Effect of Strain Path and the Magnitude of Prestrain on the Formability of a Low Carbon Steel: On the Textural and Microtextural Developments

Abstract

A low carbon steel (0.07-wt % carbon) sheet metal was deformed in five different strain paths, from equi-biaxial tension to plane strain to near uniaxial tension, by in-plane stretching. Textural developments were characterized by X-ray Orientation Distribution Function (ODFs) and the same were simulated using different Taylor type deformation texture models. A strong difference in bulk texture developments was observed at respective strain paths. The textural differences largely explain the changes observed in normal anisotropy values obtained by mechanical testing. The new deformation texture simulation model, Lamel, was quite successful in predicting quantitatively such textural differences. Microscopically, the significant features of the substructures were “strain localizations”—first generation dense dislocation walls (DDWs) and micro bands (MBs). Both in-grain rotations and estimated stored energies did depend on the relative appearance of such strain localizations. These, on the other hand, were distinctly related to the textural softening or dM/dε, where M and ε are the Taylor factor and true strain, respectively.