采用金相显微镜、扫描电镜、X射线衍射仪等实验手段,研究了质量分数为1%、3%和5%的Zr对Al-20Si铝合金铸态组织的影响。结果表明,随着Zr质量分数的增加,初生硅颗粒尺寸逐渐变大。加入Zr后,反应生成了AlSi4Zr5,毒化了形核核心,使晶粒长大;同时Zr使初生硅周围分枝状的α-Al"晕圈"形成充分,减小了对初生硅生长的抑制。
The effects of addition of Zr whose content was 1%,3% and 5% on as-cast microstructure of Al-20Si aluminum alloy were investigated using optical microscope,scanning electron microscope,X-ray diffraction,etc.The results showed that the size of primary silicon particles became bigger gradually with the increasing of the content of Zr.After the addition of Zr,the AlSi4Zr5 was obtained,and Zr poisoned the nucleuses causing the grain size growth;at the same time,α-Al dendritic halos surrounding the primary silicon particles were developed fully,and reduced the inhibition effect of growth of the primary silicon.