A comprehensive study of interfacial microstructure and corrosion behavior of AA2219 to 304SS inertia friction welded joints

The AA2219/304SS bars are inertia friction welded. Research demonstrated high heat input can promote the precipitation of the strengthening phases to form the Cu-rich layer. Whereas the plastic deformation and flow of the Al alloy can inhibit the formation of the Cu-rich layer. The thicker Cu-rich layer acts as a cathode to aggravate the damage to the Al alloy at the interface. Moreover, the formation of the Cu-rich layer and the coarsening of the strengthening phase reduce the Cu element content in the recrystallization grains of Al alloy, making the Cu-poor grains more susceptible to pitting attack.