An ab initio investgation of ideal tensile and shear strength of TiVNbMo high-entropy alloy

We investigate the elastic constants, ideal tensile strength, and ideal shear strength of single-phase TiVNbMo high entropy alloy (HEA) via a combination of the density functional theory (DFT) with the vitural lattice approximation (VCA). The coherent potential approximation (CPA) was employed to confirm the reliability of VCA for TiVNbMo by comparing the calculated elastic moduli. The tensile strength σ of TiVNbMo is about 10 GPa at the strain ε=0.14 along the orthorhombic path, while σ=19 GPa at the strain ε=0.18 along the tetragonal path. The ideal shear strength is σ=8.5 GPa at ε=0.20 under {110}<111> shear, while σ=1.25 GPa at strain ε=0.10 for {211}<111> shear. The results imply that the alloying formation of TiVNbMo does not enhance the inherent ductility, while the inherent strengh is also low compared to the pure metals V, Nb and Mo.