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Title: Compatibility of refractory metals with sodium in the presence of oxygen and UO/sub 2/

Technical Report ·
DOI:https://doi.org/10.2172/5576792· OSTI ID:5576792

Compatibility of Ta-10W, Ta-8W-2Hf, Mo, Mo-13Re, Mo-26Re, Mo-41Re, TZM, Re, and Re-5W alloys with Na and UO/sub 2/ were studied in two temperature regimes. In the first regime Yates order experiments with three independent variables 300 greater than or equal to T less than or equal to 800/sup 0/C, 10 greater than or equal to t less than or equal to 130 hours, and 2 greater than or equal to (0) less than or equal to 100 ppmw oxygen potentials in Na were used to evaluate responses such as ultimate tensile strength, fracture energy, weight gain, and hardness. Samples were exposed to Na in individual crucibles with a fixed amount of oxygen. In the second regime, approx.600 less than or equal to T less than or equal to 2000/sup 0/C, tubes fabricated from the refractory alloys were loaded with UO/sub 2/ and Na containing 400 ppmw (0). The bottom of the tube was heated to 2000/sup 0/C and the top was allowed to cool naturally. A reflux condition was created in the tube and gradients approaching 250/sup 0/C/cm were obtained on the walls of the tube. All of the materials were found to be compatible with Na in the low temperature regime and Ta-10W, Ta-8W-2Hf, and Mo-41Re were found to be compatible in the high temperature regime. Re and Re-5W exhibited grain boundary failure when subjected to the high temperature test conditions. Re additions were found to enhance the tensile properties of Mo but did not significantly improve the fracture toughness as inferred from the fractography. The mechanical properties of the Ta alloys were found to be very sensitive to the impurities in the Na. Fracture initiation was found to control the tensile ductility and fracture energy (defined as the area under the load-displacement curve of the tensile test divided by the original area at the root of the notches) of the Mo, Mo-Re, and Re alloys.

Research Organization:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
5576792
Report Number(s):
SAND85-0850; ON: DE85016030
Country of Publication:
United States
Language:
English