Effect of 0.5 wt.% hydrogen addition on microstructural evolution of Ti–6Al–4V alloy in the friction stir welding and post-weld dehydrogenation process

The α + β titanium alloy, Ti–6Al–4V, was thermohydrogen processed with 0.5 wt.% hydrogen and friction stir welded using a W–Re pin tool. Defect-free joints were obtained with proper parameters. Hydrogen was removed from the joint through a post-weld dehydrogenation process. The microstructures of the as-welded and dehydrogenated joints were examined. The effect of 0.5 wt.% hydrogen addition on microstructural evolution of Ti–6Al–4V alloy in the friction stir welding and post-weld dehydrogenation process was revealed.