Geometrical theory of triple junctions of CSL boundaries

When three grain boundaries having misorientations generating coincidence s ite lattices (CSLs) meet at a triple junction, a common (triple-junction) C SL is formed. A theory is developed as a set of theorems establishing the r elationships between the geometrical parameters of the grain-boundary and t riple-junction CSLs. Application of the theory is demonstrated in detail fo r the case of the cubic crystal system. It is also shown how the theory can be extended to an arbitrary crystal lattice.