Modification of primary Mg2Si in Mg-5Si alloys with Y2O3

• Published in: Transactions of Nonferrous Metals Society of China Vol. 17; no. A01; pp. 440 - 443
• Main Author: 郑娜 王慧远 赵峰 顾振华 李栋 姜启川
• Format: Journal Article
• Language: English
• Published: 01.11.2007
• Subjects: 固体凝固法; 微观结构; 生产技术
• ISSN: 1003-6326

The Y2O3 addition to Mg-5Si alloys has a good modification effect on the primary Mg2Si. With 0.05% or 0.1% （mass fraction） Y203 additions, the primary Mg2Si begins to change from coarse dendritic shape （about 100 μm） into small polyhedral shape and therefore the alloys exhibits sub-modified microstructure. With 0.2% Y2O3 addition, most of the primary Mg2Si becomes polyhedral shape and its average size is only 25 μm or less. The Mg-5Si alloy exhibits modified microstructure. In addition, the experiments show that the reaction between Mg and Y2O3 cannot occur in the sintered Mg-6Y2O3 compact; however, the reaction among Mg, Si and Y2O3 can occur in the sintered Mg-5Si-6Y2O3 compact. Apart from the adsorption and poisoning manners, other mechanisms may exist in the modification of Y2O3 addition on the primary Mg2Si.