Effects of Sulphur on the Formation of (110)[001] Recrystallization Texture of 3.17%Si-Fe Alloy Sheets

Abstract

The effects of sulphur on the (110)[001] secondary recrystallization in 70% cold-rolled Si-Fe alloy sheets were studied with an optical microscope and an electron probe microanalyzer.
On annealing at 850°C, the colonies of fine grains with the (110)[001] orientation were formed within a region of (111)⟨112⟩ deformed matrix. Raising temperature up to 960°C, some of the (110)[001] grains were coarsened in these colonies of fine (110)[001] grains by the migration of small-angle boundaries. On the other hand, the migration of high-angle boundaries was not observed during this process. Above 980°C, coarsened (110) grains grew abnormally consuming adjacent grains which had a large orientation difference from the former.
By electron probe microanalysis, much sulphur was found at high-angle boundaries with a small radius of curvature. It may be explained that during the growth of (110)[001] grains with small-angle boundaries, the migration of high-angle ones has been inhibited by sulphide. Moreover, at a higher temperature, the high-angle boundaries could move by dissociation of sulphide.
The accumulation of sulphide along grain boundaries, which exerts a drag force on the migration of high-angle boundaries in the primary recrystallization structure and leads to the secondary recrystallization, would depend mainly on the misfit angle and some other factors relating to it. For these factors, the staying time, migration velocity of boundaries and the area swept by the boundaries should be considered.
The contribution of coincidence boundaries to the formation of the (110)[001] texture was also discussed.