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CONSTITUTION OF THE URANIUM-RICH U-Nb AND U-Nb-Zr SYSTEMS. Final Report -- Metallurgy Program 3.1.5.

Technical Report ·
DOI:https://doi.org/10.2172/4317513· OSTI ID:4317513
The uranium--niobium binary system exhibits a continuous series of solid solutions above 850 deg C. At lower temperatures a miscibility gap exists, containing a niobium-rich and a uranium-rich body-centered cubic phase. A monotectoid transformation occurs at 634 deg C. The beta-uranium phase is restricted by niobium and disappears at 4 wt.% Nb. Below 634 deg C alpha uranium and the niobium-rich gamma co-exist. The uranium--niobium--zirconium ternary system exhibits a continuous series of solid solutions at high temperatures. Miscibility gaps in the uranium-niobium and uranium--zirconium binary systems close with addition of the third element. Addition of both zirconium and niobium stabilizes the body-centered cubic gamma phase to lower temperatures. The beta-uranium phase is eliminated in ternary alloys of 4 wt.% Nb or more. The delta phase of the uranium-zirconium binary system extends into the ternary system to no more than 10 wt.% Nb. Over the major portion of the uranium-rich corner of the ternary system the equilibrium phases are alpha-U and gamma solid solution. The uranium-niobium binary system is the more dominant of the limiting systems. No new ternary phases were found. The relation of microstructures to irradiation stability is discussed. The relation of lattice strain to limits of solid solubility is also discussed. (auth)
Research Organization:
Argonne National Lab., Lemont, Ill.
Sponsoring Organization:
USDOE
DOE Contract Number:
W-31109-ENG-38
NSA Number:
NSA-12-002921
OSTI ID:
4317513
Report Number(s):
ANL-5581
Country of Publication:
United States
Language:
English