Steady-state electrochemical kinetics of structural steel in simulated fatigue crack-tip environments

Turnbull, A.; Maria, M. Saenz de Santa; Thomas, Nicky

doi:10.1016/0010-938x(88)90019-4

Cited by 7 publications

(2 citation statements)

References 4 publications

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“…The same trend has been noted for steels as well. [54] In summary, acidic NaCl enhances the crack tip hydrogen production rate and, likely, the hydrogen absorption rate, leading to increased hydrogen concentrations and increased EAC susceptibility. It should be noted that alkaline solutions do not enhance ␤-Ti alloy repassivation rates [33] nor lower film rupture rates.…”

Section: H Cathodic Inhibition Of High-strength ␤-Ti Alloy Eacmentioning

confidence: 98%

“…This differs markedly from the case of highstrength steels where oxide films are readily reduced cathodically and bulk external hydrogen charging exceeds crack tip charging at potentials negative to Ϫ900 mV SCE , except in cases of very high crack tip deformation. [54] The EAC of steels is well known to be enhanced by both strong cathodic as well as anodic polarization and inhibited by conditions in between these in neutral NaCl.…”

Section: H Cathodic Inhibition Of High-strength ␤-Ti Alloy Eacmentioning

confidence: 99%

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Understanding the potential and pH dependency of high-strength β-titanium alloy environmental crack initiation

Kolman

Scully

1997

Metall Mater Trans A

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An explanation for the strong dependency of crack initiation of precracked high-strength ␤-titanium alloys in room-temperature 0.6 M NaCl on applied potential and bulk-solution pH is presented. It is proposed that environment-assisted cracking (EAC) susceptibility in neutral aqueous NaCl results from (1) film rupture due to plastic deformation at actively deformed crack tips, (2) accelerated dissolution of titanium, (3) crack tip acidification by hydrolysis of titanium ions, (4) crack tip potential excursions toward bare metal open-circuit potentials (OCPs) during film rupture due to large ohmic voltages in the crack solution, (5) accelerated crack tip proton or water reduction concurrent with titanium dissolution, (6) bare surface-dominated hydrogen ingress into a fracture process zone, and (7) crack initiation by hydrogen embrittlement. Evidence for each of the above stages of the crack initiation scenario is presented, with emphasis on crack tip electrode kinetics and ohmic voltage calculations which govern process zone-controlled hydrogen uptake. The seven stages are consistent with the strong dependencies of crack initiation and growth in precracked high-strength ␤-titanium alloys on (1) solution pH, (2) applied potential, and (3) strain rate, and they explain the ''apparent'' EAC resistance of smooth-and blunt-notch specimens. The latter lack both occluded crack tip geometries to promote acidification and ohmic voltage drops below reversible hydrogen, as well as localization of dynamic plastic strain. Hydrogen uptake is, subsequently, limited.

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Section: H Cathodic Inhibition Of High-strength ␤-Ti Alloy Eacmentioning

confidence: 98%

Section: H Cathodic Inhibition Of High-strength ␤-Ti Alloy Eacmentioning

confidence: 99%