GAMMA-FIBER 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 Scattere d Diffraction/Orientation Imaging Microscopy (EBSD/OIM) and TEM. Durin g cold-rolling, both the alpha (RD//[110]) and the gamma (ND//[111]) f ibres were observed to be strengthened, although the increase in alpha was more pronounced. Simulations of the cold-rolling using Taylor typ e 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 corre sponding decrease in alpha, more in H (={001}[110]) than in I (=z{112} [110]), was also observed. The strong gamma-fibre recrystallization te xture 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 i n stored energy) from H double right arrow I double right arrow E doub le right arrow F. With the exception of a slight drop from E to F, inc rease in the Taylor factor always corresponded to an increase in the s tored energy. The spread of stored energies, corresponding to inhomoge neities in dislocation substructure, were observed to increase from I double right arrow H double right arrow E double right arrow F. A comb ination of the higher stored energy and the stronger inhomogeneities i n dislocation substructure is possibly responsible for the preferred n ucleation behavior causing the frequency advantage for the gamma grain s. (C) 1997 Elsevier Science S.A.