Intergranular corrosion behavior of 2219 aluminum alloy's welding join

The corrosion behavior of 2219 aluminum alloy and its welding joints (made by FSW and TIG welding) were investigated through intergranular corrosion test and polarization curve measurement. Metalloscope, laser scanning confocal microscope and scanning electron microscopy were employed to analyze the corrosion morphology, and corrosion products were measured by energy spectrometer. The results show that the corrosion behavior of 2219 aluminum alloy and its welding joints are related to precipitated phase, and the precipitation of Al₂Cu phase leads to the dissolution of poor Cu zone as the anode. The base metal shows the worst corrosion resistance ability, whose pitting corrosion develops to exfoliation corrosion along the rolling direction in corrosion media (NaCl+H₂O₂). The corrosion resistance of FSW joint is superior to that of TIG joint. TIG joint shows intergranular corrosion with network cracks, and FSW joint shows corrosion pits distributing scatteringly on the surface.