Improvement of interfacial bonding and mechanical properties of Cu-Al₂O₃composite by Cr-nanoparticle-induced interfacial modification

The strength and ductility of copper matrix composites are usually limited due to the interfacial debonding between the reinforcement and matrix. Interfacial debonding is mainly caused by the interfacial stress induced by the differences in elastic modulus and thermal expansion coefficient (CTE) between the reinforcement and matrix. Cu-Cr-Al₂O₃composite with Cr nanoparticles precipitated at the interface of Cu and Al₂O₃was fabricated. It was found that the hardness of Cu-1 wt% Cr-4 wt% Al₂O₃composite is higher than that of Cu-5 wt% Al₂O₃composite over the temperature range from 25 °C to 1000 °C. Notably, the hardness increment reached 133% at 1000 °C. In addition, the compressibility increased 36% for Cu-1 wt% Cr-4 wt% Al₂O₃composite compared with Cu-5 wt% Al₂O₃. The finite element simulation results confirmed that the interfacial residual stress in Cu-Al₂O₃composite decreased by adding Cr, resulting in the improvement in mechanical properties.