SYMMETRY ANALYSIS OF INTERFACE TRIPLE JUNCTIONS

The symmetry properties of triple junctions formed by crystal interfac es are presented using colour crystallography. Triple junctions are tr eated as composites of three crystals and are studied using the princi ple of superposition of symmetries. The conclusions are used for the u nderstanding of the equivalences and invariances within one tricrystal composite and for studying such composites from the point of view of interfacial connectivity. A dissymmetrization procedure is established through which tricrystals equivalent by symmetry and their ways of co existence can be found. Also, the relations between the symmetry prope rties of the tricrystal and those of the three bicrystals participatin g in the junction are given. Emphasis is placed on a particular class of composities that are termed variant constituted tricystals. In thes e, two out of three bicrystals belong to orientation variants of the s ame dichromatic pattern. Such composites are usual in polycrystals and can exhibit interesting symmetry properties. The ordinary symmetry an d antisymmetry in the third bicrystal can be predicted using a given a lgorithm. Appropriate examples are given to illustrate the application of the analysis.