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.