Residual Stresses in Friction-Stir-Welded 2195 and 7075 Aluminum Alloys

Surface residual stresses (RSs) were characterized along friction-stir-welded 2195 and 7075 aluminum alloy (AA) plates. The surface measurements were obtained through X-ray diffraction (XRD) at five different locations along the weld. Each location consisted of several regions across the welded plate including the weld nugget, thermomechanically affected zone (TMAZ), heat-affected zone (HAZ), and base material. Measurements revealed that RSs were not uniform along the welded plate, with the highest RSs obtained on the middle of the plate. The RSs across the weld were also asymmetric relative to the weld centerline, with RSs as high as 231 MPa in the TMAZ for the retreating side of the weld.