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A Cu-0.41Mg-0.06Ca (wt.%) alloy was designed and prepared by melting and casting in air atmosphere, followed by equal channel angular pressing (ECAP) process up to 12 passes via Bc route at room temperature. The microstructure and properties of the alloy were investigated by means of hardness test, tensile test, electrical conductivity measurement and electron microscopes observation. After 12 ECAP passes, the initial coarse grains were refined significantly and the average grain sizes decreased to 0.57 μm. The coarse Cu5Ca phase was also fragmented and had the sizes of about 1–3 μm. The Cu-Mg-Ca alloy after 12 ECAP passes showed excellent comprehensive properties, with a yield strength of 619 MPa, an electrical conductivity of 67.86 %IACS and a total elongation of 10.4%. Compared with the Cu-Mg alloy under the same condition, the yield strength of the designed alloy after 12 ECAP passes was improved by 30 MPa and the electrical conductivity increased by 0.63 %IACS accompanied by almost same total elongation. The good comprehensive properties were attributed to the ECAP process and the addition of Ca. The ECAP process provided much high yield strength increments which accounted for more than 80% of the yield strengths after 12 ECAP passes. In addition, the addition of Ca in the Cu-Mg alloy promoted the grain refinement, improved the work hardening ratio, and increased the electrical conductivity.

Magnesium was added into Cu-Cr alloy to overcome the traditional limitations of high-cost and large-scale manufacturing of Cu-Cr alloys and to unveil the acting mechanism of Mg on the microstructure and properties of Cu-Cr alloy. Effect of magnesium on microstructure and properties of Cu-Cr alloy has been investigated by means of hardness test, electrical conductivity measurement, transmission electron microscopy, three-dimension atom probe tomography technique and X-ray diffraction analysis. The precipitation sequence of Cu-Cr-Mg alloy was similar with that of binary Cu-Cr alloy. Additional magnesium in Cu-Cr alloy accelerated the process of precipitates nucleation, restrained the growth of the precipitates by segregating along precipitates surface during aging. This enhanced the stability of the deformation microstructure and improved the mechanical properties of the alloy. Cu-Cr-Mg alloy showed a better comprehensive properties and softening resistance performance than Cu-Cr alloy at elevated temperature. After aged at 480 °C, Cu-Cr-Mg alloy had a tensile strength of 540 MPa and an electrical conductivity of 79.2 %IACS for the peak aging states, and it still maintained a tensile strength of 515 MPa and an electrical conductivity of 80.8 %IACS after 4 h aging.