Study on Microstructure and Corrosion Resistance of 6061 Aluminium Alloy Friction Stir Welded Joint

The friction stir welding of 4 mm thick 6061-T6 aluminum alloy plate was carried out.The corrosion behavior of the weld area was studied by immersion corrosion test and electrochemical corrosion test, and the microstructure of the joint was investigated by using optical microscopy and TEM.The results show that the grain in FSW nugget area of 6061 aluminum alloy is significantly refined, and the content of the second phase at grain boundary is small; the resistance to exfoliation corrosion and intergranular corrosion of the nugget area is better than that of heat affected zone.Compared with the heat affected zone, the nugget zone has higher corrosion potential and lower corrosion current density, which shows better corrosion resistance.