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Title: Oxide Morphology of C26M at 300 - 600 °C

Technical Report ·
DOI:https://doi.org/10.2172/1475313· OSTI ID:1475313
 [1];  [1];  [1];  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Iron-chromium-aluminum (FeCrAl) alloys are of interest to the nuclear materials community due to their resistance to high temperature steam oxidation under accident conditions. The present work investigates oxide formation at temperatures relevant to light water reactor cladding operation following extended aging to assess growth kinetics, chemical composition, and microstructure of oxide formation on an Oak Ridge National Laboratory developed Fe-12Cr-6Al- 2Mo-0.2Si-0.03Y alloy (designated ‘C26M’). Aging treatments were performed for 100-2000 hours in stagnant air at 300, 400, 500, and 600 °C, respectively. Oxide growth behavior under the investigated conditions follows a logarithmic time dependence. When the oxidization temperature is 400 °C or below, the oxide is amorphous. At 500 °C, crystalline α-Al2O3 oxide film develops and the correlated logarithmic rate constant decreases significantly, indicating enhanced oxidation resistance of the formed oxide film. In addition, Mo segregation at grain boundaries has been observed when the aging temperature exceeds 500 °C. The results of this study can be viewed as an upper bounding result for potential oxide coarsening on the cladding inner surface during reactor operation.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Office of Nuclear Energy (NE)
DOE Contract Number:
AC52-06NA25396
OSTI ID:
1475313
Report Number(s):
LA-UR-18-29225
Country of Publication:
United States
Language:
English