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First-principles Calculations of Electronic Structures and Elastic Properties of 14H-LPSO and W Phases in Mg-Zn-Y Alloy |
XU Zhichao1, FENG Zhongxue1, SHI Qingnan1, YANG Yingxiang2
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1 Faculty of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093; 2 Key Laboratory of Advanced Materials of Yunnan Province, Kunming 650093 |
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Abstract The density of states, electronic structure and elastic constants of 14H-LPSO and W phase in Mg-Zn-Y alloy were analyzed by means of first-principles calculations from CASTEP program based on density functional theory (DFT). The calculated lattice parameters were consistent with the experimental and literature values. The calculated band structure and density of states demonstrates that the bonding of the 14-LPSO occur mainly among the valence electrons of Mg3s, Zn4s, Y5s, Y4p orbits, and the energy is in a range from -8 eV to 3 eV. Similarly, the bonding of the Mg3Y2Zn3 occur mainly among the valence electrons of Mg3s, Zn3p, Y4d orbits, and the energy is in a range from -8 eV to 0.5 eV. In addition, the charge densities respectively on (011) plane of Mg3Y2Zn3 phase and (0001) plane of 14H phase were analyzed, and the results indicate that the Zn-Y band exhibits covalent features, the covalent bonding of phase is stronger than that of 14-LPSO phase. According to the calculated elastic canstants, the bulk moduli, shear moduli, Yong’s moduli, Poisson’s ratio value and elastic anisotropy were derived. Furthermore, comparing the 14H-LPSO,W phase with Mg, the plasticity of the three phase is Mg>14H-LPSO>W. The W phase has the biggest hardness among three phases.
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Published: 25 March 2018
Online: 2018-03-25
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