Premium
A MICRO‐MECHANICS MODEL OF CORROSION‐FATIGUE CRACK GROWTH IN STEELS
Author(s) -
Rios E. R.,
Wu X. D.,
Miller K. J.
Publication year - 1996
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1996.tb00174.x
Subject(s) - materials science , crack closure , fracture mechanics , stress concentration , corrosion fatigue , crack growth resistance curve , fatigue limit , composite material , torsion (gastropod) , crack tip opening displacement , structural engineering , corrosion , plasticity , engineering , surgery , medicine
Principles of Microstructural Fracture Mechanics (MFM) are used to develop a model for the characterization of environment‐assisted short fatigue crack growth. Fatigue cracks are invariably initiated at corrosion pits formed at inclusions, hence the analysis includes stress concentration effects at pits that lead to the propagation of fatigue cracks the rates of which are considered to be proportional to the crack tip plastic displacement. This plasticity is constrained by microstructural barriers which are overcome in a non‐aggressive environment at critical crack lengths only when the applied stress is higher than the fatigue limit. However, the superposition of an aggressive environment assists fatigue damage via crack tip dissolution, enhancement of crack tip plastic deformation, the introduction of stress concentrations at pits and a reduction of the strength of the microstructural barrier. These environment effects are manifested in a drastic reduction of the fatigue limit and higher crack propagation rates. The model is compared with fatigue crack propagation data of a BS251A58 steel tested in reversed torsion when submerged in a 0.6M NaCl solution.