The mechanical and thermodynamic properties of ZrAl2 under pressure from first-principles investigation

Abstract

The mechanical and thermodynamic properties of ZrAl2 alloy under high pressure are investigated by first-principles based on the density functional theory. Due to all the elastic constants of ZrAl2 alloy satisfy generalized stabilities criteria, ZrAl2 is mechanically stable under pressure up to 100[Formula: see text]GPa. By analyzing the value of B/G and Poisson’s ratio [Formula: see text] which are correlated with the ductility and brittleness of material, we found that ZrAl2 belongs to brittle material at pressure of 0–70[Formula: see text]GPa and will change from brittleness to ductility at 70[Formula: see text]GPa. Combining with high bulk modulus B and shear modulus G, the mechanical of properties will be improved under high pressure. Moreover, the thermodynamic properties, such as the Debye temperature [Formula: see text], heat capacity [Formula: see text] and thermal expansion [Formula: see text], are discussed using the quasi-harmonic Debye model. We noted that the Debye temperature [Formula: see text] is mainly dependent on the pressure and the effect of temperature on the heat capacity [Formula: see text] is more important than the applied pressure.