A Metallographic Study of the Swelling of Uranium and Uranium Alloys

Technical Report · Wed Aug 17 04:00:00 EDT 1960

DOI:https://doi.org/10.2172/4136507· OSTI ID:4136507

Boltax, A. ^[1]; Lumbert, A. R. ^[1]; Green, H. M. ^[1]

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1. Nuclear Metals, Inc., Concord, MA (United States)

The behavior of inert gases were studied in inoculated uranium and uranium alloy (U-1.6, 2.8, and 10 ^w/o Mo, U-2 ^w/o Zr, U-0.3 Cr - 0.3 Mo, U-l and 2 ^w/o C, and U-3.8 ^w/o Si) samples. Helium was injected into metal samples by alpha particle irradiation krypton by glow-discharge techniques. Following gas inoculation, samples were given various isothermal and thermal cycling heat treatments to permit the formation of gas bubbles. The gas bubbles were observed in the light microscope after mechanical polishing and after chemical etching and in the electron microscope after cathodic vacuum etching. Helium gas bubbles were observed in the cyclotron-irradiated samples following various heat treatments between 475 and 1075°C. The majority of the gas bubbles in any sample, independent of heat treatment, were between 0.05 and 2 microns in diameter (10¹⁰ to 10¹⁴ per cc), and accounted for up to 10 percent porosity. Post-irradiation heat treatments above 900°C gave rise to the formation of a small number (about 10⁵ per cc) of large bubbles between 10 and 150 microns in diameter which accounted for porosities up to several hundred percent. The large volume increase caused by the latter bubbles is similar to that observed in metallic reactor fuel elements irradiated at temperatures above 400°C. Effects of recrystallization and phase transformations on the behavior of the helium gas bubbles were noted. The nucleation and growth characteristics of the small and large bubbles are discussed.

• Research Organization: Nuclear Metals, Inc., Concord, MA (United States)
• Sponsoring Organization: US Atomic Energy Commission (AEC)
• NSA Number: NSA-15-004289
• OSTI ID: 4136507
• Report Number(s): NMI--1239
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALPHA PARTICLES
BUBBLES
CARBIDES
CATHODES
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CLEANING
CYCLOTRONS
EFFICIENCY
ELECTRON MICROSCOPY
ETCHING
EXPANSION
FUEL ELEMENTS
GASES
GLOW DISCHARGES
HEAT TREATMENTS
HELIUM
HIGH TEMPERATURE
INERT GASES
INJECTION
IRRADIATION
KRYPTON
METALLOGRAPHY
MICROSCOPY
MOLYBDENUM ALLOYS
PHASE DIAGRAMS
POROSITY
RECRYSTALLIZATION
SILICIDES
TEMPERATURE
THICKNESS
URANIUM
URANIUM ALLOYS
VACUUM
ZIRCONIUM ALLOYS