Many specific properties of aluminum alloys including light
weight and good structural strength enable them to be applied
for structural parts.Therefore, all the defects related to the presence of brittle inter dendritic
and eutectic phases are eliminated [6].But conventional fusion welding of
aluminum alloys results in numerous welding defects which includes voids, hot cracking, distortion, precipitates dissolution, loss
of work hardening and lack of penetration in the joints [2,3].The aluminum alloys AA6XXX and AA5XXX are extensively used in the
fabrication of aircraft structures and other structural applications
[1].Structural parts and frames composed of these
aluminum alloys can be welded using sound welding techniques
commonly used in industries.Friction stir welding (FSW) is an appropriate solid state welding
technique to effectively join any combination of dissimilar aluminum alloys [4].Shigematsu et al. [9] attempted to join 3 mm thick dissimilar AA5083 and AA6061 alloys
using FSW and examined the microstructure and the mechanicalA nonconsumable rotating tool harder than
the base material is plunged into the abutting edges of the plates
to be joined under sufficient axial force and advanced along the
line of the joint.