Abstract
Samples of the welds from the Midland and Palisades reactors in the unirradiated condition and after neutron irradiation to a high fluence of up to 3.4 × 1023 m-2 (E > 1 MeV) have been characterized with the Oak Ridge National Laboratory's local electrode atom probe. High number densities, ∼5 and ∼7 × 1023 m-3, respectively, of ∼2-nm-diameter copper-, nickel-, manganese- and silicon-enriched precipitates were observed after neutron irradiation. These copper-enriched precipitates were observed both in the matrix of the steel and also preferentially located along the dislocations. No appreciable differences were observed in the sizes or the compositions of the precipitates in the matrix and on the dislocations. The average interparticle distance along the dislocations was 11 ± 3 nm. Phosphorus segregation was also evident along the dislocations in both welds. No other nanoscale intragranular phases were observed in these neutron irradiated welds.
Original language | English |
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Pages (from-to) | 248-261 |
Number of pages | 14 |
Journal | Journal of Nuclear Materials |
Volume | 361 |
Issue number | 2-3 SPEC. ISS. |
DOIs | |
State | Published - Apr 15 2007 |
Funding
Research at the Oak Ridge National Laboratory SHaRE User Center was sponsored by the Division of Materials Sciences and Engineering, US Department of Energy, under contract DE-AC05-00OR22725 with UT-Battelle, LLC and by the Office of Nuclear Regulatory Research, US Nuclear Regulatory Commission under inter-agency agreement DOE 1886-N695-3W with the US Department of Energy. The authors acknowledge the Charpy impact and fracture testing by E. Manneschmidt and R. Swain.