Effects of cold rolling and low-temperature annealing on microstructure and mechanical properties of rapidly solidified Cu–3Ag-0.5Zr alloy

Abstract

The effects of cold rolling and low-temperature annealing on the microstructure and mechanical properties of Cu–3Ag-0.5Zr alloy prepared by gas atomization and hot isostatic pressing (HIP) were investigated. The HIPed alloy provides a fine and homogeneous microstructure for the subsequent rolling. The high density of dislocations, the large number of ultrafine grains, and the interaction between dislocations and fine precipitates (nano-sized Ag and micro-sized Cu4AgZr) are responsible for the high hardness (193 Hv), excellent tensile strength (654 MPa), but relatively low elongation (5.6%). Low-temperature annealing achieves a desirable combination of high strength and moderate elongation. After annealing at 350 °C for 2 h, the tensile strength, yield strength and elongation are 584 MPa, 534 MPa and 13%, respectively. When annealed for 8 h, the tensile strength and yield strength decrease to 558 MPa and 504 MPa, respectively, while the elongation recovers to 16.5%. The increased elongation is mainly attributed to the recovery of dislocation-accumulation ability and the slight grain growth.