Sodium corrosion of alloy 718 at 649 degrees C

Technical Report · Sat Sep 01 00:00:00 EDT 1984

DOI:https://doi.org/10.2172/5692038· OSTI ID:5692038

Cowgill, M G

The effects of exposure of Alloy 718 to flowing sodium at 649{degree}C have been studied for times ranging from 4000 h to 20,000 h. Data are reported for metal loss, chemical composition changes, depth of intergranular attack and microhardness changes. Relationships have been developed to describe the dependence of corrosion rate on temperature and sample location (the downstream effect), and the variation of intergranular attack depth with exposure time. The surface topography of exposed samples was observed to vary with sample location, a fact which was attributed to changes in the dissolution potentials for the constituent elements. The corrosive attack was found to be non-uniform and subsurface porosity, associated with the intergranular attack, was detected after the longer exposure periods. Ferritic phase formation was noted both on the surface and internally. The microhardness data indicated that the material started to over-age at or just before 4000 h at 649{degree}C. 11 refs., 34 figs., 13 tabs.

• Research Organization: Westinghouse Electric Corp., Pittsburgh, PA (United States). Advanced Energy Systems Div.
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AT02-80CH94049
• OSTI ID: 5692038
• Report Number(s): WAESD-NA-94000-16; ON: DE91015599
• Country of Publication: United States
• Language: English

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