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The microstructure and mechanical properties of a Cu–Cr–Ag alloy at the different processing stages were investigated using hardness measurements, scanning electron microscopy, and transmission electron microscopy. The combined effects of dislocation strengthening and precipitation strengthening were shown to remarkably enhance the hardness of the alloy. Coherent Cr-rich precipitates with a face-centred cubic structure, formed during aging, were shown to be the main source of age strengthening, and the introduction of pre-deformation led to acceleration of their precipitation. Nevertheless, recovery occurring during aging caused significant softening in the cold-drawn samples. Analysis of the microstructural evolution during cold drawing and aging was used as an effective tool to optimise the thermomechanical process and improve the mechanical properties.

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Microstructure, precipitation hardening response, and mechanical and physical properties of Cu-Cr-Ag alloy and Cu-Cr-Ag-Ce alloy have been investigated using transmission electron microscopy, scanning electron microscope, optical microscope, electrical conductivity analysis, and tensile test. The influence of element Ce on the matrix refinement, impurity removal, and precipitation in the Cu-Cr-Ag alloys has been analyzed. The experimental results show that the strength and electrical conductivity of Ce containing alloys are greater than those of Ce-free alloys after each processing step. Improvement of strength and electrical conductivity of the Cu-Cr-Ag alloy by adding Ce element is attributed to removing oxygen and sulfur from as-cast alloy.

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In recent years, the commercially available Cu–Sn alloy has attracted great interest within the new energy vehicles and industrial robots industries because of its relatively excellent comprehensive performance as compared to those of Cu–Ag and Cu–Mg alloys. In this work, we study the possibility of improving the tensile strength of Cu–Sn alloy via Mg addition. Our results show that, the addition of Mg could significantly improve the strength of the Cu–Sn alloy, the tensile strength of the Cu–Sn alloy was increased from 399MPa to 427MPa by 0.02 wt.% Mg addition after 80% cold-rolled reduction. This can be ascribed to the combined effect of the acceleration of the grain refinement and the promotion of the sub-structures formation by Mg addition during cold rolling process. Larger number density and more uniformly distributed sub–structures with an average size of 120 nm were formed in Mg-contained alloy than that in Mg-free alloy after 80% reduction. However, the Mg addition slightly decreased the electrical conductivity (EC) of the alloy (1.5%IACS), because of the lattice distortion caused by Mg atoms.

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