Abstract:The microstructure, tensile properties, Charpy impact toughness and corrosion resistance of Ti-6Al-3Nb-2Zr-1Mo-xTa (x=0, 0.5, 1.0, 3.0 and 5.0) alloys were investigated. The results indicated that, except for the lamellar structure Ti-6Al-3Nb-2Zr-1Mo-5Ta alloy, the bimodal structure was obtained in Ti-6Al-3Nb-2Zr-1Mo-xTa (x=0, 0.5, 1.0 and 3.0) after hot deformation during α+β region. The results of XRD pattern and selected area electron diffraction indicate that, no new phase was indentified after adding Ta element although the XRD peaks of both α and β phases shift toward the low angle side as the increasing of Ta content. For the bimodal structure Ti-6Al-3Nb-Zr-1M0-xTa alloy, the yield strength (YS), ultimate tensile strength (UTS) and microhardness increase due to the increasing of molybdenum equivalent (Mo[eq]). The impact absorb energy dependence on the Ta content is opposite to YS, UTS and microhardness, and their value are consistent with the area of shear lip region on the impact fracture surface. when the Ta content is more than 1.0 wt%, the resistance to corrosion of Ti-6Al-3Nb-2Zr-1Mo-xTa alloys decrease due to the increasing of standard balancing potential difference between α and β phase as the Ta content increasing. After potentiodynamic polarization tests, the samples surface area are covered with lots of corrosion pits, which are mainly distributed in the αp grain interior and α/β interface. Combining YS, impact toughness and corrosion performance, Ti-6Al-3Nb-2Zr-1Mo-1Ta alloy exhibits the best compatibility, suggests its promising potential for marine applications.