Influence of Annealing Conditions on Formability in Dissimilarly Oriented A1050P-O Tailored Blanks Welded by Friction Stir Welding

This study focused on the influence of annealing on the deformation behavior and weld-bead formability of dissimilarly oriented tailor-welded blanks (D-TWBs) fabricated by friction stir welding of 1-mm-thick JIS A1050P-O aluminum sheets. To confirm the annealing effect, D-TWBs with the weld bead perpendicular to the tensile direction were evaluated under different temperature states. Tensile stress–strain curves and logarithmic strain distributions of D-TWBs in the tensile, width, and thickness directions were evaluated. Fracture generally occurred on the base material near the weld bead, whereas annealed D-TWBs fractured away from the weld bead. Annealing increased the axial strain capacity, improved early-stage strain uniformity, and reduced lateral contraction and scatter in the width direction. In contrast, annealing increased the thickness-direction thinning and scatter, indicating an elevated propensity for out-of-plane localization that can dominate the final fracture. Overall, annealing promoted smoother strain transfer around the weld bead and improved deformation of weld bead, although the improvement showed a threshold-type dependence on the temperature state.