Ab initio pseudopotential calculations on the effect of Mn doped on lattice parameters of L10 TiAl

Effects of ternary alloying with Mn on the electronic structure and lattice geometry of TiAl compounds are studied using ab-initio pseudopotential method combined with the technique of atomic relaxation. The calculation are preformed on three supercells with different percentage content of Mn. Fine k-point mesh and cutoff energy are chosen to ensure the precision and numerical convergence. Our results show that the effect of Mn atom on lattice parameters of TiAl is strong and nonuniform. The dopant of Mn can cause lattice contraction of TiAl along its c-axes. As a result, the lattice tetragonality of TiAl, which is known to relate with the intrinsic brittleness, can be reduced. The electronic structure of supercells illustrates that such a contraction is primarily contributed by the strong charge accumulation along the first nearest neighbors in the Ti–Mn directions.