Ab Initio Study of Elastic and Mechanical Properties in FeCrMn Alloys

Razumovskiy, Vsevolod I.; Hahn, Carola; Lukas, Marina; Romaner, Lorenz

doi:10.3390/ma12071129

Cited by 8 publications

(2 citation statements)

References 74 publications

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“…The ANNNI model accounts for the interactions between the next-nearest-neighbor stacking planes and has been shown to be a reasonable choice in terms of accuracy and computational cost for ab initio calculations for Fe-based fcc alloys. [47,48] The self-consistent density functional theory total energy calculations were performed by the exact muffin-tin orbital method (EMTO) combined with the coherent potential approximation (CPA) to treat the electronic structure of random atomic configurations. [49,50] The one-electron thermal excitations were included using the Fermi-Dirac distribution function.…”

Section: Ab Initio Calculationsmentioning

confidence: 99%

In Situ Bulk Observations and Ab Initio Calculations Revealing the Temperature Dependence of Stacking Fault Energy in Fe–Cr–Ni Alloys

Neding

Gorbatov

Tseng

et al. 2021

Metall Mater Trans A

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The dependence of stacking fault energy ($${\gamma }_{\text{SFE}}$$ γ SFE ) on temperature in austenitic Fe–Cr–Ni alloy powders was investigated by in situ high energy synchrotron X-ray diffraction and ab initio calculations in the temperature range from − 45 °C to 450 °C. The X-ray diffraction peak positions were used to determine the stacking fault probability and subsequently the temperature dependence of γSFE. The effect of temperature on the diffraction peak positions was found to be mainly reversible; however, recovery of dislocations occurred above about 200 °C, which also gave an irreversible contribution. Two different ab initio-based models were evaluated with respect to the experimental data. The different predictions of the models can be explained by their respective treatment of the magnetic moments for Cr and Ni, which is critical for the alloy compositions investigated. Ab initio calculations, taking longitudinal spin fluctuations (LSF) into consideration within the quasi-classical phenomenological model, predict a temperature dependence of $${\gamma }_{\rm SFE}$$ γ SFE in good agreement with the experimentally evaluated trend of increasing γSFE with increasing temperature: $$\left|\Updelta {\gamma }_{\rm SFE}/\Updelta T\right|=0.05 {\text{mJ}} {\text{m}}^{-2}/{\text{K}}.$$ Δ γ SFE / Δ T = 0.05 mJm - 2 / K . The temperature effect on γSFE is similar for all three investigated alloys: Fe–18Cr–15Ni, Fe–18Cr–17Ni, Fe–21Cr–16Ni (wt pct), while their room temperature $${\gamma }_{\rm SFE}$$ γ SFE are evaluated to be 22, 25, 20 mJ m−2, respectively.

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Section: Ab Initio Calculationsmentioning

confidence: 99%

In Situ Bulk Observations and Ab Initio Calculations Revealing the Temperature Dependence of Stacking Fault Energy in Fe–Cr–Ni Alloys

Neding

Gorbatov

Tseng

et al. 2021

Metall Mater Trans A

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“…However, there have been other studies which described an increase of stacking fault energy with N [13], or even a non-monotonous dependence [14]. Moreover, in recent publications it was stated that-in contrast to twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) steels-for the calculation of SFE in austenitic alloys containing N, the existing methods are is still not reliable [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Dislocation Structure of a CrMnN and a CrNi Austenite after Cyclic Deformation

Fluch

Kapp

Spiradek-Hahn

et al. 2019

Metals

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In the literature, the effects of nitrogen on the strength of austenitic stainless steels as well as on cold deformation are well documented. However, the effect of N on fatigue behaviour is still an open issue, especially when comparing the two alloying concepts for austenitic stainless steels-CrNi and CrMnN-where the microstructures show a different evolution during cyclic deformation. In the present investigation, a representative sample of each alloying concept has been tested in a resonant testing machine at ambient temperature and under stress control single step tests with a stress ratio of 0.05. The following comparative analysis of the microstructures showed a preferred formation of cellular dislocation substructures in the case of the CrNi alloy and distinct planar dislocation glide in the CrMnN steel, also called high nitrogen steel (HNS). The discussion of these findings deals with potential explanations for the dislocation glide mechanism, the role of N on this phenomenon, and the consequences on fatigue behaviour.

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Synergistic deformation pathways in a TWIP steel at cryogenic temperatures: In situ neutron diffraction

Tang

Wang

et al. 2020

Acta Materialia

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High manganese steels are promising candidates for applications in cryogenic environments. In this study, we investigate the mechanical and microstructural responses of a high manganese twinning induced plasticity (TWIP) steel at a low-temperature range (from 373 to 77 K) via in situ neutron diffraction qualification and correlative microscopy characterization. During plastic deformation, stacking fault probability and dislocation density increased at a faster rate at a lower temperature, hence, higher dislocation density and denser mechanical twins were observed, confirmed by microscopic observation. Stacking fault energy was estimated, dropping linearly from 34.8 mJm -2 at 373 K to 17.2 mJm -2 at 77 K. A small amount of austenite transferred to martensite when deforming at 77 K. The contributions to flow stress from solutes, grain boundary, dislocation, and twinning were determined at different temperatures, which shows that the high work strain hardening capacity of the TWIP steel originates from the synergetic strengthening effects of dislocations and twin-twin networks. These findings reveal the relationship among stacking fault energy, microstructure, and deformation mechanisms at the low-temperature range, paving a way in designing TWIP steels with the superb mechanical performance for cryogenic applications.

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Ab Initio Study of Elastic and Mechanical Properties in FeCrMn Alloys

Cited by 8 publications

References 74 publications

In Situ Bulk Observations and Ab Initio Calculations Revealing the Temperature Dependence of Stacking Fault Energy in Fe–Cr–Ni Alloys

In Situ Bulk Observations and Ab Initio Calculations Revealing the Temperature Dependence of Stacking Fault Energy in Fe–Cr–Ni Alloys

Comparison of the Dislocation Structure of a CrMnN and a CrNi Austenite after Cyclic Deformation

Synergistic deformation pathways in a TWIP steel at cryogenic temperatures: In situ neutron diffraction

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