The grain boundary dislocation structures of three Fe-4at%Si bicrystals, with an additional misorientation of the order of 2°, were studied by means of transmission electron microscopy: one was of Σ = 5 [001](310) type and two were of Σ = 9 [110] (1¯14) type. It was found that, in the Σ = 5 case, 2 Burgers vectors of the structure were not simple basic complete displacement shift lattice vectors, and were larger than any of them. This permitted the formation of a preferred grain boundary dislocation structure with an hexagonal net that was composed of 3 screw dislocations and an independent set of parallel edge dislocations. In the Σ = 9 case, the grain boundary dislocation structure comprised 3 apparently independent sets of parallel dislocations. The Burgers vectors of 2 of the sets were established to be basic displacement shift lattice vectors in screw and edge orientations with respect to the grain boundary plane. In the third set, formed by separated groups of 4 dislocations, no corresponding basic displacement shift lattice vector existed. A previously published table of predicted grain boundary dislocation structures, for symmetrical coincidence boundaries of up to Σ = 11, was adjusted on the basis of the new results.

Refined Prediction and Observation of Dislocation Structures in Low Σ Symmetrical Grain Boundaries. A.Gemperle, J.Gemperlová, N.Zárubová: Interface Science, 2002, 10[1], 59-65