Atomic-scale investigation of hydrogen distribution in a Ti–Mo alloy

Ingress of hydrogen is often linked to catastrophic failure of Ti-alloys. Here, we quantify the hydrogen distribution in fully β and α + β Ti–Mo alloys by using atom probe tomography. Hydrogen does not segregate at grain boundaries in the fully β sample but segregates at some α/β phase boundaries with a composition exceeding 20 at.% in the α + β sample. No stable hydrides were observed in either sample. The hydrogen concentration in β phases linearly decreases from ~13 at. % to ~4 at. % with increasing Mo-content, which is ascribed to the suppression of hydrogen uptake by Mo addition