Effect of WO3 addition on the fabrication of oxide dispersion-strengthened Cu alloys by mechanical alloying of CuYZr alloy powders

• Novel oxide dispersion-strengthened Cu alloys were fabricated by mechanical alloying of CuYZr alloy powders with the addition of WO 3 as a process control agent and oxygen supplier. • The addition of WO 3 resulted in near 100% recovery of ODS-Cu powders and the formation of uniformly dispersed Y-Zr complex oxides. • 2.44 wt% WO 3 enabled ODS-Cu to have both superior mechanical properties and favorable thermal diffusivity. • Microstructural evolution and strengthening mechanisms in the ODS-Cu were systematically elucidated by combining atom probe tomograph and scanning transmission electron microscopy. Copper alloys are promising candidates for heat sink applications in fusion reactors due to their excellent thermal conductivity. However, oxide dispersion-strengthened (ODS) copper alloys fabricated via mechanical alloying suffer from coarse powder morphologies, low production rates, and inhomogeneous distributions of dispersed oxides. In this study, a novel oxide dispersion-strengthened (ODS) Cu alloy system was developed using gas-atomized Cu–0.80wt.%Y–0.81wt.%Zr powders combined with WO 3 powder as a process control agent. The results demonstrate that adding WO 3 significantly reduced the average powder size after ball milling and increased the powder recovery rate to nearly 100 %. Furthermore, three-dimensional atom probe analysis and transmission electron microscopy confirmed that WO 3 underwent complete decomposition during milling, releasing oxygen that facilitated the internal oxidation of Y and Zr. leading to the formation of fine Y–Zr complex oxides with an average particle size of approximately 5.2 nm. The dispersed W particles and Y–Zr complex oxides jointly hinder dislocation movement, resulting in a maximum Vickers hardness of 274 HV. This study provides a feasible approach to improve the powder refinement and oxide dispersion in ODS-Cu alloys, which is expected to advance their processability and industrial applicability.