J 2021

The Effect of Hydrogen on the Stress-Strain Response in Fe3Al: An ab initio Molecular-Dynamics Study

ŠESTÁK, Petr, Martin FRIÁK a Mojmír ŠOB

Základní 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
Název: CERIT Scientific Cloud (Akronym: CERIT-SC)
Investor: Ministerstvo školství, mládeže a tělovýchovy ČR, CERIT Scientific Cloud
LM2018140, projekt VaV
Název: e-Infrastruktura CZ (Akronym: e-INFRA CZ)
Investor: Ministerstvo školství, mládeže a tělovýchovy ČR, e-Infrastruktura CZ