scholarly journals Adsorption, diffusion and aggregation of Ir atoms on graphdiyne: a first-principles investigation

2020 ◽  
Vol 22 (44) ◽  
pp. 25841-25847
Author(s):  
Xin Liu ◽  
Meng Xu ◽  
Yu Han ◽  
Changgong Meng
Keyword(s):  
First Principles ◽  
Atomic Diffusion

Shifting the atomic diffusion thermodynamics, e.g. with involvement reactants, etc., would initiate the thermodynamically favorable aggregation of Ir atoms into clusters on graphdiyne.

Atomic diffusion in liquid nickel: First-principles modeling

2018 ◽  
Vol 148 (24) ◽  
pp. 244503 ◽  
Author(s):  
Martin Walbrühl ◽  
Andreas Blomqvist ◽  
Pavel A. Korzhavyi
Keyword(s):  
First Principles ◽  
Atomic Diffusion ◽  
Liquid Nickel

Atomic diffusion mediated by vacancy defects in L12-Zr3Al: A first-principles study

2020 ◽  
Vol 821 ◽  
pp. 153223
Author(s):  
Zhixin Ren ◽  
Zhe Xue ◽  
Xinyu Zhang ◽  
Jiaqian Qin ◽  
Mingzhen Ma ◽  
...  
Keyword(s):  
First Principles ◽  
Atomic Diffusion ◽  
Vacancy Defects ◽  
First Principles Study

Crystalline Structure Around the Single Vacancy in Silicon: Formation Volume and Stress Effects

1998 ◽  
Vol 532 ◽  
Author(s):  
A. Antonellip ◽  
Efthimios Kaxiras ◽  
D. J. Chadi
Keyword(s):  
Total Energy ◽  
Crystalline Structure ◽  
First Principles ◽  
Relative Concentration ◽  
Atomic Diffusion ◽  
Single Vacancy ◽  
Energy Calculations ◽  
Stress Effects ◽  
Formation Energies

ABSTRACTThe crystalline structure surrounding a single neutral vacancy in silicon is investigated through extensive first-principles total-energy calculations. The results indicate the existence of two distinct distortions of the lattice around the vacancy with essentially the same formation energies at zero pressure, but, however, with different formation volumes. The effect of hydrostatic and biaxial stresses on the relative concentration of each distortion is discussed, suggesting experimental ways to investigate the crystalline structure around the single vacancy and its role as a mediator of atomic diffusion in silicon.

First-principles investigation of point defect and atomic diffusion in Al 2 Ca

2017 ◽  
Vol 103 ◽  
pp. 6-12 ◽  
Author(s):  
Xiao Tian ◽  
Jia-Ning Wang ◽  
Ya-Ping Wang ◽  
Xue-Feng Shi ◽  
Bi-Yu Tang
Keyword(s):  
Point Defect ◽  
First Principles ◽  
Atomic Diffusion

DYNAMICAL EFFECTS AND VACANCY MOTION IN SILICON AT HIGH TEMPERATURE

1996 ◽  
Vol 07 (01) ◽  
pp. 57-64 ◽  
Author(s):  
ENRICO SMARGIASSI ◽  
ROBERTO CAR
Keyword(s):  
Molecular Dynamics ◽  
High Temperature ◽  
Melting Point ◽  
First Principles ◽  
Atomic Motion ◽  
Atomic Diffusion ◽  
First Principles Molecular Dynamics

We report a first-principles Molecular Dynamics investigation of the atomic motion in Silicon in the presence of an artificially created vacancy at high temperature (T ≥ 1200 K ). We observe that atomic diffusion events are affected by strong dynamical correlations. At temperatures close to the melting point we discover characteristic premelting phenomena which involve simultaneous jumps of several atoms and introduce a large amount of disorder in the structure.

scholarly journals Forming mechanism of equilibrium and non-equilibrium metallurgical phases in dissimilar aluminum/steel (Al–Fe) joints

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shun-Li Shang ◽  
Hui Sun ◽  
Bo Pan ◽  
Yi Wang ◽  
Adam M. Krajewski ◽  
...  
Keyword(s):  
First Principles ◽  
High Pressures ◽  
Equilibrium Phase ◽  
Dissimilar Materials ◽  
Equilibrium Phase Diagram ◽  
Atomic Diffusion ◽  
Forming Mechanism ◽  
Almost All ◽  
Steel Joints ◽  
Non Equilibrium

AbstractForming metallurgical phases has a critical impact on the performance of dissimilar materials joints. Here, we shed light on the forming mechanism of equilibrium and non-equilibrium intermetallic compounds (IMCs) in dissimilar aluminum/steel joints with respect to processing history (e.g., the pressure and temperature profiles) and chemical composition, where the knowledge of free energy and atomic diffusion in the Al–Fe system was taken from first-principles phonon calculations and data available in the literature. We found that the metastable and ductile (judged by the presently predicted elastic constants) Al6Fe is a pressure (P) favored IMC observed in processes involving high pressures. The MoSi2-type Al2Fe is brittle and a strong P-favored IMC observed at high pressures. The stable, brittle η-Al5Fe2 is the most observed IMC (followed by θ-Al13Fe4) in almost all processes, such as fusion/solid-state welding and additive manufacturing (AM), since η-Al5Fe2 is temperature-favored, possessing high thermodynamic driving force of formation and the fastest atomic diffusivity among all Al–Fe IMCs. Notably, the ductile AlFe3, the less ductile AlFe, and most of the other IMCs can be formed during AM, making AM a superior process to achieve desired IMCs in dissimilar materials. In addition, the unknown configurations of Al2Fe and Al5Fe2 were also examined by machine learning based datamining together with first-principles verifications and structure predictions. All the IMCs that are not P-favored can be identified using the conventional equilibrium phase diagram and the Scheil-Gulliver non-equilibrium simulations.

scholarly journals Forming Mechanism of Equilibrium and Non-equilibrium Metallurgical Phases in Dissimilar Materials: Illustrated With Aluminum/steel (Al-Fe) Joints

2021 ◽  
Author(s):  
Shun-Li Shang ◽  
Hui Sun ◽  
Bo Pan ◽  
Yi Wang ◽  
Adam M. Krajewski ◽  
...  
Keyword(s):  
First Principles ◽  
High Pressures ◽  
Equilibrium Phase ◽  
Dissimilar Materials ◽  
Equilibrium Phase Diagram ◽  
Atomic Diffusion ◽  
Forming Mechanism ◽  
Almost All ◽  
Steel Joints ◽  
Non Equilibrium

Abstract Forming metallurgical phases has a critical impact on the performance of dissimilar materials joints. Here, we shed light on the forming mechanism of equilibrium and non-equilibrium intermetallic compounds (IMCs) in the dissimilar aluminum/steel joints with respect to processing history (e.g., the pressure- and temperature-profiles) and chemical composition, where the used knowledge of free energy and atomic diffusion in the Al-Fe system was taken from first-principles phonon calculations and data available in the literature. We found that the metastable while ductile (judged by the presently predicted elastic constants) Al6Fe is a pressure (P) favored IMC observed in the processes involving high pressures. The MoSi2-type Al2Fe is a brittle and a strong P-favored IMC observed at high pressures. The stable, brittle h-Al5Fe2 is the most commonly observed IMC (followed by q-Al13Fe4) in almost all processes, such as fusion/solid-state welding and additive manufacturing (AM), since h-Al5Fe2 is temperature-favored, possessing high thermodynamic driving force of formation and the fastest atomic diffusivity among all Al-Fe IMCs. Notably the ductile AlFe3, the less ductile AlFe, and most of the other IMCs can be formed during AM, making AM a superior process to achieve desired IMCs in dissimilar materials. In addition, the unknown configurations of Al2Fe and Al5Fe2 were also examined by machine learning based datamining together with first-principles verifications and structure predictor. All the IMCs, which are not P-favored, can be identified using the conventional equilibrium phase diagram and the Scheil-Gulliver non-equilibrium simulations.

Modeling of Thermodynamic and Diffusion Properties in Ionic Materials

2016 ◽  
Vol 8 ◽  
pp. 1-30 ◽  
Author(s):  
Bi Cheng Zhou ◽  
Zi Kui Liu
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Diffusion Theory ◽  
Ab Initio Molecular Dynamics ◽  
Atomic Diffusion ◽  
Oxide Ceramic ◽  
Ionic Materials ◽  
And Diffusion ◽  
Diffusion Properties

In this chapter, the modeling techniques of the thermodynamic and diffusion properties based on density functional theory in ionic materials, specifically oxide ceramic materials or ionic conductor materials are reviewed. Section 1 is the introduction of this book chapter. Section 2 is devoted to introduce the modeling methods of first-principles finite temperature thermodynamics, including quasi-harmonic phonon calculations and the Debye model. In the phonon model, the frozen phonon method, the linear response method, and the newly developed mixed-space method to model ionic polar materials are discussed. Section 3 introduces the general atomic diffusion theory, first-principles transition state calculations (double-well approach), and ab initio molecular dynamics simulations of the diffusion coefficients in ionic materials. Section 4 discusses some of the recent works of first-principles prediction of the thermodynamic and diffusion properties of ionic materials from our group and in the literature, with a focus on oxides for energy applications. Section 5 summarizes this book chapter.

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