The dislocation structures of the vicinal grain boundaries, S5 [001](310)A in Cu and S3 [101](1¯2¯1)A in Fe-4at%Si, were described. A theoretical method was proposed for predicting dislocation structures in grain boundaries from S3 to S11. It exploited analogies, in basic DSC vector configurations, that existed between the present 2 cases and other low- S symmetrical boundaries. Both types of experimentally investigated dislocation structures were expected to contain dislocations with 4 Burgers vectors. Three of them could make up an hexagonal net which comprised either mainly screw dislocations while the fourth Burgers vector formed a set of parallel edge dislocations (type-I) or it comprised 1 edge dislocation and 2 mainly screw dislocations while the fourth Burgers vector formed a set of parallel screw dislocations (type-II). Possible grain boundary planes for symmetrical grain boundaries up to S11 were found. Basic DSC vectors were calculated using a method which was based upon a matrix that was formed from the 3 smallest non-coplanar diffraction vectors that were common to both grains. Only the basic DSC vectors were considered for the formation of dislocation structures. The characters (screw, mixed, edge) of the Burgers vectors with respect to the boundary planes were determined. Reactions between basic DSC vectors, which resulted in another basic DSC vector, were found by inspection. If there were only 1 possibility, this combination was expected to form the hexagonal net. When the hexagonal net was type-I or II, it was checked whether the fourth vector also corresponded to the correct structure-type. In some cases, 2 different reactions between basic vectors were possible. It was supposed that the hexagonal net which contained 3 mainly-screw dislocations would be preferred. It was found that, in all cases except S5 [001](120)A and S9, the hypothetical geometrical configurations belonged to structures type I or II. The definitive form of the grain-boundary dislocation structure which was predicted for special deviations from coincidence was designed in such a way that the rotation produced by it corresponded to the experimental value, and the structure produced no long-range shear stresses in the boundary plane.

On the Possibility of Predicting the Dislocation Structures of Low-S Symmetrical Grain Boundaries. A.Gemperle, T.Vystavel, J.Gemperlová: Materials Science Forum, 1999, 294-296, 393-6