The estimation of energy and elastic properties of TiAlNb materials based on results of first principles calculations

2021 ◽  
Vol 2021 (3) ◽  
pp. 55-65
Author(s):  
L. Ovsiannikova ◽  
◽  
N. Rozhenko ◽  
Keyword(s):  
Bulk Modulus ◽  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
Cluster Structure ◽  
Cohesion Energy ◽  
First Principles Calculations ◽  
Electronic Density ◽  
Β Phase ◽  
Bcc Structure

The results of research of isolated TiAlNb clusters are presented. The models of isolated clusters of 27, 59, 65 atoms in size which is fragments of the bcc structure have been constructed. The models stoichiometry imitate α-, γ-, α+γ- and β-phase TiAlNb alloys. The structural, cohesive and electronic properties of these clusters have been investigated within the framework of electronic density functional theory with PBE0 functional with a set of MINI basis functions with application of Gaussian'03 and GAMESS software packages. It was found that upon transition of the cluster structure from the α- to the β-phase, the cohesion energy increases and the crystal lattice period decreases. This corresponds to an increase in the values of the structure strength and density. For the calculation of the bulk modulus were utilized value of changes in energy and volume of cluster, got in research. The bulk modulus of the isolated β-phase TiAlNb cluster is predicted. This bulk modulus near to 142.4 GPa. The result was extended to volumetric structures. The investigation showed that bulk modulus of Ti2AlNb materials near to 163.6 GPa. Comparison of calculation results with experimental values of elastic moduli of materials with similar structure and composition is carried out. The comparison revealed the agreement between the calculated values and the results of experiments. A method is proposed for evaluating the elastic properties of TiAlNb alloys based on the results of first principles calculations. Keywords: cluster, aluminide titanium, bulk modulus, computer material science.

Elastic Properties and Electronic Structures of L12-TiAl3 and L12-Ti(Al,Pt)3: A Density Functional Theory Investigation

2015 ◽  
Vol 817 ◽  
pp. 816-825
Author(s):  
Bo Huang ◽  
Yong Hua Duan ◽  
Sun Yong ◽  
Ming Jun Peng
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Structural Parameters ◽  
First Principles Calculations ◽  
Elastic Parameters ◽  
Electronic Density ◽  
Functional Theory ◽  
Experimental Values

First-principles calculations have been carried out to investigate the elastic properties and electronic structures of L12-TiAl3and L12-Ti (Al, Pt)3. The optimized structural parameters were largely consistent with the experimental values. The electronic density of states (DOS) and the differences of charge density distribution were given. The independent single-crystal elastic constants and polycrystalline elastic parameters such as bulk modulusB, Young’s modulusE, shear modulusG, Poisson’s ratioνand anisotropy valueAhave been calculated by Voigt-Reuss-Hill averaging scheme. The results indicate that the L12-Ti (Al, Pt)3exhibits larger anisotropy and more ductile than L12-TiAl3.

THEORETICAL INVESTIGATION OF THE ELASTIC PROPERTIES AND LATTICE DYNAMICS OF THE MgSxSe1-x ALLOY

2007 ◽  
Vol 21 (05) ◽  
pp. 249-259 ◽  
Author(s):  
K. BOUAMAMA ◽  
P. DJEMIA
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Lattice Dynamics ◽  
Density Functional ◽  
Local Density ◽  
Lattice Parameter ◽  
First Principles Calculations ◽  
Virtual Crystal Approximation ◽  
Functional Theory ◽  
Density Functional Perturbation Theory

Structural and elastic properties as well as lattice dynamics of ternary MgS x Se 1-x alloy have been studied using first-principles calculations. These are done using density functional theory (DFT) and density functional perturbation theory (DFPT) within the local density approximation (LDA) and employing the virtual-crystal approximation (VCA). We found that the lattice parameter, the elastic constants and the phonon frequencies follow a quadratic law in x.

First-Principles Calculations of Elastic Properties of HoBi and ErBi

2013 ◽  
Vol 664 ◽  
pp. 672-676
Author(s):  
De Ming Han ◽  
Gang Zhang ◽  
Li Hui Zhao
Keyword(s):  
Shear Modulus ◽  
Physical Properties ◽  
Bulk Modulus ◽  
Elastic Properties ◽  
Lattice Constant ◽  
Elastic Constants ◽  
First Principles ◽  
Energy Band ◽  
First Principles Calculations ◽  
Future Work

We present first-principles investigations on the elastic properties of XBi (X=Ho, Er) compounds. Basic physical properties, such as lattice constant, elastic constants (Cij), isotropic shear modulus (G), bulk modulus (B), Young’s modulus (Y), Poisson’s ratio (υ), and Anisotropy factor (A) are calculated. The calculated energy band structures show that the two compounds possess semi-metallic character. We hope that these results would be useful for future work on two compounds.

scholarly journals ELASTIC PROPERTIES OF TRANSITION METAL DIOXIDES: XO2 (X = Ru, Rh, Os, andIr)

2008 ◽  
Vol 19 (08) ◽  
pp. 1269-1275 ◽  
Author(s):  
YANLING LI ◽  
ZHI ZENG
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Shear Modulus ◽  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Debye Temperatures ◽  
Metal Dioxides

The elastic properties of rutile transition metal dioxides XO2 ( X = Ru , Rh , Os , and Ir ) are investigated using first-principles calculations based on density functional theory. Elastic constants, bulk modulus, shear modulus, and Young's modulus as well as Possion ratio are given. OsO 2 and IrO 2 show strong incompressibility. The hardness estimated for these dioxides shows that they are not superhard solids. The obtained Debye temperatures are comparative to those of transition metal dinitrides or diborides.

Stability of Ordered B2-βO and Disordered BCC-β Phases in Tial - A First Principles Study

2021 ◽  
Vol 1016 ◽  
pp. 1159-1165
Author(s):  
Florian Pyczak ◽  
Victoria Kononikhina ◽  
Andreas Stark
Keyword(s):  
First Principles ◽  
Density Functional ◽  
High Energy ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Tial Alloys ◽  
Β Phase ◽  
Phase Ordering ◽  
Strength And Ductility

Either at higher temperatures or when a certain alloying element content is exceeded, γ-TiAl alloys contain the β phase (bcc) or its ordered derivate βo (B2). The relatively soft β phase can facilitate hot deformation, but βo is detrimental for creep strength and ductility. Thus, knowledge about βo→β phase transformation is desirable. Surprisingly, even for the binary Ti-Al system it is under discussion whether the ordered βo phase exists. Also, the effect of alloying elements on the β phase ordering is still unclear. In the present work the ordering of the β phase in binary Ti-(39,42,45)Al and ternary Ti-42Al-2X alloys (X=Fe, Cr, Nb, Ta, Mo) which was experimentally investigated by neutron and high energy X-ray diffraction is compared with the results of first principles calculations using density functional theory. Except for Cr the experimentally determined and the predicted behavior correspond.

First-Principle Studies Al-Fe-Ti-Cr-Zn-Cu High Entropy Solid Solutions with Pressure-Induced

2014 ◽  
Vol 809-810 ◽  
pp. 333-347 ◽  
Author(s):  
Lan Xin Wang ◽  
Shan Yao ◽  
Bin Wen
Keyword(s):  
Bulk Modulus ◽  
Elastic Properties ◽  
Solid Solutions ◽  
Density Functional ◽  
Mechanical Stability ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
High Entropy ◽  
Bcc Structure ◽  
Fcc Structure

The structural properties, elastic properties, mechanical stability, and phase transition of equiatomic Al-Fe-Ti-Cr-Zn-Cu high entropy solid solutions from binary (Al-Fe) to hexanary (Al-Fe-Ti-Cr-Zn-Cu) composition with pressure-induced have been analyzed using density functional theory calculations. The results indicate that the lattice parameters decrease, the mass densities increase with the pressure-increased. The mechanically stability may improve with the pressure increased appropriately for ternary Al-Fe-Ti and quaternary Al-Fe-Ti-Cr. The Young’s modulus has nothing to do with the pressure-induced, but the bulk modulus increases with the pressure increased. The elastic properties were also calculated using Voigt-Reuss-Hill (VRH) approximations. The brittle and ductile properties were studied by Poisson’s ratios and the ratios of shear modulus to bulk modulus. The calculated results of the enthalpy indicate that the binary to hexanary high entropy solid solutions transform the FCC structure to the BCC structure at a certain pressure.

scholarly journals Elastic Properties and Electronic Properties of MxNy (M = Ti, Zr) from First Principles Calculations

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1640 ◽  
Author(s):  
Yangqi Ji ◽  
Xiaoli Yuan
Keyword(s):  
Electronic Properties ◽  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Central Force ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Space Group ◽  
Group I

The elastic properties and electronic properties of MxNy (M = Ti, Zr) TiN, Ti2N, Zr3N4, ZrN with different structures have been investigated using density functional theory. Through the calculation of the elastic constants, it was found that all of these structures meet the mechanical stability except for ZrN with space group P63mc. Their mechanical properties are studied by a comparison of various parameters. The stiffness of TiN is larger than that of ZrN with space group Fm 3 ¯ m. Ti2N’s stiffness with space group I41/amdz is larger than Ti2N with space group P42/mnm. Zr3N4’s stiffness with space group Pnam is largest in three structures of Zr3N4. TiN, Ti2N and ZrN are non-central force, Zr3N4 is central force. TiN and ZrN with space group Fm 3 ¯ m are brittle, and TiN is brittler than ZrN with space group Fm 3 ¯ m. The two kinds of Ti2N are brittle and Ti2N with space group I41/amdz is larger. Three structures of Zr3N4 are tough and Zr3N4 with space group I 4 ¯ 3d is the toughest. Meanwhile, the electronic properties of TiN, Ti2N, Zr3N4 and ZrN were calculated, possible superconducting properties of the studied materials were predicted.

Understanding The Nb-Ti-A1 System: First Principles Calculations

1994 ◽  
Vol 364 ◽  
Author(s):  
Michael J. Mehl
Keyword(s):  
High Temperature ◽  
Bulk Modulus ◽  
Total Energy ◽  
Crystal Structures ◽  
Lattice Constant ◽  
Density Of States ◽  
First Principles ◽  
First Principles Calculations ◽  
Electronic Density ◽  
Cubic Phases

AbstractThe discovery of ductile cubic phases in the Nb-Ti-Al system has led to increased study of these high-temperature intermetallics. I have performed first-principles calculations for ordered crystal structures in this system, paying particular attention to the Nb7Ti7Al2 structure. Somewhat surprisingly, the electronic density of states, lattice constant, and bulk modulus are nearly independent of the ordering of these materials, even though the changes in the total energy are significant.

STRUCTURAL, ELECTRONIC, THERMODYNAMIC AND THERMAL PROPERTIES OF ZINC-BLENDE InP, InAs AND THEIR InAsx P1-x TERNARY ALLOYS VIA FIRST PRINCIPLES CALCULATIONS

2013 ◽  
Vol 27 (27) ◽  
pp. 1350166 ◽  
Author(s):  
O. NEMIRI ◽  
S. GHEMID ◽  
Z. CHOUAHDA ◽  
H. MERADJI ◽  
F. EL HAJ HASSAN
Keyword(s):  
Thermal Properties ◽  
Bulk Modulus ◽  
Band Gap ◽  
Lattice Constant ◽  
First Principles ◽  
Density Functional ◽  
Experimental Studies ◽  
Ternary Alloys ◽  
Full Potential ◽  
First Principles Calculations

First-principles calculations are performed to study the structural, electronic, thermodynamic and thermal properties of the InP and InAs bulk materials and InAs x P 1-x ternary alloys using the full potential-linearized augmented plane wave method (FP-LAPW) within the density functional theory (DFT). The dependence of the lattice constant, bulk modulus, band gap, Debye temperature, heat capacity and mixing entropy on the composition x was analyzed. The lattice constant for InAs x P 1-x alloys exhibits a marginal deviation from the Vegard's law. A large deviation of the bulk modulus from linear concentration dependence (LCD) was observed for our alloys. We found that the composition dependence of the energy band gap is almost linear by using the mBJ and EV-GGA approximations. The microscopic origins of the gap bowing were explained and detailed by using the approach of Zunger and co-workers. Furthermore, the calculated phase diagram shows a miscibility gap for these alloys with a high critical temperature. Thermal effects on some macroscopic properties of InAs x P 1-x alloys are predicted using the quasi-harmonic Debye model, in which the phononic effects are considered. This is the first quantitative theoretical prediction of the thermal properties of the InAs x P 1-x alloys, and we still expect the confirmation of experimental studies.

First-Principles Calculations of the Structure and Magnetic Phases of FeAs2 Compound under Pressure

SPIN ◽  
2018 ◽  
Vol 08 (04) ◽  
pp. 1850016 ◽  
Author(s):  
O. Sebaa ◽  
Y. Zaoui ◽  
K. O. Obodo ◽  
H. Bendaoud ◽  
L. Beldi ◽  
...  
Keyword(s):  
Phase Transition ◽  
First Principles ◽  
Density Functional ◽  
Stable Phase ◽  
Spin Orbit Coupling ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Electronic Density ◽  
Functional Theory ◽  
Spin Ordering

Understanding of different magnetic configurations for the FeAs2 iron pnictide compound is carried out using first-principles studies based on spin density functional theory (DFT) within the generalized gradient approximation (GGA), including the spin–orbit coupling (SOC). The calculated stable phase is in the marcasite (Pnnm) with nonmagnetic spin-ordering. We find that the FeAs2 compound in the nonmagnetic (NM) marcasite phase undergoes pressure-induced phase transition to the antiferromagnetic (AFM1) marcasite phase at 12[Formula: see text]GPa, then to the AFM CuAl2 ([Formula: see text]4/mcm) phase at 63[Formula: see text]GPa. The phase transition is also accompanied by semiconducting (marcasite phase) to metallic (CuAl2 phase) transition. The calculated electronic density of states profile shows the hybridization of the Fe-3[Formula: see text] and As-4[Formula: see text] orbitals plays an important role in determining the electronic and magnetic characters of this compound. The associated phase transition results in increased Fe-3d orbitals around the Fermi energy level.

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