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.

Automated summary

A dual-scale hybrid HfB2/Cu-Hf composite with HfB2 microparticles and Cu5Hf nanoprecipitates was prepared, and its contribution to mechanical properties and high-temperature performances was studied. The hybrid structure showed improved strain distribution and strength due to the pinning effect of HfB2 particles and strengthening effect of Cu5Hf nanoprecipitates. Both nanoprecipitates and HfB2 particles contributed to the high-temperature performance, with nanoprecipitates affecting the strength and HfB2 particles inhibiting grain coarsening and maintaining high-density dislocations.