Elastic constants and thermodynamic properties of Mg 2 Si x Sn 1− x from first-principles calculations

2009 ◽  
Vol 18 (5) ◽  
pp. 1979-1984 ◽  
Author(s):  
Liu Na-Na ◽  
Song Ren-Bo ◽  
Du Da-Wei
2018 ◽  
Vol 73 (12) ◽  
pp. 1157-1167 ◽  
Author(s):  
He Ma ◽  
Xiaoyou Li ◽  
Wei Jiang ◽  
Xudong Zhang

AbstractFirst-principles calculations were carried out to explore the structural stability, elastic moduli, ductile or brittle behaviour, anisotropy, dynamical stability, and thermodynamic properties of pure Al and CeT2Al20 (T = Ti, V, Cr, Nb, and Ta) intermetallics. The calculated formation enthalpy and phonon frequencies confirm that these intermetallics satisfy the conditions for structural stability. The elastic constants Cij, elastic moduli B, G, and E, and the hardness Hv indicate these intermetallics have higher hardness and the better resistance against deformation than pure Al. The values of Poisson’s ratio (v) and B/G indicate that CeT2Al20 intermetallics are all brittle materials. The anisotropic constants and acoustic velocities confirm that CeT2Al20 intermetallics are all anisotropic, but CeV2Al20, CeNb2Al20, and CeTa2Al20 are nearly isotropic. Importantly, the calculated thermodynamic parameters show that CeT2Al20 intermetallics exhibit better thermodynamic properties than pure Al at high temperature.


2014 ◽  
Vol 92 (11) ◽  
pp. 1464-1469
Author(s):  
Xudong Zhang ◽  
Haifeng Shi

First-principles calculations have been performed to investigate the structural stability, elastic, lattice dynamic, and thermodynamic properties of Na2Se under high pressure. Our results demonstrate that Na2Se in the antifluorite structure phase keeps dynamically stable until 30 GPa. The elastic constants and thermodynamic quantities under high pressure are also calculated and discussed.


2019 ◽  
Vol 8 (1) ◽  
pp. 258-265 ◽  
Author(s):  
Heng Li ◽  
Xin Zhang ◽  
Qijun Liu ◽  
Yangyang Liu ◽  
Haifeng Liu ◽  
...  

Abstract The structural, mechanical and thermodynamic properties of tungsten-based alloys, including W0.5Ti0.5,W0.67Zr0.33,W0.666Ti0.1667Zr0.1667,W0.67Hf0.33 and W0.666Ti0.1667Hf0.1667, have been investigated in this paper by first-principles calculations based on density functional theory (DFT). The calculated elastic constants and mechanical stability criteria of cubic crystals indicated that all of these cubic alloys are mechanical stable. The mechanical properties, including bulk modulus (B), shear modulus (G), Young’s modulus(E), ratio B/G, Poisson’s ratio, Cauchy pressure and Vickers hardness are derived from the elastic constants Cij. According to calculated elastic modulus and Vickers hardness, the W0.666Ti0.1667Hf0.1667 alloy has the greatest mechanical strength. The Vickers hardness of these cubic alloys rank as follows: W0.666Ti0.1667Hf0.1667 > W0.67Zr0.33 > W0.666Ti0.1667Zr0.1667 > W0.5Ti0.5 > W0.67Hf0.33. Moreover, calculated ratio B/G, Poisson’s ratio, Cauchy pressure indicated that the ductility of W0.666Ti0.1667Hf0.1667 alloy is the worst among these alloys. The ductility of these cubic alloys rank as follows: W0.67Hf0.33 > W0.5 Ti0.5 > W0.67Zr0.33 > W0.666Ti0.1667Zr0.1667 > W0.666Ti0.1667Hf0.1667. What is noteworthy is that both mechanical strength and ductility of W0.666Ti0.1667Hf0.1667 are greater than pure W. Finally, Debye temperature, melting point and thermal conductivity have been predicted through empirical formulas. All these results will provide scientific data for the study on new product development of electrode materials.


2011 ◽  
Vol 335-336 ◽  
pp. 328-332 ◽  
Author(s):  
Na Na Liu ◽  
Jian Lin Sun ◽  
Di Wu

Elastic constants and some thermodynamic properties of Cu and copper oxides were studied by first-principles total energy calculations. The elastic constants of Cu and copper oxides were calculated on pressure. It was shown that the calculated elastic constants of Cu, Cu2O and CuO at zero pressure were well consistent with previous experimental data. The specific heat capacities and thermal expansion coefficient of Cu and copper oxides were successfully obtained. The calculated specific heat capacities of Cu were well consistent with the previous experimental data.


2016 ◽  
Vol 71 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Qun Wei ◽  
Haiyan Yan ◽  
Xuanmin Zhu ◽  
Zhengzhe Lin ◽  
Ronghui Yao

AbstractStructural, mechanical, and electronic properties of orthorhombic rhenium phosphide (Re2P) are systematically investigated by using first principles calculations. The elastic constants and anisotropy of elastic properties are obtained. The metallic character of Re2P is demonstrated by density of state calculations. The quasi-harmonic Debye model is applied to the study of the thermodynamic properties. The thermal expansion, heat capacities, and Grüneisen parameter on the temperature and pressure have been determined as a function of temperature and pressure in the pressure range from 0 to 100 GPa and the temperature range from 0 to 1600 K.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Menouer ◽  
O. Miloud Abid ◽  
A. Benzair ◽  
A. Yakoubi ◽  
H. Khachai ◽  
...  

AbstractIn recent years the intermetallic ternary RE2MgGe2 (RE = rare earth) compounds attract interest in a variety of technological areas. We therefore investigate in the present work the structural, electronic, magnetic, and thermodynamic properties of Nd2MgGe2 and Gd2MgGe2. Spin–orbit coupling is found to play an essential role in realizing the antiferromagnetic ground state observed in experiments. Both materials show metallicity and application of a Debye-Slater model demonstrates low thermal conductivity and little effects of the RE atom on the thermodynamic behavior.


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