Mechanical anisotropy and grain interaction in recrystallized aluminum

Abstract

Axial compression tests up to 50 pct deformation were performed on rolled and fully recrystallized aluminum sheet stock (AA5754, AA5182, and AA6016) in the direction perpendicular to the sheet. Textures were measured using both X-rays and orientation imaging microscopy (OIM). In all three cases, a systematic in-plane anisotropy was observed, with more strain taking place in the transverse than in the rolling direction. Previous attempts to simulate this in-plane anisotropy for AA5754, starting from the X-ray initial textures and using a one-site polycrystal model, resulted in predictions of more deformation along the rolling than along the transverse direction. An analysis of the OIM textures indicates that there is a nonrandom spatial correlation of the recrystallization and retained rolling components. As a consequence, we implemented grain interaction and co-rotation in a viscoplastic self-consistent (VPSC) polycrystal model, in order to be able to account for orientation correlations. Such an approach allows us to describe the large- and small-angle misorientation distributions, as a function of deformation and to compare them with the available experimental evidence. Concerning the in-plane anisotropy, we conclude that it is very sensitive to details in the texture representation, rather than on grain interactions. Grain-interaction and co-rotation effects, however, have the effect of inducing less severe deformation textures, which is in better agreement with the experimental evidence.