Partitioning evaluation of mechanical properties and the interfacial microstructure in a friction stir welded aluminum alloy/stainless steel lap joint

The mechanical properties and interfacial microstructure of slices of a friction stir welded aluminum alloy/stainless steel dissimilar lap joint were characterized. The strength in the center region and on the advancing side was larger than that at the retreating side. A sound joint that fractured at the base metal was obtained where the amorphous layer was formed due to the mechanical alloying effects of kneading, whereas interfacial fracture occurred where oxide films originally covered by the plate surfaces were mixed.