Effect of pressure on mechanical and thermodynamic properties of Al<sub>7</sub>Cu<sub>2</sub>Fe phase

Abstract

The band structures and elastic anisotropy of Al₇Cu₂Fe phase under various pressures are studied by using the Vienna ab-initio simulation package (VASP) based on density functional theory. The results show that Al₇Cu₂Fe phase is still metallic in the pressure range of 0 to 50 GPa and the pressure can improve the expansion of atomic orbital in the energy band. The elasti anisotropy in (100) and (010) planes of Al₇Cu₂Fe phase enhances with the increase of pressure, while the elasti anisotropy in (110) planes shows a fluctuating upward trend from 0 GPa to 50 GPa. Based on the quasi-harmonic Debye model, the changes of bulk modulus (B), Debye temperature (Θ_{<italic>D</italic>}), heat capacity (C_v and C_p) and thermal expansion coefficient (α) of Al₇Cu₂Fe phase with pressure and temperature are studied. The effects of applied pressure and temperature on thermodynamic properties of the Al₇Cu₂Fe phase is opposite. The values of B and Θ_{<italic>D</italic>} decrease with temperature and increase with the pressure. In addition, the variation trends of C_v, C_p and α under pressure and temperature are basically the same.