Title

Microstructural Characterization of U-Nb-Zr, U-Mo-Nb, and U-Mo-Ti Alloys via Electron Microscopy

Authors

Authors

A. Ewh; E. Perez; D. D. Keiser;Y. H. Sohn

Comments

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Abbreviated Journal Title

J. Phase Equilib. Diffus.

Keywords

experimental phase equilibria; isothermal equilibration; materials; characterization; metallic alloys; phase equilibria; ternary phase; diagram; transmission electron microscopy; IRRADIATION BEHAVIOR; AL; ALUMINUM; GROWTH; FUELS; Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy &; Metallurgical Engineering

Abstract

Ternary uranium molybdenum alloys are being examined for use as dispersion and monolithic nuclear fuels in research and test reactors. In this study, three such ternary alloys, with compositions U-10Nb-4Zr, U-8Mo-3Nb, and U-7Mo-3Ti in wt.%, were examined using scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM) with high angle annular dark field (HAADF) imaging via scanning transmission electron microscopy (STEM). These alloys were homogenized at 950 degrees C for 96 h and were expected to be single-phase bcc-gamma-U. However, upon examination, it was determined that despite homogenization, each of the alloys contained a small volume fraction precipitate phase. Through SEM and XRD, it was confirmed that the matrix retained the bcc-gamma-U phase. TEM specimens were prepared using site-specific focused ion beam ( FIB) in situ lift out (INLO) technique to include at least one precipitate from each alloy. By electron diffraction, the precipitate phases for the U-10Nb-4Zr, U-8Mo-3Nb, and U-7Mo-3Ti alloys were identified as bcc-(Nb, Zr), bcc-(Mo,Nb), and bcc-(Mo,Ti) solid solutions, respectively. The composition and phase information collected in this study was then used to construct ternary isotherms for each of these alloys at 950 degrees C.

Journal Title

Journal of Phase Equilibria and Diffusion

Volume

31

Issue/Number

3

Publication Date

1-1-2010

Document Type

Article; Proceedings Paper

Language

English

First Page

216

Last Page

222

WOS Identifier

WOS:000278094900002

ISSN

1547-7037

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