Abstract: The 6063 aluminum alloy plates were welded by friction stir welding(FSW). The corrosion properties of friction stir welding seams and base materials were studied by the methods of static gravimetric, exfoliation corrosion and polarization curves. Their microstructure and corrosion morphology were observed by the Optical Microscope(OM) and Scanning Electron Microscope(SEM). The results show that: after 48 h corrosion, the pitting corrosion on base materials was serious, and there was partly exfoliation corrosion on base materials too. However, the pitting corrosion on welding seams was not obvious after friction stir welding. Furthermore, the self-corrosion potential of welding seams is higher than that of base materials, and they are -666 V and -704 V respectively. The average corrosion rate of the welding seams is far less than that of the base materials, and the value is 0.379 g/(m²·h) and 2.186 g/(m²·h) respectively. The small grains and the dissolution at the second phase are primary reasons for the improvement of the corrosion resistance of welding seams during the FSW.

Key words: friction stir welding; 6063 aluminum alloy; welding seam; corrosion properties