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

Metals

Jonathan Gregory Gigax¹  Todd Edward Steckley²  Matthew M. Schneider³  Benjamin Paul Eftink³  Calvin Robert Lear³  Stuart Andrew Maloy³  Thomas J. Lienert⁴ 

[1] MPA-CINT, Los Alamos National Laboratory, Los Alamos, NM 87545, USA;MST-16, Los Alamos National Laboratory, Los Alamos, NM 87545, USA;MST-8, Los Alamos National Laboratory, Los Alamos, NM 87545, USA;TechSource, Los Alamos, NM 87544, USA;

关键词: solid-state welding;    capacitive discharge resistance welding;    pressure resistance welding;    oxide-dispersion-strengthened;    nanostructured ferritic alloys;    cladding;   

DOI  :  10.3390/met12010023

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown