Interactions between hard phase, twins and dislocations strengthen dual-phase Cu-Fe alloys

Design: concept of dual-phase copper alloys was attractive to improve the mechanical performance of Cu. However, a systematic understanding of the interactions between second phase, twins, and dislocations in dualphase copper alloys during deformation was urgent for further strengthening their mechanical properties. Herein, models of dual-phase Cu-Fe alloys with different Fe contents were established and simulated to deeply investigate the interaction between Cu matrix and Fe-enriched phase during deformation as well as the dislocation proliferation and structural changes at the atomic scale. It was found that numerous dislocations and twins were produced in Cu matrix during the deformation process, while grain boundaries of Fe-enriched phases were able to effectively impede the movement of dislocations, resulting in an enhancement of the alloy's strength. Furthermore, new grain boundaries were appeared in the Fe-enriched phase of the dual-phase Cu-Fe alloys at higher strain rates, resulting in a certain grain refinement. With the increasing temperature, the main deformation mechanism of dual-phase Cu-Fe alloys were changed from dislocation slip to grain boundary slip. In addition, the additional Fe content can significantly strengthen the alloys, and the changes in the mechanical properties of dual-phase Cu-Fe alloys during deformation were verified via experiments.