1. Brazing, Laser, and Electron-Beam Welding of Additively Manufactured GRCop-84 Copper for Phased Array Lower Hybrid Launchers
- Author
-
Stephen Wukitch and Andrew Seltzman
- Subjects
Nuclear and High Energy Physics ,Materials science ,Alloy ,chemistry.chemical_element ,Welding ,engineering.material ,Condensed Matter Physics ,01 natural sciences ,Copper ,010305 fluids & plasmas ,law.invention ,chemistry ,law ,Soldering ,0103 physical sciences ,Electron beam welding ,Surface roughness ,engineering ,Brazing ,Selective laser melting ,Composite material - Abstract
Recent advances in selective laser melting 3-D printing technology allow additive manufacturing of lower hybrid current drive (LHCD) RF launchers from a new material, Glenn Research Copper 84 (GRCop-84), a Cr2Nb (8 at. % Cr, 4 at. % Nb) precipitation hardened alloy, in configurations unachievable by conventional machining. Cr2Nb crystals pin grain boundaries within the copper matrix resulting in high tensile strength and resistance to annealing at elevated temperatures. Brazing, laser, and electron-beam welding (EBW) techniques are explored for joining a thin-walled GRCop-84 waveguide with zero porosity and minimal internal surface roughness. GRCop-84 wets well with the silver solder, CuSil, and Cusil-ABA brazes, once the durable surface oxide is mechanically removed. GRCop-84 melt pool size and flow during EBW is reduced compared to oxygen-free copper (OFC). Pulsed laser and e-beam welding maintains the Cr2Nb precipitate size; precipitate coarsening occurs in conduction mode e-beam welding.
- Published
- 2020