Observing Dislocations Transported by Twin Boundaries in Al Thin Film: Unusual Pathways for Dislocation-Twin Boundary Interactions.
basic_science · Level V
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- Record sourced from PubMed, PMID 35876496.
- Also identified by DOI 10.1021/acs.nanolett.2c01763.
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Abstract
Twins are generally regarded as obstacles to dislocations in face-centered cubic metals and can modify individual dislocations by locking them in twin boundaries or obliging them to dissociate. Through in situ tensile experiments on Al thin film in a transmission electron microscope, we report a dynamic process of dislocations being transported by twin lamella via periodic twinning and detwinning at the atomic scale. Following this process, a 60° dislocation first transforms into a sessile step of the twin boundary, then migrates under stress as a step and finally reverts back into a 60° dislocation. Our results reveal a novel evolution route of dislocations by a dislocation-twin interaction where the twins act as transport vehicles rather than as obstacles. The potential implications of this mechanism on toughening are also discussed.