Papers by Keyword: Misorientation Profiles

Abstract: In extra-low carbon steels, the generation of specific nucleation sites in the deformed microstructure determines the formation of an optimum recrystallization texture. In particular, during the cold rolling of the steel sheets, transition bands are generated in order to accommodate the different deformation paths followed by the deformation bands (DB-s) within the grains. -fibre grains (ND-fibre grains) are, in general terms, more fragmented than -fibre grains (RD-fibre grains). Consequently, the higher orientation gradients and stored energy levels of the -fibre grains determine the ND-fibre annealing texture. Nevertheless, during recrystallization of the ELC steel, nucleation in different type of transition bands (TB-s) between α-fibre components has also been observed in the present work. From a previous crystallographic classification of transition bands done by the authors, the effect of the lattice curvature, either by gradual or sharp orientation gradients, is studied during early recrystallisation stages. Specifically, the crystallographic characteristics of recrystallized nuclei formed at transition bands generated between α-fibre components are analyzed using electron back-scatter diffraction (EBSD). This technique enables the orientation of deformation bands, the misorientation across them, the orientation of the new recrystallized grains and the misorientation of those grains with the adjacent matrix grains to be determined. Recrystallization of components different to α at the expense of α components has also been found.

Abstract: During annealing of cold rolled steel sheets, the evolution of the texture, to produce the characteristic texture of a recrystallised material, depends on a series of factors, including the starting deformation texture, composition and processing conditions. In the present work, electron backscattered diffraction (EBSD) techniques have been used to investigate the deformation substructures being developed by cold rolling into grains belonging to different texture components. The strain localisation, the deformation banding, the spread in orientation into grains with different orientations are some of the aspects that have been considered. Annealing cycles at different temperatures have also been carried out in order to promote recovery and initial stages of recrystallisation . The obtained substructures have been compared to the as-cold rolled ones. It has been observed that recovery induces the dislocation structures to arrange into subgrains. Associated to the ND fibre, a network of relatively high angle boundaries develop within the subgrain structure. The recrystallisation nuclei have been observed to evolve from such a network.