First principles calculations of formation energies and elastic constants of inclusions α-Al2O3, MgO and AlN in aluminum alloy

2016 ◽  
Vol 30 (16) ◽  
pp. 1650085 ◽  
Author(s):  
Yu Liu ◽  
Yuanchun Huang ◽  
Zhengbing Xiao ◽  
Chuge Yang ◽  
Xianwei Reng
Keyword(s):  
Elastic Properties ◽  
Rock Salt ◽  
Elastic Constants ◽  
Ground State ◽  
First Principles ◽  
Aluminum Matrix ◽  
First Principles Calculations ◽  
Anisotropy Index ◽  
State Formula ◽  
Formation Energies

In this paper, the formation energies and elastic constants of [Formula: see text]-Al2O3, MgO and AlN in both rock salt (cubic) and wurtzite (hexagonal) structures were investigated by first principles calculations. The results show that the formation energy being −17.8, −6.3, −3.06 and −3.46 eV/formula unit for [Formula: see text]-Al2O3, MgO, AlN (rock salt) and AlN (wurtzite). It suggests that in the ground state, [Formula: see text]-Al2O3 is relatively more stable than MgO and AlN. The elastic properties for a polycrystalline in the ground state were calculated with the obtained elastic constants, the elastic properties reveal the rock salt structure AlN is the hardest particles among all the inclusions, and all of these inclusions are classified as brittle materials, which is detrimental to the ductile nature of aluminum matrix. The calculated anisotropy index shows that the AlN (wurtzite) and [Formula: see text]-Al2O3 have a lower degree of anisotropy compared with MgO and AlN (rock salt). The calculated results are in good agreement with the values of experimental and other works.

New Pt-based Superalloy System Designed from First Principles

2008 ◽  
Vol 1128 ◽  
Author(s):  
Vsevolod I. Razumovskiy ◽  
Eyvaz I. Isaev ◽  
Andrei V. Ruban ◽  
Pavel A. Korzhavyi
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Defect Formation ◽  
Alloy System ◽  
First Principles Calculations ◽  
Phonon Spectra ◽  
Ultrahigh Temperature ◽  
New Generation ◽  
Formation Energies ◽  
Temperature Applications

AbstractPt-Sc alloys with the γ-γ′ microstructure are proposed as a basis for a new generation of Pt-based superalloys for ultrahigh-temperature applications. This alloy system was identified on the basis of first-principles calculations. Here we discuss the prospects of the Pt-Sc alloy system on the basis of calculated elastic properties, phonon spectra, and defect formation energies.

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 First-principles calculations of structural, electronic, magnetic and elastic properties of Mo 2 FeB 2 under high pressure

2018 ◽  
Vol 5 (7) ◽  
pp. 172247
Author(s):  
Bin Wang ◽  
Benyuan Ma ◽  
Wei Song ◽  
Zhe Fu ◽  
Zhansheng Lu
Keyword(s):  
Heat Capacity ◽  
High Pressure ◽  
Elastic Properties ◽  
First Principles ◽  
Dynamic Properties ◽  
Magnetic Moments ◽  
Debye Model ◽  
Ferromagnetic Phase ◽  
First Principles Calculations ◽  
Anisotropy Index

The structural, electronic, magnetic and elastic properties of Mo 2 FeB 2 under high pressure have been investigated with first-principles calculations. Furthermore, the thermal dynamic properties of Mo 2 FeB 2 were also studied with the quasi-harmonic Debye model. The volume of Mo 2 FeB 2 decreases with the increase in pressure. Using the analysis of the density of the states, atom population and Mulliken overlap population, it is observed that as the pressure increases, the B–B bonds are strengthened and the B–Mo covalency decreases. Moreover, for all pressures, Mo 2 FeB 2 is detected in the anti-ferromagnetic phase and the magnetic moments decrease with the increase in pressure. The calculated bulk modulus, shear modulus, Young's modulus, Poisson's ratio and universal anisotropy index all increase with the increase in pressure. From thermal expansion coefficient analysis, it is found that Mo 2 FeB 2 shows good volume invariance under high pressure and temperature. The examination of the dependence of heat capacity on the temperature and pressure shows that heat capacity is more sensitive to temperature than to pressure.

First-Principles Calculations of the Elastic Properties of the Nickel-Based L12 Intermetallics

1995 ◽  
Vol 408 ◽  
Author(s):  
D. Iotova ◽  
N. Kioussis ◽  
S. P. Lim ◽  
S. Sun ◽  
R. Wu
Keyword(s):  
Electronic Structure ◽  
Total Energy ◽  
Ab Initio ◽  
Elastic Properties ◽  
Elastic Constants ◽  
First Principles ◽  
Anisotropy Factor ◽  
Full Potential ◽  
First Principles Calculations ◽  
Linear Muffin Tin Orbital

AbstractThe elastic constants of the L12-type ordered nickel-based intermetallics Ni3X (X = Mn, Al, Ga, Si, Ge), have been calculated by means of ab initio total-energy electronic structurecalculations based on the full-potential linear-muffin-tin-orbital (FLMTO) method. Theorigins in the electronic structure of the variation of the elastic constants, bulk and shearmoduli are investigated across the series, and the effects of the anisotropy of bonding chargedensity on the shear anisotropy factor and the degree of ductility is discussed.

Structural and elastic properties of TiN and AlN compounds: first-principles study

2014 ◽  
Vol 32 (2) ◽  
pp. 220-227 ◽  
Author(s):  
Meriem Fodil ◽  
Amine Mounir ◽  
Mohammed Ameri ◽  
Hadj Baltache ◽  
Bachir Bouhafs ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Elastic Properties ◽  
Rock Salt ◽  
Elastic Constants ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Data ◽  
Generalized Gradient ◽  
Tin Compounds ◽  
Shear Moduli

AbstractFirst-principles calculations of the lattice constants, bulk modulus, pressure derivatives of the bulk modulus and elastic constants of AlN and TiN compounds in rock-salt (B1) and wurtzite (B4) structures are presented. We have used the fullpotential linearized augmented plane wave (FP-LAPW) method within the density functional theory (DFT) in the generalized gradient approximation (GGA) for the exchange-correlation functional. Moreover, the elastic properties of cubic TiN and hexagonal AlN, including elastic constants, bulk and shear moduli are determined and compared with previous experimental and theoretical data. Our results show that the structural transition at 0 K from wurtzite to rock-salt phase occurs at 10 GPa and −26 GPa for AlN and TiN, respectively. These results are consistent with those of other studies found in the literature.

scholarly journals First principles calculations of the structural, electronic, magnetic, and thermodynamic properties of the Nd2MgGe2 and Gd2MgGe2 intermetallic compounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Menouer ◽  
O. Miloud Abid ◽  
A. Benzair ◽  
A. Yakoubi ◽  
H. Khachai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermodynamic Properties ◽  
Ground State ◽  
First Principles ◽  
Essential Role ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Rare Earth Compounds ◽  
First Principles Calculations ◽  
Antiferromagnetic Ground State

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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