scholarly journals First-Principles Determination Of The Effects Of Boron And Sulfur On The Ideal Cleavage Fracture In Ni3Al

1995 ◽  
Vol 409 ◽  
Author(s):  
Sheng N. Sun ◽  
Nicholas Kioussis ◽  
Mikael Ciftan ◽  
A. Gonis
Keyword(s):  
Cleavage Fracture ◽  
First Principles ◽  
Cleavage Plane ◽  
Full Potential ◽  
Fracture Properties ◽  
Electronic Mechanism ◽  
Strain Relationship ◽  
First Time ◽  
The Ideal

AbstractThe effects of boron and sulfur impurities on the ideal cleavage fracture properties of Ni3Al under tensile stress are investigated for the first time using the full-potential linearmuffin- tin-orbital (FLMTO) total-energy method, with a repeated slab arrangement of atoms simulating an isolated cleavage plane. Results for the stress-strain relationship, ideal cleavage energies, ideal yield stress and strains with and without impurities are presented, and the electronic mechanism underlying the contrasting effects of boron and sulfur impurities on the ideal cleavage of Ni3Al is elucidated.

First-principles determination of the effects of boron and sulfur on the ideal cleavage fracture inNi3Al

1996 ◽  
Vol 54 (5) ◽  
pp. 3074-3078 ◽  
Author(s):  
Sheng N. Sun ◽  
Nicholas Kioussis ◽  
Mikael Ciftan
Keyword(s):  
Cleavage Fracture ◽  
First Principles ◽  
The Ideal

First-principles study of the ideal cleavage fracture of Cr2Nb microalloyed by X (Al, Ni, Co, Ti)

2009 ◽  
Vol 17 (6) ◽  
pp. 394-399 ◽  
Author(s):  
Chenliang Li ◽  
Biao Wang ◽  
Yuanshi Li ◽  
Rui Wang
Keyword(s):  
Cleavage Fracture ◽  
First Principles ◽  
First Principles Study ◽  
The Ideal

First Principles Study on Structural, Electronic, Elastic and Thermal Properties of OsAl and OsSi

2014 ◽  
Vol 1047 ◽  
pp. 71-77 ◽  
Author(s):  
Nikita Acharya ◽  
Bushra Fatima ◽  
Sunil Singh Chouhan ◽  
Sankar P. Sanyal
Keyword(s):  
Thermal Properties ◽  
First Principles ◽  
Full Potential ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Plane Wave Method ◽  
Lattice Constants ◽  
First Principles Study ◽  
First Time ◽  
Good Agreement

First - principles study on structural, electronic, elastic and thermal properties of B2phase OsAl and OsSi have been reported usingab-initio full potential linearized plane wave method (FP-LAPW) method within generalized gradient approximation (GGA). We have calculated ground state and electronic properties such as lattice constant (a0), bulk modulus (B0), its pressure derivative (B0') and density of states at Fermi level N(EF). Lattice constants are in good agreement with other results. The elastic constants (C11, C12and C44) are also calculated for these compounds. Ductility has been analyzed by Pugh’s rule (B/GH) ratio and Cauchy’s pressure (C12-C44). To the best of our knowledge, these properties are calculated first time.

scholarly journals Атомная и электронная структура реконструкций поверхности (111) в кристаллах ZnSe и CdSe

2018 ◽  
Vol 60 (1) ◽  
pp. 187
Author(s):  
В.Л. Бекенев ◽  
С.М. Зубкова
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
A Charge ◽  
Quantum Espresso ◽  
First Time ◽  
Vacuum Gap ◽  
The Ideal

AbstractThe atomic and electron structure of four variants of polar (111)-(2 × 2) surfaces in ZnSe and CdSe terminated by a cation, namely, the ideal, relaxed, reconstructed, and relaxed after reconstruction surfaces, are calculated for the first time from the first principles. The surface is simulated by a film with a thickness of 12 atomic layers and a vacuum gap of ~16 Å in the layered superlattice approximation. Four fictitious hydrogen atoms with a charge of 0.5 electrons each are added for closing dangling Se bonds on the opposite side of the film. Ab initio calculations are performed using the QUANTUM ESPRESSO software based on the density functional theory. It is shown that relaxation results in splitting of atomic layers. We calculate and analyze the band structures and total and layer-wise densities of electron states for four variants of the surface.

Structure determination of (Fe3O4)n+(n = 1 − 3) clusters via DFT

2016 ◽  
Vol 30 (19) ◽  
pp. 1650239 ◽  
Author(s):  
Yanhua Li ◽  
Congzhong Cai ◽  
Chengjun Zhao ◽  
Yonghong Gu
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Global Minimum ◽  
Pso Algorithm ◽  
Experimental Ir ◽  
Functional Theory ◽  
Exchange Correlation ◽  
First Time ◽  
In Virtue Of

In virtue of the particle swarm optimization (PSO) algorithm, the global minimum candidate structures with the lowest energy for [Formula: see text] clusters were obtained by first-principles structural searches. The geometric structures and spin configurations of three cationic [Formula: see text] clusters have been identified for the first time by comparing the experimental IR spectra with the calculated results from density functional theory by using different exchange-correlation functionals. It is found that the lowest energy structures of these clusters are of a shape of hat, boat and tower, respectively, with a ferrimagnetic arrangement of spins, and M06L functional is more suitable for [Formula: see text] clusters than other ones.

Structures of Na0.74WO3

2003 ◽  
Vol 59 (5) ◽  
pp. 584-587 ◽  
Author(s):  
C. N. W. Darlington ◽  
J. A. Hriljac ◽  
K. S. Knight
Keyword(s):  
Normal Modes ◽  
Stable Phase ◽  
Cubic Phase ◽  
Temperature Phase ◽  
Modes Of Vibration ◽  
Diffraction Patterns ◽  
First Time ◽  
Low Temperature Phase ◽  
The Ideal

The structures of the four phases exhibited by Na0.74WO3, sodium tungstate, with a change in temperature have been refined from powder diffraction patterns obtained on the high-resolution powder diffractometer (HRPD), ISIS, Rutherford Appleton Laboratory, England. At temperatures above 430 K, the stable phase has the ideal perovskite structure, with space group Pm\bar 3m (No. 221). Below that temperature, the octahedra are tilted about pseudocubic 〈100〉 directions; the tilts are produced by the condensation of the normal modes of vibration of the octahedra in the high-temperature cubic phase. Using Glazer's notation, the tilt system undergoes the following sequence:a^+a^+a^+ \buildrel {\rm 293\, K} \over \longrightarrow a^+a^+a^0 \buildrel {\rm 343\, K} \over \longrightarrow a^0a^0a^+ \buildrel {\rm 430\, K} \over \longrightarrow a^0a^0a^0 .The structural refinements presented here confirm the sequence of the transitions first proposed by Clarke [(1977). Phys. Rev. Lett. 39, 1550–1553]. This is the first time that a structure determination of a perovskite with the tilt system a + a + a 0 has been reported in the literature. In addition, we evaluate the weights, or importance, of the condensed modes in each low-temperature phase.

Effects of X (V, W, Mo, Hf, Ta, Zr) additions on the ideal cleavage fracture of Cr2Nb: First-principles determination

2010 ◽  
Vol 18 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Chenliang Li ◽  
Jerlai Kuo ◽  
Biao Wang ◽  
Rui Wang
Keyword(s):  
Cleavage Fracture ◽  
First Principles ◽  
The Ideal
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