Point Defects in FCC Fe-Cr-Ni Alloys

Dimitrov, C.; Benkaddour, A.; Dimitrov, O.; Corbel, C.; Moser, P.

doi:10.4028/www.scientific.net/msf.15-18.1275

Cited by 30 publications

(57 citation statements)

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“…61 The binding interaction of Cr has been validated by comparing molecular-dynamics simulations 12 with resistivity recovery experiments. 62,63 There is a good agreement between USPP 21 and PAW results. The results of 64 are not included in Fig.…”

Section: Solute-š110‹ Self-interstitial Interactionssupporting

confidence: 59%

Ab initiostudy of solute transition-metal interactions with point defects in bcc Fe

Olsson

Klaver²,

Domain³

2010

Phys. Rev. B

204

152

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The properties of 3d, 4d, and 5d transition-metal elements in ␣-Fe have been studied using ab initio density-functional theory. The intrinsic properties of the solutes have been characterized as well as their interaction with point defects. Vacancies and interstitials of ͗110͘ and ͗111͘ orientations have been considered in order to discern trends that may explain experimental evidence of solute influences on radiation response and possibly aid future material design regarding the choice of alloy composition. Depending on the solute element, the different interactions are governed by the chemical interactions and the solute size factor. It is shown that magnetic interactions play an important role for the properties of the center series 3d elements, especially so for the antiferromagnetically coupling V, Cr, and Mn. For the 4d, 5d, and remaining 3d elements the interaction with point defects is mainly governed by the solute size factor. The solute-solute interaction is mostly repulsive with a few exceptions. The interactions with vacancies are in most cases binding; but the second nearest neighbor configurations exhibit strong repulsion for the early transition metals. Cr and Mn interact strongly binding with interstitial defects. The trends of the solute defect interactions have been determined to depend on the characteristic local deformation. Early transition metals interact stronger with defects than late ones of equal size factor.

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Section: Solute-š110‹ Self-interstitial Interactionssupporting

confidence: 59%

Ab initiostudy of solute transition-metal interactions with point defects in bcc Fe

Olsson

Klaver²,

Domain³

2010

Phys. Rev. B

204

152

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“…[2][3][4][5][6] owing to the difficulty in precisely determining atomic quantities 7 such as the formation and migration energies of a single vacancy or that of an interstitial. These physical properties can also be greatly affected by impurities 5 and the influence of the local environment is difficult to properly probe.…”

Section: Introductionmentioning

confidence: 99%

First-principles study of point defects in an fcc Fe-10Ni-20Cr model alloy

Piochaud¹,

Klaver²,

Adjanor³

et al. 2014

Phys. Rev. B

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The influence of the local environment on vacancy and self-interstitial formation energies has been investigated in a face-centered-cubic (fcc) Fe-10Ni-20Cr model alloy by analyzing an extensive set of first-principle calculations based on density functional theory. Chemical disorder has been considered by designing special quasirandom structures and four different collinear magnetic structures have been investigated in order to determine a relevant reference state to perform point defect calculations at 0 K. Two different convergence methods have also been used to characterize the importance of the method on the results. Although our fcc Fe-10Ni-20Cr would be better represented in terms of applications by the paramagnetic state, we found that the antiferromagnetic single-layer magnetic structure was the most stable at 0 K and we chose it as a reference state to determine the point defect properties. Point defects have been introduced in this reference state, i.e., vacancies and Fe-Fe, Fe-Ni, Fe-Cr, Cr-Cr, Ni-Ni, and Ni-Cr dumbbell interstitials oriented either parallel or perpendicular to the single layer antiferromagnetic planes. Each point defect studied was introduced at different lattice sites to consider a sufficient variety of local environments and analyze its influence on the formation energy values. We have estimated the point defect formation energies with linear regressions using variables which describe the local environment surrounding the point defects. The number and the position of Ni and Cr first nearest neighbors to the point defects were found to drive the evolution of the formation energies. In particular, Ni is found to decrease and Cr to increase the vacancy formation energy of the model alloy, while the opposite trends are found for the dumbbell interstitials. This study suggested that, to a first approximation, the first nearest atoms to point defects can provide reliable estimates of point defect formation energies.

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“…A recent work [39] which combines molecular dynamics (MD), atomistic KMC (AKMC) coupled to a neural network, and rate theory (RT) succeeded in reproducing several experimental results of RR in dilute [35,36] and concentrated electron-irradiated Fe-Cr alloys [37]. That work reproduces well the recovery stages due to correlated recombinations but has a limited range of application given that it only simulates a single recombination process in stage II and is not able to accurately reproduce the amplitude of stage III.…”

mentioning

confidence: 99%

Decoupling of defect and short-range order contributions to resistivity recovery measurements in binary alloys

et al. 2014

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We report a new and improved approach that uses low-temperature resistivity recovery measurements to study the defect kinetics in metallic binary alloys. This method is able to decouple the effect related to the irradiation defect contribution to the resistivity from that of the short-range order, which is enhanced by the free migration of defects. This approach can provide reliable experimental data which are more suitable for comparisons with current computational models. Furthermore, the difference in this method with respect to the classical one is that our method gives information concerning the role of vacancies and interstitials on short-range order. The method is applied to a model alloy Fe-5%Cr, of interest for fusion applications, where short-range order effects have been previously found to play a role. In general, concentrated alloys have enough solute concentration to perturb the electronic structure and the phonon spectrum. Typically this composition range starts at 1%-2% of the solute concentration. These perturbations lead to an atomic configuration which is never fully random; there are certain atomic correlations that can be described as short-range order (SRO). The SRO parameters (α i ) are defined as the correlation between first-and next-nearest neighbors (NN) of an atom [1]. Every alloy has different SRO equilibrium configurations for every solute concentration and temperature [2], which also depend on the thermomechanical process experienced [3,4]. Quenching experiments have been widely used to study the kinetics of ordering [2][3][4][5][6][7][8] given the linear relation of the resistivity (ρ) with α i (cf. Refs. [1,8]). Concurrently, resistivity recovery (RR) experiments have been commonly used to investigate radiation effects in pure metals, based on the recovery of the residual resistivity up to its original value after low-temperature irradiation and subsequent isochronal annealing [9][10][11][12][13][14][15][16][17]. However, in the case of concentrated alloys, the presence of migrating defects allows solute rearrangements and changes in the SRO, which in turn affect the residual resistivity of the alloy. This effect might thus significantly alter the RR results and their interpretation, as it has been discussed in the case of Fe-Cr [18,19].In the field of energy advanced materials development there is specific interest in the study of Cr effects on nuclear alloys [20,21], given that Cr concentrations (C Cr ) close to 9% reduce swelling [22,23], reduce the radiation-induced ductile-brittle transition temperature (DBTT) [24], and increase protection against corrosion [25]. The physics of these effects is not yet well understood though it is believed that the minimum of the SRO parameters might play a role in affecting the kinetics of radiation defects in a concentrated Fe-Cr system. Indeed, it has been proven that α i change their sign at C Cr close to 10% [26][27][28]. At C Cr < 11% the SRO becomes negative, i.e., Cr tends to distribute as far * begona.gomez-ferrer@externos.ciemat.es...

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Point Defects in FCC Fe-Cr-Ni Alloys

Cited by 30 publications

References 0 publications

Ab initiostudy of solute transition-metal interactions with point defects in bcc Fe

Ab initiostudy of solute transition-metal interactions with point defects in bcc Fe

First-principles study of point defects in an fcc Fe-10Ni-20Cr model alloy

Decoupling of defect and short-range order contributions to resistivity recovery measurements in binary alloys

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