Entity

Time filter

Source Type


Duan Y.-H.,Kunming University of Science and Technology | Duan Y.-H.,Key Laboratory of Advance Materials in Rare and Precious and Nonferrous Metals | Hu W.-C.,Nanchang University | Sun Y.,Kunming University of Science and Technology | Peng M.-J.,Kunming University of Science and Technology
Journal of Alloys and Compounds | Year: 2014

By means of first-principles calculations within the generalized gradient approximation, the structural properties, phase stabilities and anisotropic elastic properties of binary Zintl compounds Ca2Pb, Sr2Pb and Ba2Pb as a function of pressure have been investigated. Results of formation enthalpies show that they are energetically stable at ground state, and the stability of Ca2Pb is better with the increasing pressure. Based on the calculated elastic constants Cij, elastic properties, including bulk modulus B, shear modulus G, Young's modulus E and Poisson's ratios v, were evaluated by the use of Voigt-Reuss-Hill (VRH) approximation. The mechanical anisotropies were characterized by several anisotropic indexes and three-dimensional surface construction, and the results indicate that these Zintl compounds exhibit anisotropic mechanical properties. Finally, the Debye temperatures and sound velocities along [100], [0 1 0] and [0 01] directions under high pressure were also calculated. © 2014 Elsevier B.V. All rights reserved.


Huang B.,Kunming University of Science and Technology | Huang B.,Key Laboratory of Advance Materials in Rare and Precious and Nonferrous Metals | Duan Y.-H.,Kunming University of Science and Technology | Duan Y.-H.,Key Laboratory of Advance Materials in Rare and Precious and Nonferrous Metals | And 4 more authors.
Ceramics International | Year: 2015

To better clarify and understand the applications of the transition-metal monoborides, first principles calculations were performed to investigate the structural properties, phase stability, elastic properties, and thermal conductivity of NaCl-type, FeB-type and CrB-type MB (M=Ti, Zr and Hf) monoborides. The results of equilibrium structures, cohesive energies and formation enthalpies are in good agreement with available experimental and other theoretical data. Based on the elastic constants, the polycrystalline elastic properties including bulk modulus, shear modulus, Young's modulus and Poisson's ratio, are obtained by Voigt-Reuss-Hill approximation. All these monoborides are mechanically stable. The elastic anisotropies of monoborides are investigated via the various anisotropic indexes and the 3D surface constructions, and the order of elastic anisotropy is NaCl-type>CrB-type>FeB-type. By using the Cahill's model, the minimum thermal conductivities of these monoborides were also investigated, and the results indicate that the minimum thermal conductivities show a dependence on direction. © 2015 Elsevier Ltd and Techna Group S.r.l.


Duan Y.H.,Kunming University of Science and Technology | Duan Y.H.,Key Laboratory of Advance Materials in Rare and Precious and Nonferrous Metals | Sun Y.,Kunming University of Science and Technology | Zhou S.G.,Kunming University of Science and Technology
Computational Materials Science | Year: 2013

The atomic fluorine adsorption in variety of sites on the Mg (0 0 0 1) surface has been systematically investigated through first-principles density functional theory (DFT) methods for coverages θ ≤ 1.0 monolayer. It is found that the fcc-hollow site is the energetically most favorable for the whole coverage range considered. The adsorption energy decreases with the coverage θ. It can be also concluded from analysis of the charge density and density of states that the charges transfer from the substrate Mg atoms to the F atoms leads to the appearance of a dipole moment. With the increasing coverage, it becomes increasingly difficult to transfer electrons from Mg atoms to F atoms, resulting in the dipole moment to decline. © 2013 Elsevier B.V. All rights reserved.


Duan Y.H.,Kunming University of Science and Technology | Duan Y.H.,Key Laboratory of Advance Materials in Rare and Precious and Nonferrous Metals | Sun Y.,Kunming University of Science and Technology | Peng M.J.,Kunming University of Science and Technology
Computational Materials Science | Year: 2014

To better clarify and understand the ground-state physical properties of Pb-Ba intermetallic compounds, phase stabilities, elastic properties and electronic structures of Pb-Ba intermetallic compounds have been investigated by using first-principles calculations within local density approximation. The formation enthalpies of these compounds indicate that they are thermodynamically stable. The bulk modulus B, shear modulus G, Young's modulus E and Poisson's ratio v were evaluated. The brittle and ductile properties were discussed by using B/G and Poisson's ratio. The hardness was also estimated by using a semi-empirical equation. The mechanical anisotropy was characterized by calculating several different anisotropic indexes and the 3D figures of directional dependences of reciprocals of elastic moduli. Finally, the electronic structures were also discussed. © 2014 Elsevier Inc. All rights reserved.


Duan Y.H.,Kunming University of Science and Technology | Duan Y.H.,Key Laboratory of Advance Materials in Rare and Precious and Nonferrous Metals | Sun Y.,Kunming University of Science and Technology | Peng M.J.,Kunming University of Science and Technology | Zhou S.G.,Kunming University of Science and Technology
Journal of Alloys and Compounds | Year: 2014

To better clarify and understand the anisotropic elastic properties of Ca-Pb intermetallic compounds, the structural and elastic properties of the Ca-Pb compounds (Ca3Pb, Ca2Pb, Ca5Pb 3, CaPb and CaPb3) have been investigated by using the first-principles calculations based on density functional theory. The calculated equilibrium structural parameters are in good agreement with the available experimental data. Elastic properties including bulk modulus, shear modulus, Young's modulus and Poisson's ratio, are obtained by Voigt-Reuss-Hill approximation. All Ca-Pb compounds are mechanically stable. The brittle and ductile properties are discussed by using B/G and Poisson's ratio. The elastic anisotropies of Ca-Pb compounds are investigated via the anisotropic index and the 3D figures of directional dependences of reciprocals of elastic moduli. Finally, the anisotropic sound velocities and Debye temperatures of the Ca-Pb compounds are predicted. © 2014 Elsevier B.V. All rights reserved.

Discover hidden collaborations