Abstract
This work focuses on the study and comparison of the sensitivity to hydrogen induced damage from cathodic charging or gaseous environment for a martensitic steel Its aim is to identify the experimental conditions for a possible equivalence in terms of hydrogen embrittlement. Understanding the impact of some factors such as the characteristics of the electrolyte (composition, pH, temperature…) or the native oxide layer in a gaseous environment is crucial to establish this equivalence.
The surface activity in a deaerated electrolyte (NaCl 3.5%) is investigated via cathodic polarizations in order to identify the Hydrogen Evolution Reaction steps and subsequently to highlight the relationship between the hydrogen fugacity and the overpotential. The comparison of the reduction of area after tensile tests carried out in the two media (overpotential and gas pressure) is analysed. Fractographic analysis are performed in order to investigate the fracture mechanisms and therefore to verify the relevance of the similarity of damage mechanisms. Eventually, two coefficients linked to the equivalent fugacity are calculated for different specimen geometries.