Effect of β-Stabilizing Transition Elements on Elastic Modulus of Ti-M Systems

Abstract

New titanium alloys with a low elastic modulus have been developed for biomedical applications to avoid the stress shielding effect of the artificial prosthesis. The newly developed alloys contained the transition elements like Nb, Ta, Zr which were non-cytotoxicity elements. These elements produced β, ω, and α'' phases with heat treatment conditions in titanium alloys and determined the elastic modulus of the alloys. However, the clear mechanism of the low elastic modulus alloys has not been known. In the present paper, the total energy and elastic modulus of β and α'' phases were calculated using a first principle calculation employing the generalized gradient approximation (GGA). The mechanism of the low elastic modulus was discussed with calculated values.

Effect of Al and Nb on the trigger stress for stress-induced martensitic transformation during tensile loading in Ti–Al–Nb alloys

“…If E M < E ␤ , the contribution of the above term is favourable for the transformation, whereas if E M > E ␤ , the contribution of this term can become resistive for the transformation. Earlier studies [17,18] on variation of modulus as a function of Nb content indicate that elastic modulii of martensite ␣ and ␤ are a strong function of Nb content in Ti-Nb system. It is, however, extremely difficult to measure the modulus of the ␣ plates, even by using sophisticated techniques such as nanoindentation, because of their fine size.…”