Superior mechanical property of Ti-Fe-O material via doping low content iron oxide in pure Ti

This work focused on simultaneously harnessing iron (Fe) and oxygen (O), two of the most powerful stabilizing elements and strengtheners for α + β Ti alloys. Here we integrated alloy design with field-assisted sintering technology (FAST) and hot-rolling (HR) to demonstrate a series of Ti-Fe-O compositions that exhibited outstanding mechanical properties. The cost-effective iron oxide powder (Fe₂O₃) was innovatively employed as a precursor to completely dissolve into pure Ti matrix. The results revealed that the content of Fe and O was precisely controlled, which achieved an ultra-high tensile strength of close to 1012 MPa, at no expense of elongation-to-failure (∼31 %), with incorporating merely 0.71 wt% Fe₂O₃. The increment in the Fe content was effective in increasing the β-Ti phase volume fraction and refining the primary α (α_p) Ti grains, meanwhile the O promoted the precipitation of acicular secondary α phase (α_s). The dominant strengthening factors for the Ti-Fe-O alloys were grain refinement, β-Ti hard phase dispersion, and solid solution strengthening. In particular, α_s twinning behavior was observed in Ti-0.71 wt% Fe₂O₃ sample that is favorable to excellent ductility. These findings provided a novel approach to designing low-cost and high-performance Ti alloys by using cheap iron oxide and paved a new way for potential industry use.