SPD Procedure and High Performance of Ultrafine-Grained Cu-Mg Alloy for Electrical Railway

Continuous Con-form plus equal-channel angular pressing (EACP) was applied to produce ultrafine-grained Cu-Mg contact wire materials with high strength and good conductivity, aim to push back the catenary barrier of high-speed trains by maximizing the tension and improving the power delivery. Microstructure change and mechanical properties of Cu-Mg alloys after various severe-plastic-deformation (SPD) routes were investigated by microscopic analysis and tensile tests. The results show that the Cu-0.2wt% Mg samples after multi-pass ECAP at 473K obtain ultrafine grains with homogeneously distributed secondary phases, having obviously improved strength. The more passes of ECAP make the finer grains and the higher strength of Cu-0.2 Mg alloy, but the strength increment of ECAPed alloys is appreciably lower with increasing ECAP temperature up to 673K. Grain refinement via continuous SPD procedures can endow Cu-Mg contact wire materials superior strength, high conductivity and anti-softening characteristics, which are advantageous to high-frequency electrification railway systems.