γ-Fibre recrystallization texture in IF-steel: an investigation on the recrystallization mechanisms

Development of recrystallization texture in cold-rolled Ti-bearing IF-steel was investigated using X-ray diffraction, Electron Back Scattered Diffraction/Orientation Imaging Microscopy (EBSD/OIM) and TEM. During cold-rolling, both the alpha (RD//[110]) and the gamma (ND//[111]) fibres were observed to be strengthened, although the increase in alpha was more pronounced. Simulations of the cold-rolling using Taylor type theories demonstrated an approximate predictability of the textural changes. Recrystallization strengthened the gamma, as F (= {111}[112]) increased but E (={111}[110]) remained essentially unchanged. A corresponding decrease in alpha, more in H (={001}[110]) than in I (=z{112}[110]), was also observed. The strong gamma-fibre recrystallization texture was mainly due to the larger numbers (i.e. 'frequency advantage') of the gamma-oriented grains, as the gamma rains were no larger than grains of other orientations. TEM studies showed an increase in cell size and a decrease and cell misorientation (which means an increase in stored energy) from H double right arrow I double right arrow E double right arrow F. With the exception of a slight drop from E to F, increase in the Taylor factor always corresponded to an increase in the stored energy. The spread of stored energies, corresponding to inhomogeneities in dislocation substructure, were observed to increase from I double right arrow H double right arrow E double right arrow F. A combination of the higher stored energy and the stronger inhomogeneities in dislocation substructure is possibly responsible for the preferred nucleation behavior causing the frequency advantage for the gamma grains. (C) 1997 Elsevier Science S.A.status: publishe