Superplastic behavior of friction-stir welded Al–Mg–Sc–Zr alloy in ultrafine-grained condition

The present work was undertaken to improve superplastic ductility of friction-stir welded joints ultrafine-grained (UFG) Al–Mg–Sc–Zr alloy. In order suppress the undesirable abnormal grain growth, which typically occurs in heavily deformed base material, UFG material produced at elevated temperature. It suggested that new processing route could reduce dislocation density structure and thus enhance its thermal stability. found, however, approach resulted a relatively high fraction low-angle boundaries which, turn, retarded grain-boundary sliding during subsequent tests. Therefore, despite successful inhibition growth base-material zone, deformation still preferentially concentrated fully-recrystallized stir zone material. As result, maximal elongation-to-failure did not exceed 700%.