Effect of activated flux on penetration depth, microstructure and mechanical properties of Ti-6Al-4V TIG welds

The microstructure traits and structural integrity of Ti-6Al-4 V welds of 5 mm thickness are discussed. The use of activated flux in the tungsten inert gas (ATIG) welding technique is adopted in this study using the oxide surfactant. Bead on trials attested that the depth of penetration (DOP) is enhanced with a corresponding rise in welding current upon the use of oxide surfactant. Microstructure studies depicted the presence of acicular alpha' structure of martensitic needles and Widmanstatten alpha platelets with beta-Ti grain boundaries throughout the fusion zone. Tensile studies indicated that the strength of the joints of ATIG welds was better, as the failures were experienced in the parent metal. The impact toughness of the ATIG weldments was insignificantly reduced when compared to the base metal owing to the coarsened grains in the weld zone. The findings of this study attests the use of low cost welding technique for joining Ti-6Al-4 V of 5 mm thickness for improved properties.