Hydrides in α-Ti: Characterization and effect of applied external stresses Original Research Article

The hydrides precipitated in commercially pure titanium, produced by cathodic hydrogenation followed by a thermal diffusion treatment, have been characterized using optical and electron microscopy. δ and γ-hydrides have been observed in specimens with low hydrogen concentrations (⩽500 wppm). Hydrides with image habit plane were the most abundant ones. Hydrides with {0 0 0 1} and image habit planes, both with the same matrix–hydride crystallographic relationship, have also been recognized. The image habit plane was confirmed by transmission electron microscopy with a image and image orientation relationship. The distribution of the orientation of the hydride platelets was studied with increasing levels of constant load applied during a cooling process. The relative frequency of precipitated hydrides in planes perpendicular to the tensile axis was increased and this was more remarkable when the orthogonal plane corresponds to a prismatic plane.