Sc和Zr对Al-Mg铸造合金组织和力学性能的影响

采用金相显微镜、扫描电镜和能谱分析，研究Sc、Zr对Al-Mg铸造合金组织和力学性能的影响。结果表明，添加0．2％～0．4％的Sc，会使合金铸态组织中的部分树枝晶变为等轴晶，且Sc含量越高，合金铸态组织越细；随着Sc含量的增加，合金的抗拉强度升高，Sc含量为0．4％的合金抗拉强度提高30％。添加0．1％～0．2％的Zr也会使合金铸态组织中的部分树枝晶变为等轴晶，但是效果不如Sc；随着Zr含量的增加，合金的延伸率升高，Zr含量为0．2％的合金延伸率高达11．9％。

Effect of Se and Zr on as-east Microstructures and Mechanical Properties of Al-Mg Cast Alloys

As cast microstructures and mechanical properties of Al--Mg cast alloys with or without Sc and Zr were investigated by optical microscope, scanning electronic microscope （SEM） as well as energy dispersion spectrum analysis. The results indicate that an addition of 0.2-0.4 mass% Sc can change the growth morphology of grains from dendritic to fine equa-axis. The higher Sc addition, the better the as-cast grain will be. The tensile strength is increased by the addition of Sc and reached about 30% up at a 0.4 mass% Sc addition in the alloy. On the other hand, an addition of 0.1-0.2 mass% Zr is also able to refine the grain size, and can change the growth morphology from dendritic to fine equa-axis grain, but it was not more effective than Sc. However, the addition of Zr can increase the ductility of the cast alloys, and the elongation was increased up to 11.9%.