Theoretical study of the effects of alloying elements on the strength and modulus of β-type bio-titanium alloys

Titanium alloys are favorable implant materials for orthopedic applications, due to their desirable mechanical properties and biochemical compatibility (or bio-inertness). However, current bio-titanium alloys still possess too high an elastic modulus compared with that of the bone, which can lead to premature failure of the implant. Here, a theoretical methodology for the design and development of low modulus Ti alloys and/or structures is provided by means of electronic structural calculations using the discrete variational cluster method (DVM). The preliminary study concentrated on two β-Ti atomic clusters consisting of 15, and 27 atoms, respectively. The binding energies between titanium and various alloying atoms within the clusters were first calculated, from which strength and modulus were then estimated. The results of the calculation suggested that Nb, Mo, Zr and Ta were suitable alloying elements for β-type titanium alloys, capable of enhancing the strength and reducing the modulus of the materials.