蛇形通道复合Sr变质处理对Al-28Si合金微观组织的影响  

Effects of Serpentine Channel Composite Sr Modification on Microstructure of Al-28Si Alloy

作　　者：刘亚博 毛卫民[1] 闫鹏宇 王冰坤 范菁 颜丙栋 Liu Yabo;Mao Weimin;Yan Pengyu;Wang Bingkun;Fan Jing;Yan Bingdong(School of Materials Science and Engineering,University of Science and Technology Beijing)

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《特种铸造及有色合金》2021年第5期619-624,共6页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51771032)。

摘　　要：针对传统铸造过共晶Al-Si合金中存在粗大初生Si和针片状共晶Si的问题,采用蛇形通道复合Sr变质处理工艺制备了Al-28Si合金半固态浆料,对半固态浆料的显微组织以及初生Si的析出温度进行了研究。结果表明,该工艺可充分细化初生Si、有效变质共晶Si,初生Si尺寸由165.26μm细化到45.68μm,共晶Si由长针状转变为点状、蠕虫状。随着Sr加入量的增加,初生Si的析出温度先升高后降低,初生Si的晶粒尺寸呈增大趋势。具有大量纤维状分支的共晶Si在长大时受到了铝相抑制。According to the problems in coarse primary silicon and acicular eutectic silicon in traditional hypereutectic Al-Si alloy,the semi-solid slurry of Al-28 Si alloy was prepared by serpentine channel composite Sr modification process.The microstructure of the semi-solid slurry and the precipitation temperature of primary silicon were investigated.The results reveal that the composite process can fully refine the primary silicon and effectively modify the eutectic silicon.The primary silicon is refined from 165.26μm to 45.68μm,and the structure of eutectic silicon is transformed from acicular to punctate and worm-like.With the increase of the Sr addition,the precipitation temperature of primary silicon is increased at first and then decreased,and the grain size shows an increasing trend.The growth of eutectic silicon with a large number of fibrous branches is limited by aluminum phase.

关 键 词：Al-28Si合金 蛇形通道 SR 初生SI 共晶Si 

分 类 号：TG249.26[金属学及工艺—铸造] TG146.21[一般工业技术—材料科学与工程]