Stability and mechanical properties of Ti-Nb-Ta ternary alloys

Abstract First-principles calculations were conducted to explore the influence of Ta incorporation on the stability, mechanical properties, and electronic structure of Ti 50 Nb (50− x ) Ta x (0≤ x ≤50, x at.%) alloys. The results indicate that Ta addition increases lattice parameters and formation energy while maintaining structural stability across all compositions. Elastic constants confirm mechanical stability and reveal increasing stiffness with higher Ta content. Projected density of states (PDOS) analysis reveals that Ta enhances metallic bonding and alters the electronic environment near the Fermi level, which aligns with the observed mechanical improvements, including higher stiffness, rigidity, and hardness. The calculated Young's modulus of 39-72 GPa offers better compatibility with bone than conventional implants, with Poisson's ratio confirming sufficient ductility. These findings suggest that these alloys hold potential for biomedical applications, offering a balance between mechanical performance and structural stability.