Effect of Al on Microstructure and Properties of Cu−Be−Ni Alloy Processed by Thermo-Mechanical Treatment
The microstructural evolution and property response of Cu−0.3Be−2.0Ni and Cu−0.3Be−2.0Ni−0.2Al alloys subjected to solution treatment at 950 °C for 30 min, 70% cold rolling, and aging at 450 °C for 60 min were systematically investigated. The baseline Cu−0.3Be−2.0Ni alloy precipitates predominantly the Ni−Be phase with a transformation sequence of γ″→γ′→γ, whereas the Al-modified alloy exhibits co-precipitation of Ni3Al and nanoscale Be−Ni phases. This synergistic precipitation yields a hardness of HV 268, yield strength of 824 MPa, tensile strength of 881 MPa, elongation of 9%, and electrical conductivity of 47% IACS in the Cu−0.3Be−2.0Ni−0.2Al alloy, compared to HV 238, 785 MPa, 840 MPa, 10%, and 50% IACS for the Al-free counterpart. Relative to conventional aging, thermo-mechanical treatment increases hardness by 13% and conductivity by 6.8% in the Al-containing alloy, while the Al-free alloy shows a 6% hardness increase with marginal conductivity improvement. The co-precipitation mechanism effectively compensates for the strength loss typically associated with reduced Be content, demonstrating a viable pathway for low-cost, high-performance Cu−Be alloys.