The effect of Al-17wt.%Si alloy melt overheating on solidification process and microstructure evolution

The effect of overheating on the solidification process and microstructure evolution in AlSi17 silumin was discussed. The alloy melt was held for 40 minutes at 780, 860, 940 and 1020oC, and then cast at a temperature of 780oC to standard ceramic probe. Characteristic parameters of the AlSi17 alloy solidification process, especially Tliq, TE, Tsol, were determined. Examinations of microstructure were also carried out, showing that the higher was the overheating temperature, the higher was the degree of the primary silicon crystals refinement.