FINAL REPORT ON MISCIBILITY GAPS IN Nb-U AND Nb-U-Zr SYSTEMS

Technical Report · Thu Jan 01 04:00:00 EST 1959

DOI:https://doi.org/10.2172/4207229· OSTI ID:4207229

The miscibility gap in the U-Nb system has been established using metallographic and x-ray techniques. The monotectoid temperature is placed at 640 deg plus or minus 2 deg C and the composition limits at that temperature are 65 to 70 at.% Nb and 17.5 plus or minus 1 at.% Hb. The 700, 650, and 600 deg C isothermal sections of the U-Nb- Zr system have also been investigated. Each of the miscibility gaps present in the limiting binary sections was found to be closed by additions of the third element. At 700 deg C the U- Zr gap is closed by addition of less than 5 at.% Nb. The behavior of the Zr-Nb gap is less certain owing to the sluggish reactions close to this binary system but the gap appears to be closed by about 15 at.% U. The U-Nb gap has been studied in more detail and is closed by 14 at.% Zr. To a near approxiation the teniary U-Nb gap can be considered to be bounded by the composition lines 33 at.% U, 14 at.% Zr, and about 20 at.% Nb depending on temperature. A notable feature is that at Nb and Zr compositions approximately corresponding to a line of minimum lattice distortion, the gamma phase at 600 deg C bulges toward the U corner. As a result of the closure of the gaps the gamma phase is stable over a large area of the diagram at temperatures down to at least 600 deg C. (auth)

• Research Organization: Fulmer Research Inst., Ltd., Stoke Poges, Bucks, England
• NSA Number: NSA-14-006678
• OSTI ID: 4207229
• Report Number(s): NP-8237; R-126/4
• Country of Publication: United States
• Language: English

Related Subjects

ADDITIVES
EUTECTICS
HIGH TEMPERATURE
LATTICES
METALLOGRAPHY
METALS
CERAMICS AND MATERIALS
MIXING
NIOBIUM
NIOBIUM ALLOYS
PHASE DIAGRAMS
STABILITY
TEMPERATURE
URANIUM
URANIUM ALLOYS
X RADIATION
ZIRCONIUM
ZIRCONIUM ALLOYS