Thermodynamic properties of Zr<sub>2</sub>Al under high pressure from first-principles calculations

Abstract

The equations of state (EOS) and other thermodynamic properties of hcp structure Zr2Al are studied using first-principles calculations based on the plane wave pseudopotential density functional theory method within the generalized gradient approximation (GGA) for exchange and correlation. It is demonstrated that the ratio c/a of about 1.208 is the most stable structure for the hcp Zr2Al, which is consistent with the experimental data. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the dependences of relative volume V /V0 on pressure P, cell volume V on temperature T are successfully obtained. The variations of the Debye temperature Θ, the thermal expansion a , the Gruneisen parameter γ and the heat capacity Cv with pressure P and temperature T are investigated systematically in the ranges of 0–100 GPa and 0–1500 K. PACS: 65.40.-b; 81.05.Bx