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U.S. Department of Energy
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Kinetic analysis of grain boundary Cr concentration during thermal or irradiation exposure

Conference ·
OSTI ID:350100
;  [1]
  1. Pacific Northwest National Lab., Richland, WA (United States)
Grain boundary Cr concentration influences resistance to intergranular stress corrosion cracking of stainless steel reactor core components. Therefore it is important to understand (1) how initial thermal processing affects thermal nonequilibrium segregation (TNES), (2) how service exposure affects radiation-induced segregation (RIS), and (3) how temperature affects post-irradiation annealing (PIA). In this study, each process is shown to be controlled by Cr-vacancy interactions. Mechanistic predictions are in accord with measured kinetics of changes in grain boundary Cr concentration for RIS and PIA but not for TNES. Inconsistencies between TNES model predictions and TNES measured segregation suggest that multiple solute-defect interactions must be considered and not just the simple interaction between Cr and vacancies. Furthermore, analysis of RIS of enriched TNES profiles suggests that Cr is chemically bound to the grain boundary such that the boundary concentration is influenced both by RIS in the matrix outside of the boundary plane and by chemistry within the TNES enriched boundary. Mechanistic understanding of changes in Cr concentration at grain boundaries may suggest mitigating measures for reduced in-core cracking by control of heat treatments, alloy chemistry and PIA.
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
350100
Report Number(s):
CONF-980316--
Country of Publication:
United States
Language:
English