scholarly journals Ab initio thermodynamics of carbon segregation on dislocation cores in bcc iron

2019 ◽  
Vol 27 (7) ◽  
pp. 074002 ◽  
Author(s):  
B Lüthi ◽  
F Berthier ◽  
L Ventelon ◽  
B Legrand ◽  
D Rodney ◽  
...  
2013 ◽  
Vol 112 (13) ◽  
pp. 1745-1754 ◽  
Author(s):  
D.A. Mirzaev ◽  
A.A. Mirzoev ◽  
K.Yu. Okishev ◽  
A.V. Verkhovykh

2021 ◽  
Vol 63 (7) ◽  
pp. 830
Author(s):  
М.С. Ракитин ◽  
А.А. Мирзоев

A fundamental understanding of the localization of H atoms in steel is an important step towards a theoretical description of the mechanisms of hydrogen embrittlement at the atomic level. Ab initio calculations within the framework of density functional theory (DFT) is used to investigate the effect of various substitutional impurities Mg, Al, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo , Pd and Cd on the energy of hydrogen dissolution in the lattice of bcc iron. The electronic and elastic contributions of various impurities to the dissolution energy are distinguished, and their influence on the binding energy of hydrogen and impurities is analyzed. The existence of a linear dependence of the energy of hydrogen dissolution on the magnitude of the change in the electron density of the intra-tetrahedral pore after the introduction of a hydrogen atom into it is shown. The results obtained made it possible to formulate the key mechanisms for controlling the localization of hydrogen in bcc iron by substitution impurities.


2015 ◽  
Vol 252 (9) ◽  
pp. 1966-1970 ◽  
Author(s):  
Alexander Aminulaevich Mirzoev ◽  
Dzhalal Aminulovich Mirzaev ◽  
Anastasiia Vladimirovna Verkhovykh

2016 ◽  
Vol 870 ◽  
pp. 550-557 ◽  
Author(s):  
A.V. Verkhovykh ◽  
A.A. Mirzoev ◽  
G.E. Ruzanova ◽  
D.A. Mirzaev ◽  
K.Yu. Okishev

The paper presents the results of both ab initio and thermodynamic analysis of vacancy and divacancy formation and hydrogen interaction with them in alpha (bcc) iron. Ab initio calculations were performed by DFT method using LAPW in WIEN2k package. Monovacancy formation energy was found to be 2.15 eV and divacancy binding energy 0.22 ± 0.01 eV. Equlibrium fraction of vacancies bound into divacancies is of the order of 10–5 even at the highest temperatures close to bcc → fcc transformation point. Hydrogen has a strong interaction with monovacancies (vacancy-hydrogen binding energy decreasing from 0.60 to 0.31 eV for the first–fifth H atom inside a single vacancy) but has only a small effect on divacancy formation energy that is equal to 0.28, 0.19 and 0.17 for the case of joining of VH + V, VH + VH and VH2 + VH2, respectively. This means that the presence of hydrogen cannot significantly increase the equilibrium concentration of divacancies.


2016 ◽  
Vol 124 ◽  
pp. 249-258 ◽  
Author(s):  
Maaouia Souissi ◽  
Ying Chen ◽  
Marcel H.F. Sluiter ◽  
Hiroshi Numakura

2007 ◽  
Vol 124-126 ◽  
pp. 1625-1628 ◽  
Author(s):  
Woo Sang Jung ◽  
Soon Hyo Chung ◽  
Heon Phil Ha ◽  
Ji Young Byun

An ab initio study was carried out on interface energies at coherent interfaces between bcc Fe and MXs (NaCl structure, M = Ti, Zr, Hf, V, Nb, Ta, X=C, N). The interface energies have positive values for carbides and nitrides of group IVB metals (Ti, Zr, Hf), while they have negative values for carbides and nitrides of group VB metals (V, Nb, Ta). Influence of bond energy was estimated using the discrete lattice plane/nearest neighbor broken bond (DLP/NNBB) model. It was found that the dependence of interface energy on the type of carbides and nitrides was closely related to changes of the bond energies between Fe, M and X(=C, N) atoms before and after formation of the interfaces Fe/MX.


2016 ◽  
Vol 115 ◽  
pp. 259-268 ◽  
Author(s):  
Jingliang Wang ◽  
Rebecca Janisch ◽  
Georg K.H. Madsen ◽  
Ralf Drautz

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