Mechanisms of multiple V-doping in tuning mechanical and hydrogen storage properties of ZrCo alloys

Zirconium‑cobalt (ZrCo) alloy is a promising candidate for replacing uranium in tritium storage, yet its practical application is limited by disproportionation-induced capacity decay. This study explores the effect of multi-V doping on the configurations, mechanical properties, and hydrogen storage behavior of ZrCo alloys. Specifically, V dopants induce lattice contraction owing to their smaller atomic radius and exhibit an energetically preferred homogeneous dopant dispersion. Mechanistically, the substitutional strengthening effect is highly sensitive to the concentration and configuration of V dopants, with an optimal concentration of ∼11.1%. Furthermore, multiple-V doping can enhance the thermodynamic stability of hydrogen at OCT1 interstitial sites and lower the migration barrier for hydrogen diffusion, thereby facilitating hydriding/dehydriding kinetics in ZrCo alloys. For β -phase hydrides, it significantly improves the anti-disproportionation performance through a synergistic mechanism involving structural reduction of 8e site volume, thermodynamic destabilization of H(8e) occupation, and kinetic facilitation of H(8e) egress. These findings provide a theoretical basis for designing high-performance ZrCoalloys for advanced tritium storage applications. • The lattice volume gradually decreases with the increasing V substitution. • Substitutional strengthening depends on V concentration and configuration. • Multi-V doping thermally stabilizes H occupancy via strain & electronic effects. • Synergistic effects in V doping improves anti-disproportionation performance.