Precipitation behavior and electrical conductivity and mechanical properties of Cu-0.9Be-1.5Ni-0.04Y alloy

The optimum solid solution and aging processes for Cu-0.9Be-1.5Ni-0.04Y alloys, as well as the microstructure and strengthening mechanisms during aging were investigated. The results show that the optimum solid solution and aging temperatures are 980℃ and 480℃, respectively. During aging treatment at 480°C, the precipitation sequence of the Cu-0.9Be-1.5Ni-0.04Y alloy was supersaturated α solid solution → GP zone → γʺ phase → γʹ phase → γ phase. As increasing the aging time, the microhardness and yield strength of the alloy showed a trend of increasing and then decreasing, with the maximum of 220.9 HV and 626 MPa, respectively. The strengthening mechanisms of the nanoscale γ" and γ' phases in Cu-0.9Be-1.5Ni-0.04Y alloy were the shear mechanism and orowan mechanism, respectively. The electrical conductivity of the alloy increased and then remained more or less constant with increasing aging time, with a maximum of 39.78%IACS. The difference between the theoretical and measured values of the electrical conductivity of the alloy after aging at 480℃ for different times was less than 1%.