THE TOPOGRAPHY OF SOLID–LIQUID INTERFACES OF METAL CRYSTALS GROWING FROM THE MELT

Abstract

An improved technique of separating the liquid portion of the metal from the adjacent crystal has been developed. Microscopic examination of the interfaces prepared by this method has revealed a new surface structure. It has been found that the presence or absence of the structure depends on the crystallographic orientation of the specimen. The structures have been observed in all of the metals investigated in the present work, namely lead, tin, and zinc. A detailed study of the structure has been made in the case of lead. It was observed that, when the angle between the macroscopic plane of the interface and either the (111) or the (001) plane was less than a certain critical value, the interface consisted of steps or terraces approximately 0.001 mm. high. A mechanism for the formation of those steps is proposed.