High-strength diffusion bonding of oxide-dispersion-strengthened tungsten and CuCrZr alloy through surface nano-activation and Cu plating

Oxide-dispersion-strengthened tungsten (ODS-W) and a CuCrZr alloy were bonded by a three-step process: (i) surface nano-activation, (ii) copper plating followed by annealing, and (iii) diffusion bonding. The morphological and structural evolutions of ODS-W and the interface of the ODS-W/CuCrZr joint during these processes have been thoroughly studied by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, and high-resolution transmission electron microscopy. After surface nano-activation, a nanoporous structure of ODS-W with an average pore size of ~100 nm was obtained, and the Y2O3 particles therein remained unchanged. A Cu coating was tightly bonded with the surface nano-activated ODS-W after Cu plating and annealing. An interaction layer embedded with nanosized W particles was formed at the interface between ODS-W and plated Cu after the three-step process. Consequently, well-cohesive ODS-W/Cu and ODS-W/Y2O3/Cu interfaces were formed. The ODS-W/CuCrZr joint showed high shear strengths (up to 201 MPa) and effective bonded area ratios (>98%). The developed three-step bonding process between ODS-W and the CuCrZr alloy provides an effective support for future plasma-facing components in nuclear fusion reactor applications. •High-strength bonding of immiscible ODS-W and CuCrZr was realized by combination of surface nano-activation and Cu plating.•Surface nano-activation of ODS-W was achieved by the sequential anodization and deoxidation annealing.•A Cu coating was tightly bonded with the surface nano-activated ODS-W through controllable Cu plating and annealing.•An interfacial Cu layer embedded with nanosized W particles was formed at the ODS-W/CuCrZr joint interface.•Well-cohesive ODS-W/Cu and ODS-W/Y2O3/Cu interfaces lead to excellent performance of the ODS-W/CuCrZr joint. [Display omitted]