Strength-plasticity synergistic enhancement of dispersion strengthened copper by interaction of nano-Al2O3 and Cr particles

To further regulate the coordinated matching of mechanical properties and plastic deformation ability of Al₂O₃/Cu composites. In this paper, Al₂O₃/Cu-Cr composites with different Cr contents were prepared by replacing some Al₂O₃ particles with Cr using a deformation heat treatment process, and the effects of Cr contents on the microstructure, electrical conductivity, and mechanical properties of Al₂O₃/Cu-Cr composites were investigated with a focus on the contribution of the composite strengthening mechanism. The results show that with the increase of Cr content and the decrease of Al₂O₃ content, the strength of the composites gradually decreases, and the plasticity and electrical conductivity are enhanced. Among them, the elongation of 1.1 Al₂O₃/Cu-0.3Cr composites was enhanced from 10% to 15% while the strength was not considerably reduced. The addition of Cr promotes grain growth and dynamic recrystallization, whereas Al₂O₃ particles enhance the aging precipitation response of Cr particles. The results of strength mechanism calculations show that the tensile strength of Al₂O₃/Cu-Cr composites mainly consists of Orowan strengthening caused by Al₂O₃ particles and dislocation strengthening in cold rolled deformation, while the dislocation strengthening is weakened at higher Cr content.