scholarly journals Partitioning of Interstitial Segregants during Decohesion: A DFT Case Study of the Σ3 Symmetric Tilt Grain Boundary in Ferritic Steel

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2971 ◽  
Author(s):  
Xiang Huang ◽  
Rebecca Janisch
Keyword(s):  
Grain Boundary ◽  
Multicomponent System ◽  
Negative Influence ◽  
Single Element ◽  
Hydrogen Atoms ◽  
Free Surfaces ◽  
Symmetric Tilt ◽  
Solution Energy ◽  
Tilt Grain Boundary ◽  
Partitioning Pattern

The effect of hydrogen atoms at grain boundaries in metals is usually detrimental to the cohesion of the interface. This effect can be quantified in terms of the strengthening energy, which is obtained following the thermodynamic model of Rice and Wang. A critical component of this model is the bonding or solution energy of the atoms to the free surfaces that are created during decohesion. At a grain boundary in a multicomponent system, it is not immediately clear how the different species would partition and distribute on the cleaved free surfaces. In this work, it is demonstrated that the choice of partitioning pattern has a significant effect on the predicted influence of H and C on grain boundary cohesion. To this end, the Σ 3 ( 112 ) [ 1 1 ¯ 0 ] symmetric tilt grain boundary in bcc Fe with different contents of interstitial C and H was studied, taking into account all possible distributions of the elements, as well as surface diffusion effects. H as a single element has a negative influence on grain boundary cohesion, independent of the details of the H distribution. C, on the other hand, can act both ways, enhancing or reducing the cohesion of the interface. The effect of mixed H and C compositions depends on the partition pattern. However, the general trend is that the number of detrimental cases increases with increasing H content. A decomposition of the strengthening energy into chemical and mechanical contributions shows that the elastic contribution dominates at high C contents, while the chemical contribution sets the trend for high H contents.

Atomistic simulation of shear-coupled motion of [1 1 0] symmetric tilt grain boundary in α-iron

2018 ◽  
Vol 148 ◽  
pp. 141-148 ◽  
Author(s):  
Jian Yin ◽  
Yi Wang ◽  
Xiaohan Yan ◽  
Huaiyu Hou ◽  
Jing Tao Wang
Keyword(s):  
Grain Boundary ◽  
Atomistic Simulation ◽  
Coupled Motion ◽  
Symmetric Tilt ◽  
Tilt Grain Boundary

Atomistic investigation of the effects of symmetric tilt grain boundary structures on irradiation response of the α-Fe containing carbon in solution

2019 ◽  
Vol 166 ◽  
pp. 82-95 ◽  
Author(s):  
Seyed Mehrdad Zamzamian ◽  
Seyed Amirhossein Feghhi ◽  
Mohammad Samadfam ◽  
Maryam Darvishzadeh
Keyword(s):  
Grain Boundary ◽  
Symmetric Tilt ◽  
Tilt Grain Boundary

Effect of zinc-doping on tensile strength of Σ5 bcc Fe symmetric tilt grain boundary

2020 ◽  
Vol 171 ◽  
pp. 109204 ◽  
Author(s):  
Wangjun Peng ◽  
Hao Peng ◽  
Guangxin Wu ◽  
Jieyu Zhang
Keyword(s):  
Tensile Strength ◽  
Grain Boundary ◽  
Symmetric Tilt ◽  
Zinc Doping ◽  
Tilt Grain Boundary

Atomic Structure of ZnO Σ13 [0001]/{134¯0} Symmetric Tilt Grain Boundary

2013 ◽  
Vol 97 (2) ◽  
pp. 617-621 ◽  
Author(s):  
Ji-Young Roh ◽  
Yukio Sato ◽  
Yuichi Ikuhara
Keyword(s):  
Grain Boundary ◽  
Atomic Structure ◽  
Symmetric Tilt ◽  
Tilt Grain Boundary

Investigation of Copper Segregation to the Σ5(310)/[001] Symmetric Tilt Grain Boundary in Aluminum

1999 ◽  
Vol 589 ◽  
Author(s):  
Jürgen M. Plitzko ◽  
Geoffrey H. Campbell ◽  
Wayne E. King ◽  
Stephen M. Foiles
Keyword(s):  
Electron Microscopy ◽  
Grain Boundary ◽  
Low Voltage ◽  
Theoretical Calculations ◽  
High Vacuum ◽  
Analytical Electron Microscopy ◽  
Ultra High Vacuum ◽  
Face Centered Cubic ◽  
Symmetric Tilt ◽  
Tilt Grain Boundary

AbstractThe Σ5 (31O)/[001] symmetric tilt grain boundary (STGB) in the face centered cubic (FCC) metal aluminum with 1at% copper has been studied. The model grain boundary has been fabricated by ultra-high vacuum diffusion bonding of alloy single crystals. The segregation of the copper has been encouraged by annealing the sample after bonding at 200 °C. TEM samples of this FCCmaterial were prepared with a new low voltage ion mill under very low angles.The atomic structure of the Σ5(310)/[001] STGB for this system was modeled with electronic structure calculations. These theoretical calculations of the interface structure indicate that the Cu atoms segregate to distinct sites at the interface. High resolution electron microscopy (HRTEM) and analytical electron microscopy including electron energy spectroscopic imaging and X-ray energy dispersive spectrometry have been used to explore the segregation to the grain boundary. The HRTEM images and the analytical measurements were performed using different kinds of microscopes, including a Philips CM300 FEG equipped with an imaging energy filter. The amount of the segregated species at the interface was quantified in a preliminary way. To determine the atomic positions of the segregated atoms at the interface, HRTEM coupled with image simulation and a first attempt of a holographic reconstruction from a through-focal series have been used.

X-ray diffraction study of a Si Σ13 symmetric tilt grain boundary

2010 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
S. D. Rhead ◽  
P. B. Howes ◽  
M. Roy ◽  
J. L. Rawle ◽  
C. Nicklin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Grain Boundary ◽  
Diffraction Study ◽  
Light Source ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Truncation Rod ◽  
Symmetric Tilt ◽  
Tilt Grain Boundary

We present an X-ray diffraction study of a semiconductor symmetric tilt grain boundary. The theory of crystal truncation rod scattering is extended to bicrystal interfaces and compared with experimental data measured at the Diamond Light Source.

Investigation of the Effects of Hydrogen Atoms Concentration on the Tungsten Sigma 5 (310) Symmetric Tilt Grain Boundary

2016 ◽  
Author(s):  
Kabiru Atiku ◽  
Xue Yang
Keyword(s):  
Molecular Dynamics ◽  
Thermal Properties ◽  
Grain Boundary ◽  
Material Selection ◽  
Nuclear Fusion ◽  
Boundary Energy ◽  
Simulation Software ◽  
Mechanical And Thermal Properties ◽  
Hydrogen Atoms ◽  
Symmetric Tilt

The objective of this work is to investigate the effects of the concentration of hydrogen atoms at the tungsten Σ5 (310) grain boundary (GB) on the GB energy and the GB pulling force. Tungsten (W) is the most preferred plasma facing material (PFM) for the future nuclear fusion reactors such as in the proposed DEMO (demonstration power plant) and ITER (international thermonuclear experimental reactor — which is at the moment the largest Tokamak nuclear fusion reactor under construction in the world. Tungsten is considered as a PFM because of its excellent thermal properties, low-sputtering yield and high melting point. However, hydrogen (H) atoms have an affinity for tungsten grain boundary, and are trapped there permanently. In addition, it makes it prone to failure. W will be exposed to extremely high fluences of H isotopes. The low-energy H isotopes will be retained in the tungsten material leading to the formation of blisters in W and causes degradation of the mechanical and thermal properties of W. Therefore for safety reason, the effect of hydrogen atoms at the tungsten Σ5 (310) symmetric tilt-GB needs to be investigated. This will greatly aid in better designing of fusion wall materials. In addition, the full understanding of the tungsten grain boundary energy and the force required to pull the grain boundary apart will also help in better material selection. Classic molecular dynamics method was used for the investigation. LAMMPS-a sophisticated, classical atomic and molecular dynamics modelling and simulation software, is a vital tool adopted for the investigation of the effects of hydrogen atoms in tungsten Σ5 (310) symmetric tilt-GB. Tersoff potential for W-H interactions was used for the modelling. The size of the simulation box is 10 × 100 × 10 lattices and it consists of 21262 W atoms. Periodic boundaries were used for all sides of the system. Conjugate gradient method was used for the minimization. The trajectories of the atoms were visualized using visual molecular dynamics (VMD) software. The GB energies are calculated to be −924.060 J/m2, −923.898 J/m2 and −743.414 J/m2 for pure W, W with one H atom and W with 30 H atoms are at the GB respectively. In addition, the forces required to separate the GB apart are 0.0279551eV/Ang for pure W, 0.024789eV/Ang and 0.0185eV/Ang for W with one H and 30 H atoms at the GB respectively. The result shows that hydrogen acts as a grain boundary embrittler and weakens the GB strength. The GB energy reduces as the concentration of hydrogen at the tungsten GB increases. In addition, the more the hydrogen atoms at the tungsten GB the lesser the value of the force required to pull the GB apart. However, the GB energies and pulling forces starts increasing slowly when H atoms exceed a certain number depending on the H atoms distribution around the W GB.

The rigid-body displacement observed at the Σ = 5, (310)-[001] symmetric tilt grain boundary in central transition bcc metals

2002 ◽  
Vol 82 (8) ◽  
pp. 1573-1594
Author(s):  
Geoffrey H. Campbell ◽  
Mukul Kumar ◽  
Wayne E. King ◽  
James Belak ◽  
John A. Moriarty ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Rigid Body ◽  
Bcc Metals ◽  
Central Transition ◽  
Symmetric Tilt ◽  
Rigid Body Displacement ◽  
Tilt Grain Boundary
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