TY - JOUR
T1 - Contribution of first-principles energetics to Al-Mg thermodynamic modeling
AU - Zhong, Yu
AU - Yang, Mei
AU - Liu, Zi Kui
N1 - Funding Information:
This work is supported by the NSF CAREER Award under the grant DMR-9983532 and NSF ITR project under the grant DMR-0205232. First-principles calculations were carried out on the LION clusters at the Pennsylvania State University supported in part by the NSF grants (DMR-9983532, DMR-0122638, and DMR-0205232) and in part by the Materials Simulation Center and the Graduate Education and Research Services at the Pennsylvania State University. The authors would also like to acknowledge Mr. Dongwon Shin for providing hcp SQS structures and Ms. Sara Prins for her comments and careful reading of the manuscript.
PY - 2005/12
Y1 - 2005/12
N2 - 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.
AB - 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.
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U2 - 10.1016/j.calphad.2005.08.004
DO - 10.1016/j.calphad.2005.08.004
M3 - Article
AN - SCOPUS:27644455499
SN - 0364-5916
VL - 29
SP - 303
EP - 311
JO - Calphad: Computer Coupling of Phase Diagrams and Thermochemistry
JF - Calphad: Computer Coupling of Phase Diagrams and Thermochemistry
IS - 4
ER -