Cost-effective alloying with vanadium for enhanced thermal stability of Al–5Cu alloys

Al–Cu alloys have attracted attention for their high performance among commercial aluminum alloys, retaining strength up to 200 °C owing to precipitation hardening. This study examines the influence of vanadium additions on the precipitation and coarsening behavior of θ′ precipitates in Al–5Cu alloys. The addition of V increased the activation energy for θ′ precipitation from 58.39 kJ/mol to 86.20 kJ/mol, effectively retarding precipitation kinetics by reducing Cu diffusivity through strong vacancy binding. Furthermore, the coarsening rate of θ′ precipitates at 300 °C was reduced in the V-containing alloy. As a result, the yield strength and tensile strength of the V-containing alloy increased by 16–17 % in the peak-aged condition, and by 32–58 % after thermal exposure at 300 °C. Although V does not stabilize θ’ precipitates through interfacial segregation, it provides a cost-effective alternative for enhancing thermal stability through a diffusion-controlled mechanism. These results contribute to the development of Al–Cu alloys with improved performance and enhanced microstructural stability.