Modification mechanism of hypereutectic Al-Si alloy with P-Na addition

来源期刊：中国有色金属学报(英文版)2003年第6期

论文作者：吴树森 涂小林 福田葉椰 菅野利猛 中江秀雄

文章页码：1285 - 1289

Key words：hypereutectic Al-Si alloys; modification mechanism; grain refinement; modification

Abstract: Effect of P-Na united modification on Al-22%Si-1.0%Cu-0.5%Mg-0.5%Mn alloy was studied. The results show that the refining effect of P-Na addition on primary silicon is superior to that of P and the former could modify eutectic silicon at the same time. Effects of P-Na modification on crystallization and microstructure of hypereutectic Al-Si alloys were studied with Electron-Scanning Microscope, Electron-Probe and X-ray diffractometer. The modification mechanism represents that on one hand, the primary silicon is refined by AlP as heterogeneous nucleus; on the other hand, when Na is added at the same time, P atoms are difficult to diffuse in the melt, and then enrichs on the growing faces of silicon phase. Moreover, a SiP compound was also discovered in Si crystals, which prevents the growth of silicon phase and refines the primary silicon.