Microstructure of friction stir welded joints in AA5182

Two 2.5 mm thick hot mill stock sheets of AA5182 aluminum alloy were pretreated differently before friction stir welding, one was cold rolled by 20% reduction in thickness whereas the other was 20% cold rolled then recovery annealed at 230 degrees C for 100 hours. After friction stir welding of these two sheets, a uniform dynamic recrystallized microstructure of fine grain size with no evidence of abnormal grain growth in the heat affected zone of the weld was obtained. X-ray pole figure study showed that the weld zone comprised of triclinic texture components which were recognizably of rotated cube texture and could be quantitatively analyzed. The predicted sheet formability of the weld zone is better than that of the start material.