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

摘要

The mechanical and thermodynamic properties of ZrAl2 alloy under high pressure are investigated by firrst-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 GPa. By analyzing the value of B/G and Poisson's ratio upsilon which are correlated with the ductility and brittleness of material, we found that ZrAl2 belongs to brittle material at pressure of 0-70 GPa and will change from brittleness to ductility at 70 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 Theta(D), heat capacity C-p and thermal expansion alpha, are discussed using the quasi-harmonic Debye model. We noted that the Debye temperature Theta(D) is mainly dependent on the pressure and the effect of temperature on the heat capacity C-p is more important than the applied pressure.