Impact of multi-pass friction stir processing on microhardness of AA1050/AA6082 dissimilar joints

Abstract

The AA1050 and AA6082 aluminum plates were used to produce a dissimilar joint using the friction stir welding (FSW) technique. The produced dissimilar joint was then processed. The processing used is the multi-pass friction stir processing (FSP). Different tests were then conducted on the processed AA1050- AA6082 joints. The results on microstructural analysis revealed that as the number of FSP passes were increased the grain sizes reduced. The ultimate tensile strength of the multi-pass increased with a decrease in elongation as compared to that of a single pass with the same material positioning AA1050-AA6082 joints. For the surface morphology, the fracture surfaces were characterized by dimples on both the first and fourth pass. As the number of passes increased it was noticed that the dimples became smaller. The microhardness was found to have a minor dependency on the number of FSP passes.