Corrosion and Wear Properties of Low-Modulus TiZrNb-Based Complex Concentrated Alloys under Simulated Physiological Conditions

Titanium (Ti) and its alloys have evolved through multiple generations to possess enhanced biomedical performance. However, challenges such as stress shielding, low yield strength, and inadequate corrosion resistance persist in conventional Ti-based alloys. In this study, we explore the complex concentrated alloy (CCA) approach to develop two novel Ti-Zr-Nb alloys: Ti₅₀Zr₃₅Nb₁₅ and Zr₅₀Ti₃₅Nb₁₅. These compositions were designed using CALPHAD-based phase stability predictions based on nontoxic lightweight approach and fabricated via vacuum arc melting, yielding a single-phase body-centered cubic (BCC) structure with large equiaxed grains. The CCAs exhibit higher hardness (∼1.95 GPa) and lower elastic modulus (∼99-102 GPa) than traditional Ti alloys, making them more compatible with human bone. Electrochemical analyses, performed under simulated physiological conditions (Hanks' solution and at 37 °C) confirm superior corrosion resistance for both the CCAs. Tribological studies (performed in Hanks' solution and at 37 °C) reveal improved wear behavior, with the formation of smeared patches reducing material loss and enhancing surface stability. The combination of high hardness, low modulus, excellent corrosion resistance, and favorable wear characteristics under simulated physiological conditions, makes these CCAs promising candidates for next-generation orthopedic and dental implant applications.