Effects of processing paths on the microstructure, mechanical properties and electrical conductivity of dilute Al-Zr-Sc alloy conductive wires

Understanding and clarifying the evolution of microstructure and performance of Al-Zr-Sc alloy wires during processing paths is a crucial issue in developing heat-resistant conductors with high strength and high electrical conductivity (EC). In this study, the microstructure evolution and corresponding performance changes of Al-0.2Zr-0.06Sc alloy wires produced by three processing paths are investigated. Results indicate that ageing treatment + hot extrusion + cold drawing processing path can produce the highest strength Al-Zr-Sc wires attributed to favorable interactions among precipitation strengthening of Al₃(Zr,Sc) phases, grain boundary strengthening and dislocation strengthening. High EC is attained by the hot extrusion + ageing treatment + cold drawing processing path, which reveals the importance of dynamic precipitation of Al₃Sc phases during hot extrusion and further precipitation of solute atoms during ageing treatment for improving the EC. The processing path using hot extrusion + cold drawing + ageing treatment achieves the highest EC of the Al-Zr-Sc wire, but the strength decreases significantly due to the loss of dislocation strengthening. Additionally, the pinning effect of Al₃Sc and Al₃(Zr,Sc) ensures good heat resistance of Al-Zr-Sc wires. These results provide guidance for the process design of Al-Zr-Sc wires with variable combinations of strength and EC.