Study on microstructure and properties of aged Cu–Cr–Zr–Mg–RE alloy

Electrical conductivity, tensile strength and micro-hardness of Cu–0.43wt.% Cr–0.17wt.% Zr–0.05wt.% Mg–0.1wt.% RE alloy were investigated after cold working and aging treatment. The results show that good combination of the physical and mechanical properties can be obtained after aging at 450°C for 4h. The analysis of the microstructure by high resolution transmission electron microscopy (HRTEM) show that three kinds of strengthening phases, such as chromium-rich phase, zirconium-rich phase and the CrCu2(Zr, Mg) particles were observed. Most of the chromium-rich phase and zirconium-rich phase dispersed separately, and few of them congregated together in the matrix. The CrCu2(Zr, Mg) phase may be decomposed into chromium-rich phase and zirconium-rich phase at aging temperature above 450°C.