Abstract
We have monitored the full-stage precipitate evolution in Cu-0.55Cr-0.07Zr alloy during aging at 480 °C (753 K) up to 14 days (20160 min), using micro-hardness, positron annihilation spectroscopy, electron microscopy and atom probe tomography. Cr-rich precipitates form during the early stages of aging, and after 5.5 min the distribution is characterised by a number density of 8×1023 m-3 and an average precipitate size of 2.5 nm. At that time, Zr segregation is also detected at the precipitate sites. Longer aging times lead to precipitate coarsening, simultaneously with the occurrence of a Zr-rich shell around precipitates potentially to help reduce local coherency strains. Peak aging of the alloy is attained after 120 min of aging, and overaging induces further precipitate coarsening and the transition from spherical to disc-like morphology. At the longest aging time of 14 days, the precipitates maintain a face-centred cubic symmetry, reaching an average size of ∼9 nm at a density of 0.2×1022 m-3. The presence of Zr atoms at the precipitate site and interface, and the disc-like morphology of overaged precipitates, should be considered when assessing the precipitate stability under irradiation and the precipitate/matrix interface as a potential sink for radiation-induced lattice defects.
Original language | English |
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Pages (from-to) | 801-810 |
Number of pages | 10 |
Journal | Journal of Materials Research and Technology |
Volume | 20 |
Early online date | 1 Aug 2022 |
DOIs | |
Publication status | Published - Sept 2022 |
Bibliographical note
Funding Information:The authors of this work acknowledge the support of Culham Centre for Fusion Energy ( CCFE ). Mike Gorley would like to acknowledge funding from the EPSRC Grant EP/T012250/1. We also thank the International Research Centre for Nuclear Materials Science of the Institute for Materials Research, Tohoku University, for their financial travel support, as well as access to equipment and assistance in carrying out PAS and 3D-AP experiments.
Publisher Copyright:
© 2022 The Author(s).
Keywords
- Cu-base alloys
- fusion reactor technology
- heat treatment
- microstructure characterization
- precipitation
ASJC Scopus subject areas
- Ceramics and Composites
- Biomaterials
- Surfaces, Coatings and Films
- Metals and Alloys