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

► 0.5 wt% hydrogen is added to Ti-6Al-4V alloy, donated as Ti-6Al-4V-0.5 H alloy. ► Ti-6Al-4V-0.5 H alloy was friction stir welded using a W-Re pin tool. ► Hydrogen was removed from the as-welded joint by post-weld dehydrogenation. ► The effect of 0.5 wt% hydrogen addition on microstructural evolution is revealed.