Towards stacking fault energy engineering in FCC high entropy alloys

Khan, Tasneem; Kirk, Tanner; Vazquez, G.; Singh, Prashant; Smirnov, A. V.; Johnson, Duane D.; Youssef, Khaled; Arróyave, Raymundo

doi:10.1016/j.actamat.2021.117472

Cited by 68 publications

(12 citation statements)

References 86 publications

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“…A martensitic transformation can be an alternative since it "turns on" as a result of a decrease in the SFE with a further decrease in the test temperature. At the same time, the SFE is noticeably higher in the studied alloys doped with carbon [36][37][38], and the "activation" of deformation mechanisms, additional to dislocation slip, may not occur in this temperature range.…”

Section: Effect Of Test Temperaturementioning

confidence: 84%

“…This was necessary because, according to several studies [36,37], carbon atoms dissolved in the fcc lattice of the Co-Cr-Fe-Mn-Ni HEA system increase the stacking fault energy (SFE). A decrease in the cobalt concentration in the alloys with fcc lattice acts in the same way [38]. The SFE increase can lead to a change of deformation mechanism of the material and, thus, affect the properties.…”

Section: Introductionmentioning

confidence: 95%

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Structure and low-temperature micromechanical properties of as-cast and SPD-processed high-entropy Co25−xCr25Fe25Ni25Cx alloys

Rusakova

Fomenko

Huang

et al. 2022

Low Temperature Physics

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The effect of carbon additions on the structure and mechanical properties of high-entropy alloys Co25− xCr25Fe25Ni25C x ( x = 0, 1, 3, at. %) in two structural states, as-cast coarse-grained (CG) samples and nanocrystalline (NC) obtained by severe plastic deformation (SPD), was studied. The SPD was performed by high-pressure torsion at room temperature. The mechanical properties were investigated by microindentation in the temperature range of T = 77−300 K. It was found that in the as-cast state, all alloys had a dendritic microstructure and an inhomogeneous distribution of elements. At x = 0 and x = 1, the dendrites were enriched in iron and nickel, and the interdendrite regions were enriched in chromium. At x = 3, in the interdendrite regions, a eutectic consisting of a multicomponent matrix and fine eutectic dendrites of M7C3 carbide, where M is predominantly chromium, was formed. The main phase in alloys had an fcc lattice, while the solubility of carbon in it was about 1 at. %. SPD led to the effective refinement of the microstructure (the size of the coherent scattering regions was about 30−50 nm), to an increase in the dislocation density up to (1−1.5)⋅1015 m−2 and to an increase in the concentration of stacking faults. The microhardness of CG alloys at room temperature increased monotonically with increasing carbon concentration, while in NC alloys the maximum microhardness HV was achieved at 1 at. % of carbon. The reason for this anomalous behavior of the microhardness of NC alloys is an increase in the grain size and a decrease in the dislocation density in the alloy with x = 3 compared to the alloy with x = 1. As the temperature decreased from room temperature to the temperature of liquid nitrogen, the microhardness of CG and NC alloys increased by about 1.5−1.7 and 1.2−1.5 times, respectively, which indicates the thermally-activated nature of plastic deformation under the indenter. The results obtained indicate that the main role in the hardening of the CG alloys Co25− xCr25Fe25Ni25C x is due to solid solution and dispersion hardening, while in NC alloys it is hardening due to a decrease in the grain size (according to the Hall-Petch relation) and an increase in the dislocation density (according to the Taylor relation).

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Section: Effect Of Test Temperaturementioning

confidence: 84%

Section: Introductionmentioning

confidence: 95%

Structure and low-temperature micromechanical properties of as-cast and SPD-processed high-entropy Co25−xCr25Fe25Ni25Cx alloys

Rusakova

Fomenko

Huang

et al. 2022

Low Temperature Physics

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“…ML was employed to bridge the gap between the atomistic calculations and the larger system sizes. Khan et al [30] incorporated DFT calculations along with Gaussian vector regression and support vector regression for the prediction of SFE for CoCrFeMnNiV composition space. Furthermore, a hierarchical ML model has been developed for the correlation study of the structure and properties of CCAs [31].…”

Section: Introductionmentioning

confidence: 99%

Accelerated prediction of stacking fault energy in FCC medium entropy alloys using multilayer perceptron neural networks: correlation and feature analysis

Mahato,

Gurao,

Biswas

2024

Modelling Simul. Mater. Sci. Eng.

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A multilayer perceptron neural networks (MLPNN) model is developed for robust and quick prediction of stacking fault energy (SFE) to overcome the challenges faced in the calculation of SFE via experimentation and atomistic calculations in FCC medium entropy alloys (MEA). The present investigation employs a three-step hybrid feature selection approach to obtain a comprehensive understanding of the prominent features that influence the SFE, as well as the interrelationships among these features. The feature space encompasses various features related to composition, lattice stability, and elemental properties, of medium entropy alloys (MEAs). The findings indicate that the estimation of SFE relies on five crucial factors: temperature, lattice stability, specific heat, ionization energy, and Allen electronegativities. Furthermore, a mathematical relationship for the estimation of the SFE is derived, considering the various influencing and prominent factors. Consequently, the MLPNN model for robust SFE prediction in MEAs is developed and the performance is evaluated using R2 scores, with values of 0.87 and 0.85 obtained for the training and testing datasets, respectively. This efficient strategy introduces a novel opportunity for the engineering of SFE in the extensive range of alloy chemistry of MEAs, enabling the quick prediction of SFE, and facilitating the systematic exploration of new alloys for the development of mechanisms that may accommodate deformation through octahedral/partial slip, twinning, and/or transformation.

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“…The stacking fault energy (SFE), which is associated with chemical composition, is one of the most important parameters that influences activated deformation mechanisms, that is, dislocation slip, twinning, and martensitic transformation, during thermomechanical processing and recrystallization [ 16–18 ]. In low-SFE alloys, dislocations are dissociated into partials, and planar arrays of stacking faults would result in twinning or phase transformation.…”

Section: Introductionmentioning

confidence: 99%

Effects of molybdenum on hot deformation behavior and microstructural evolution of Fe ₄₀ Mn ₄₀ Co ₁₀ Cr ₁₀ C _0.5 high entropy alloys

Ebrahimian

Rizi

Hong

et al. 2023

Science and Technology of Advanced Materials

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The remarkable properties of high-entropy alloys (HEAs) have resulted in their increased research interest and prompted the use of various strategies to enhance their mechanical properties. In this study, the effects of Mo on the hot compressive deformation behavior of carbon-containing FeMn 40 Co 10 Cr 10 HEAs in the temperature range of 800–1000°C and strain rate of 0.001–0.1 s −1 was investigated. The microstructural evolutilon and phase structure were characterized by X-ray diffraction and electron backscattered diffraction. The effects of strain, strain rate, and deformation temperature on the thermally activated deformation restoration process of the Fe 39.5 Mn 40 Co 10 Cr 10 C 0.5 and Fe 38.3 Mn 40 Co 10 Cr 10 C 0.5 Mo 1.7 HEAs during hot compression were represented by the Zener–Hollomon parameter. Dynamic recrystallization was initiated at 800°C with the strain rate of 0.001–0.1 s −1 . The precipitation of the M 23 C 6 carbide along the grain boundaries and within the matrix exerted a strong pinning effect on the grain/subgrain boundaries and promoted dynamic recrystallization through the particle-stimulated nucleation of recrystallization. Moreover, the addition of Mo to the Fe 39.5 Mn 40 Co 10 Cr 10 C 0.5 HEA changed the dynamic recrystallization mechanism by reducing the stacking fault energy and enhancing the reverse phase transformation. The heterogeneous microstructure composed of ultrafine, fine, and larger grains in the Fe 38.3 Mn 40 Co 10 Cr 10 C 0.5 Mo 1.7 HEA could be obtained by the nucleation of new recrystallized grains at large deformed grain boundaries adjacent to the first necklace structures and shear bands.

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Towards stacking fault energy engineering in FCC high entropy alloys

Cited by 68 publications

References 86 publications

Structure and low-temperature micromechanical properties of as-cast and SPD-processed high-entropy Co25−xCr25Fe25Ni25Cx alloys

Structure and low-temperature micromechanical properties of as-cast and SPD-processed high-entropy Co25−xCr25Fe25Ni25Cx alloys

Accelerated prediction of stacking fault energy in FCC medium entropy alloys using multilayer perceptron neural networks: correlation and feature analysis

Effects of molybdenum on hot deformation behavior and microstructural evolution of Fe ₄₀ Mn ₄₀ Co ₁₀ Cr ₁₀ C _0.5 high entropy alloys

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Towards stacking fault energy engineering in FCC high entropy alloys

Cited by 68 publications

References 86 publications

Structure and low-temperature micromechanical properties of as-cast and SPD-processed high-entropy Co25−xCr25Fe25Ni25Cx alloys

Structure and low-temperature micromechanical properties of as-cast and SPD-processed high-entropy Co25−xCr25Fe25Ni25Cx alloys

Accelerated prediction of stacking fault energy in FCC medium entropy alloys using multilayer perceptron neural networks: correlation and feature analysis

Effects of molybdenum on hot deformation behavior and microstructural evolution of Fe 40 Mn 40 Co 10 Cr 10 C 0.5 high entropy alloys

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Effects of molybdenum on hot deformation behavior and microstructural evolution of Fe ₄₀ Mn ₄₀ Co ₁₀ Cr ₁₀ C _0.5 high entropy alloys