Evolution of the Deformed Substructure Obtained by Cold-Rolling in IF Steel

The aim of this study is to acquire more quantitative data on the cold-deformed state, in order to determine the key parameters for nucleation (like orientation gradient, dislocation density, degree of fragmentation…) and to correlate these to parameters which can be predicted by a mean field deformation model. Experimentally, a Ti-IF hot band has been deformed by cold rolling up to 51%. The deformed microstructures are finely characterised using EBSD inside the SEM. It appears then that the heterogeneity of deformation inside the grains begins very early. Some grains undergo fragmentation whereas some others deform very homogeneously. Misorientation and degree of fragmentation are found to be orientation and rolling level dependent. These deformation parameters are plotted against the Taylor factor, calculated in each grain.