Solubility Products for Precipitate Phases in Steels from First-principles Calculations

2011 ◽  
Vol 1296 ◽  
Author(s):  
Tetyana Klymko ◽  
Chaitanya Krishna Ande ◽  
Marcel Sluiter
Keyword(s):  
Ab Initio ◽  
First Principles ◽  
First Principles Calculations ◽  
Experimental Phase Diagram ◽  
Formation Enthalpies ◽  
Enthalpy And Entropy ◽  
Solubility Products ◽  
Diagram Analysis ◽  
Insight Into

ABSTRACTThe work presented gives an insight into using formation enthalpies determined from ab initio calculations for computing solubility products in steels. The role of enthalpy and entropy contributions to the solubility product is discussed. As an illustration of the method, we present solubility products for observed stoichiometric precipitate phases in ferrite from first-principles calculations and in austenite as obtained from the combined approach based on ab initio and experimental phase diagram analysis. The results are compared with experimental data where available.

The role of stoichiometry in superconducting Nb1−βSnβ: electronic and vibrational properties from ab initio calculations

2016 ◽  
Vol 18 (48) ◽  
pp. 32840-32846 ◽  
Author(s):  
F. Gala ◽  
G. De Marzi ◽  
L. Muzzi ◽  
G. Zollo
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
First Principles ◽  
Vibrational Properties ◽  
First Principles Calculations ◽  
Superconducting Properties ◽  
A15 Phase ◽  
Stoichiometry Ratios

Using first principles calculations the electronic, vibrational and superconducting properties of Nb3Sn compounds with different stoichiometry ratios in the A15 phase have been studied.

First-principles calculations to identify key native point defects in Sr4Al14O25

2022 ◽  
Author(s):  
William Lafargue-Dit-Hauret ◽  
Camille Latouche ◽  
Bruno Viana ◽  
Mathieu Allix ◽  
Stéphane Jobic
Keyword(s):  
Ab Initio ◽  
Point Defects ◽  
First Principles ◽  
Defect Formation ◽  
Computational Study ◽  
Host Lattice ◽  
First Principles Calculations ◽  
Native Point Defects ◽  
Formation Enthalpies ◽  
First Time

This article reports for the first time an in-depth ab initio computational study on intrinsic point defects in Sr4Al14O25 that serves as host lattice for numerous phosphors. Defect Formation Enthalpies...

Theory of Point Defects and Complexes in GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
Jörg Neugebauer ◽  
Chris G. Van de Walle
Keyword(s):  
First Principles ◽  
State Of The Art ◽  
Growth Parameters ◽  
Free Carrier ◽  
First Principles Calculations ◽  
Acceptor Doping ◽  
Native Defects ◽  
Chemical Potentials ◽  
Insight Into

ABSTRACTWe have studied the electronic and energetic properties of native defects, impurities and complexes in GaN applying state-of-the-art first-principles calculations. An analysis of the numerical results gives direct insight into defect concentrations and impurity solubility with respect to growth parameters (temperature, chemical potentials) and into the mechanisms limiting the doping levels in GaN. We show how compensation and passivation by native defects or impurities, solubility issues, and incorporation of dopants on other sites influence the acceptor doping levels. The role of hydrogen in enhancing the p-type doping is explained in detail. We also discuss the mechanisms responsible for the experimentally observed limitation of the free-carrier concentration in p-type GaN.

scholarly journals A DFT investigation of the role of oxygen vacancies on the structural, electronic and magnetic properties of ATiO3 (A = Mn, Fe, Ni) multiferroic materials

2018 ◽  
Vol 20 (45) ◽  
pp. 28382-28392 ◽  
Author(s):  
R. A. P. Ribeiro ◽  
E. Longo ◽  
J. Andrés ◽  
S. R. de Lazaro
Keyword(s):  
Magnetic Properties ◽  
First Principles ◽  
Oxygen Vacancies ◽  
First Principles Calculations ◽  
Deep Insight ◽  
Multiferroic Materials ◽  
Multiferroic Properties ◽  
Surface Models ◽  
Insight Into

In order to achieve deep insight into the multiferroic behavior and electronic properties of intrinsic oxygen vacancies in ATiO3 (A = Mn, Fe, Ni), first-principles calculations were carried out for bulk and non-polar (110) surface models, showing that controlling oxygen vacancies can be a valuable strategy to tailor the multiferroic properties.

An effective and efficient approach to p-type AlN by Be2:O codoping from first-principles calculations

2016 ◽  
Vol 30 (20) ◽  
pp. 1650257
Author(s):  
Meng Zhao ◽  
Wenjun Wang ◽  
Jun Wang ◽  
Junwei Yang ◽  
Weijie Hu ◽  
...  
Keyword(s):  
First Principles ◽  
Ionization Energy ◽  
Hole Concentration ◽  
Valence Band Maximum ◽  
First Principles Calculations ◽  
Mutual Compensation ◽  
Efficient Approach ◽  
P Type ◽  
Codoping Method

Various Be:O-codoped AlN crystals have been investigated via first-principles calculations to evaluate the role of the different combinations in effectively and efficiently inducing p-type carriers. It is found that the O atom is favored to bond with two Be atoms. The formed Be2:O complexes decrease the acceptor ionization energy to 0.11 eV, which is 0.16 eV lower than that of an isolated Be in AlN, implying that the hole concentration could probably be increased by 2–3 orders of magnitude. The electronic structure of Be2:O-codoped AlN shows that the lower ionization energy can be attributed to the interaction between Be and O. The Be–O complexes, despite failing to induce p-type carriers for the mutual compensation of Be and O, introduce new occupied states on the valence-band maximum (VBM) and hence the energy needed for the transition of electrons to the acceptor level is reduced. Thus, the Be2:O codoping method is expected to be an effective and efficient approach to realizing p-type AlN.

Computational and Experimental Insights into the Role of Acidic Molecules on the Corrosion Behavior on 7A46 Aluminum Alloy

2021 ◽  
Vol 21 (4) ◽  
pp. 2221-2233
Author(s):  
Yaru Liu ◽  
Qinglin Pan ◽  
Xiangdong Wang ◽  
Ye Ji ◽  
Qicheng Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
First Principles ◽  
First Principles Calculations ◽  
Corrosive Media ◽  
Corrosion Depth ◽  
Corrosion Mechanisms ◽  
Nanoscale Level

The corrosion mechanisms for different corrosive media on the aged 7A46 aluminum alloy were systematically investigated at nanoscale level. The combination of empirical intergranular and exfoliation corrosion behavior was employed, and coupled with first-principles calculations. Results revealed that the dispersed distribution of matrix precipitates (MPs) leads to the enhancement of the corrosion resistance pre-ageing (PA) followed by double-ageing (PA-DA) alloy. The deepest corrosion depth of PA-DA alloy was in hydrochloric acid, and the calculation result demonstrates that the passivation effect in combination with the accumulation of corrosion products in nitric acid protect the PA-DA alloy from further corrosion.

Insight into adsorption mechanism of water on tricalcium silicate from first-principles calculations

2022 ◽  
Vol 152 ◽  
pp. 106684
Author(s):  
Yunjian Li ◽  
Haoqiang Ai ◽  
Kin Ho Lo ◽  
Youchao Kong ◽  
Hui Pan ◽  
...  
Keyword(s):  
First Principles ◽  
Adsorption Mechanism ◽  
Tricalcium Silicate ◽  
First Principles Calculations ◽  
Insight Into

scholarly journals Ab Initio Study of the Electronic, Vibrational, and Mechanical Properties of the Magnesium Diboride Monolayer

2019 ◽  
Vol 4 (2) ◽  
pp. 37 ◽  
Author(s):  
Jelena Pešić ◽  
Igor Popov ◽  
Andrijana Šolajić ◽  
Vladimir Damljanović ◽  
Kurt Hingerl ◽  
...  
Keyword(s):  
Ab Initio ◽  
First Principles ◽  
Materials Science ◽  
Magnesium Diboride ◽  
Poisson Ratio ◽  
Single Layer ◽  
First Principles Calculations ◽  
Significant Interest ◽  
Science Community ◽  
Fundamental Research

Magnesium diboride gained significant interest in the materials science community after the discovery of its superconductivity, with an unusually high critical temperature of 39 K. Many aspects of the electronic properties and superconductivity of bulk MgB 2 and thin sheets of MgB 2 have been determined; however, a single layer of MgB 2 has not yet been fully theoretically investigated. Here, we present a detailed study of the structural, electronic, vibrational, and elastic properties of monolayer MgB 2 , based on ab initio methods. First-principles calculations reveal the importance of reduction of dimensionality on the properties of MgB 2 and thoroughly describe the properties of this novel 2D material. The presence of a negative Poisson ratio, higher density of states at the Fermi level, and a good dynamic stability under strain make the MgB 2 monolayer a prominent material, both for fundamental research and application studies.

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