Figure 3.

Light optical microscopy (LOM) microstructure of the billet in the intermediate zone after etching with 0.5% HF aqueous solution (a) in the as-cast billet it is possible to observe β-AlFeSi plate-like particles (light grey) and Mg₂Si coarse particles originate from non equilibrium solidification both located at grain boundary and (b) after homogenization treatment β-AlFeSi needles transforms into α-AlFeSi discontinuous fragments in grain boundary (light grey) and Mg₂Si particles transform into round particles (black).