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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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At least 271 records · Page 15

Exceptional fatigue resistance and impact toughness of additively manufactured nickel alloy 625 by laser powder bed fusion

A thorough understanding of the processing-structure property relationships of additively manufactured (AM) parts is critical for applications. Detailed microstructural, tensile, axial fatigue, and Charpy impact properties were evaluated of AM nickel alloy 625 builds produced by laser-beam powder-bed-fusion, with powders manufactured using different atomization conditions. Post-heat treatment resulted in a recrystallized, equiaxed grain structure that eliminated anisotropy in tensile properties between the build and transverse directions. Axial fatigue properties along the build direction were similar to design handbook wrought fatigue data. Furthermore, Charpy impact energy values were superior to wrought data in the hot-rolled condition. Fractography was performed on failed fatigue and Charpy specimens and the fracture surfaces of Charpy specimens were found to be covered predominantly by fine dimples.

36 MATERIALS SCIENCE↗

Imidazoles and imidazolium cations with exceptional alkaline stability

The invention provides: imidazole and imidazolium compounds of formulas (I) and (II): polymers containing a plurality of imidazolium-containing repeating units of formula (III′): and membranes and devices comprising the polymers. Also provided are methods of making the inventive compounds and polymers.

Coates, Geoffrey W.↗