BICRYSTALLOGRAPHY.

Abstract

In this paper a crystallographic framework and methodology are presented that enable the derivation of the symmetry of any bicrystal comprising a planar interface between two crystals of the same or different form. If the crystals are different the interface is an interphase boundary, and if they are the same the interface is a grain boundary. The methodology employed in this treatment of bicrystal symmetry is to use the theory of the symmetry of composites. A composite is regarded here as an entity comprising two components, which may be crystal lattices, as in a dichromatic pattern, or lattice complexes, as in a dichromatic complex, or crystals, as in a bicrystal.