Elucidating the contribution of mobile hydrogen-deformation interactions to hydrogen-induced intergranular cracking in polycrystalline nickel. (1st October 2018)

• Record Type: Journal Article
• Authors: Harris, Zachary D.; Lawrence, Samantha K.; Medlin, Douglas L.; Guetard, Gael; Burns, James T.; Somerday, Brian P.
• Is Part Of: Acta materialia. Volume 158(2018)
• Page Start: 180
• Page End: 192
• Publication Date: 2018-10-01
• Subjects: Intergranular failure -- Nickel -- Hydrogen embrittlement -- Dislocations -- Grain boundaries; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2018.07.043
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Uniaxial mechanical testing conducted at room temperature (RT) and 77 K on hydrogen (H)-exposed nickel was coupled with targeted microscopy to evaluate the influence of deformation temperature, and therefore mobile H-deformation interactions, on intergranular cracking in nickel. Results from interrupted tensile tests conducted at cryogenic temperatures (77 K), where mobile H-deformation interactions are effectively precluded, and RT, where mobile H-deformation interactions are active, indicate that mobile H-deformation interactions are not an intrinsic requirement for H-induced intergranular fracture. Moreover, an evaluation of the true strain for intergranular microcrack initiation for testing conducted at RT and 77 K suggests that H which is segregated to grain boundaries prior to the onset of straining dominates the H-induced fracture process for the prescribed H concentration of 4000 appm. Finally, recent experiments suggesting that H-induced fracture is predominately driven by mobile H-deformation interactions, as well as the increased susceptibility of coherent twin boundaries to H-induced crack initiation, are re-examined in light of these new results. Graphical abstract: Image 1