Microstructures and properties of TIG welded 5A06-Al: responses to variable Ar-He alternating supplying conditions

Abstract

During the TIG welding process, the interactions between arc plasma and molten pool could be periodically influenced by supplying Ar–He shield gas alternatively, which would affect the solidification and forming of the weld metal. In this work, the responses of microstructures and mechanical properties of the TIG welded 5A06 joint to the variable Ar–He alternating supplying conditions were investigated systematically. The variable shielding gas supply had a grain refining effect on the weld seam due to more violent and impacting effect on the molten pool. Moreover, the number of strengthening phases increased and became more dispersed, which increased the tensile strength further. The electrochemical experiment showed that the weld seam under continuous gas supply had better corrosion resistance.