Hybrid effect on mechanical properties and high-temperature performance of copper matrix composite reinforced with micro-nano dual-scale particles

A dual-scale hybrid HfB 2 /Cu-Hf composite with HfB 2 microparticles and Cu 5 Hf nanoprecipitates was designed and prepared. The contribution of the hybrid effect to the mechanical properties and hightemperature performances was studied from macro and micro perspectives, respectively. The hybrid of dual-scale particles can make the strain distribution of the composite at the early deformation stage more uniform and delay the strain concentration caused by the HfB 2 particle. The dislocation pinning of HfB 2 particles and the coherent strengthening of Cu 5 Hf nanoprecipitates simultaneously play a strengthening role, but the strength of the hybrid composite is not a simple superposition of two strengthening models. In addition, both Cu 5 Hf nanoprecipitates and HfB 2 microparticles contribute to the high-temperature performance of the composite, the growth and phase transition of nanoprecipitates at high temperature will reduce their contribution to strength, while the stable HfB 2 particles can inhibit the coarsening of matrix grains and maintain the high-density geometrically necessary dislocations (GNDs) in the matrix, which ensures more excellent high-temperature resistance of the hybrid composite. As a result, the hybrid structure can simultaneously possess the advantages of multiple reinforcements and make up for the shortcomings of each other. Finally, a copper matrix composite with high strength, high conductivity, and excellent high-temperature performance is displayed. & COPY; 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.