Interlocked interface of W–Y2O3/CuCrZr joint obtained by W–Y2O3 surface nanoporosification and Cu magnetron sputtering

Abstract

The development of a method for bonding W–Y2O3 composites and CuCrZr heat sinks, which can meet the requirements of future magnetic confinement fusion devices, is a key problem that needs to be urgently solved. In this work, CuCrZr was vacuum-diffusion-bonded with W–Y2O3 modified using surface nanoporosification, Cu magnetron sputtering, and annealing. Columnar Cu grains grew perpendicular to the surface nanoporous structure with a preferential Cu [111] orientation during sputtering deposition. A Cu layer was formed on the W–Y2O3 nanoporous surface after Cu sputtering deposition and annealing, resulting in an interlocked and tightly bonded interface. The obtained W–Y2O3/CuCrZr joint exhibited a shear strength of 217 MPa, which was much higher than that of a joint without interface modification (147 MPa). The interface of the W–Y2O3/CuCrZr joint was composed of an interaction layer formed by nano-sized W particles and sputter-deposited Cu. Deposited Cu was embedded in the surface nanopores on W–Y2O3, forming a semi-coherent W/Cu interface, realizing mechanical metallurgical bonding between the W–Y2O3 alloy and Cu, and thus enhancing the interface bonding strength. Improving the strength of W–Y2O3/CuCrZr joints by constructing a well-integrated interface facilitates the development of plasma-facing components for future China Fusion Engineering Test Reactor (CFETR).