scholarly journals Relationship between the Behavior of Hydrogen and Hydrogen Bubble Nucleation in Vanadium

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 322
Author(s):  
Zhengxiong Su ◽  
Sheng Wang ◽  
Chenyang Lu ◽  
Qing Peng
Keyword(s):  
Hydrogen Atom ◽  
First Principles ◽  
Bound States ◽  
Hydrogen Molecule ◽  
Vacancy Cluster ◽  
Bubble Nucleation ◽  
Hydrogen Bubble ◽  
First Principles Calculations ◽  
Hydrogen Atoms ◽  
Macroscopic Deformation

Hydrogen plays a significant role in the microstructure evolution and macroscopic deformation of materials, causing swelling and surface blistering to reduce service life. In the present work, the atomistic mechanisms of hydrogen bubble nucleation in vanadium were studied by first-principles calculations. The interstitial hydrogen atoms cannot form significant bound states with other hydrogen atoms in bulk vanadium, which explains the absence of hydrogen self-clustering from the experiments. To find the possible origin of hydrogen bubble in vanadium, we explored the minimum sizes of a vacancy cluster in vanadium for the formation of hydrogen molecule. We show that a freestanding hydrogen molecule can form and remain relatively stable in the center of a 54-hydrogen atom saturated 27-vacancy cluster.

Investigation of hydrogen diffusion behavior in 12Cr2Mo1R(H) steel by electrochemical tests and first-principles calculation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiang Qiu ◽  
Kun Zhang ◽  
Qin Kang ◽  
Yicheng Fan ◽  
Hongyu San ◽  
...  
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Hydrogen Atom ◽  
Hydrogen Embrittlement ◽  
First Principles ◽  
Hydrogen Diffusion ◽  
First Principles Calculations ◽  
Content Type ◽  
Diffusion Behavior ◽  
Hydrogen Diffusion Coefficient

Purpose This paper aims to study the mechanism of hydrogen embrittlement in 12Cr2Mo1R(H) steel, which will help to provide valuable information for the subsequent hydrogen embrittlement research of this kind of steel, so as to optimize the processing technology and take more appropriate measures to prevent hydrogen damage. Design/methodology/approach The hydrogen diffusion coefficient of 12Cr2Mo1R(H) steel was measured by the hydrogen permeation technique of double electrolytic cells. Moreover, the influence of hydrogen traps in the material and experimental temperature on hydrogen diffusion behavior was discussed. The first-principles calculations based on density functional theory were used to study the occupancy of H atoms in the bcc-Fe cell, the diffusion path and the interaction with vacancy defects. Findings The results revealed that the logarithm of the hydrogen diffusion coefficient of the material has a linear relationship with the reciprocal of temperature and the activation energy of hydrogen atom diffusion in 12Cr2Mo1R(H) steel is 23.47 kJ/mol. H atoms stably exist in the nearly octahedral interstices in the crystal cell with vacancies. In addition, the solution of Cr/Mo alloy atom does not change the lowest energy path of H atom, but increases the diffusion activation energy of hydrogen atom, thus hindering the diffusion of hydrogen atom. Cr/Mo and vacancy have a synergistic effect on inhibiting the diffusion of H atoms in α-Fe. Originality/value This article combines experiments with first-principles calculations to explore the diffusion behavior of hydrogen in 12Cr2Mo1R(H) steel from the macroscopic and microscopic perspectives, which will help to establish a calculation model with complex defects in the future.

scholarly journals Rectifying Performance of Heterojunction Based on α-Borophene Nanoribbons with Edge Passivation

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Guoliang Yu ◽  
Wence Ding ◽  
Xianbo Xiao ◽  
Xiaobo Li ◽  
Guanghui Zhou
Keyword(s):  
Electronic Transport ◽  
First Principles ◽  
First Principles Calculations ◽  
Zigzag Edge ◽  
Hydrogen Atoms ◽  
Rectification Effect ◽  
Structural Details ◽  
Potential Applications ◽  
Matching Degree ◽  
The Right

Abstract We propose a planar model heterojunction based on α-borophene nanoribbons and study its electronic transport properties. We respectively consider three types of heterojunctions. Each type consists of two zigzag-edge α-borophene nanoribbons (Z αBNR), one is metallic with unpassivated or passivated edges by a hydrogen atom (1H-Z αBNR) and the other is semiconducting with the edge passivated by two hydrogen atoms (2H-Z αBNR) or a single nitrogen atom (N-Z αBNR). Using the first-principles calculations combined with the nonequilibrium Green’s function, we observe that the rectifying performance depends strongly on the atomic structural details of a junction. Specifically, the rectification ratio of the junction is almost unchanged when its left metallic ribbon changes from ZBNR to 1H-Z αBNR. However, its ratio increases from 120 to 240 when the right semiconducting one varies from 2H-Z αBNR to N-Z αBNR. This rectification effect can be explained microscopically by the matching degree the electronic bands between two parts of a junction. Our findings imply that the borophene-based heterojunctions may have potential applications in rectification nano-devices.

scholarly journals DISPERSION INTERACTION OF ATOMS WITH SINGLE-WALLED CARBON NANOTUBES DESCRIBED BY THE DIRAC MODEL

2011 ◽  
Vol 03 ◽  
pp. 555-563 ◽  
Author(s):  
YU. V. CHURKIN ◽  
A. B. FEDORTSOV ◽  
G. L. KLIMCHITSKAYA ◽  
V. A. YUROVA
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Atom ◽  
Interaction Energy ◽  
Hydrogen Molecule ◽  
Single Walled Carbon Nanotubes ◽  
Hydrogen Atoms ◽  
Single Walled Carbon ◽  
Atoms And Molecules ◽  
Proximity Force Approximation ◽  
Walled Carbon Nanotubes

We calculate the interaction energy and force between atoms and molecules and single-walled carbon nanotubes described by the Dirac model of graphene. For this purpose the Lifshitz-type formulas adapted for the case of cylindrical geometry with the help of the proximity force approximation are used. The results obtained are compared with those derived from the hydrodymanic model of graphene. Numerical computations are performed for hydrogen atoms and molecules. It is shown that the Dirac model leads to larger values of the van der Waals force than the hydrodynamic model. For a hydrogen molecule the interaction energy and force computed using both models are larger than for a hydrogen atom.

First-principles calculations of hydrogen molecule adsorption on Ti (0001)-(2×1) surface

2009 ◽  
Vol 255 (17) ◽  
pp. 7512-7516 ◽  
Author(s):  
J.X. Guo ◽  
L. Guan ◽  
F. Bian ◽  
Q. Li ◽  
B. Geng ◽  
...  
Keyword(s):  
First Principles ◽  
Hydrogen Molecule ◽  
First Principles Calculations ◽  
Molecule Adsorption

scholarly journals Hydrogenated derivatives of hexacoordinated metallic Cu2Si monolayer

RSC Advances ◽  
2018 ◽  
Vol 8 (70) ◽  
pp. 39976-39982 ◽  
Author(s):  
E. Unsal ◽  
F. Iyikanat ◽  
H. Sahin ◽  
R. T. Senger
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Surface Functionalization ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Derivatives Of

Herein, we carried out first-principles calculations based on density functional theory to investigate the effects of surface functionalization with hydrogen atoms on structural, dynamical and electronic properties of Cu2Si monolayer.

scholarly journals DISPERSION INTERACTION OF ATOMS WITH SINGLE-WALLED CARBON NANOTUBES DESCRIBED BY THE DIRAC MODEL

2011 ◽  
Vol 26 (22) ◽  
pp. 3958-3966 ◽  
Author(s):  
YU. V. CHURKIN ◽  
A. B. FEDORTSOV ◽  
G. L. KLIMCHITSKAYA ◽  
V. A. YUROVA
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Atom ◽  
Interaction Energy ◽  
Hydrogen Molecule ◽  
Single Walled Carbon Nanotubes ◽  
Hydrogen Atoms ◽  
Single Walled Carbon ◽  
Atoms And Molecules ◽  
Proximity Force Approximation ◽  
Walled Carbon Nanotubes

We calculate the interaction energy and force between atoms and molecules and single-walled carbon nanotubes described by the Dirac model of graphene. For this purpose the Lifshitz-type formulas adapted for the case of cylindrical geometry with the help of the proximity force approximation are used. The results obtained are compared with those derived from the hydrodymanic model of graphene. Numerical computations are performed for hydrogen atoms and molecules. It is shown that the Dirac model leads to larger values of the van der Waals force than the hydrodynamic model. For a hydrogen molecule the interaction energy and force computed using both models are larger than for a hydrogen atom.

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