The formation of H bubbles at small-angle tilt grain boundaries in W films

2016 ◽  
Vol 18 (48) ◽  
pp. 33103-33108 ◽  
Author(s):  
Zhihai He ◽  
H. Y. He ◽  
R. Ding ◽  
B. C. Pan ◽  
J. L. Chen
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Small Angle ◽  
First Principles ◽  
First Principles Calculations ◽  
Tilt Grain Boundary

The accumulation of H at the small-angle tilt grain boundary (GB) in the W(001) surface is investigated, on the basis of the first-principles calculations.

First-Principles Studies on Grain Boundary Energies of [110] Tilt Grain Boundaries in Aluminum

2007 ◽  
Vol 561-565 ◽  
pp. 1837-1840 ◽  
Author(s):  
Y. Inoue ◽  
Tokuteru Uesugi ◽  
Yorinobu Takigawa ◽  
Kenji Higashi
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
First Principles ◽  
Boundary Structure ◽  
First Principles Calculations ◽  
Atomic Structures ◽  
Grain Boundary Structure ◽  
Transmission Electron ◽  
Tilt Grain Boundary

The grain boundary structure and its energy are necessary for the fundamental understanding of the physical properties of materials. In aluminum, three distinct atomic structures of a Σ9(221)[110] tilt grain boundary have been reported in previous studies using atomistic simulations and a high-resolution transmission electron microscopy (HRTEM). In this work, we studied the atomic structure and energy of the Σ9 tilt grain boundary in aluminum using first-principles calculations. A comparison of the grain boundary energies among the three distinct Σ9 tilt grain boundaries determined through first-principles calculations allowed us to identify the most stable atomic structure of Σ9 tilt grain boundary in aluminum.

Properties of Iron Atoms at Grain Boundaries in Fe and Fe72Al28

1998 ◽  
Vol 527 ◽  
Author(s):  
O. Schneeweiss ◽  
I. Turek ◽  
J. Čermák ◽  
P. Lejček
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Single Crystals ◽  
First Principles ◽  
Magnetic Moments ◽  
Emission Mössbauer Spectroscopy ◽  
First Principles Calculations ◽  
Hyperfine Parameters ◽  
Impurity Atoms ◽  
Atomic Spacing

ABSTRACTLocation of diffused 57Co atoms in single crystals, bicrystals and polycrystals of pure iron and Fe72Al28alloy were investigated by means of emission Mössbauer spectroscopy. To interpret the results, first principles calculations of iron atom magnetic moments and hyper-fine field were carried out. From comparison of M6ssbauer spectra of single crystals with those of bicrystals and polycrystals, an information about grain boundary positions occupied by diffusing atoms is obtained. It is shown that about 5% of the diffusing atoms at the {112} grain boundary of iron are located at the positions either having impurity atoms in the nearest neighbourhood or characterized by larger atomic spacing in comparison with the bulk. In the Fe72Al28 a dominating portion of diffusing atoms have different surrounding than in grain volume. An enrichment of grain boundaries by aluminum could explain their hyperfine parameters.

First-Principles Calculations of Stacking Faults and Grain Boundaries in Metals

1990 ◽  
Vol 213 ◽  
Author(s):  
K. Hampel ◽  
D.D. Vvedensky ◽  
S. Crampin
Keyword(s):  
Magnetic Properties ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
First Principles ◽  
Stacking Faults ◽  
First Principles Calculations ◽  
Comprehensive Description ◽  
Planar Defects ◽  
Detailed Understanding ◽  
Defect Energies

ABSTRACTA detailed understanding of planar defects plays an important role in the search for a comprehensive description of the mechanical behaviour of metals and alloys. We present calculations for isolated stacking faults and grain boundaries using the layer Korringa-Kohn-Rostoker method including an assessment of the force theorem, which has already proven itself in evaluating defect energies for elemental close-packed metals. These ab initio total energy calculations will be supplemented by a study of the changes in bonding and local magnetic properties near a symmetric Σ5 (310) grain boundary in Fe

Co-segregation behavior of Sc and Zr solutes and their effect on the Al Σ5 (210) [110] symmetrical tilt grain boundary: a first-principles study

2019 ◽  
Vol 21 (35) ◽  
pp. 19437-19446
Author(s):  
Zhengbing Xiao ◽  
Jiawei Hu ◽  
Yu Liu ◽  
Fang Dong ◽  
Yuanchun Huang
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
First Principles ◽  
First Principles Calculations ◽  
Segregation Behavior ◽  
First Principles Study ◽  
Symmetrical Tilt ◽  
Tilt Grain Boundary

The research into the co-segregation behavior of Sc and Zr solutes and their effect on the mechanical properties of the Al Σ5 (210) [110] grain boundary was carried out by first principles calculations.

scholarly journals The Electronic Structure of Grain Boundaries in NB

1990 ◽  
Vol 209 ◽  
Author(s):  
Erik C. Sowa ◽  
A. Gonis ◽  
X. -G. Zhang
Keyword(s):  
Electronic Structure ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Multiple Scattering ◽  
First Principles ◽  
Scattering Theory ◽  
Real Space ◽  
First Principles Calculations ◽  
Densities Of States ◽  
Local Densities

ABSTRACTWe present first-principles calculations of the electronic structure of Nb grain boundaries. These are the first such calculations for a bcc metal using the real-space multiple-scattering theory (RSMST). Local densities of states near a Σ5 twist grain boundary are compared to those for bulk Nb.

Solute Segregation at Σ11(113)[110] Grain Boundary and Effect of the Segregation on Grain Boundary Cohesion in Aluminum from First Principles

2010 ◽  
Vol 654-656 ◽  
pp. 942-945 ◽  
Author(s):  
Tokuteru Uesugi ◽  
Kenji Higashi
Keyword(s):  
Free Surface ◽  
Grain Boundary ◽  
First Principles ◽  
Solute Segregation ◽  
First Principles Calculations ◽  
Symmetric Tilt ◽  
Tilt Grain Boundary ◽  
Grain Boundary Embrittlement ◽  
Boundary Embrittlement

We investigate the energy of segregation of solute Ca at symmetric tilt grain boundary in aluminum from the first-principles calculations. As energy of segregation of Ca is negative, Ca atoms tend to segregate at the grain boundary. Furthermore, on basis of the Rice-Wang model, we study the effect of the segregation of Ca on the grain boundary embrittlement of aluminum. Our first-principles calculations of energies of segregation at grain boundary and free surface show that Ca behaves as embrittler.

First-Principles Investigation of Intergranular Fracture in Copper by Grain Boundary Segregation of Sulfur

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Xudong Wang ◽  
Lahouari Benabou
Keyword(s):  
Grain Boundary ◽  
First Principles ◽  
Cohesive Energy ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
First Principles Calculations ◽  
Order Of Magnitude ◽  
Symmetrical Tilt ◽  
Solute Atoms ◽  
Tilt Grain Boundary

Grain boundary (GB) embrittlement by sulfur in fcc CuΣ5(012)[100] symmetrical tilt grain boundary (STGB) is simulated by first-principles calculations. The surface and grain boundary segregation energies are estimated by progressively placing solute atoms in the potential segregation sites in the boundaries. Based on the calculated segregation energies, the cohesive energy of the grain boundary is evaluated as a function of the sulfur atoms concentration. It is found that, when a two atomic layers’ concentration is attained, the cohesive energy is reduced by one order of magnitude compared to its value for the clean grain boundary.

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