Brazing characteristics, microstructure, and wettability of laser powder bed fusion additive manufactured GRCop-84 compared to CuCrZr and OFC, and brazing to titanium-zirconium-molybdenum alloy limiters

•GRCop-84 braze wetting is similar CuCrZr, though less than oxygen free copper, wet sanding to 240 grit (Ra=0.24 µm) was considered the optimal surface roughness.•High intergranular diffusion rates occur for silver containing brazes in GRCop-84.•Active brazes such as Ticusil, Cusil-ABA, and Palcusil-25 wet titanium-zirconium-molybdenum alloy without a plating as does 50Au-50Cu braze, allowing direct brazing to GRCop-84 for the construction of plasma facing limiters.•Sulfamate nickel plating on titanium-zirconium-molybdenum promotes wetting of non-active brazes such as cusil while plating GRCop-84 with copper greatly enhances braze wetting.•Silver diffusing through GRCop-84 depleted Cr2Nb precipitates from the copper grain and deposited agglomerations of coarsened precipitates within silver-rich regions of intergranular diffusion once a density threshold was reached. Laser Powder Bed Fusion (L-PBF) of Glenn Research Copper 84 (GRCop-84), a Cr2Nb (8 at. % Cr, 4 at. % Nb) precipitation hardened alloy, produces a fully dense, high conductivity alloy with a yield strength of 500 MPa and ultimate tensile strength (UTS) of 740 MPa with 20% elongation; superior to other competing copper alloys. Braze wetting characteristics of GRCop-84 with Ag-Cu-X, and Au-Cu brazes were similar to CuCrZr, but less than oxygen free copper. No difference in wetting was observed between infill and surface contour areas in L-PBF GRCop-84. Wet sanding to 240 grit (Ra=0.24 µm) was considered the optimal surface condition. Silver diffusing through GRCop-84 depleted Cr2Nb precipitates from the copper grain and deposited agglomerations of coarsened precipitates within silver-rich regions of intergranular diffusion once a density threshold was reached. Microstructure modification was minimized with 50Au-50Cu braze implying that silver caused precipitate coarsening and agglomeration, and not high temperature exposure. Coarsened precipitates were observed on the surface within braze pools implying a contribution to braze wetting. Palcusil-25, Ticusil, CuSil-ABA, and 50Au-50Cu brazes were suitable for brazing to unplated Titanium-Zirconium-Molybdenum (TZM), while sulfamate nickel plating to allows wetting with CuSil or other non-active brazes. Vacuum brazing techniques were developed to join a 1 mm thick layer of TZM to the front of additive manufactured GRCop-84 waveguides considering the brazing characteristics of both GRCop-84, TZM, and internal stress from the difference in coefficient in