Microstructure evolution and mechanical properties of Cu-3Ag-xZr alloys processed by equal channel angular pressing

Abstract In the present study, microstructure evolution and mechanical properties of the Cu-3Ag-xZr alloys processed by equal channel angular pressing (ECAP) at room temperature were investigated. The results indicated that significant grain refinement can be achieved, and the average grain sizes are remarkably refined to 0.41 ± 0.1 μm and 0.39 ± 0.05 μm after 8 P for Zr-free and Zr-containing alloys, respectively. The continuous dynamic recrystallization (CDRX) should be responsible for such refinement mechanism. For Zr-containing alloy, the original coarse island-like Cu4AgZr particles are crushed into nearly spherical particles with the average size less than 5 μm during the subsequent deformation process. In addition, the Cu-3Ag-xZr alloys processed by ECAP after 8 P present the excellent comprehensive properties with yield strength of 587 MPa and of 627 MPa, as well as the electrical conductivity of 84.5%ICAS and 70.7%ICAS for the Zr-free and Zr-containing alloys, respectively. Accordingly, a quantitative calculation based on the established strengthening mechanism was conducted, indicating that the significant strengthening effect originates from the formation of subgrain structure. It is anticipated that this research would provide a feasible way for the preparation of high-performance Cu-3Ag-xZr alloys.