Optimization of microstructure and properties of new Al-Ce-Sc alloy wires in drawn state

The current aluminum alloy conductor still has contradictions in conductivity, heat resistance, and strength that cannot be resolved simultaneously, and it cannot meet the requirements of large-capacity transmission lines. In this work, Al-RE alloy wires with a composite addition of Ce and Sc elements were prepared by extrusion and drawing. The effects of the composite addition of Ce and Sc on the microstructure, mechanical properties, electrical conductivity , and heat resistance of industrial pure aluminum alloys were studied. Results show that the grain refinement of the alloy with a compound addition of 0.1 wt% Ce and 0.2 wt% Sc was better, with an average grain size of 7.2 μm. The comprehensive performance of Al-0.1Ce-0.2Sc alloy wire is the best, with UTS of 218.9 MPa, YS of 215.6 MPa, EL of 5.1 %, and electrical conductivity (EC) of 60.68 % IACS. The fine coherent nano-Al 3 Sc phases precipitated during hot extrusion and drawing have excellent strengthening effects and high thermal stability, which can significantly enhance the strength and heat resistance of the alloy. The addition of the element Ce results in the formation of the phases Al 13 Fe 3 Ce and AlCeSiFe, which significantly reduces the concentration of Fe and Si atoms in the aluminum matrix , thereby reducing the scattering of electrons and increasing the EC of the alloy. The Al-0.1Ce-0.2Sc alloy wire showed a tensile strength residual of up to 96.8 % after a heat resistance test at 230°C × 1 h. The damping properties of several alloys were also evaluated, among which the Al-0.1Ce-0.2Sc alloy wire has excellent high-temperature damping properties with an internal dissipation value of up to 0.25. The Al-0.1Ce-0.2Sc alloy conductor simultaneously possesses high-strength, high-conductivity, high-heat-resistance, and high-damping properties, which provides a data reference for the subsequent design of heat-resistant aluminum conductor materials with both strength and conductivity. • Al-RE alloy wires have point-like or rounded micron-sized second phases, which are mainly Al 13 Fe 3 Ce, Al 11 Ce 3 and AlCeSiFe phases. • The UTS, YS, EL, and conductivity of Al-0.1Ce-0.2Sc alloy wires were 218.9 MPa, 215.6 MPa, 5.1 %, and 60.68 % IACS, respectively. • The addition of the Ce element results in the formation of Al 13 Fe 3 Ce and AlCeSiFe phases, which purify the aluminum matrix. • Al-RE alloy wires in this study meet the national standard for heat-resistant aluminum alloy wires (NRLH1).