Interstitial boron in tungsten: modeling of lattice tetragonality

In the framework of linear density functional theory we study conditions of formation of W-B solid solutions. On the basis of the coherent potential approximation, we consider ordering tendencies, study electronic structure and provide total energy calculations. We present the energetics and electronic structure changes of a homogeneous axis deformation (Bain transformation) in W-B solid solutions. Our modeling shows that an increase of the atomic fraction of boron leads to a decrease of the number of states at the Fermi level N(EF), thus decreasing the metallic character in the system. At the same time for boron concentrations higher than 0.15 we find once more an increase of N(EF). We demonstrate the behavior of the total density of states (DOS) in the vicinity of the Fermi energy with (001) displacive transformation and see drastic changes in the DOS for tetragonality c/a changes from 1 to 1.4.