Partitioning Behavior of Nb, Ta, and Zr in Fully Lamellar γ/α ₂ Titanium Aluminides and Its Effect on the Lattice Misfit and Creep Behavior

Previous investigations revealed that Nb, Ta, and Zr improve the creep properties of fully lamellar titanium aluminides significantly. The enhanced can originate from different potential effects alloying elements. Herein, elements’ partitioning between α2-Ti3Al γ-TiAl their influence on lattice parameters ternary Ti–44Al–5X (X = Zr) alloys are investigated in comparison with a binary Ti−44Al alloy by atom probe tomography high-energy X-ray diffraction. Ta partitions nearly equally α2 γ, Nb accumulates slightly enriches strongly γ. As all elements have larger radius than Ti, stronger to γ decreases misfit more. synchrotron measurements show clear resulting misfits γ- ⟨ 110 ] 101 direction as well c/a ratio. In accordance theoretical calculations based behavior, Ti–44Al–5Ta over Ti–44Al–5Nb Ti–44Al–5Zr. ratio A correlation measured Ti−44Al−5X primary strains is found, strain decreasing misfit.