Enhancing Titanium Alloys with Fe Microalloying: A Review

Microalloying strategy can effectively enhance the overall performance of commercial pure titanium and TC4 alloy, expanding their applications in the petrochemical, aerospace, and biomedical fields. Iron, as a β-stabilizing and strengthening element, decreases the β transus temperature and refines as-cast microstructure of pure Ti and TC4 alloy. The effect of Fe microallying on microstructural evolution and performances of pure Ti and TC4 alloy have been summarized and analyzed from the perspectives of the first-principles calculations on the effects of multi-alloying elements on phase transformations, changes in microstructural morphology, variations in mechanical properties and fracture toughness. The strengthening factors of Fe microalloying is 223 MPa/wt.% for pure titanium and 481 MPa/wt% for TC4 alloy, which is resulted from the effective grain refinement and strong hindrance of crack propagation by the Fe-enriched β films at the phase boundaries.