scholarly journals First-Principles Study on the Mechanical Properties and Electronic Structure of V Doped WCoB and W2CoB2 Ternary Borides

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 967 ◽  
Author(s):  
Tong Zhang ◽  
Haiqing Yin ◽  
Cong Zhang ◽  
Ruijie Zhang ◽  
Xue Jiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Shear Modulus ◽  
Density Of States ◽  
Formation Energy ◽  
Partial Density ◽  
Doping Content ◽  
Transition Elements ◽  
Covalent Bonds ◽  
Ternary Boride

For the purpose of exploring new hard materials and doping methods, the structural, mechanical and electronic properties of WCoB and W2CoB2 ternary boride were investigated with 0, 8.33, 16.67, 25 and 33.33 at.% V doping content and W2CoB2 with 0, 5, 10, 15 and 20 at.% V doping content by first-principle calculations. The cohesive energy, impurity formation energy and formation energy indicate the structural stability of V doped WCoB and W2CoB2. The elastic constants and mechanical properties imply that V doping leads to the decrement of shear modulus and the increment of ductility. Two different kinds of hardness models verify that V doping contributes to the decrement of hardness, which is closely related to shear modulus. The electronic structure is analyzed by DOS (density of states), PDOS (partial density of states) and charge density difference, which indicate the formation of weaker B–V covalent bonds, W–V and W–W metallic bonds lead to the decrement of mechanical properties. Compared with previous studies of Cr, Mn doped WCoB and W2CoB2, V doping leads to worse mechanical properties and hardness, indicating V may not be a suitable choice of doping transition elements.

First Principles Investigation of Electronic Structure, Chemical Bonding, Elastic and Optical Properties of Novel Rhenium Nitrides

2012 ◽  
Vol 512-515 ◽  
pp. 883-889
Author(s):  
Qing Lin Xia ◽  
Liu Xian Pan ◽  
Yuan Dong Peng ◽  
Li Ya Li ◽  
Hong Zhong Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Density Of States ◽  
Chemical Bonding ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Hexagonal Phase ◽  
Partial Density

we investigate the electronic structure, chemical bonding, optical and elastic properties of the novel rhenium nitrides, hexagonal phase re3n and re2n by using density-functional theory (dft) within generalized gradient approximation (gga). the calculated equilibrium lattice constants of both re3n and re2n are in reasonable agreement with the experimental results. the band structure along the higher symmetry axes in the Brillouin zone, the density of states (dos) and the partial density of states (pdos) are presented. the calculated energy band structures and dos show that re3n and re2n are metal compounds. The dos and pdos show that the dos at the fermi level (ef) is located at the bottom of a valley and originate mainly from the 5d electrons of re. population analyses suggest that the chemical bonding in re3n and re2n has predominantly covalent character with mixed covalent and ionic characteristics. the dielectric function, reflectivity, absorption coefficient, refractive index, electron energy-loss function and optical conductivity are presented in an energy range for discussing the optical properties of re3n and re2n. basic mechanical properties, such as elastic constants cij, bulk modulus b and shear modulus g are calculated. The young’s modulus e, poisson's ratio ν and bh/gh are also predicted. results conclude that the hexagonal phase re3n and re2n are mechanical stable and behaves in a ductile manner. polycrystalline elastic anisotropy is also derived from polycrystalline bulk modulus b and shear modulus g.

Electronic Structure and Mechanical Properties of Zircaloy-2 and Zircaloy-4: A First Principle Study

2013 ◽  
Author(s):  
Chunhai Lu ◽  
Wenkai Chen ◽  
Min Chen ◽  
Shijun Ni ◽  
Chengjiang Zhang
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Zirconium Alloy ◽  
Local Density ◽  
Partial Density ◽  
Total Density ◽  
First Principle ◽  
Density Of State ◽  
Virtual Crystal Approximation ◽  
Anisotropic Mechanical Properties

The local-density approximation (LDA) coupled with the virtual crystal approximation (VCA) method electronic structure is applied to evaluate elastic constants, bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio mechanic properties of metal zirconium, Zircaloy-2 and Zircaloy-4. The results show that there is no obvious difference in band structure and total density of state (DOS) between metal zirconium and zirconium alloy. However, p and d electron partial density of state (PDOS) presents the slight difference between metal zirconium and zirconium alloy. Zircaloy-2 and Zircaloy-4 present better elastic mechanical properties than metal zirconium. The metal zirconium and zirconium alloy show the anisotropic mechanical properties.

Effect of Cr doping on the mechanical properties and electronic structure of WCoB ternary boride by first-principles calculations

2018 ◽  
Vol 32 (21) ◽  
pp. 1850240 ◽  
Author(s):  
Tong Zhang ◽  
Haiqing Yin ◽  
Cong Zhang ◽  
Xuanhui Qu ◽  
Qingjun Zheng
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Structural Stability ◽  
First Principles ◽  
Formation Enthalpy ◽  
First Principles Calculations ◽  
Metal Interactions ◽  
Metal Metal ◽  
Ternary Boride ◽  
Cr Doping

The lattice parameters, structural stability, mechanical properties, hardness and electronic structure of WCoB with Cr alloying were investigated by using first-principles calculations. The Cr atom was selected to replace 0, 1, 2, 3, 4 Co atoms in WCoB crystal and 0, 1, 2 Co atoms in W2CoB2 crystal. The calculated cohesive energy and formation enthalpy showed that all structures can retain good structural stability with different Cr doping content. The calculated mechanical properties showed Cr doping will decrease the shear modulus, Young’s modulus, bulk modulus and hardness, but increase the ductility. The larger number of valence electrons of Cr led to the increasing of bond covalence and population. According to the electronic structures analysis, the nonmetal–metal hybridization and metal–metal interactions contributed to relatively high toughness.

First-Principles Study of Electronic Structure and Optical Properties of V-Doped CrSi2

2015 ◽  
Vol 1104 ◽  
pp. 125-130 ◽  
Author(s):  
Fang Gui ◽  
Shi Yun Zhou ◽  
Wan Jun Yan ◽  
Chun Hong Zhang ◽  
Shao Bo Chen
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Density Of States ◽  
Density Functional ◽  
Partial Density ◽  
Optical Parameters ◽  
Total Density ◽  
Type Semiconductor ◽  
Refractive Index Increase ◽  
P Type

The electronic structure and optical properties of V-doped CrSi2 have been calculated by using the first-principle peudo-potential plane-wave method based on the density functional theory.The parameters and properties of structure were given and the theory data were offered to research the effect of V doping into CrSi2. The calculations of energy band structure, total density of states, partial density of states of V-doped CrSi2were analysed. Fermi level enters into valence band which makes the V-doped CrSi2to be p-type semiconductor that improves the electrical conductivity of material. Additionally, the optical parameters of V-doped CrSi2were also discussed. It was found that both static dielectric constant and static refractive index increase after doping.

Electrical transport and mechanical properties of thermoelectric tin selenide

RSC Advances ◽  
2016 ◽  
Vol 6 (14) ◽  
pp. 11562-11569 ◽  
Author(s):  
Kriti Tyagi ◽  
Bhasker Gahtori ◽  
Sivaiah Bathula ◽  
Niraj Kumar Singh ◽  
Swati Bishnoi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Band Structure ◽  
Density Of States ◽  
Electrical Transport ◽  
Electronic Band Structure ◽  
Partial Density ◽  
Electronic Band ◽  
Tin Selenide ◽  
Partial Density Of States

Electronic band structure and partial density of states for Cmcm phase of SnSe.

First principles study of influence of alloying elements on TiAl: Lattice distortion

1999 ◽  
Vol 14 (7) ◽  
pp. 2824-2829 ◽  
Author(s):  
Y. Song ◽  
R. Yang ◽  
D. Li ◽  
W. T. Wu ◽  
Z. X. Guo
Keyword(s):  
Electronic Structure ◽  
Bond Strength ◽  
Density Of States ◽  
First Principles ◽  
Lattice Distortion ◽  
Alloying Elements ◽  
Cluster Method ◽  
Partial Density ◽  
Ternary Additions ◽  
The Individual

The influence of ternary additions Cr, Fe, Mn, Ni, Zr, Nb, Mo, Hf, Ta, Si, Ga, Ge, In, and Sb, as well as the anti-site defects of both Ti and Al, on lattice parameters of TiAl were studied by the first principles electronic structure calculations with a discrete variational cluster method. The results of the calculation show that the effect of ternary additions on the distortion of TiAl lattice varies with the substitution behavior of the individual alloying element involved. The addition of alloying elements in TiAl causes a change in the electronic structure and the density of states of the system and results in variation of the bond strength between the atoms. The total and partial density of states (DOS) of binary TiAl and of ternary TiAl–M, M = Cr, Zr, and Sb, etc., were comparatively examined. The relationship between the DOS and the bond strength is discussed. The present work suggests that the origin of the lattice distortion of the ternary TiAl–M systems lies in the variation of the electronic structure.

First-principle investigation of electronic structure and mechanical properties of AlMgB14

2009 ◽  
Vol 1224 ◽  
Author(s):  
Liwen F Wan ◽  
Scott P Beckman
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Ab Initio ◽  
Density Of States ◽  
Fermi Energy ◽  
First Principle ◽  
Metal Atoms ◽  
Structural And Electronic Properties ◽  
The Impact ◽  
Atomic And Electronic Structure

AbstractThe structural and electronic properties of AlMgB14 are investigated using ab initio methods. The impact of vacancies and electron doping on the crystal’s atomic and electronic structure is investigated. It is found that removing metal atoms does not influence the density of states, except for changes to the Fermi energy. The density of states of the off-stoichiometric Al0.75Mg0.75B14 crystal and the AlMgB14 crystal with five electrons removed are nearly identical. The removal of six electrons results in an 11% contraction in the crystal’s volume. This is associate with the removal of electrons from the B atoms’ 2p-states.

ELECTRONIC STRUCTURE AND GROUND STATE PROPERTIES OF NON-MAGNETIC NiPt SYSTEMS

2003 ◽  
Vol 17 (25) ◽  
pp. 4447-4456 ◽  
Author(s):  
DURGA PAUDYAL ◽  
ABHIJIT MOOKERJEE
Keyword(s):  
Electronic Structure ◽  
Density Of States ◽  
Ground State ◽  
Cohesive Energy ◽  
Formation Energy ◽  
Relativistic Correction ◽  
Orbital Method ◽  
High Concentration ◽  
Charge Neutrality ◽  
Ground State Properties

We have studied the electronic properties like density of states and band structures and also the ground state properties like formation energy, cohesive energy, bulk modulus and structural energy of NiPt system using the linearized muffin-tin orbital method introduced by Andersen.1,2 In an earlier communication we had argued that both charge neutrality and scalar relativistic corrections are very important for the high concentration of Pt alloys. The calculations here, were, therefore, carried out with charge neutrality as well as with and without scalar relativistic correction for comparison.

First-Principles Investigation Density of States for LiNi1-xCoxO2 with x=0, 1/3, 2/3 and 1

2011 ◽  
Vol 239-242 ◽  
pp. 1862-1865 ◽  
Author(s):  
Yi Jie Gu ◽  
Yun Bo Chen ◽  
Hong Quan Liu ◽  
Hui Kang Wu ◽  
Xiao Wen Huang ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Crystal Field ◽  
Density Of States ◽  
Density Functional ◽  
Electronic Structure Calculations ◽  
Crystal Field Splitting ◽  
Partial Density ◽  
Exchange Splitting ◽  
Field Splitting ◽  
Structure Calculations

Computational studies have been carried out on the LiNi1-xCoxO2compounds based on density-functional theory. Quantum-mechanical calculations are performed using a total-energy pseudopotential code. Density of states and partial density of states are calculated with the considering the spin state of Ni and Co. Electronic structure calculations suggest that the exchange splitting is controlled by Co content. As the Co content increased, the exchange splitting decreased. Electronic structure calculations show that the crystal field splitting is controlled by the second content. With Co contents increasing, the crystal field splitting decreased for LiNi1-xCoxO2with x=0, 1/3 and 2/3. The study also shows that the interaction of Ni ion with surrounding O ions and Li ions will be changed and prevents Li ions from leaving LiNiO2with the increasing substitution Co for Ni in LiNiO2.

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