The many particle electron interaction in DFT is captured by an universal exchange-correlation functional for which a wide choice of approximations have been proposed. In the present calculations, we employ the generalized gradient approximation within the Perdew-Burke-Ernzerhof parametrization. The electron-ion interactions are described by pseudopotentials (PPs) using the plane-wave basis projector augmented-wave (PAW) approach . The PPs used in our calculations are the set provided with the respective VASP distributions. We chose PPs treating s and p semi-core states as valence states in the cases of V, Nb, and p semi-core states as valence states in case of Ta. These are the VASP-developer-recommended potentials for DFT calculations, as outlined in . The electronic densities and potentials are expanded in planewaves with an energy cutoff of 350 eV. A 2 × 2 × 2 k-mesh and the VASP precision setting "normal" were used. Thus, such chosen mesh and cutoff energy guarantee accuracy of the calculation by dropping the error below 4 meV per atom. Methfessel-Paxton smearing of electronic occupations near the Fermi level were introduced with a broadening of 0.2 eV. The alloys are modeled by supercells containing 128 randomly distributed atoms. In the initial structure, the atoms occupy perfect BCC lattice cites. These initial structures were optimized until an energy change of less than 10 -4 eV was achieved and forces acting on the atoms do not exceed 10 -2 eV/Å.