Effect of processing and heat treatment on behavior of Cu-Cr-Zr alloys to railway contact wire

A new series of Cu-Cr-Zr alloys to be used as railway contact wire, Cu-0.26 wt pct Cr-0.15 wt pct Zr, Cu-0.13 wt pct Cr-0.41 wt pct Zr, and Cu-0.34 wt pct Cr-0.41 wt pct Zr, were studied. The results indicated that processing and aging treatment had an effect on the microstructure, tensile strength, and electrical conductivity behavior of the Cu-Cr-Zr alloys. Process I (solution treatment + cold work + aging) was superior to process II (cold work + solution treatment + aging), because precipitation can occur heterogeneously at the dislocations and subcells. An appropriate processing and aging treatment may improve the properties of the alloys due to the formation of fine, dispersive, and coherent precipitates within the matrix. It is demonstrated that the best combination of tensile strength and electrical conducitivity, on the order of 599 MPa and 82 pct IACS (International Annealed Copper Standard), respectively, can be obtained in alloy Cu-0.34 wt pct Cr-0.41 wt pct Zr in the solution-heat-treated, cold-worked, and aged condition. The mechanism of tensile and conductive properties of Cu-Cr-Zr alloy is also discussed.