First-principles study of Be content on the structural and mechanical properties of TiAl alloy

The effect of large range Be addition (0–20.83 at.% Be) on the lattice distortion as well as dislocation mobility in TiAl was examined by density functional theory (DFT) calculations. The calculation of the formation energy showed that Be obviously decreases the phase stability. The shearing energy barrier of the TiAl alloys with Be solute is weakened by stages during the static shear deformation process. Further analysis of the partial density of states reveals that the physical origin is closely related with the content and atomic configuration of Be. The weakening effect of shearing energy barrier at the first stage occurs because of the decrement in the phase stability, which is induced by low Be addition related long-range alloying effect. The notable weakening effect at the second stage originates from the reduced p–d and enhanced p–p bonding, which is induced by large Be addition related short-range alloying interaction.