First-principles investigations on the phase stability, elastic and thermodynamic properties of Zr–Al alloys.

In this paper, we employ first-principles methods based on electronic density functional theory (DFT) to investigate the phase stability, elastic and thermodynamic properties of Zr–Al binary substitutional alloys which are Zr3Al, Zr2Al, ZrAl, ZrAl2 and ZrAl3. By analyzing the elastic constants and enthalpy of formation, those phases both satisfy the generalized stability criteria and the results show that ZrAl2 is the most stable. Due to high bulk modulus B, shear modulus G and Youngs modulus Y, ZrAl2 also possesses excellent mechanical properties. Moreover, it is expected that there will be covalent bonding between Zr and Al atom in ZrAl2 compound, which is confirmed by the electronic structure and the differences of charge density discussions. In the end, based on the calculated elastic modulus, the elastic wave velocity, Debye temperature ΘD and specific heat CV are discussed. As a result, ZrAl3 possesses the highest Debye temperature and sound velocity, meaning a larger associated thermal conductivity and higher melting temperature [ABSTRACT FROM AUTHOR]