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

Titanium alloys are favorable implant materials for orthopedic applications , due to their desirable mechanical properties and biochemical compatibilit y (or bio-inertness). However, current bio-titanium alloys still possess to o 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 provid ed by means of electronic structural calculations using the discrete variat ional cluster method (DVM). The preliminary study concentrated on two beta- Ti atomic clusters consisting of 15, and 27 atoms, respectively. The bindin g 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 suita ble alloying elements for beta-type titanium alloys, capable of enhancing t he strength and reducing the modulus of the materials. (C) 1999 Elsevier Sc ience S.A. All rights reserved.