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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

The Sporadic History of Rubidium and its Role in Corrosion of Steel Related to Nuclear Material Storage

The influence of rubidium (Rb), both in its metallic and oxidized states, on the corrosion resistance of steels has direct relevance to the storage of radioactive Kr-85 containing nuclear materials. Kr-85 undergoes a ß-decay to generate stable, metallic Rb. The literature to date is sparse, contained primarily in company reports and divisive as to whether Rb metal, or its oxides, can lead to corrosion of steel materials. In both the direct storage of Kr-85 and used nuclear fuel that will contain Kr-85, if Rb is corrosive then continual decay of the Kr-85 will generate an increasingly corrosive environment for the steel canister it is stored in. This review was written to consolidate the known data to date on Rb corrosion of steels to identify consistencies, contradictions and remaining gaps in our understanding of the Rb : steel system.

krypton, corrosion, steel, Rubidium↗
DOE OSTI2015

Orientation gradients in relation to grain boundaries at varying strain level and spatial resolution

The resolution dependence of orientation gradients was studied in a well-annealed 99.9995% pure polycrystalline copper pulled to failure in tension. Owing to the well developed neck, different regions in the sample correspond to different tensile strains. Post-mortem characterization was performed using EBSD on cross-sections containing the tensile axis. Kernel average misorientation (KAM) was calculated as a metric to establish correlation between defect accumulation and microstructural features, with a threshold of 5° to focus on intra-granular gradients. The region with the lowest strain (2%) showed high KAM values adjacent to grain boundaries compared to the grain interior, regardless of the point spacing, i.e. the spatial resolution. However, in the region with the highest strain (13%) a strong dependence on resolution was found. For point spacings of 0.5 μm or smaller, the same correlation of high KAM with locations near boundaries was found. At coarse spacings i.e. low spatial resolution, by contrast, the reverse was found in that the highest KAM values appear in the grain interiors, as previously observed in X-ray microscopy on the same sample which had a similar coarse resolution. An analysis of orientation gradients parallel to, and perpendicular to boundaries suggested that the latter tend to be the larger of the two. This helps to explain why boundary-adjacent points have low KAM values. The conclusion is that measurement of local orientation gradient requires a resolution that is comparable to the dislocation substructure.

36 MATERIALS SCIENCE↗