Theoretical predictions of thermodynamic and mechanical properties of TMAl (TM = Ni, Fe, Ti)

In this work, the thermodynamic properties of TMAl (TM = Ni, Fe, Ti) compounds were studied at a temperature of 0–1000 K and a pressure of 0–40 GPa through first principles based on density functional theory. The thermal expansion coefficient α and Debye temperature (θD) is sensitive to temperature and pressure. The single crystal elastic constants and polycrystalline elastic properties were calculated by the stress–strain method and Voigt–Reuss–Hill approximation. By analyzing the elastic anisotropy index (AU, Acomp, Ashear, and A1, A2, A3) and the surface structure and projection of Young’s modulus, the anisotropy of TMAl compounds was discussed. In addition, the sound velocities, anisotropy of the sound velocities and the electronic structures were also discussed.