Article ID Journal Published Year Pages File Type
10644375 Calphad 2005 9 Pages PDF
Abstract
Despite numerous investigations, all previous efforts on thermodynamic modeling of Al-Mg have suffered from inaccurate energetics of solid phases. In the present work, the first-principles calculations were performed using VASP based on the pseudo-potentials and a plane wave basis set. The enthalpies of formation of the ε-Al30Mg23 phase, end-members of the γ-Al12Mg17 phase, and three laves phases at the Al2Mg composition were calculated at 0 K. Special quasi-random structures (SQS's) were used to mimic random fcc and hcp solution phases, and their enthalpies of mixing were predicted by first-principles calculations. The Al occupancy in the γ-Al12Mg17 phase is also studied by first-principles calculations, and the sublattice model (Mg)5(Al,Mg)12(Al,Mg)12 was verified as the proper model to describe the γ-Al12Mg17 phase. The complete thermodynamic description of the Al-Mg binary system was evaluated by this combined CALPHAD/first-principles calculations approach and was shown to be in a good agreement with experimental data with better defined energetics of solid phases than the previous modeling.
Related Topics
Physical Sciences and Engineering Materials Science Materials Science (General)
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