First-principles calculations on finite temperature elastic properties of B2-AlRE (RE = Y, Tb, Pr, Nd, Dy) intermetallics

Abstract

a b s t r a c tWe have investigated the finite temperature elastic properties of AlRE (RE ¼ Y, Tb, Pr, Nd, Dy) with B2-type structures from first principles. The phonon free energy and thermal expansion are obtained from the quasiharmonic approach based on density-functional perturbation theory. The static volumedependent elastic constants are obtained from energyestrain functions by using the first-principles total-energy method. The comparison between our predicted results and the ultrasonic experimental data for a benchmark material Al provides excellent agreements. At T ¼ 0 K, our calculated values of lattice equilibrium volume and elastic moduli of our calculated AlRE (RE ¼ Y, Tb, Pr, Nd, Dy) intermetallics agree well with the previous theoretical results. The temperature-dependent elastic constants exhibit a normal behavior with temperature, i.e., decrease and approach linearity at higher temperature and zero slope around zero temperature. Furthermore, the anisotropy ratio and sound velocities as a function of temperature have also been discussed.

Elastic and thermodynamic properties of the Ti2AlNb orthorhombic phase from first‐principles calculations

“…With the development of temperature‐dependent mechanical theories and computational materials science, first‐principles calculations have been widely used to predict the mechanical and thermodynamic properties at finite temperature . The variation of the temperature‐dependent elastic properties was considered mainly to be due to the temperature‐dependent volumes, which can be predicted successfully by using density functional theory (DFT) combined with quasi‐harmonic approximation (QHA).…”