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研究了Sb含量对Mg2Si/Al-5Si复合材料显微组织的影响。结果表明,随着Sb含量的增加,初生Mg2Si颗粒形貌明显发生了细化,Mg2Si形态由变质前的汉字体和枝晶状变为细小的、均匀分布的颗粒状,Mg2Si体积分数也有所增加。当Sb含量为0·4%时,细化效果达到最佳,由变质前的52μm变为25μm。当Sb含量超过0·4%后,Mg2Si颗粒尺寸开始粗化,因此,过量的Sb对Mg2Si颗粒的细化无益。Sb对Mg2Si颗粒的细化主要由于AlSb引起的异质形核作用,Sb使液相线温度和熔体表面张力σLV降低,对Mg2Si颗粒的细化也具有一定的作用。
The effect of Sb content on the microstructure of Mg2Si / Al-5Si composites was studied. The results show that with the increase of Sb content, the morphology of primary Mg2Si particles is obviously refined. The morphology of Mg2Si particles changes from fine Chinese characters and dendrites to fine and uniformly distributed particles, and the volume fraction of Mg2Si also increases. When the Sb content is 0.4%, the refining effect is best, from 52μm before modification to 25μm. When the Sb content exceeds 0.4%, the grain size of Mg2Si starts to be coarsened, and therefore excess Sb does not contribute to the refinement of Mg2Si grains. Sb refinement of Mg2Si particles mainly due to heterogeneous nucleation caused by AlSb, Sb liquidus temperature and the melt surface tension σLV decreased, the refinement of Mg2Si particles also have a role.