STATISTICS OF ASYMMETRICAL [001] TILT GRAIN-BOUNDARIES

A model is developed to generate systematically various asymmetrical grain boundaries differing in grain misorientations and boundary plane inclinations. The model is applied to the [001] tilt grain boundaries in the b.c.c. lattice. Calculated frequencies of asymmetrical boundaries with large interplanar spacing in dependence on the coincidence site lattice parameter SIGMA can be compared with the experimentally observed occurrence of misorientations with low and high SIGMA values. A critical value of SIGMA, dividing the misorientations between special (with low SIGMA) and general ones, however, cannot be determined by purely geometrical means.