INELASTIC NEUTRON-SCATTERING STUDY OF HYDROGEN EMBRITTLEMENT IN TITANIUM-ALLOYS

Inelastic neutron scattering studies have been carried out on the mixe d alpha and beta phase of the titanium alloy IMI T318 for hydrogen loa dings ranging from 400 to 15 500 ppm (a hydrogen loading of 80 ppm gav e a spectrum too weak for interpretation). For a hydrogen content of 1 5 500 ppm, metal subsurface tetrahedral interstitial sites were occupi ed. As the hydrogen content was decreased, it became evident that an a dditional site was occupied, this was assigned to hydrogen in surface threefold symmetry binding sites.