Effect of intermediate annealing and reduction ratio on the texture evolution and formability in AA5083

Abstract

In the present study, the effect that intermediate annealing (IA) and reduction ratio (RR) exert on the microstructure and texture evolution in AA5083 sheets was investigated. The initial hot-rolled AA5083 sheet was subjected to the following thermomechanical process: primary cold rolling (CR-1) → intermediate annealing (IA) → secondary cold rolling (CR-2) → final annealing (FA). A reference (Ref) specimen was subjected only to CR-1 → CR-2 → FA with no IA process. Through-thickness microstructural heterogeneities were observed in the initial hot-rolled AA5083 sheet, and these features persisted in the CR-1 and IA specimens. The CR-2 and FA specimens, however, showed no through-thickness heterogeneities. Cold rolling enhanced the plane-strain texture components (Copper, Brass and S) whereas annealing enhanced the recrystallization texture components (Cube and ND-Rotated-Cube (RC)). Following FA, the non-IA (Ref) specimen showed a larger fraction of Cube and ND-RC components by comparison with specimens that had undergone IA. When the r-values predicted using the visco-plastic self-consistent (VPSC) model were compared with the experimental results, the r-value for the non-IA (Ref) specimen was smaller than those for the IA specimens after FA. The average r-value increased gradually (in a 45° direction) as the RR of CR-2 was decreased (70–40%). Controlling the RR of the CR-2 after IA resulted in isotropic sheets with enhanced formability. The largest r-value was observed in FA specimens with a small RR during CR-2. A balance between retaining deformation texture and the evolvement of the Cube component was responsible for the larger r-value.