SHAPE TRANSFORMATION OF PLASTIC CRYSTALS UNDER THE EFFECT OF SURFACE-ENERGY - ADAMANTANE IN TEMPERATURE-GRADIENT CONDITIONS

The spontaneous transformation of a polycrystal into a single crystal at high temperatures is observed with adamantane samples. Since the plastic crystal phase at such temperatures is not elastically strained it is concluded that the process is due to the surplus of surface energy in the system. The spontaneous transformation to the equilibrium form of crystals under temperature gradient conditions is investigated. The effect is established both of the surface energy and the shape of the isothermic surfaces.