Abstract:The effects of Ni content (0-2.10 wt.%) on the precipitated phase, strength and electrical conductivity of Cu-0.4wt.%Be alloy were investigated, and the influencing mechanism was analyzed. The results showed that the addition of Ni promoted the precipitation of strengthening phase in the alloy and remarkably enhanced the strengthening effect. When the Ni content was increased from 0 to 2.10 wt.%, the strength of the aged alloy initially increased and then decreased, and approached the maximum when the Ni content was 1.50 wt.%. The peak-aging parameters of the alloy containing 1.50 wt.% Ni were the aging temperature of 400 °C and the aging time of 60 min, where the tensile strength and yield strength of the aged alloy were 611 and 565 MPa, respectively, which were 2.8 times and 6.1 times those of the alloy without Ni. The electrical conductivity of the alloy with Ni increased with the aging time, and decreased with the increase of Ni content. With an increase of the aging time at 400 °C, phase transition sequence of the Cu-0.4Be-1.5Ni alloy was γ″ phase →γ′ phase →γ phase. For the aging time of 60 min, a large number of dispersed nano-scale coherent γ″ phase and γ′ phase formed in the alloy with a remarkable strengthening effect, which was mainly responsible for the high strength of the alloy.

Key words: Cu-Be alloy; alloying; phase transformation; microstructure; mechanical properties; electrical conductivity