Evolution of microstructures and mechanical properties in similar and dissimilar friction stir welding of AA5086 and AA6061

► Similar and dissimilar friction stir welding of AA6061 and AA5086 are studied. ► Peak temperature in AA6061/AA6061 joints is the highest. ► Natural aging after FSW significantly alters mechanical properties of SZ and HAZ. ► Finer grain size is achieved in AA6061 side both in similar and dissimilar joints.