(中南工业大学材料科学与工程系，长沙 410083)
摘 要: 制备了Al-5Mg、Al-5Mg-0.2Sc、Al-5Mg-0.1Zr和Al-5Mg-0.2Sc-0.1Zr四种铸态合金，采用金相显微镜和扫描电镜观察分析了微量Sc和Zr对Al-Mg合金铸态组织的晶粒细化作用及其机理。结果发现，0.2%的Sc并未使Al-Mg合金产生晶粒细化作用，而 0.2%的Sc与0.1%的Zr复合添加则使Al-Mg合金产生了极其强烈的晶粒细化作用。这一作用的产生，是由于Sc、Zr与Al在合金熔体中生成了A l-3Sc和Al-3Zr复合粒子，这种粒子在合金凝固过程中，起到了非均质晶核细化晶粒的作用。
关键字: 钪 Al-Mg合金 非均质晶核 细化作用
（Central South University of Technology, Changsha 410083）
Abstract:Al-5Mg, Al-5Mg-0.2Sc, Al-5Mg-0.1Zr and Al-5M g-0.2Sc-0.1Zr cast alloys have been prepared. The effect of trace Sc and Zr on grain refinement of Al-5Mg cast alloy was studied using optical microscopy and scanning electron microscopy with EDS. The results showed that adding 0.2%Sc and 0 .1%Zr to Al-5Mg alloy leads to strong grain refinement but adding only 0.2%Sc to Al-5Mg alloy has no grain refinement phenomenon. This is because, during solidification, Al-3Sc/Al-3Zr composite particles were formed in the melt playing a role of the nuclei of imhomogenized crystallization.
Key words: scandium aluminium alloy grain refinement
