Abstract
Interfacial morphology at the beginning of the instability of planar solid-liquid interface was observed in Al–Zn alloys after quenching specimens during the unidirectional solidification. Interfacial holes occured at the beginning of the instability which were distributed regularly or irregularly depending on the growth condition of crystal as predicted by the theory. In the case of the regular distribution of the holes, the reasonable interfacial energy between solid and liquid was obtained comparing with the theory but in the irregular case it was erroneous.
