Corrosion Fatigue
Definition
Fatigue crack initiation and growth accelerated by a corrosive environment. Unlike SCC, it does not require a specific environment-material combination and can occur in materials that resist SCC.
- Mechanism
- Fatigue crack growth accelerated by a corrosive environment
- Environment specificity
- Does not require a specific material-environment pairing
- Compared to
- Stress corrosion cracking (SCC)
- Occurs in
- Materials that resist SCC
Common questions
How would a failure analyst distinguish corrosion fatigue from plain SCC on a fracture surface?+
Corrosion fatigue typically shows fatigue striations or beach marks combined with corrosion products, indicating cyclic loading in a corrosive environment, whereas SCC shows intergranular or transgranular cracking without the striation pattern, tied to a specific material-environment combination.
Why does corrosion fatigue matter in equipment failure investigations even without an aggressive chemical environment?+
Because it does not need a special corrosive medium, ordinary moisture or mildly corrosive service conditions combined with cyclic stress can be enough to accelerate crack growth well beyond what dry fatigue alone would produce.
Related terms
- Crevice Corrosion
- Corrosion in confined geometry , under gaskets, at lap joints, between fastener and plate , driven by oxygen depletion and acidification inside...
- Galvanic Corrosion
- Electrochemical attack that accelerates the dissolution of the more active (anodic) metal when two dissimilar metals are electrically coupled in an electrolyte.
- Pitting Corrosion
- Localised attack producing narrow, deep craters where the passive film breaks down. Pitting is self-propagating once initiated because the pit interior becomes...
- Selective-Phase Corrosion
- Attack that preferentially dissolves one phase or element from a multi-phase alloy, leaving the other phase intact but structurally weakened. Dezincification of...
- Stress-Corrosion Cracking (SCC)
- A failure mode combining sustained tensile stress with a specific corrosive environment, producing branching, often intergranular cracks that grow at stress intensities...