THE PREPARATION OF SINGLE CRYSTALS AND BICRYSTALS BY THE CONTROLLED SOLIDIFICATION OF MOLTEN METALS

Abstract

An account is given of the methods that have been developed for the production of single crystals and bicrystals of a wide variety of metals by controlled freezing of the molten metal in a horizontal "boat". Orientations are controlled by a "seeding" technique. A detailed qualitative analysis is given of the factors associated with the presence of "stray" crystals. Their formation is discussed in terms of nucleation and in terms of their subsequent survival, and attention is drawn to the significance of purity, of speed of growth, and of the temperature gradient in the liquid.