Abstract
A physical model for the nucleation of fatigue cracks in a high-strength steel is developed from microstructural observations of fatigue specimens, subject to simultaneous cyclic uniaxial and agressive environment (natural sea water), and theoretical results for the stress concentration at surface discontinuities. The results show that for high-cycle stress corrosion fatigue conditions, where the applied stresses are too low to cause bulk cyclicplasticity of the matrix, fatigue crack nucleation does not occur as long as the inclusions remain undamaged and firmly bonded to the matrix, and as long as no pitting has occurred. Stress corrosion fatigue crack nucleation is found to occur only after the progressive debonding and fatigue damage of alumina inclusions has lead to the formation of holes at the specimen surface. The fatigue cracks being nucleated by a highly localized cyclic-plasticity effect at points of maximum stress concentration on the hole boundary.
| Original language | English |
|---|---|
| Pages | 333-340 |
| Number of pages | 8 |
| State | Published - 1988 |
ASJC Scopus subject areas
- General Engineering