金 反重力铸造 微观组织 冷却速率 含Fe相 

分 类 号：TG292[金属学及工艺—铸造]