Influence of hydrogen on electrochemical behavior of Ni-based superalloy 718. (11th January 2018)

• Record Type: Journal Article
• Authors: Odemer, Grégory; Andrieu, Eric; Blanc, Christine
• Is Part Of: International journal of hydrogen energy. Volume 43:Number 2(2018)
• Page Start: 1006
• Page End: 1011
• Publication Date: 2018-01-11
• Subjects: Nickel alloys -- Hydrogen embrittlement -- Electrochemistry -- Galvanic coupling; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2017.11.081
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Numerous studies have shown that Ni-based superalloy 718 may be sensitive to hydrogen embrittlement and have highlighted the dominant roles played by the hydrogen solubility and the hydrogen trapping. Samples were hydrogenated by cathodic polarization in molten salts under different conditions to vary the diffusible hydrogen content and to saturate the different hydrogen traps present in the microstructure strengthened by precipitation. Open circuit potential and galvanic coupling measurements were conducted in order to characterize the effect of diffusible and trapped hydrogen on electrochemical behavior and to discuss the possibility of galvanic coupling between zones with different hydrogen contents. Highlights: We examined the effect of hydrogen on electrochemical behavior of alloy 718. H enrichment led to a shift of the OCP of alloy 718 towards more negative values. Local galvanic couplings were active in parallel to classical SCC and HE phenomena. Galvanic couplings could enhance the resultant damage.