Abstract: A self-designed computer-aided solidification simulation system for large-size ingots was employed to determine the eutectic coupled-zone of Al-(7-14 wt%) Si alloys at low freezing rate with a temperature gradient of liquid on solidification interface tower than 20 K cm~(-1). Experimental parameters for the formation of a fully eutectic microstructure in a dia.38×70 mm ingot have been successfully obtained under various conditions for Al-(11.3 -13.0 wt%) Si alloys.Eutectic coupled growth charactersitics under this condition was also discussed.

Key words: Al-Si alloy, eutectic-like microstructure, solidification simulation, coupled-zone