Dislocation interaction with hydrides in titanium containing a low hydrogen concentration

Abstract

The dislocation configurations and their interactions with γ-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]_γ//[0001]_α axis, occurred in both of them. Accordingly cell structures with misorientations up to 10° about the same [0001]_α 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.

Acknowledgement

This work was financially supported by the National Science Foundation of China under grants 50271075 and G19990650.