Effect of Si and Ti5Si3 on the adhesion at the α-Al2O3/γ-TiAl interface and oxygen diffusion in the alloy

The effect of silicon and Ti 5 Si 3 films on the adhesion properties of the α-Al 2 O 3 /γ-TiAl interface and oxygen diffusion in TiAl was studied using the projector augmented-wave method within density functional theory. It was shown that the formation of intermediate silicide layers at the oxide–alloy interface can lead to a significant decrease in the oxygen diffusion coefficient. At the same time, adhesion at the oxide–silicide interface remains high, while for the silicide–alloy interface, the values of ∼2.26–2.80 J/m 2 typical for interfaces with metallic and metal-covalent bonds were obtained.