TY - JOUR
T1 - Thermodynamic and mechanical properties of lanthanum-magnesium phases from density functional theory
AU - Wróbel, J.
AU - Hector, L. G.
AU - Wolf, W.
AU - Shang, S. L.
AU - Liu, Z. K.
AU - Kurzydłowski, K. J.
N1 - Funding Information:
This study was partly supported by the European Union in the framework of European Social Fund through the Warsaw University of Technology Development Program which is administrated by the Center for Advanced Studies. The TERMET project (no. POIG.01.01.02-00-097/09) financed by the European Regional Development Fund within the Innovative Economy Operational Program is also acknowledged for supporting this work. SLS and ZKL acknowledge the support of the U.S. National Science Foundation with the Grant No. DMR-1006557 . The authors wish to acknowledge the staff of the High Performance Computing Center at General Motors. Additional computational resources, networking, and support were provided by GM Information Systems and Services.
PY - 2012/1/25
Y1 - 2012/1/25
N2 - Thermodynamic and mechanical properties of the six known phases in the La-Mg phase diagram, viz. LaMg, LaMg2, LaMg3, La 5Mg41, La2Mg17, and LaMg 12, and their elemental antecedents, Mg and La, are computed with density functional theory (DFT) using the PBE and PBEsol exchange-correlation functionals. Phase stability analyses show that both LaMg2 and La5Mg41 are metastable at low temperatures which is consistent with experiments and vibrational spectra. We generalize an existing approach for computing the crystallographic dependence of Young's modulus and Poisson's ratio, which is presently limited to cubic systems, to address any space group symmetry using 0 K elasticity tensor components (Cij) from DFT. Isothermal and isentropic Cij(T) are computed with the quasiharmonic approximation (QHA) as are the linear thermal expansion of the cubic compounds, the average linear thermal expansion for the non-cubic compounds, the bulk modulus, and the constant pressure heat capacity. A critical comparison of theoretical results from the PBE and PBEsol functionals is made with available experimental data.
AB - Thermodynamic and mechanical properties of the six known phases in the La-Mg phase diagram, viz. LaMg, LaMg2, LaMg3, La 5Mg41, La2Mg17, and LaMg 12, and their elemental antecedents, Mg and La, are computed with density functional theory (DFT) using the PBE and PBEsol exchange-correlation functionals. Phase stability analyses show that both LaMg2 and La5Mg41 are metastable at low temperatures which is consistent with experiments and vibrational spectra. We generalize an existing approach for computing the crystallographic dependence of Young's modulus and Poisson's ratio, which is presently limited to cubic systems, to address any space group symmetry using 0 K elasticity tensor components (Cij) from DFT. Isothermal and isentropic Cij(T) are computed with the quasiharmonic approximation (QHA) as are the linear thermal expansion of the cubic compounds, the average linear thermal expansion for the non-cubic compounds, the bulk modulus, and the constant pressure heat capacity. A critical comparison of theoretical results from the PBE and PBEsol functionals is made with available experimental data.
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U2 - 10.1016/j.jallcom.2011.09.085
DO - 10.1016/j.jallcom.2011.09.085
M3 - Article
AN - SCOPUS:80655146782
SN - 0925-8388
VL - 512
SP - 296
EP - 310
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
IS - 1
ER -