The effect of low-temperature aging on the microstructure and deformation of uranium- 6 wt% niobium: An in-situ neutron diffraction study

Journal Article · Thu Sep 08 00:00:00 EDT 2016 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2016.09.004· OSTI ID:1458938

Brown, Donald William  ^[1]; Bourke, Mark Andrew M. ^[1]; Clarke, Amy Jean ^[2]; Field, Robert D. ^[1]; Hackenberg, Robert Errol  ^[1]; Hults, William L. ^[1]; Thoma, Daniel J ^[3]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Colorado School of Mines, Golden, CO (United States). Dept. of Metallurgical and Materials Engineering
3. Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering

The mechanical properties of uranium-niobium alloys evolve with aging at relatively low temperatures due to subtle microstructural changes. In-situ neutron diffraction measurements during aging of a monoclinic U-6Nb alloy at temperatures to 573 K were performed to monitor these changes. Further, in-situ neutron diffraction studies during deformation of U-6Nb in the as-quenched state and after aging for two and eight hours at 473 K were completed to assess the influence of microstructural evolution on mechanical properties. With heating, large anisotropic changes in lattice parameter were observed followed by relaxation with time at the aging temperature. The lattice parameters return to nearly their initial values with cooling. Finally, the active plastic deformation mechanisms including, in order of occurrence, shape-memory de-twinning, mechanical twinning, and slip-mediated deformation do not change with prior aging. However, the resistance to motion of the as-quenched martensitic twin boundaries increases following aging, resulting in the observed increase in initial yield strength.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1458938
• Alternate ID(s): OSTI ID: 1396805
• Report Number(s): LA-UR-16-22216; TRN: US1901529
• Journal Information: Journal of Nuclear Materials, Vol. 481, Issue C; ISSN 0022-3115
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE