摘要
采用OM、SEM、EDS、XRD等研究复合变质剂组成对AZ91D镁合金铸态和固溶态组织的影响,并分析晶粒细化作用机理。结果表明,适当加入三元复合碳变质剂可使AZ91D镁合金的晶粒尺寸显著减小,在相同的实验条件下,当3种碳化物组分Mg CO3、Si C、C2Cl6的质量比为3:1:1时,能够获得最好的细化效果。一方面,Mg CO3、C2Cl6在熔体中分解出的C与Al发生原位反应,生成的大量Al4C3颗粒均匀分散到熔体中,直接成为α-Mg的形核核心;另一方面,在α-Mg晶体生长过程中部分细小的Al4C3颗粒与Si C颗粒一起被固液界面推移至晶界,起到阻碍晶体长大作用,使α-Mg晶粒得到有效细化。
The effects of complex inoculants on the as-cast and solid-solution state microstructure of AZ91 D magnesium alloy and the grain refinement mechanism were investigated by OM, SEM, EDS and XRD. The results show that the grain size of AZ91 D magnesium alloy decreases effectively after the complex carbon inoculants are added. The best refinement result can be achieved when the mass ratio of Mg CO3, C2Cl6 and Si C is set as 3:1:1. On one hand, the amount of Al4C3 particles induced by carbon-containing compound including Mg CO3 and C2Cl6 can directly serve as the heterogeneous nucleus of primary α-Mg phase. On the other hand, some of the fine Al4C3 and Si C particles are pushed by solid-liquid interface between α-Mg phases and the melt, and distribute along the crystal boundary, so as to impede the growth of α-Mg grains, and the α-Mg grains are greatly refined finally.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2015年第4期883-889,共7页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(51264032
51361022)
教育部留学回国人员科研启动基金资助项目(第44批)
