Experimental measurement of out-of-plane displacement in crack propagation under gaseous hydrogen

• Published in: International journal of hydrogen energy 2017-04, Vol.42 (15), p.10568-10578
• Main Authors: Bilotta, Giovambattista, Henaff, Gilbert, Halm, Damien, Arzaghi, Mandana
• Format: Article
• Language: English
• Subjects: Crack propagation; Engineering Sciences; Fatigue; Hydrogen; Out-of-plane displacement; Physics; Steel
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2017.02.084

A huge enhancement of fatigue crack growth rates was observed on a 15-5PH martensitic stainless steel under gaseous hydrogen. The observation of fracture surfaces showed a change in fracture mechanisms depending on hydrogen pressure and loading condition, namely the stress intensity factor amplitude and the loading frequency. The present study was undertaken in order to analyze the effect of gaseous hydrogen on the out-of-plane displacement at the crack tip plasticity by means of out-of-plane displacement measurements. An interferometric microscope was used to obtain high resolution measurements of out-of-plane displacement. These measurements showed an increase in out-of-plane displacement in presence of gaseous hydrogen compared to an inert or slightly aggressive environment, depending on the hydrogen pressure and the maximum stress intensity factor applied during static or cyclic loading. •Tremendous enhancement of fatigue crack growth rate under hydrogen in 15-5PH steel.•Important increase of out-of-plane displacement at crack tip under hydrogen.•No significant change of in-plane plastic zone size under hydrogen.•Out-of-plane displacement increase related to change in failure modes.