本文研究了微量磷对Al-Si共晶合金组织的影响,研究结果表明,磷与钠之间存在一个比例(P:Na=1:2.2),磷多余时出现初晶硅,钠多余时共晶硅得到细化,获得变质组织。变质剂最佳加入量和合金中磷、钠原始含量密切有关。剩余磷量高时,变质剂加入量取上限,剩余磷量低时取下限。反之,有钠量剩余时,可以不必变质,这就是无磷硅铝明不变质就具有变质组织的原因。 文中提出了过渡理论,试图解释钠不能作为长效变质剂的机理。 In this paper, the effect of trace phosphorus on the microstructure of Al-Si eutectic alloy was studied. The results show that there is a ratio between P and Na (P: Na = 1: 2.2) Crystallization of silicon was refined to obtain metamorphic tissue. The best addition modifier and alloy phosphorus, sodium is closely related to the original content. When the residual phosphorus content is high, the maximum amount of modifier is taken and the lower limit is taken when the residual phosphorus content is low. Conversely, the amount of sodium remaining, you can not have metamorphism, which is non-degenerate phosphorus-free aluminum silicate with metamorphic tissue reasons. The paper presents a transitional theory that attempts to explain the mechanism by which sodium can not act as a long-acting modifier.