Effect of local texture and residual stress on the bendability of extruded 6000-series Al alloy profiles

In this study, X-ray cosα measurement was optimized with 3-axis oscillation to perform highly accurate measurements of residual stress in extruded Al alloy (A6061 and A6005C) profiles having preferred orientations and large grain sizes. In A6005C, a grain-growth region was observed just below the surface–bulk boundary and visualized via texture differences. The regions of preferred orientations corresponded well with the major changes in the residual stress as a function of depth from the surface. The boundary of the (110) and (100) textures corresponded well with the first local maximum in the von Mises stress (σvM) for both the alloys. The grain-growth region of A6005C corresponded to the region between the first and second local maxima of σvM. The principal stress (σ1) direction was almost parallel to the extrusion direction in the grain-growth region of A6005C. The changes in the σ1 direction with depth resulted in the observed anisotropic bending behavior.