Effect of strontium on crystallization of Mg₂Si phase in Al-Si-Mg casting alloys

来源期刊：中国有色金属学报(英文版)2002年第3期

论文作者：廖恒成 丁毅 孙国雄

文章页码：409 - 413

Key words：Al-Si-Mg alloy; strontium modification; Mg₂Si; crystallization

Abstract: Optical microscope and SEM were used to observe the changes of the microstructure of Al-11.6%Si-0.4%Mg alloys with varying strontium additions and the effect of strontium on the crystallization of Mg₂Si phase was discussed. It is found that Mg₂Si phase nucleates on the surfaces of the eutectic silicon flakes in the unfully modified alloys, growing as meshwork or bamboo-shoot shape, however, very few and fine Mg₂Si particles phase are isolated at the boundaries of the eutectic cells in the fully modified alloys. Strontium has an important influence on the crystallization of Mg₂Si phase in Al-Si-Mg casting alloys and it is thought to be related to the increase of the amount of dendritic α phase and the modifying degree of eutectic silicon phase.