Quantum-Mechanical Simulation of the Defects Influence on the Shear Rupture in γ-TiAl

2019 ◽  
Vol 806 ◽  
pp. 130-135
Author(s):  
Anton Gnidenko
Keyword(s):  
Titanium Aluminide ◽  
Density Functional ◽  
Shear Resistance ◽  
Quantum Mechanical ◽  
Alloying Element ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Shear Rupture ◽  
Negative Effect ◽  
Titanium Vacancy

The effect of point defects on the shear rupture resistance in titanium aluminide is investigated by the density functional theory and pseudopotential methods. Vacancies, as well as substitution atoms – tungsten and chromium were considered as points defects. The shear was simulated in the(111) slip plane for two directions, namely [110] and [11-2]. It is shown that for a {111}<110> sliding system, vacancies significantly reduce the shear resistance. However, when alloying element occupies a titanium vacancy, it can partially compensate for this negative effect.

Computer Simulation of Plastic Deformation in Tial Alloys in the Presence of Chromium

2018 ◽  
Vol 386 ◽  
pp. 383-387 ◽  
Author(s):  
Anton Gnidenko
Keyword(s):  
Computer Simulation ◽  
Plastic Deformation ◽  
Shear Modulus ◽  
Titanium Aluminide ◽  
Shear Resistance ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Tial Alloys ◽  
Shear Rupture ◽  
Titanium Vacancy

Quantum-mechanical calculations were used to investigate shear rupture in intermetallic titanium aluminide (TiAl) alloys in the presence of vacancy or chromium dopant. The substitution of both Ti and Al atoms by Cr atoms in the γ-TiAl crystal lattice was considered. The simulation of shear was carried out in the (111) slip plane along two directions, namely the [110] and [11-2]. The decrease in the shear resistance of the defects present in the γ-TiAl lattice was estimated. It was shown that when chromium occupies a titanium vacancy, it can compensate for this defect by increasing the shear modulus for the {111} <110> slip system.

Theoretical study of NO3− interacting with carbon nanotube

Open Physics ◽  
2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Silvete Guerini ◽  
David Azevedo ◽  
Maria Lima ◽  
Ivana Zanella ◽  
Josué Filho
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Quantum Mechanical ◽  
Mechanical Interaction ◽  
Electronic Density ◽  
Functional Theory ◽  
Consistent Field ◽  
The Density Functional Theory ◽  
Self Consistent Field ◽  
Field Form

AbstractThis paper deals with quantum mechanical interaction of no 3− with (5,5) and (8,0) swcnts. To perform this we have made an ab initio calculation based on the density functional theory. In these framework the electronic density plays a central role and it was obtained of a self-consistent field form. It was observed through binding energy that NO3− molecule interacts with each nanotube in a physisorption regime. We propose these swcnts as a potential filter device due to reasonable interaction with NO3− molecule. Besides this type of filter could be reusable, therefore after the filtering, the swcnts could be separated from NO3− molecule.

scholarly journals Phase Stability in U-6Nb Alloy Doped with Ti from the First Principles Theory

2020 ◽  
Vol 10 (10) ◽  
pp. 3417
Author(s):  
Alexander Landa ◽  
Per Söderlind ◽  
Amanda Wu
Keyword(s):  
Phase Stability ◽  
First Principles ◽  
Density Functional ◽  
Room Temperature ◽  
Rapid Quenching ◽  
Quantum Mechanical ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Effect Of Impurities

First-principles calculations within the density-functional-theory (DFT) approach are conducted in order to explore and explain the effect of small amounts of titanium on phase stability in the U-6Nb alloy. During rapid quenching from high to room temperature, metastable phases α′ (orthorhombic), α″ (monoclinic), and γ0 (tetragonal) can form, depending on Nb concentration. Important mechanical properties depend on the crystal structure and, therefore, an understanding of the effect of impurities on phase stability is essential. Insights on this issue are obtained from quantum-mechanical DFT calculations. The DFT framework does not rely on any material-specific assumptions and is therefore ideal for an unbiased investigation of the U-Nb system.

scholarly journals Quantum Mechanical Investigations into Thermochemistry Properties and Electronic, Structural of Nanocrystals

2019 ◽  
Vol 29 (3) ◽  
pp. 133
Author(s):  
Huda M. Jawad
Keyword(s):  
Density Functional ◽  
Gallium Phosphide ◽  
Zero Point ◽  
Basis Set ◽  
Quantum Mechanical ◽  
Generalized Gradient ◽  
Actual System ◽  
Functional Theory ◽  
Point Energy ◽  
The Density Functional Theory

This paper presents quantum mechanical investigations that is into electronic and thermochemistry properties of Gallium phosphide. It also investigates diamondoids and nanocrystals using the density functional theory. This is done at the generalized gradient approximation of Perdew et al basis set. This has been used to create Gaussian 09 program auxiliary by Gaussian view. In order to full investigate the ionization potential, affinity, valance bond, conduction bond, zero point energy and thermochemistry properties. The result GaP diamondoids. Electron affinity and conduction band, decreases as a function of the total number of Ga and P atoms in most of the investigated range. Ionization energies zero point and valance bands increased with the number of Ga and P atoms but there are fluctuations in tetramantane and hexamantane In fact, since the present diamondoids are built from nearly cubic cages. Thermochemistry entails calculation of frequency which also includes thermochemical analysis of actual system comprising of thermal energy correction, heat capacity and entropy.

scholarly journals A theoretical study of (9, 0) Singlewalled Carbon Nanotubes using quantum mechanical techniques

2021 ◽  
Vol 4 (1) ◽  
pp. 10
Author(s):  
Deepa Sharma ◽  
Neena Jaggi
Keyword(s):  
Thermodynamic Properties ◽  
Band Gap ◽  
Density Functional ◽  
Tight Binding ◽  
Finite Energy ◽  
Quantum Mechanical ◽  
Simulation Studies ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Material Studio

First principles simulation studies using the density functional theory have been performed on (9, 0) Zigzag Singlewalled Carbon Nanotube (SWCNT) to investigate its electronic, optical and thermodynamic properties using CASTEP (Cambridge Sequential Total Energy Package) and DFTB (Density Functional based Tight Binding) modules of the Material Studio Software version 7.0. Various functionals and sub-functionals available in the CASTEP Module (using Pulay Density Mixing treatment of electrons) and various eigen-solvers and smearing schemes available in the DFTB module (using smart algorithm) have been tried out to chalk out the electronic structure. The analytically deduced values of the band gap obtained were compared with the experimentally determined value reported in the literature. By comparison, combination of Anderson smearing scheme and standard diaogonalizer produced best results in DFTB module while in the CASTEP module, GGA (General Gradient approximation) functional with RPBE (Revised-perdew-Burke-Ernzerh) as Sub-functional was found to be the most consistent. These optimized parameters were then used to determine various electronic, optical and thermodynamic properties of (9, 0) Singlewalled Nanotube. (9, 0) Singlewalled Nanotube, which is extensively being used for sensing NH3, CH4 & NO2, has been picked up in particular as it is reported to exhibit a finite energy band gap in contrast to its expected metallic nature. The study is of utmost significance as it not only probes and validates the simulation route for predicting suitable properties of nanomaterials but also throws light on the comparative efficacy of the different approximation and rationalization quantum mechanical techniques used in simulation studies.

QUANTUM MECHANICAL MODELING OF THE COBALT MONOLAYER BEHAVIOR ON A TIC SURFACE

2020 ◽  
Author(s):  
Антон Александрович Гниденко
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Cobalt Atom ◽  
Binding Energies ◽  
Pseudopotential Method ◽  
Quantum Mechanical ◽  
Mechanical Modeling ◽  
Functional Theory ◽  
The Density Functional Theory

Методами теории функционала плотности и псевдопотенциала исследована адгезия монослоя кобальта с поверхностью TiC(001). Показана необходимость поворота монослоя кобальта относительно подложки для получения достоверных результатов. Рассмотрены две стабильные атомные конфигурации для системы 4TiC/5Co, рассчитаны энергии связи, приходящиеся на один атом кобальта. The adhesion of a cobalt monolayer on the TiC (001) surface is studied using the density functional theory and pseudopotential method. The necessity of cobalt monolayer rotation relative to the substrate to obtain reliable results is shown. Two stable atomic configurations for the 4TiC/5Co system are considered, and the binding energies per cobalt atom are calculated.

scholarly journals Strain Investigation on Spin-Dependent Transport Properties of γ-Graphyne Nanoribbon Between Gold Electrodes

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yun Li ◽  
Xiaobo Li ◽  
Shidong Zhang ◽  
Liemao Cao ◽  
Fangping Ouyang ◽  
...  
Keyword(s):  
Transport Properties ◽  
High Performance ◽  
Density Functional ◽  
Strain Engineering ◽  
Molecular Junctions ◽  
Spin Splitting ◽  
Functional Theory ◽  
Spin Dependent Transport ◽  
The Density Functional Theory ◽  
Dependent Transport

AbstractStrain engineering has become one of the effective methods to tune the electronic structures of materials, which can be introduced into the molecular junction to induce some unique physical effects. The various γ-graphyne nanoribbons (γ-GYNRs) embedded between gold (Au) electrodes with strain controlling have been designed, involving the calculation of the spin-dependent transport properties by employing the density functional theory. Our calculated results exhibit that the presence of strain has a great effect on transport properties of molecular junctions, which can obviously enhance the coupling between the γ-GYNR and Au electrodes. We find that the current flowing through the strained nanojunction is larger than that of the unstrained one. What is more, the length and strained shape of the γ-GYNR serves as the important factors which affect the transport properties of molecular junctions. Simultaneously, the phenomenon of spin-splitting occurs after introducing strain into nanojunction, implying that strain engineering may be a new means to regulate the electron spin. Our work can provide theoretical basis for designing of high performance graphyne-based devices in the future.

scholarly journals Electron-phonon interaction in In-induced √7 ×√3 structures on Si(111) from first-principles

2021 ◽  
Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov
Keyword(s):  
Density Functional Theory ◽  
Double Layer ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Single Layer ◽  
Phonon Interaction ◽  
Functional Theory ◽  
Electron Phonon Interaction ◽  
The Density Functional Theory

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...

Sign in / Sign up

Export Citation Format

Share Document