“…Hydrogen has a low solubility in the a-phase at room temperature (about 20-100 lg g À1 ), and hydrogen-induced cracking (HIC) occurs when the hydrogen content exceeds the critical concentration at which the precipitation of brittle titanium hydrides in the a-phase, but primarily along the grain boundaries, takes place [11,12]. Hydrogen transport in titanium and its alloys can occur by lattice diffusion, short-circuit diffusion along grain boundaries, or by dislocation motion.…”