EBSD Study on Two Modes of Metal Flow Transfer in Friction Stir Weldment

In this study, the metal flow phenomenon of friction-stir-welded AA6082-T6 and AA2014-T6 alloys is studied in detail and correlated with hardness measurement. The FSW process was carried out with optimized process parameters obtained from Taguchi’s method L9 orthogonal array of tool rpm (1200 rpm), welding speed (70 mm/min) and tilt angle of 2°. Cross-sectional view of dissimilar weldment interestingly showed the two modes of metal flow phenomenon within the weld matrix. EBSD analysis revealed that the weld matrixes of first mode region had almost equal fractions of LAGBs and HAGBs, whereas the second mode region had the lower fractions of LAGBs compared to HAGBs, which was due to the severe plastic deformation associated with tool shoulder.