Grain Boundary Characteristics of Isolated Grains in Conventional Grain Oriented Silicon Steel

During the secondary recrystallization of GO, isolated grains are often observed in secondary-recrystallized Goss grains (matrix). In an extraction experiment, the crystallographic relations between single isolated grains and matrix grains respectively were investigated in the case of CGO. Although the Σ5 grain boundary to the Goss orientation was the most frequent in the primary recrystallization texture, no Σ5 boundary could be observed at the onset temperature of secondary recrystallization; hence it was concluded that the Σ5 boundary was most mobile in this case. On the other hand, in the case of HGO, it has already been reported that the Σ9 is most mobile. The reason why the dominant grain boundary may differ for the same Goss orientation could be the temperature dependency of the grain boundary features, i.e., mobility and/or grain boundary energy. Furthermore, the Σ3 was more mobile than GGB (general grain boundary) at the higher temperature, which corresponded to the lower temperature range of HGO.