Prediction of corrosion fatigue crack growth rate in alloys. Part I: General corrosion fatigue model for aero-space aluminum alloys

• Published in: Corrosion science 2018-08, Vol.141, p.22-29
• Main Authors: Kovalov, Danyil, Fekete, Balázs, Engelhardt, George R., Macdonald, Digby D.
• Format: Article
• Language: English
• Subjects: Aeration; Al-Li alloy; Alloy development; Aluminum alloys; Aluminum base alloys; Aluminum-lithium alloys; Corrosion; Corrosion fatigue; Corrosion rate; Crack propagation; Crack tip; Crack tips; Cyclic loads; Fatigue failure; Fracture mechanics; Mathematical models; Modelling; Potential drop; Prediction; Predictions; Sodium chloride; Stress corrosion cracking; Uniform attack (corrosion)
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2018.06.034

•A General Corrosion Fatigue Model (GCFM) was developed.•GCFM based on consideration of advection between the crack and external environment.•Crack growth rate is regarded as the sum of the stress corrosion cracking and cyclic loading.•The GCFM predicts change in the potential drop and current density during crack propagation. In this work, a General Corrosion Fatigue Model (GCFM) was developed for predicting corrosion fatigue crack growth rate (CFCGR) in metals under cyclical loading. The GCFM is based on an equation for the potential drop from the external surface to the crack tip of metals as derived from the principle of differential aeration. Development of the GCFM involves consideration of cyclic loading on the CFCGR and of advection between the in-crack and external environment. We demonstrate the influence of corrosion environment and cyclic loading on the crack growth rate in Al-Li alloys in a 1:1 electrolyte (0.6 M NaCl).