On nanoscale Al precipitates forming in eutectic Si particles in Al–Si–Mg cast alloys

 Nanoscale Al precipitates with satellite-like outgrowths have been observed in eutectic Si particles in Al–Si–Mg alloys. Investigation by high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy indicates that the outgrowth is a void in the aluminium. The void interface plane in the Al crystal is {1 1 1} and is parallel with {0 0 1} Si. It is very likely that the outgrowth is related to the precipitation of Al in the Si particles and to the stability of the Al precipitates.