INFLUENCE OF Sr AND Sb ON SOLIDIFICATION OF Al-Si ALLOYS

The influence of Sr and Sb on the solidification process of Al-Si alloys. was investigated by differential thermal analysis(DTA). The contact angles between the melt and silicon substrates were measured, and the interfacial energies were calculated. It was obtained that Sr and Sb in the melt raised the Al-Si eutectic nucleation temperature and retarded the eutectic crystallization. Sr and Sb in the melt had no thermodynamic tendeney to absorb on silieon crystals, which was contrary to the traditional point of view. But Sr and Sb might accumulate on silicon crystals and affect the growth of Al-Si eutectics because the partition coefficients were less than 1.