(上海交通大学 金属基复合材料国家重点实验室， 上海 200030)
摘 要: 研究了Sr以及Ce-Sr复合添加剂对Al/Mg2Si/Si自生复合材料凝固组织的影响规律。当Ce、 Sr的加入量分别为1.0%和0.7%（质量分数）时， Mg2Si增强体以细小短棒状形态出现， 其平均粒径为12μm， 这比未经细化处理的Mg2Si增强体的平均粒径降低52%。 同时， 单位面积Mg2Si晶粒平均数量为未经细化处理时的4~6倍。 单独加入Sr时， 复合材料的组织细化则不如Ce-Sr复合处理时的稳定。 对相关机制的研究表明，上述细化元素对Mg、 Si原子在合金熔体中扩散的不同程度的抑制是微观组织得以细化的根本原因。
关键字: Al基复合材料；自生复合材料; Mg2Si; 组织细化
（State Key Laboratory of Metal Matrix Composites,
Shanghai Jiaotong University, Shanghai 200030, China）
Abstract: The effect of Sr and Ce-Sr refiners on the microstructure of as-cast Al/Mg2Si/Si in-situ composite was investigated. When the addition contents of element Ce and Sr are 1.0% and 0.7%(mass fraction) respectively, Mg2Si reinforcements exist in short rod-like shape, and the average size of Mg2Si reinforcements can be reduced to 12μm, which is 48% of that without refiners. Moreover, the average number per unit area of Mg2Si reinforcements can increase by 4-6 times compared with the untreated one. The microstructure refinement effect of composites by Sr addition is less stable than that by Ce-Sr addition. Based on the mechanism analyses, it is concluded that the suppression of the diffusion of Mg and Si element by refiners contributes highly to the microstructure refinement.
Key words: Al-base composites; in-situ composites; Mg2Si; microstructure refinement
