On the suitability of slow strain rate tensile testing for assessing hydrogen embrittlement susceptibility. (February 2020)

• Record Type: Journal Article
• Authors: Martínez-Pañeda, Emilio; Harris, Zachary D.; Fuentes-Alonso, Sandra; Scully, John R.; Burns, James T.
• Is Part Of: Corrosion science. Volume 163(2020)
• Publication Date: 2020-02
• Subjects: Hydrogen embrittlement -- Environment-assisted cracking -- SSRT -- Phase field fracture; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2019.108291
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: The onset of sub-critical cracking during slow strain rate tensile (SSRT) testing is assessed. Hydrogen diffusion alone cannot explain measured intergranular fracture depths. A new phase field formulation is developed for the coupled hydrogen-deformation problem. Simulations indicate the onset of sub-critical cracking well before specimen failure. Sub-critical cracking is shown to obfuscate the interpretation of SSRT metrics. Abstract: The onset of sub-critical crack growth during slow strain rate tensile testing (SSRT) is assessed through a combined experimental and modeling approach. A systematic comparison of the extent of intergranular fracture and expected hydrogen ingress suggests that hydrogen diffusion alone is insufficient to explain the intergranular fracture depths observed after SSRT experiments in a Ni–Cu superalloy. Simulations of these experiments using a new phase field formulation indicate that crack initiation occurs as low as 40% of the time to failure. The implications of such sub-critical crack growth on the validity and interpretation of SSRT metrics are then explored.