First-principle investigation of electronic structures and interactions of foreign interstitial atoms (C, N, B, O) and intrinsic point defects in body- and face-centered cubic iron lattice: A comparative analysis

Ahlawat, Sarita; Srinivasu, K.; Biswas, Arpon; Choudhury, Niharendu

doi:10.1016/j.commatsci.2019.109167

Cited by 17 publications

(6 citation statements)

References 56 publications

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“…Furthermore, the vacancy formation energies calculated in the two crystal cells are, respectively, 2.18 and 1.59 eV. The vacancy formation energies in the crystal cell without H atoms are basically consistent with other scholars’ results (2.02 and 2.17 eV) (Ohnuma et al , 2009; Ahlawat et al , 2019). The vacancy formation energy decreases after adding H atoms near the vacancies, implying that H atoms can promote the formation of vacancies in bcc-Fe.…”

Section: Resultssupporting

confidence: 90%

Investigation of hydrogen diffusion behavior in 12Cr2Mo1R(H) steel by electrochemical tests and first-principles calculation

Qiu

Zhang

Kang

et al. 2021

ACMM

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Purpose This paper aims to study the mechanism of hydrogen embrittlement in 12Cr2Mo1R(H) steel, which will help to provide valuable information for the subsequent hydrogen embrittlement research of this kind of steel, so as to optimize the processing technology and take more appropriate measures to prevent hydrogen damage. Design/methodology/approach The hydrogen diffusion coefficient of 12Cr2Mo1R(H) steel was measured by the hydrogen permeation technique of double electrolytic cells. Moreover, the influence of hydrogen traps in the material and experimental temperature on hydrogen diffusion behavior was discussed. The first-principles calculations based on density functional theory were used to study the occupancy of H atoms in the bcc-Fe cell, the diffusion path and the interaction with vacancy defects. Findings The results revealed that the logarithm of the hydrogen diffusion coefficient of the material has a linear relationship with the reciprocal of temperature and the activation energy of hydrogen atom diffusion in 12Cr2Mo1R(H) steel is 23.47 kJ/mol. H atoms stably exist in the nearly octahedral interstices in the crystal cell with vacancies. In addition, the solution of Cr/Mo alloy atom does not change the lowest energy path of H atom, but increases the diffusion activation energy of hydrogen atom, thus hindering the diffusion of hydrogen atom. Cr/Mo and vacancy have a synergistic effect on inhibiting the diffusion of H atoms in α-Fe. Originality/value This article combines experiments with first-principles calculations to explore the diffusion behavior of hydrogen in 12Cr2Mo1R(H) steel from the macroscopic and microscopic perspectives, which will help to establish a calculation model with complex defects in the future.

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Section: Resultssupporting

confidence: 90%

Investigation of hydrogen diffusion behavior in 12Cr2Mo1R(H) steel by electrochemical tests and first-principles calculation

Qiu

Zhang

Kang

et al. 2021

ACMM

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“…Similar to conventional FCC metals and alloys, the average formation energies of oxygen interstitials in octahedral sites are lower compared to the case of oxygen at tetrahedral sites. [ 40 ] However, as shown in Figure 2d, their wide distribution of formation energies of oxygen interstitials exhibits a significantly overlapped area between octahedral and tetrahedral sites. Thus, from the energetics perspective, both tetrahedral and octahedral interstitial oxygen should exist in the NiCoCrO alloy, and the amount of octahedral O is more than that of tetrahedral O, which is consistent with experimental observations.…”

Section: Resultsmentioning

confidence: 99%

Dynamic Homogenization of Internal Strain in Multi‐Principal Element Alloy via High‐Concentration Doping of Oxygen with Large Mobility

Song,

Zhang,

et al. 2023

Small Methods

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Internal strain and its distribution within the crystal lattice play crucial roles in modulating dislocation activities, thereby affecting mechanical properties of materials. Through the synergistic application of integrated differential phase contrast, in situ transmission electron microscopy characterizations, and computational simulations, a method is unveiled for homogenizing dislocation pinning in NiCoCr multi‐principal element alloy (MPEA) through the introduction of a high concentration of oxygen atoms with high diffusion mobility. The doping of massive oxygen atoms creates a high density of strong local pinning points for dislocation motion. Notably, oxygen interstitials exhibit remarkable diffusion and mobility across different octahedral and tetrahedral sites within the distorted crystal lattice of NiCoCrO alloy, even at room temperature. The capability allows for the release of severe stress concentrations arising from dislocation entanglement and the establishment of new strong local pinning points at alternative locations in a uniform way, enabling the material with high strength and outstanding deformability. These findings suggest that interstitial atoms can exhibit significant mobility, even at ambient temperature, in complex MPEAs with spreading lattice distortion, opening new possibilities for dislocation engineering.

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“…The total elongation to fracture of the material in the current study also did not show any significant change following the cathodic H charging. Atomistic simulations suggest that the interstitial alloying element C occupies the octahedral interstitial sites in fcc-Fe, [39] which are also the favorable sites for H in an fcc-Fe. [38,40] A higher C content in the austenite matrix hence would prevent H from entering those sites which could give rise to a very small H diffusion coefficient, albeit this needs further work for confirmation.…”

Section: Discussionmentioning

confidence: 99%

A Carbon‐Stabilized Austenitic Steel with Lower Hydrogen Embrittlement Susceptibility

Khanchandani,

Zeiler,

Strobel

et al. 2023

steel research int.

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High‐strength steels are susceptible to H‐induced failure, which is typically caused by the presence of diffusible H in the microstructure. The diffusivity of H in austenitic steels with face‐centered cubic (fcc) crystal structure is slow. The austenitic steels are hence preferred for applications in the hydrogen‐containing atmospheres. However, the fcc structure of austenitic steels is often stabilized by the addition of Ni, Mn, or N, which are relatively expensive alloying elements to use. Austenite can kinetically also be stabilized using C. Herein, an approach is applied to a commercial cold work tool steel, where C is used to fully stabilize the fcc phase. This results in a microstructure consisting of only austenite and M7C3 carbide. An exposure to H by cathodic hydrogen charging exhibits no significant influence on the strength and ductility of the C‐stabilized austenitic steel. While this material is only a prototype based on an existing alloy of different purposes, it shows the potential for low‐cost H‐resistant steels based on C‐stabilized austenite.

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First-principle investigation of electronic structures and interactions of foreign interstitial atoms (C, N, B, O) and intrinsic point defects in body- and face-centered cubic iron lattice: A comparative analysis

Cited by 17 publications

References 56 publications

Investigation of hydrogen diffusion behavior in 12Cr2Mo1R(H) steel by electrochemical tests and first-principles calculation

Investigation of hydrogen diffusion behavior in 12Cr2Mo1R(H) steel by electrochemical tests and first-principles calculation

Dynamic Homogenization of Internal Strain in Multi‐Principal Element Alloy via High‐Concentration Doping of Oxygen with Large Mobility

A Carbon‐Stabilized Austenitic Steel with Lower Hydrogen Embrittlement Susceptibility

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