Calculation of electric field effects on the Gibbs free energy of the Al-Li-Mg alloy

Based on the Thomas-Fermi model, the calculation methods of the monatomic Gibbs free energy were found. The interior potential boundary condition under electric field was defined. The calculation methods of Gibbs free energy for the monatomic, compound, and solid solution with electric field were set up. Under the influence of electric field, the Gibbs free energy of Al is the most sensitive, followed by those of Li and Mg. At the solution temperature the Gibbs free energies of Al₃Li and its elements under electric field are not symmetrical about the zero point of electric field, whereas at the aging temperature their values are symmetrical about the zero point of electric field. At the solution temperature near the zero point of electric field, the Gibbs free energy of Al₃Li is higher than that of Al-2.14%Li. And at 460 K the Gibbs free energy of Al₃Li is lower than that of Al-2.14wt.%Li under electric field. The Gibbs free energy of 1420 alloy decreases from both sides of electric field to the zero point at the aging temperature.