The liquid of binary Al-7%Si alloys

both high purity and commom purity

has been superheated in the temperature range of 700-1200℃. The influences of superheating on the microstruture

microhardness

grain size and thermal analysis of solidification have been studied.High super-heating increases the α-Al dendrite size

has little effect on eutectic structure

doesn’t change the eutectic temperature and reduces slightly the primary solidification temperature. The changes of microhardness are not obvious

and the grain sizes are not affected for high purity alloys

but they are enlarged for commom purity alloys when superheating.