Characterizing solute hydrogen and hydrides in pure and alloyed titanium at the atomic scale

Ti has a high affinity for hydrogen and is a typical hydride formers. Ti-hydride are brittle phases which probably cause premature failure of Ti-alloys. Here, we used atom probe tomography and electron microscopy to investigate the hydrogen distribution in a set of specimens of commercially pure Ti, model and commercial Ti-alloys. Although likely partly introduced during specimen preparation with the focused-ion beam, we show formation of Ti-hydrides along {\alpha} grain boundaries and {\alpha}/\b{eta} phase boundaries in commercial pure Ti and {\alpha}+\b{eta} binary model alloys. No hydrides are observed in the {\alpha} phase in alloys with Al addition or quenched-in Mo supersaturation.