HVEM observation of dislocation-free zones at crack tips in iron single crystals
- 1 April 1988
- journal article
- research article
- Published by Taylor & Francis in Philosophical Magazine A
- Vol. 57 (4) , 677-684
- https://doi.org/10.1080/01418618808214417
Abstract
The distribution of dislocations in the vicinity of a crack tip has been studied in single crystals of iron during in situ tensile deformation in a high-voltage electron microscope. The results show that a large number of dislocations are emitted from the crack tip during crack propagation in thick specimens. The emitted dislocations immediately move away from the crack tip, creating a dislocation-free zone (DFZ) near the crack tip. The dislocations come to rest in a plastic zone located some distance from the crack tip and form dense tangles. These observations are discussed in terms of the model of elastic interaction between a crack and dislocations.Keywords
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