不同变质剂对细晶铝锭共晶铝硅合金微观组织的影响

Effect of Different Modifiers on the Microstructure of Fine Grain Ingot of Eutectic Al-Si Alloy

利用金相显微镜和扫描电镜研究了RE、P和P+RE变质对细晶铝锭共晶铝硅合金组织中硅相的影响。结果表明,RE是共晶铝硅合金很好的变质剂,它可以球化共晶硅,当RE加入量为0.5%时,共晶硅相尺寸最小,达到2.7μm,圆形度为0.8;当RE加入量大于0.6%时,共晶硅相粗化,并且组织中出现了初晶硅。P变质对共晶铝硅合金组织有显著的影响,使组织在共晶成分出现初晶硅,对共晶硅没有变质作用。P+RE联合变质时,P有毒化RE变质共晶硅的作用,合金组织中的共晶硅没有单独RE变质时球化的好;当P加入量为0.1%,RE加入量为0.4%时合金组织中初晶硅最小,为14.5μm,达到联合变质的最佳效果。

The effect of modification on the morphology of silicon phases of eutectic Al-Si alloy was studied by refining grain AI ingots with RE, P and P ＋ RE modifier respectively, the mcirostructure was analyzed by optical microscope and scanning electron microscopy. The results show that RE is a good modifier for the eutectic Al-Si alloy, which can spheroidize the eutectic Si phases. When RE addition is 0.5wt. %, the finest eutectic Si phases can be obtained. The average diameter of eutectic silicon particles can reach 2.7 lure and the roundness is 0.8. When RE addition is above 0.6wt. %, the eutectic Si phase becomes coarse and the primary silicon appears. P modifier has a significant effect on the microstructure of eutectic AI-Si alloys, which makes the primary silicon appear in the eutectic AI-Si alloy and has not modification effect on the eutectic silicon phases. When P＋ RE complex modifier is used, the size of eutectic silicon particle is bigger than that sole RE is used, P since P can weaken RE modification effect. When 0. l wt. % P ＋ 0.4wt. % RE are added in the eutectic Al-Si alloys, the size of primary silicons is minimum with 14.5 μm, thus obtain the optimal modification effect on the eutectic Al-Si alloys.