Microstructures and electrochemical performance of 6082-T6 aluminum alloy welds prepared by bobbin friction stir welding

Friction-stir welding(FSW) of 12-mm-thick plates of 6082 Al was conducted by bobbin-tool.Microstructure and potentiodynamic polarization behavior were examined by optical microscope and CHI660A three-electrode electrochemical workstation.The results indicated that the microstructure of the weld was remarkably reshaped under the condition of the stir-pin rotation speed 600 r/min, travel speed 300 mm/min and tilt angle 0° of the stirring tool.The equiaxed grain microstructures were formed due to dynamical recrystallization in the nugget zone.The corrosion test results showed that the pitting corrosion of base material was more severe than that of bobbin-tool FSW weld, and the corrosion morphology was much rough than that of bobbin-tool FSW weld.The corrosion potential of the weld was positive and higher than that of parent material.The corrosion current density of bobbin-tool FSW weld was lower than that of parent material.