Structural, elastic and mechanical properties of Hf-doped TiAl2 and α-TiAl3 intermetallic compounds: first-principle calculations

In this work, structural, elastic and mechanical properties of Hf-doped TiAl2 and α-TiAl3 alloys up to 4 wt. % in increments of 0.5 wt. % have been investigated by first-principle calculations within density functional theory for the first time. The structural models have been established using the virtual crystal approximation (VCA) method. Theoretical calculations indicate that calculated lattice constants agree well with previous studies. The formation energies of the alloys having more than 2 wt.% Hf concentration are lower than pure TiAl2 and α-TiAl3 alloys. Obtained elastic constants and elastic values indicate that Hf doping improves mechanical properties. Ductility has been improved when Hf addition is greater than 2.5 wt. % for α-TiAl3 alloy and 3.5 wt. % for TiAl2 alloys as compared to the pure states of these alloys. Further, the machinability index has been calculated. Graphical abstract