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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 ,起到了异质生核作用
The addition of Sr as a modifier to an Al Si alloy can cause the morphology of the eutectic silicon to change from a coarse sheet (or acicular) to a fine fibrous one, but also promote the formation of long columnar dendrites. In order to suppress long columnar branches In this study, the effects of Zr on the microstructure of Sr metamorphous Al Si alloy were investigated by metallographic microscope and scanning electron microscope.The results show that the dendrite α (Al) is equiaxed with the addition of Zr The main length of long columnar dendrites is shortened, and the morphology and size of eutectic silicon are not affected obviously. When the amount of Zr added is 0 5% ~ 0 6%, the dendrite α is completely equiaxed, which is due to the melting The body formed ZrAl3 particles in the alloy solidification process, played a heterogeneous nucleation role