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. • V addition delays θ’ precipitation in Al-5Cu alloys. • V addition reduces the coarsening rate of precipitates at 300 °C. • A small addition of 0.5 wt.% V improves yield strength after thermal exposure by 58%. • V offers a cost-effective thermal stabilizer in Al-Cu alloys.