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本文借助扫描电镜、电子探针等分析手段,详细地考察了Sr,Sb对纯度不同、成分不同的Al-Si合金在不同冷速下的变质作用,作出了五种Al-Si合金的含Sr(或Sb)量-冷却速度-显微组织的诺谟图,可供生产现场选择最佳加Sr、加Sb量作依据。实验结果表明,Al-Si合金加Sr后变质存在一个变质阈值,超过这个阈值时,即便在投缓慢的冷速(4.5℃/min)下,仍能获得完全变质的组织。这个变质阈值随着冷速的减慢而增大。Sr,Sb均能消除硅晶体的非自发形核基底,阻止初晶硅析出,但对共晶硅生长形态的影响不同。
In this paper, by means of scanning electron microscopy, electron probe and other analytical tools, the effects of Sr and Sb on the metamorphism of Al-Si alloys with different purity and composition at different cooling rates were investigated in detail. Five Al-Si alloys containing Sr (Or Sb) amount - cooling rate - Microstructure of the nomogram for the production site to choose the best plus Sr, Sb added as the basis. The experimental results show that there is a metamorphic threshold in Al-Si alloy after Sr addition, and beyond this threshold, fully metamorphic structure can be obtained even at slow cooling rate (4.5 ℃ / min). This metamorphism threshold increases as the cooling rate slows. Both Sr and Sb can eliminate non-spontaneous nucleation of silicon crystals and prevent the precipitation of primary silicon, but have different effects on the growth morphology of eutectic silicon.