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The structure, electronic, elasticity and thermodynamic properties, phonon spectra of Be12V alloy under high temperatures and pressure are investigated by using first-principles calculations based on pseudo-potential plane-wave density functional theory method within using the generalized gradient approximation (GGA) and quasi-harmonic Debye model. The results show that the calculated equilibrium structural parameters of Be12V are in good agreement with the experiments. Under high pressure, the elastic constant of Be12V alloy increases with the increase of pressure. The all elastic constants satisfy the Born's mechanical criterion, indicating that Be12V crystal is dynamic stable under the applied pressure (0 GPa50 GPa), and the pressure has little effect on the electronic properties of Be12V. The phonon spectra and phonon density of states under pressure from 0 GPa to 50 GPa are presented for the Be12V and discussed the effects of pressure on some properties. By the quasi-harmonic Debye model, the thermodynamic properties of Be12V under high temperature and pressure were predicted, and the relationship of heat capacity, thermal expansion coefficient with temperature and pressure was obtained in the range of 0–1300 K and 0–20 GPa, respectively.

The structural, elastic, and thermodynamic properties of cubic-Fe2TiAl under high temperatures and pressures are investigated by performing ab initio calculation and using the quasi-harmonic Debye model. Some ground state properties such as lattice constant, bulk modulus, pressure derivative of the bulk modulus, and elastic constants are in good agreement with the available experimental results and theoretical data. The thermodynamic properties of Fe2TiAl such as thermal expansion coefficient, Debye temperature, and heat capacity in ranges of 0 K—1200 K and 0 GPa—250 GPa are also obtained. The calculation results indicate that the heat capacities at different pressures all increase with temperature increasing and are close to the Dulong—Petit limit at higher temperatures, Debye temperature decreases with temperature increasing, and increases with pressure rising. The cubic-Fe2TiAl is stable mechanically under 250 GPa. Moreover, under lower pressure, thermal expansion coefficient rises rapidly with temperature increasing, and the increasing rate becomes slow at higher pressure.