Pressure-dependence of mechanical and thermodynamic properties of Al₃Zr in Al–Li alloys from first-principles calculations

ABSTRACT

The pressure-dependence of mechanical, electronic and thermodynamic properties of metastable (L1₂ type) and stable (D0₂₃ type) Al₃Zr precipitations in Al–Li alloys were investigated by employing the first-principle calculations. The calculated equilibrium parameters are in good agreement with experimental and previous calculation results available. Elastic properties including bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio and universal anisotropic index are determined by Voigt–Reuss–Hill approximation. It is found that for both phases, external pressure can improve the mechanical stability, ductility and plasticity. The electronic structures are determined to reveal the bonding characteristics of both phases. In addition, both phonon method and Gibbs program have been proposed to predict thermodynamic properties of two phases. All of these results can help to have a better understanding of the physical and chemical properties of Al₃Zr precipitations in Al–Li alloy. And can offer theoretical guidance for the weight lighting, energy conservation and emissions reduction in the design of new aluminium alloys.

KEYWORDS:

• First-principle calculations
• mechanical properties
• thermal properties
• Al–Li alloys

Additional information

Funding

This work was supported by the National Key Research and Development Program of China [grant numbers 2017YFB1103701, 2016YFB0701201, 2016YFB0701203], the Natural Science Foundation of China [grant numbers 51761037, 51671101, 51464034], the Natural Science foundation of Jiangxi Province [grant numbers 20172BCB22002, 20171BCD40003, 20161BAB206128], the Science and Technology Key Research Plan in Jiangxi Educational Department [grant numbers GJJ150010, GJJ150038], the funding of Key Laboratory of Superlight Materials & Surface Technology (Harbin Engineering University) Ministry of Education.