Evidence for excess vacancies at sliding grain boundaries during superplastic deformation
Rapid quenching of Al-Mg alloys during superplastic deformation has revealed the presence of nano-scale cavities along many grain boundaries. They were observed only under deformation conditions where grain boundary sliding was the dominant mechanism. Fine-probe compositional measurements revealed that the cavity surface is enriched in Mg, and in situ heating in the transmission electron microscope demonstrated that they are not stable above 175 C. Kinetic analysis of cavity formation during a quench concludes that the cavities did not exist during deformation but were formed as the sample cooled. It is proposed that these cavities are evidence for a localized excess of vacancies during grain boundary sliding.
- Research Organization:
- Pacific Northwest National Lab., Richland, WA (US)
- Sponsoring Organization:
- US Department of Energy
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 20005388
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 15-16 Vol. 47; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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