A high strength and elastic carbon containing near-α Ti alloy prepared by hot isostatic pressing process

In this paper, we report a near-α Ti alloy with tensile fracture strength and Young's modulus of 1072 MPa and 131 GPa, respectively. This alloy was compositionally designed by adding 0.4 wt% carbon to conventional Ti-6.5Al-2Sn-3Zr-1.5Mo-1.5Nb-0.4Si-0.2Y near-α Ti alloy. It has been found that the microstructure of as-cast alloy is characterized by lamellar α plates with rod-like secondary carbides along prior-β grain boundaries. After hot isostatic pressing processed, the carbides were mostly dissolved into matrix, the shape of carbides was changed from coarse and long rods to fine ellipsoid particulates. Besides, the carbon in solid solution is speculated to have the effect on the refinement of α2 phase. It is the solid solution strengthening, refinement of α2 phase and carbides and the elimination of cast defects that result in superior strength and elastic modulus to conventional Ti alloys. This work has implication to the application of Ti alloys for the aeronautics components which bear large bending moment.