What conditions are necessary for a crack to propagate from a carbide into the ferrite matrix in steel, according to the Griffith criterion?
Understand the Problem
The question is asking about the Griffith criterion in the context of crack propagation in steel, specifically from a carbide inclusion into the ferrite matrix. The Griffith criterion essentially states the conditions under which a crack will grow spontaneously. The question asks which of the provided options correctly reflects a necessary condition for this to occur.
Answer
A crack propagates when the energy released is equal to or greater than the energy required to create a new crack surface.
According to the Griffith criterion, a crack will propagate from a carbide into the ferrite matrix when the energy released during crack propagation is equal to or greater than the energy required to create the new crack surface. This is also influenced by factors like plastic strain, decreasing temperature, and stress concentration at flaws.
Answer for screen readers
According to the Griffith criterion, a crack will propagate from a carbide into the ferrite matrix when the energy released during crack propagation is equal to or greater than the energy required to create the new crack surface. This is also influenced by factors like plastic strain, decreasing temperature, and stress concentration at flaws.
More Information
The Griffith criterion is a fundamental concept in fracture mechanics that predicts the conditions under which a crack in a brittle material will propagate spontaneously. It considers the balance between the energy released by crack growth and the energy required to create new surfaces.
Tips
A crack will not always propagate, the conditions in the material must allow for the crack to penetrate the ferrite.
Sources
- Fracture Mechanics & Failure Analysis: Griffith theory of brittle fracture - slideshare.net
- Griffith theory of brittle fracture - webstor.srmist.edu.in
- Micromechanics of cleavage fracture initiation in ferritic steels by ... - researchgate.net
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