Hydrides in (alpha)-Ti: Characterization and effect of applied external stresses

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. (delta) and (gamma)-hydrides have been observed in specimens with low hydrogen concentrations )=<500 wppm). Hydrides with {0 1 1 0} habit plane were the most abundant ones. Hydrides with {0 0 0 1} and {1 0 1 7} habit planes, both with the same matrix-hydride crystallographic relationship, have also been recognized. The {1 0 1 2} habit plane was confirmed by transmission electron microscopy with a {0 1 1 1} // {0 0 1} and (left angle bracket)2 1 1 0(right angle bracket) // (left angle bracket)1 1 0(right angle bracket) 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.