Elastic properties of the O phase in Ti-Al-Nb alloys

Room-temperature elastic properties of the O phase in the Ti-Al-Nb system have been studied using resonant ultrasound spectroscopy (RUS). The isotropic elastic constants of the O-phase in the polycrystalline ternary alloys Ti-27Al-20Nb and Ti-27Al-25Nb were obtained. The results show that the room-temperature bulk, Young's, and shear moduli of these alloys are around 120, 130 and 50 GPa, respectively. The room temperature Poisson's ratios are about 0.3. The Debye temperatures, θD, were estimated to be approximately 410 K. The effect of alloying Ti-27Al-20Nb with the transition metal elements Mo, Ta, Zr and V, and with silicon, on the elastic properties has been investigated. The variation of the Young's modulus with temperature has been determined for ternary alloys and quaternary alloys using compression tests