2021
The Effect of Hydrogen on the Stress-Strain Response in Fe3Al: An ab initio Molecular-Dynamics Study
ŠESTÁK, Petr, Martin FRIÁK a Mojmír ŠOBZákladní údaje
Originální název
The Effect of Hydrogen on the Stress-Strain Response in Fe3Al: An ab initio Molecular-Dynamics Study
Autoři
ŠESTÁK, Petr, Martin FRIÁK (garant) a Mojmír ŠOB (203 Česká republika, domácí)
Vydání
Materials, MDPI, 2021, 1996-1944
Další údaje
Jazyk
angličtina
Typ výsledku
Článek v odborném periodiku
Obor
10302 Condensed matter physics
Stát vydavatele
Švýcarsko
Utajení
není předmětem státního či obchodního tajemství
Odkazy
Impakt faktor
Impact factor: 3.748
Kód RIV
RIV/00216224:14310/21:00124083
Organizační jednotka
Přírodovědecká fakulta
UT WoS
000682110900001
Klíčová slova anglicky
Fe3Al; hydrogen; embrittlement; molecular dynamics; strength; ab initio; fracture
Štítky
Příznaky
Mezinárodní význam, Recenzováno
Změněno: 9. 2. 2022 10:54, Mgr. Marie Šípková, DiS.
Anotace
V originále
We performed a quantum-mechanical molecular-dynamics (MD) study of Fe3Al with and without hydrogen atoms under conditions of uniaxial deformation up to the point of fracture. Addressing a long-lasting problem of hydrogen-induced brittleness of iron-aluminides under ambient conditions, we performed our density-functional-theory (DFT) MD simulations for T = 300 K (room temperature). Our MD calculations include a series of H concentrations ranging from 0.23 to 4 at.% of H and show a clear preference of H atoms for tetrahedral-like interstitial positions within the D0(3) lattice of Fe3Al. In order to shed more light on these findings, we performed a series of static lattice-simulations with the H atoms located in different interstitial sites. The H atoms in two different types of octahedral sites (coordinated by either one Al and five Fe atoms or two Al and four Fe atoms) represent energy maxima. Our structural relaxation of the H atoms in the octahedral sites lead to minimization of the energy when the H atom moved away from this interstitial site into a tetrahedral-like position with four nearest neighbors representing an energy minimum. Our ab initio MD simulations of uniaxial deformation along the < 001 > crystallographic direction up to the point of fracture reveal that the hydrogen atoms are located at the newly-formed surfaces of fracture planes even for the lowest computed H concentrations. The maximum strain associated with the fracture is then lower than that of H-free Fe3Al. We thus show that the hydrogen-related fracture initiation in Fe3Al in the case of an elastic type of deformation as an intrinsic property which is active even if all other plasticity mechanism are absent. The newly created fracture surfaces are partly non-planar (not atomically flat) due to thermal motion and, in particular, the H atoms creating locally different environments.
Návaznosti
LM2015085, projekt VaV |
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LM2018140, projekt VaV |
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