Structure of molten Al–Si alloys

The temperature variation of the structure and microstructure of molten eutectic Al_1−xSi_x alloys (x = 0.122 and 0.20) have been studied by neutron diffraction and small-angle neutron scattering (SANS), as well as measurements performed on pure liquid Al. All measurements have been performed at five temperatures in a heating–cooling loop. The SANS results unambiguously show that for the eutectic alloy (x = 0.122) the microstructure changes with increasing temperature in a partly reversible way while for the hypereutectic (x = 0.20) alloy the change is almost completely irreversible. This change in microstructure also manifests itself in the shape of the static structure factor S(Q).