Dislocation interaction with hydrides in titanium containing a low hydrogen concentration

The dislocation configurations and their interactions with gamma-hydrides were investigated in cyclically strained titanium containing 77 ppm hydrogen. At least three sets of dislocations could be activated in hydride precipitates. To accommodate the inhomogeneous strain between the matrix and the hydrides a crystal rotation, which is a rotation about the [001](gamma)//[0001](alpha) axis, occurred in both of them. Accordingly cell structures with misorientations up to 10degrees about the same [0001](alpha) axis formed in the matrix near the interface. A mechanism for the crystal rotation and cell formation was proposed. Also hydride dissolution and strain-induced hydrides were observed at the intersections of slip bands with hydrides, and this was considered to be a process controlled by the hydrogen-transport effect of slipping dislocations.