First-principle calculation on mechanical and thermal properties of B2-NiSc with point defects

摘要

Using the first-principles plane-wave pseudo-potential method based on density functional theory, the effect of vacancy and anti-position defect on the mechanical and thermal properties of B2-NiSc intermetallics were discussed in detail. Several parameters, such as the shear modulus, bulk modulus, modulus of elasticity, C_(11)-C_(12), the Debye temperature and Poisson's ratio, have been calculated to evaluate the effect of vacancy and anti-position defect on the hardness, ductility and thermal properties of B2-NiSc intermetallics. The results show that V_(Ni), Sc_(Ni), V_(Sc) and Ni_(Sc) the four point defects all make the crystal hardness decrease and improve plasticity of B2-NiSc intermetallics. The entropy, enthalpy and free energy of V_(Ni), Sc_(Ni), V_(Sc) and Ni_(Sc) are monotonously changed as temperature changes. From the perspective of free energy, Ni_(Sc) is the most stable, while Sc_(Ni) is the most unstable. Debye temperature of NiSc intermetallics with four different point defects shows V_(Ni), Sc_(Ni), V_(Sc) and Ni_(Sc) the four point defects all reduce the stability of B2-NiSc intermetallics.