First principles studies on structural, elastic and electronic properties of new TiMoNbZr alloys for biomedical applications

Highlights: • Effect of Nb and Zr additions on properties of four β-TiMo alloys is examined. • Phases, Young's modulus and charge densities were sensitive to the additions. • New Ti6Mo4Nb4Zr having E = 32.2 GPa, due to softening of C′ and C₄₄ shear moduli • The low-elastic modulus of the alloys will be useful in orthopaedic applications. • Creates a paradigm for future studies on specific chemical alloying. Stress shielding phenomenon has become a major drawback to the use of metallic biomaterials for orthopaedic implants applications. In this study, a TiMo(Nb, Zr and Nb + Zr) alloy system was investigated to design and develop novel low elastic Young's modulus Ti based alloy for implant application. The development and application of predictive modelling and simulation are transforming the materials engineering discovery process. To this end, ab initio calculation was used to evaluate the effects of composition on structural, elastic and electronic properties of the materials. The data obtained from both theory and experiment were analysed and compared with each other. Notable findings include low elastic Young's modulus values of 70.2 GPa, 80.6 GPa, 76.5 GPa, 59.1 GPa and 32.3 GPa for the Ti6Mo6Zr, Ti6Mo6Nb, Ti6Mo6Nb2Zr, Ti6Mo5Nb3Zr and Ti6Mo4Nb4Zr alloys, respectively ascribed to the unique elastic softening of their C′ and C₄₄ shear moduli. The consistency in both results is discussed in terms of the sensitivity of the physical and electronic properties to the alloying additions. Thus, the result indicates the approach can enhance the reduction of elastic Young's modulus of metallic biomaterials for replacing some commonly used high modulus materials and prevent stress shielding in orthopaedic implants.