Misorientation Characteristics at the Growth Front of Abnormally-Growing Goss Grains in Fe–3%Si Steel

Penetrating morphologies at the growth front of abnormally-growing Goss grains in Fe–3%Si steel was examined in view of the possibility that they are the two-dimensional section of the solid-state wetting (SSW) along the triple junction line. To obtain the statistically meaningful data, 102 penetrated grain and 204 penetrating abnormally-growing Goss grain morphologies were examined. The misorientation angles of penetrating and penetrated grains were measured by electron backscattered diffraction. Among the 102 examined penetrated grain boundaries, none has low misorientation angles less than 15°, whereas 17.2% of the 204 penetrating grain boundaries have low misorientation angles, and 23.5% of them have coincidence site lattice boundaries. Besides, boundary energies of penetrating Goss grains, which were estimated from misorientation angles of the three grains in the penetrating morphology, satisfied the energetic condition for SSW along the triple junction line. These results imply that the abnormal grain growth of Goss grains in Fe–3%Si steel occurs by the mechanism of sub-boundary enhanced SSW.