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Effects of helium/DPA ratio, alloy composition and cold work on microstructural evolution and hardening of {sup 59}Ni-doped Fe-Cr-Ni alloys neutron-irradiated at 465 C

Conference ·
OSTI ID:524834
 [1]; ;  [2]
  1. Univ. of Tokyo (Japan). Dept. of Quantum Engineering and Systems Science
  2. Pacific Northwest Lab., Richland, WA (United States)

Three ternary austenitic alloys (Fe-15Cr-25Ni, Fe-15Cr-25Ni-0.04P, Fe-15Cr-45Ni in both annealed and cold worked conditions) were irradiated at 465 C to 0.15, 0.28, and 0.42 dpa at above core position in the Fast Flux Test Facility utilizing the Materials Open Test Assembly to study the separate and synergistic effects of He/dpa ratio, phosphorus addition, nickel content and cold work level on microstructural evolution and hardening. The helium/dpa ratio was varied by isotopic doping with {sup 59}Ni to enhance the production rate of helium. The helium production rate was evaluated to be 62 appm He/dpa in the {sup 59}Ni-doped specimens and 0.26 appm He/dpa in the undoped specimens. Transmission electron microscopic examinations revealed that alloy composition affected significantly the evolution of microstructure during irradiation. Phosphorus addition prevented the formation of Frank loops through the precipitation of phosphide. Nickel content influenced the nucleation of cavities. Helium production rate influenced the densities of dot-typed clusters in 25Ni alloys and cavities in 45Ni alloys.

OSTI ID:
524834
Report Number(s):
CONF-940657--
Country of Publication:
United States
Language:
English