复合碳变质剂对AZ91D镁合金的晶粒细化作用

发布时间：2018-08-06 18:34

【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。
[Abstract]:The effect of composition of composite modifier on the as-cast and solid solution microstructure of AZ91D magnesium alloy was studied by OMSEMX XRD and the mechanism of grain refinement was analyzed. The results show that the grain size of AZ91D magnesium alloy can be significantly reduced with the proper addition of ternary compound carbon modifier. Under the same experimental conditions, the best refining effect can be obtained when the mass ratio of three carbides, mg CO _ 3, Si, C _ 2Cl _ 6, is 3:1:1. On the one hand, Mg-CO3C2Cl6 reacted in situ with Al, resulting in a large number of Al4C3 particles dispersed uniformly into the melt, forming the nucleation of 伪 -Mg directly, on the other hand, During the growth of 伪 -Mg crystals, some fine Al4C3 particles and sic particles are moved to grain boundaries by solid-liquid interface, which hinders crystal growth and makes 伪 -Mg grains refine effectively.
【作者单位】：南昌大学机电工程学院;
【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)
【分类号】：TG146.22

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