Effects of tungsten inert gas (TIG) welding parameters on macrostructure, microstructure, and mechanical properties of AA6063-T5 using the controlled intermittent wire feeding method

This paper presents an automated or intermittent wire feeding method in tungsten inert gas (TIG) welding. The preliminary investigation shows the macrostructure, microstructure, and mechanical property effects on various welding parameters using one combination proportion of filler metal with various welding parameters. The result of microstructure has shown that the localized segregation occurred at the center area weld metal with high-density eutectic phase and energy dispersive X-ray spectroscopy (EDS) study has found that Mg content was higher compared to the outside region. Other sample microstructure shows columnar structure was formed in dilution boundaries, and it reveals that fast cooling rates happened when the filler wire was inserted. Also, microstructure on weld traverse section shows that the wavy-like structure depended on the heat input. The fracture mode shows that lack of heat input is susceptible to oxidation; therefore, the fracture tends to occur at weld metal in the brittle manner with reduced strength of more than 40%. Also this article presented the method to calculate length ratio (R_L) and the volume ratio (R_V) to estimate the minimum value of ratio under the condition of a good welded surface profile.