Micrographs in Fig. 4 show the morphology of modified eutectic
Si. The eutectic silicon morphology in the unmodified alloy is relatively
coarse with a lamellar structure and sharp edges as shown
in Fig. 4 samples with no Sc addition at all temperature tests. We
found that Sc addition modified the eutectic Si from a plate-like
structure to a lamellar structure. For the 0.2 wt.% Sc and 0.2 wt.%
Zr treatment, the eutectic morphology was finer and lamellar. The
addition of Zr with Sc increases the efficiency of modification of Sc. If
Zr is completely soluble in Al3Sc, a stable formation of Al3(ScxZr1−x)
phase might be expected and results in an increase in impurity on
the interface of silicon and liquid aluminum [5]. However, further
research is needed to clarify and confirm the above explanation.