Structural and Mechanical Properties of Ti1-XAlxN Studied by Ab Initio

2011 ◽  
Vol 383-390 ◽  
pp. 3331-3337 ◽  
Author(s):  
Xin Tan ◽  
Yu Qing Li ◽  
Xue Jie Liu ◽  
Yan Hui Xie
Keyword(s):  
Mechanical Properties ◽  
Elastic Constants ◽  
Cohesive Energy ◽  
Density Functional ◽  
Lattice Parameter ◽  
Industrial Applications ◽  
Mechanical And Thermal Properties ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Ductile Behavior

Ti1-xAlxN films have been shown to exhibit superior mechanical and thermal properties and are thus widely used for industrial applications. We have studied the structural and mechanical properties of fcc-TiN and fcc-Ti1-xAlxN solid solution (x=0.25 and x=0.5), using first principles calculations based on the density functional theory. These calculations provide the lattice parameter, total energy, cohesive energy, elastic constants, etc, of the TiN lattice and when Al atoms replace Ti atoms in the TiN lattice. With regard to the cohesive energy of TiN and fcc-Ti1-xAlxN, we can obtain that the fcc-Ti1-xAlxN is metastable. Via comparation and analysis, it’s shown that the lattice parameter, cohesive energy and elastic constants decrease with increasing the content of Al. However, ductile behavior is promoted by Al addition.

Ab Initio Study of the Structural and Mechanical Properties of Hf-Si-N

2010 ◽  
Vol 139-141 ◽  
pp. 22-25 ◽  
Author(s):  
Xin Tan ◽  
Yu Qing Li ◽  
Xue Jie Liu ◽  
De Gong Liu
Keyword(s):  
Mechanical Properties ◽  
First Principles ◽  
Cohesive Energy ◽  
Density Functional ◽  
Substitutional Solid Solution ◽  
Lattice Parameter ◽  
Solution Phase ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Density Functional Theory

The structural and elastic properties of HfN and Hf-Si-N have been studied, using first principles calculations based on the density functional theory. These calculations provide the lattice parameter, cohesive energy and elastic constants of fcc (NaCl)-HfN, the N-deficient Hf-Si-N and the Hf-deficient Hf-Si-N solution phase. In order to study the relative stability, binding energy of all configurations has been calculated. The results showed that it was difficult to add a Si atom into the center of the HfN cell because the cohesive energy decreased. However, if an Hf atom or an N atom was missing in the HfN, a silicon atom was possible to occupy the vacant site and form the Hf-Si-N substitutional solid solution. Moreover, the bulk modulus, shear modulus and elastic modulus increased accordingly, the mechanical properties were improved.

Mechanical Properties of Ti1-x-yAlxSiyN Nanocomposite Studied by Ab Initio

2012 ◽  
Vol 155-156 ◽  
pp. 926-930
Author(s):  
Xin Tan ◽  
Zhen Yang Xin ◽  
Xue Jie Liu ◽  
Yu Qing Li
Keyword(s):  
Mechanical Properties ◽  
Cohesive Energy ◽  
Density Functional ◽  
Mechanical Performance ◽  
Metastable Phase ◽  
Lattice Parameter ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Al Content ◽  
The Density Functional Theory

Using first principles calculations based on the density functional theory, we have studied the structural and mechanical properties of Ti1-xAlxN and Ti1-x-yAlxSiyN metastable phase. Focus on the calculation of the Ti1-x-yAlxSiyN the cohesive energy, mechanical constants, elastic modulus and shear modulus. These calculated values were analyzed, then we obtained that Ti1-xAlxN lattice parameter decreased after adding Si, while the cohesive energy was rising, the mechanical properties decreased, indicating that in the case of the Al content determined, the structure of Ti1-x-yAlxSiyN is more stable than Ti1-xAlxN, but the mechanical performance ,stiffness and brittleness are reduced.

scholarly journals First-Principles Study of Mechanical and Thermodynamic Properties of Binary and Ternary CoX (X = W and Mo) Intermetallic Compounds

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1404
Author(s):  
Yunfei Yang ◽  
Changhao Wang ◽  
Junhao Sun ◽  
Shilei Li ◽  
Wei Liu ◽  
...  
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Density Functional ◽  
Vibrational Entropy ◽  
Functional Theory ◽  
Lattice Constants ◽  
The Density Functional Theory ◽  
Ductile Behavior ◽  
Pseudo Potential

In this study, the structural, elastic, and thermodynamic properties of DO19 and L12 structured Co3X (X = W, Mo or both W and Mo) and μ structured Co7X6 were investigated using the density functional theory implemented in the pseudo-potential plane wave. The obtained lattice constants were observed to be in good agreement with the available experimental data. With respect to the calculated mechanical properties and Poisson’s ratio, the DO19-Co3X, L12-Co3X, and μ-Co7X6 compounds were noted to be mechanically stable and possessed an optimal ductile behavior; however, L12-Co3X exhibited higher strength and brittleness than DO19-Co3X. Moreover, the quasi-harmonic Debye–Grüneisen approach was confirmed to be valid in describing the temperature-dependent thermodynamic properties of the Co3X and Co7X6 compounds, including heat capacity, vibrational entropy, and Gibbs free energy. Based on the calculated Gibbs free energy of DO19-Co3X and L12-Co7X6, the phase transformation temperatures for DO19-Co3X to L12-Co7X6 were determined and obtained values were noted to match well with the experiment results.

Physical properties of chalcopyrite-type Cu1−xAgxGaTe2 by first-principles study

2016 ◽  
Vol 30 (30) ◽  
pp. 1650373 ◽  
Author(s):  
Li Xue ◽  
Yi-Ming Ren ◽  
Zheng-Long Hu
Keyword(s):  
Thermal Conductivity ◽  
Elastic Constants ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Lattice Parameter ◽  
Functional Theory ◽  
Lattice Volume ◽  
Te Material ◽  
Ag Substitution ◽  
Good Agreement

[Formula: see text] is a promising thermoelectric (TE) material for high temperature TE applications. This work systematically investigated the structural, elastic and thermodynamic properties of [Formula: see text] ([Formula: see text] = 0, 0.25, 0.5, 0.75 and 1) by density functional theory. The calculated lattice volume is expanded with the increase of Ag content, but this expansion is anisotropic. The lattice parameter along [Formula: see text]-axis is linear expansion, and along [Formula: see text]-axis is parabolic expansion, which is in good agreement with available experimental data. The phase stability of [Formula: see text] alloy is studied by analyzing the formation energy, cohesive energy and elastic constants. Shear modulus, Young’s modulus, sound velocities, Debye temperature and the minimum thermal conductivity are obtained from the calculated elastic constants. The results show that Ag substitution could reduce the lattice thermal conductivity, which is helpful for improving the TE properties of [Formula: see text].

scholarly journals Elastic Properties of Orthorhombic YBa2Cu3O7 under Pressure

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 497 ◽  
Author(s):  
Cai Chen ◽  
Lili Liu ◽  
Yufeng Wen ◽  
Youchang Jiang ◽  
Liwan Chen
Keyword(s):  
Thermal Conductivity ◽  
Debye Temperature ◽  
Elastic Constants ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Elastic Stability ◽  
Functional Theory ◽  
Conductivity Increase ◽  
Isotropic Pressure ◽  
The Density Functional Theory

The pressure dependence of the lattice and elastic constants of the orthorhombic YBa 2 Cu 3 O 7 are firstly investigated using the first principles calculations based on the density functional theory. The calculated lattice parameters at 0 GPa are in agreement with the available experimental data. By the elastic stability criteria under isotropic pressure, it is predicted that YBa 2 Cu 3 O 7 with and orthorhombic structure is mechanically stable under pressure up to 100 GPa. On the basis of the elastic constants, Pugh’s modulus ratio, Poisson’s ratio, elastic anisotropy, Debye temperature, and the minimum thermal conductivity of YBa 2 Cu 3 O 7 under pressure up to 100 GPa are further investigated. It is found that its ductility, Debye temperature, and minimum thermal conductivity increase with pressure.

Structural, elastic, electronic and thermoelectric properties of XPN2 (X = Li, Na): First-principles study

2019 ◽  
Vol 33 (21) ◽  
pp. 1950234
Author(s):  
T. Ghellab ◽  
H. Baaziz ◽  
Z. Charifi ◽  
K. Bouferrache ◽  
Ş Uğur ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Three Dimensional ◽  
Lattice Parameter ◽  
Full Potential ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Electronic Parameters ◽  
Linearized Augmented Plane Wave

Based on the density functional theory (DFT) implemented by the wien2k code which uses the full potential linearized augmented plane wave plus local orbitals (APW + lo) method, we have been able to study different physical properties of X[Formula: see text]PN2 (X = Li, Na) chalcopyrite such as structural, electronic, elastic and thermoelectric properties. According to our calculations, we have found that our structural and electronic parameters, such as the lattice parameter, energy bandgap, the tetragonal ratio, the displacement of the anions, are in very good agreement with the previous experimental and theoretical results. Based on the Voigt–Reuss–Hill approximations, we were able to compute the elastic constants: the compressibility, Young’s and the shear’s moduli, the average velocity of the elastic waves, the Debye temperature and the Poisson’s coefficient of the chalcopyrite LiPN2 and NaPN2. The elastic anisotropy is estimated and further illustrated by the three-dimensional (3D) direction of Young’s and Bulk’s moduli. Finally, using the semi-classical Boltzmann theory implemented in the BolzTraP code, we calculated the transport properties such as the Seebeck coefficient, the thermal electrical conductivity and the figure of merit of these materials.

Calculation of electronic structure and mechanical properties of DO3–Fe75-xSi25Nix intermetallic compounds by first principles

2015 ◽  
Vol 29 (13) ◽  
pp. 1550087
Author(s):  
R. Ma ◽  
M. P. Wan ◽  
J. Huang ◽  
Q. Xie
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compounds ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Elastic Parameters ◽  
Functional Theory ◽  
Ni Content ◽  
The Density Functional Theory ◽  
The Difference

Based on the density functional theory (DFT), the plane-wave pseudopotential method was used to investigate the electronic structures and mechanical properties of DO 3– Fe 75-x Si 25 Ni x(x = 0, 3.125, 6.25 and 9.375) intermetallic compounds. The elastic parameters were calculated, and then the bulk modulus, shear modulus and elastic modulus were derived. The paper then focuses on the discussion of ductility and plasticity. The results show that by adding appropriate Ni to Fe 3 Si intermetallic compound can improve the ductility. But the hardness will increase when the Ni content exceeds 6.25%. Analysis of density of states (DOS) and overlap populations indicates that with the difference of the strength of bonding and activity, there were some differences of ductility among different Ni contents. The Fe 71.875 Ni 3.125 Si 25 has the lowest hardness because the covalent bonding (Fe–Si bond and Si–Ni bond) has the minimum covalent electrons.

Study of Elastic Properies of Ti3Al Intermetallic Compound Using the Ab Initio Calculation

2014 ◽  
Vol 805 ◽  
pp. 690-693
Author(s):  
Carlos Alberto Soufen ◽  
Marcelo Capella de Campos ◽  
Carlos Alberto Fonzar Pintão ◽  
Momotaro Imaizumi
Keyword(s):  
Intermetallic Compound ◽  
Elastic Properties ◽  
Density Functional ◽  
Minimum Energy ◽  
Young Modulus ◽  
Lattice Parameter ◽  
Full Potential ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Equilibrium Lattice Parameter

The elastic properties of a Ti3Al intermetallic compound were studied using full potential (FP LAPW ) with the APW+lo method. The FP-LAPW is among the most accurate band structure calculations currently available and is based on the density functional theory with general gradient approximation for the exchange and correlation potential. This method provides the structural properties of the ground state as bulk modulus, equilibrium lattice parameter, and equilibrium minimum energy, and the elastic properties as shear modulus, young modulus, Zener coefficient (anisotropy), and Poisson coefficient. The calculated elastic properties are coherent with the elastic properties of the material.

Does Osmium Carbide Exist? Ab initio Investigation

2006 ◽  
Vol 987 ◽  
Author(s):  
M. Zemzemi ◽  
M. Hebbache ◽  
D. Zivkovic ◽  
L Stuparevic
Keyword(s):  
Mechanical Properties ◽  
Density Functional Theory ◽  
Transition Metals ◽  
Ab Initio ◽  
Density Functional ◽  
Ambient Pressure ◽  
Hexagonal Structure ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Good Agreement

AbstractTransition metals of the platinum group (Os, Ir, Pt, Ru, Re, Rh) do not form carbides and nitrides at ambient pressure. Osmium carbide seems to have been synthesized at zero pressure by Kempter and Nadler forty six years ago. According to the authors, OsC crystallizes in WC-type structure and has a hardness equal to 2000 kg mm-2. Up to date, no other experimental confirmation is available. We studied the electronic and mechanical properties of this hypothetical carbide using an approach based on the density-functional theory. We found that the work of the above mentioned authors is sound. The calculated lattice parameters are in good agreement with that given by those authors and a rough estimate also showed that the hardness given by them is reasonable. However, we found that the hexagonal structure of osmium carbide is electronically and mechanically unstable.

scholarly journals The Effect of Interaction between Nanofillers and Epoxy on Mechanical and Thermal Properties of Nanocomposites: Theoretical Prediction and Experimental Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
S. Khostavan ◽  
M. Fazli ◽  
M. Ghorbanzadeh Ahangari ◽  
Y. Rostamiyan
Keyword(s):  
Thermal Properties ◽  
Density Functional ◽  
Theoretical Study ◽  
Epoxy Polymer ◽  
Epoxy Composite ◽  
Neat Epoxy ◽  
Mechanical And Thermal Properties ◽  
Host Matrix ◽  
Functional Theory ◽  
The Density Functional Theory

Interfacial interaction between host matrix and nanofillers is a determinative parameter on the mechanical and thermal properties of nanocomposites. In this paper, we first investigated interaction between carbon nanotube (CNT) and montmorillonite clay (MMT) absorbing on epoxy surface in a theoretical study based on the density functional theory (DFT) calculations. Results showed the interaction energy of -1.93 and -0.11 eV for MMT/epoxy and CNT/epoxy, respectively. Therefore, the interaction between epoxy polymer and MMT is of the chemisorptions type, while epoxy physically interacts with CNT. In addition, thermal and mechanical analyses were conducted on nanocomposites. In DSC analysis the glass transition temperature which was 70°C in neat epoxy composite showed an improvement to about 90°C in MMT nanocomposites while it was about 70°C for CNT nanocomposites. Finally, mechanical properties were investigated and MMT nanocomposite showed a change in compressive strength which increased from 52.60 Mpa to 72.07 and 92.98 Mpa in CNT and MMT nanocomposites, respectively. Also tensile strength improved to the value of 1250.69 Mpa MMT nanocomposites while it was about 890 Mpa in both CNT nanocomposite and neat epoxy composite which corresponds to the calculation result prediction.

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