Figure 1. Comparison of irregular eutectic growth morphologies.

(a) Growth front of a eutectic mixture of borneol (faceted minor constituent) and succinonitrile²⁰. Reproduced with permission from Wiley Verlag²⁰. (b) Quenched growth front of an Al-12.7 wt%Si eutectic, where an envelope of Al encloses the faceted Si crystals⁶. According to Hellawell, this metallic ‘skin' could not have been present at temperature and must have formed during the quench⁶. Reproduced with permission from Elsevier⁶. (c) Growth front of an Al-51.6 wt%Ge, this work. The eutectic grows from the Al₂O₃ oxide skin (not pictured) into the melt. The solid–liquid interfaces in c share some semblance to that of (a) in that the faceted Ge phase (orange) leads at the growth front. Scale bar, 12 μm (a), 35 μm (b) and 40 μm (c).