摘要
Sr作为变质剂加入到Al Si合金中能导致共晶硅的形态从粗大的片状 (或针状 )转变为细小的纤维状 ,但同时也促进长柱状枝晶的形成 .为了抑制长柱状枝晶的形成 ,本研究采用金相显微镜和扫描电镜分析Zr对Sr变质近共晶Al Si铸造合金组织的影响 .结果表明 ,随着Zr加入量的增加 ,枝晶α(Al)有等轴化趋势 ,长柱状枝晶的主干长度缩短 ,且对共晶硅的形态、尺寸没有明显影响 ,当Zr加入量为 0 5 %～ 0 6 %时 ,枝晶α完全等轴化 .这是由于熔体中形成了ZrAl3颗粒 ,在合金凝固过程中 。
The addition of Sr in Al Si alloys as a modifier can result in transition of eutectic silicon from coarse plate like or acicular to fine fibrous. However,it may also lead to the formation of long columnar dendrite α phase. The influence of Zr on microstructure of near eutectic Al Si alloys was studied using optical microscopy and SEM. The result indicated that increasing of Zr addition, α dendrite tends to change from long columnar to equiaxed, and there were no noticeable changes of the eutectic silicon. When adding 0 5%-0 6%Zr, the dendrite α phase was equiaxed fairly.This is because, during solidification,ZrAl 3 particles were formed in the melt playing a role of hetergeneous nucleation.
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
2000年第6期47-51,共5页
Journal of Southeast University：Natural Science Edition
