scholarly journals First-principles calculations of mechanical and thermodynamic properties of tungsten-based alloy

2019 ◽  
Vol 8 (1) ◽  
pp. 258-265 ◽  
Author(s):  
Heng Li ◽  
Xin Zhang ◽  
Qijun Liu ◽  
Yangyang Liu ◽  
Haifeng Liu ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Mechanical Strength ◽  
Elastic Constants ◽  
Vickers Hardness ◽  
First Principles ◽  
Poisson’S Ratio ◽  
Scientific Data ◽  
Poisson's Ratio ◽  
First Principles Calculations ◽  
Cauchy Pressure

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.

First-Principles Study of the Elastic Properties of Hexagonal Phase ScAx (A=H, He)

2013 ◽  
Vol 690-693 ◽  
pp. 1723-1727
Author(s):  
Kai Min Fan ◽  
Li Yang ◽  
Jing Tang ◽  
Qing Qiang Sun ◽  
Xiao Tao Zu
Keyword(s):  
Elastic Modulus ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
First Principles ◽  
Poisson’S Ratio ◽  
Hexagonal Phase ◽  
Poisson's Ratio ◽  
First Principles Calculations ◽  
Charge Densities ◽  
Change Mechanism

First-principles calculations are performed to investigate the Young’s modulus, bulk modulus, shear modulus and Poisson’s ratio of hexagonal phase ScAx(A=H, He), where x=0, 0.0313, 0.125 and 0.25, represent the ratio of interstitial atoms A (A=H, He) to Sc atoms. The influences of hydrogen concentrations and helium concentrations on elastic modulus and Poisson’s ratio of ScAx(A=H, He) have been studied. The results indicate that hydrogen and helium have different effects on the elastic modulus of hexagonal phase scandium. The change mechanism of the Poisson’s ratio with the variation of the x ranging from 0 to 0.25 has also been studied in hexagonal phase ScAx(A=H, He). In addition, the changes in the charge densities of ScAxdue to the presence of hydrogen and helium have been calculated.

scholarly journals Nonlinear Elasticity of Borocarbide Superconductor YNi2B2C: A First-Principles Study

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Lili Liu ◽  
Cai Chen ◽  
Dingxing Liu ◽  
Zhengquan Hu ◽  
Gang Xu ◽  
...  
Keyword(s):  
High Pressure ◽  
Elastic Constants ◽  
Vickers Hardness ◽  
First Principles ◽  
Second Order ◽  
First Principles Calculations ◽  
Modulus Ratio ◽  
Third Order ◽  
Lattice Constants ◽  
Third Order Elastic Constants

First-principles calculations combined with homogeneous deformation methods are used to investigate the second- and third-order elastic constants of YNi2B2C with tetragonal structure. The predicted lattice constants and second-order elastic constants of YNi2B2C agree well with the available data. The effective second-order elastic constants are obtained from the second- and third-order elastic constants for YNi2B2C. Based on the effective second-order elastic constants, Pugh’s modulus ratio, Poisson’s ratio, and Vickers hardness of YNi2B2C under high pressure are further investigated. It is shown that the ductility of YNi2B2C increases with increasing pressure.

First-Principles Investigation of Structural Stability, Mechanical, Anisotropic, and Thermodynamic Properties of CeT2Al20 Intermetallics

2018 ◽  
Vol 73 (12) ◽  
pp. 1157-1167 ◽  
Author(s):  
He Ma ◽  
Xiaoyou Li ◽  
Wei Jiang ◽  
Xudong Zhang
Keyword(s):  
High Temperature ◽  
Thermodynamic Properties ◽  
Thermodynamic Parameters ◽  
Structural Stability ◽  
Elastic Constants ◽  
First Principles ◽  
Elastic Moduli ◽  
Formation Enthalpy ◽  
First Principles Calculations ◽  
Acoustic Velocities

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.

Novel Two-Dimensional Tetrahexagonal Boron Nitride with Sizable Bandgap and Sign-Tunable Poisson’s Ratio

Nanoscale ◽  
2021 ◽  
Author(s):  
Mehmet Emin Kilic ◽  
Kwang-Ryeol Lee
Keyword(s):  
Boron Nitride ◽  
First Principles ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Two Dimensional ◽  
First Principles Calculations

By performing first-principles calculations, a new two-dimensional (2D) boron nitride (th-BN) with perfectly ordered arrangements of tetragonal and hexagonal rings is predicted to be energetically, dynamically, thermally, and mechanically stable....

scholarly journals First-principles Study of Vickers Hardness and Thermodynamic Properties of Ti3SnC2 Polymorphs

2015 ◽  
Vol 7 (3) ◽  
pp. 53-64 ◽  
Author(s):  
M. A. Rayhan ◽  
M. A. Ali ◽  
S. H. Naqib ◽  
A. K. M. A. Islam
Keyword(s):  
Thermodynamic Properties ◽  
Vickers Hardness ◽  
First Principles ◽  
Applied Pressure ◽  
Theoretical Data ◽  
Debye Model ◽  
Covalent Bonding ◽  
First Principles Calculations ◽  
Specific Heats ◽  
Strong Covalent Bonding

We have investigated Vickers hardness and the thermodynamic properties of the recently discovered nanolaminate carbide Ti3SnC2 polymorphs using the first-principles calculations. The chemical bonding shows a combination of covalent, ionic and metallic types. The strong covalent bonding is mainly responsible for high Vickers hardness of Ti3SnC2 polymorphs. Thermodynamic properties are studied using the quasi-harmonic Debye model. The variation of bulk modulus, thermal expansion coefficient, specific heats, and Debye temperature with applied pressure (P) and temperature (T) are investigated systematically within the ranges of 0 - 50 GPa and 0 - 1000 K. The calculated results have been compared with available experimental and theoretical data.

Lattice dynamics, thermodynamics, and elastic properties of Na2Se under pressure investigated by first principles method

2014 ◽  
Vol 92 (11) ◽  
pp. 1464-1469
Author(s):  
Xudong Zhang ◽  
Haifeng Shi
Keyword(s):  
High Pressure ◽  
Thermodynamic Properties ◽  
Elastic Constants ◽  
First Principles ◽  
Lattice Dynamics ◽  
Lattice Dynamic ◽  
Thermodynamic Quantities ◽  
First Principles Calculations ◽  
Structure Phase ◽  
Elastic Lattice

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.

Poisson’s ratio in the all-inorganic perovskite monolayers

2020 ◽  
pp. 2150002
Author(s):  
Kaijun Liu ◽  
Weihao Zeng ◽  
Danyang Liu ◽  
Ruge Quhe
Keyword(s):  
Bond Length ◽  
First Principles ◽  
Poisson’S Ratio ◽  
Rotation Angle ◽  
Bond Angle ◽  
Poisson's Ratio ◽  
First Principles Calculations ◽  
Plane Anisotropy ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Poisson’s ratios of two-dimensional (2D) all-inorganic perovskites Cs2PbX4 (X = Cl, Br, I) have been calculated by the first-principles calculations. The contribution of each geometric parameter (bond length [Formula: see text], bond angle [Formula: see text], rotation angle [Formula: see text], and tilt angle [Formula: see text]) to Poisson’s ratio is obtained analytically. Through a comprehensive analysis of the geometric deformations of the perovskite under the uniaxial strain, we find that Poisson’s ratios of the perovskites are sensitive to the change of the bond length [Formula: see text] and the bond angle [Formula: see text]. In addition, the value of the bond angle [Formula: see text] in the strain-free structure mainly determines the high in-plane anisotropy of Poisson’s ratios in Cs2PbX4.

Structural, Mechanical and Electronic Properties of o-BC6N

2019 ◽  
Vol 74 (11) ◽  
pp. 1037-1042
Author(s):  
Ruijiao Jiang ◽  
Jianguo Zhang ◽  
Qun Wei ◽  
Minhua Xue
Keyword(s):  
High Pressure ◽  
Electronic Structure ◽  
Shear Modulus ◽  
Electronic Properties ◽  
First Principles ◽  
Poisson’S Ratio ◽  
Structure Study ◽  
Poisson's Ratio ◽  
First Principles Calculations ◽  
Large Anisotropy

AbstractThe mechanical and electronic properties of o-BC6N are studied by using first-principles calculations. The anisotropy studies of Young’s modulus, shear modulus and Poisson’s ratio show that o-BC6N exhibits a large anisotropy. Electronic structure study shows that o-BC6N presents metallicity under the conditions of zero and high pressure.

Elastic Constants and Thermodynamic Properties of Cu, Cu2O and CuO from First-Principles Calculations

2011 ◽  
Vol 335-336 ◽  
pp. 328-332 ◽  
Author(s):  
Na Na Liu ◽  
Jian Lin Sun ◽  
Di Wu
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Elastic Constants ◽  
First Principles ◽  
Heat Capacities ◽  
Copper Oxides ◽  
First Principles Calculations ◽  
Previous Experimental Data ◽  
Specific Heat Capacities

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.

Sign in / Sign up

Export Citation Format

Share Document