HYDRIDE FORMATION ON DISLOCATIONS IN TITANIUM

Transmission electron microscopy was used to examine titanium exposed to hydrogen gas. Hydrides were found to form on basal dislocations. The majority of dislocations present, the non-basal, remained free of hydrides. The first stage of hydride growth involves the Suzuki effect with hydrogen absorption at the preferred (001) stacking faults. The decrease in fault energy can be interpreted as a bond weakening phenomena near the dislocation. The basal dissociation and pinning by hydrides can effect slip since an additional force is necessary for constriction. There is evidence that hydrogen interstitials may be absorbed by jogs.