Microstructural Evolution and Material Flow during Friction Stir Welding of 6013 Aluminum Alloy Studied by the Stop-Action Technique

This work is part of a wide-ranging study aiming to enhance the technology dissimilar friction-stir welding aluminum and titanium. In previous study, new approach was proposed that provided an exceptionally narrow intermetallic layer. However, essential disadvantage this technique significant material softening in part. Hence, present undertaken order obtain insight into microstructural processes flow To end, stop-action applied. It found evolution included several stages. Specifically, initial underwent discontinuous static recrystallization heat-affected zone. With rotating tool, recrystallized grains experienced continuous dynamic recrystallization, which resulted grain refinement. The subsequent transportation around tool no alterations microstructure. “superplastic-like” character attributed balance between refinement coarsening. also stirred secondary deformation induced by shoulder far behind tool. concomitant changes were most pronounced at upper weld surface gave rise fine-grained