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本文通过俄歇微探针定点成份分析和X射线粉末照像方法分别对稀土在初生Si颗粒和共晶组织两相中的存在和分布特点进行了研究。结果表明:稀土变质剂使初生Si颗粒由开花状板片变成多面体颗粒状。产生这种变化的原因是和稀土吸附并阻碍Si相沿孪晶凹坑的生长有关;在Al—Si合金中,微量稀土主要存在于Si相,在Si相中分布较均匀,未发现选择性吸附和明显的浓度偏聚;微量稀土变质剂(0.09%加入)没有明显的形成化合物倾向,稀土在Si相中的固溶量浓度与杂质属相同数量级;稀土变质似不形成Si相的异质核心。
In this paper, the existence and distribution characteristics of rare earths in two phases of primary Si particles and eutectic microstructures were investigated by the method of fixed point analysis and X-ray powder photography of Auger microprobe. The results showed that the rare earth modifier changed the primary Si particles from the flowering plate into polyhedral particles. The reason for this change is that the rare earths adsorbed and hindered the growth of twinned pits along the Si phase. In Al-Si alloys, trace rare earths were mainly present in the Si phase and distributed uniformly in the Si phase. No selective adsorption was found (0.09%) did not show obvious tendency to form compounds. The concentration of rare earth in the Si phase was the same as that of the impurities; the rare earth metamorphism did not form the heterogeneous core of Si phase .