[en] Directed diffusion of hydrogen by embrittlement of titanium alloys has been studied with the help of layer-by-layer local spectral analysis of hydrogen distribution. The local concentration of hydrogen proved to depend, in particular, on stress. The mechanisms of hydrogen embrittlement in alloys of α-, (α,β)- and β-phase structures are different. Due to directed diffusion, the local concentration of hydrogen may suffice for hydrogen embrittlement even in samples where the H₂ bulk concentration is lower than the acceptable one. In α- and (α,β) alloys brittle failure results from formation of hydrides; β alloys crack because of the β-phase brittleness in hydrogen-rich areas