Microstructural and micro-mechanical analysis of 14YWT nanostructured Ferritic alloy after varying thermo-mechanical processing paths into tubing

Harvey, Cayla; El-Atwani, Osman; Kim, Hyosim; Lavender, Curt A.; McCoy, Marie; Sornin, Denis; Lewandowski, John J.; Maloy, Stuart A.; Pathak, Siddhartha

doi:10.1016/j.matchar.2020.110744

Cited by 6 publications

(1 citation statement)

References 35 publications

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“…Powder was produced by ATI Metals in Pittsburgh, PA using gas atomization and processed by Zoz, GmbH in Wenden, Germany using high intensity attritor milling for 40 h [65]. The base material rods were produced at Oak Ridge National Laboratory using hot extrusion at 850 • C [66]. Cylindrical caps (10 mm OD × 4 mm) were cut directly from the extruded rod using electrical discharge machining (EDM) and chamfered (45 • ) on one edge using a lathe.…”

Section: Methodsmentioning

confidence: 99%

Solid-State Welding of the Nanostructured Ferritic Alloy 14YWT Using a Capacitive Discharge Resistance Welding Technique

Lear

Gigax

Schneider

et al. 2021

Metals

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Joining nanostructured ferritic alloys (NFAs) has proved challenging, as the nano-oxides that provide superior strength, creep resistance, and radiation tolerance at high temperatures tend to agglomerate, redistribute, and coarsen during conventional fusion welding. In this study, capacitive discharge resistance welding (CDRW)—a solid-state variant of resistance welding—was used to join end caps and thin-walled cladding tubes of the NFA 14YWT. The resulting solid-state joints were found to be hermetically sealed and were characterized across the weld region using electron microscopy (macroscopic, microscopic, and nanometer scales) and nanoindentation. Microstructural evolution near the weld line was limited to narrow (~50–200 μm) thermo-mechanically affected zones (TMAZs) and to a reduction in pre-existing component textures. Dispersoid populations (i.e., nano-oxides and larger oxide particles) appeared unchanged by all but the highest energy and power CDRW condition, with this extreme producing only minor nano-oxide coarsening (~2 nm → ~5 nm Ø). Despite a minimal microstructural change, the TMAZs were found to be ~10% softer than the surrounding base material. These findings are considered in terms of past solid-state welding (SSW) efforts—cladding applications and NFA-like materials in particular—and in terms of strengthening mechanisms in NFAs and the potential impacts of localized temperature–strain conditions during SSW.

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Section: Methodsmentioning

confidence: 99%