| ŠESTÁK, Petr, Martin FRIÁK a Mojmír ŠOB. The Effect of Hydrogen on the Stress-Strain Response in Fe3Al: An ab initio Molecular-Dynamics Study. Materials. MDPI, 2021, roč. 14, č. 15, s. 4155-4168. ISSN 1996-1944. Dostupné z: https://dx.doi.org/10.3390/ma14154155. |
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@article{1832523,
author = {Šesták, Petr and Friák, Martin and Šob, Mojmír},
article_number = {15},
doi = {http://dx.doi.org/10.3390/ma14154155},
keywords = {Fe3Al; hydrogen; embrittlement; molecular dynamics; strength; ab initio; fracture},
language = {eng},
issn = {1996-1944},
journal = {Materials},
title = {The Effect of Hydrogen on the Stress-Strain Response in Fe3Al: An ab initio Molecular-Dynamics Study},
url = {https://www.mdpi.com/1996-1944/14/15/4155},
volume = {14},
year = {2021}
}
TY - JOUR
ID - 1832523
AU - Šesták, Petr - Friák, Martin - Šob, Mojmír
PY - 2021
TI - The Effect of Hydrogen on the Stress-Strain Response in Fe3Al: An ab initio Molecular-Dynamics Study
JF - Materials
VL - 14
IS - 15
SP - 4155
EP - 4155
PB - MDPI
SN - 19961944
KW - Fe3Al
KW - hydrogen
KW - embrittlement
KW - molecular dynamics
KW - strength
KW - ab initio
KW - fracture
UR - https://www.mdpi.com/1996-1944/14/15/4155
N2 - 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.
ER -
ŠESTÁK, Petr, Martin FRIÁK a Mojmír ŠOB. The Effect of Hydrogen on the Stress-Strain Response in Fe3Al: An ab initio Molecular-Dynamics Study. \textit{Materials}. MDPI, 2021, roč.~14, č.~15, s.~4155-4168. ISSN~1996-1944. Dostupné z: https://dx.doi.org/10.3390/ma14154155.
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