Variations in stir zone and thermomechanically affected zone of dissimilar friction stir weld of AA5083 and AA6082 alloys

Variations in composition, microhardness (in the thermomechanically affected zone) and texture in the tool domain of the dissimilar friction stir weld of AA5083-O and AA6082-T6 alloys were investigated. The contents of the major alloying elements in the weld zones were determined using inductively coupled plasma-atomic emission spectroscopy. It was observed that a slight drop in the content of the alloying elements results from the friction stir welding process with the Mg content being the most affected amongst the major alloying elements in the two alloys. By relating the mass fractions of the major alloying elements in the parent metals of both alloys to those of the stir zone, the relative proportions of the two alloys in the stir zone were estimated with the results showing that at least 60% of the materials in the stir zone are from the retreating side of the weld. It was also revealed that the changes in the hardness profile in the thermomechanically affected zone of the retreating side are predominantly influenced by changes in grain size in that domain. Finally, the investigation further revealed that the texture component in the tool shoulder domain is different from the texture component in the tool pin domain.