Generalized stacking fault energies, ductilities, and twinnabilities of CoCrFeNi-based face-centered cubic high entropy alloys

Kivy, Mohsen Beyramali; Zaeem, Mohsen Asle

doi:10.1016/j.scriptamat.2017.06.014

Cited by 154 publications

(33 citation statements)

References 49 publications

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“…The SFEs of fcc austenitic steels, particularly of high-Mn steels, have empirically been known to correlate with their deformation behaviors [63][64][65][66][67]. Also for 3d-transitionelement-based HEAs, their SFEs have also been measured in experiments [8,17,26,[68][69][70][71] and computed based on firstprinciples simulations [72][73][74][75][76][77][78][79][80][81][82][83][84]. While the impact of C atoms on the SFEs of HEAs has also been discussed in experimental fcc hcp FIG.…”

Section: A Stacking-fault Energymentioning

confidence: 99%

Impact of interstitial C on phase stability and stacking-fault energy of the CrMnFeCoNi high-entropy alloy

Ikeda

Tanaka

Neugebauer

et al. 2019

Phys. Rev. Materials

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Interstitial alloying in CrMnFeCoNi-based high-entropy alloys is known to modify their mechanical properties. Specifically, strength can be increased due to interstitial solid-solution hardening, while simultaneously affecting ductility. In this paper, first-principles calculations are carried out to analyze the impact of interstitial C atoms on CrMnFeCoNi in the fcc and the hcp phases. Our results show that C solution energies are widely spread and sensitively depend on the specific local environments. Using the computed solution-energy distributions together with statistical mechanics concepts, we determine the impact of C on the phase stability. C atoms are found to stabilize the fcc phase as compared to the hcp phase, indicating that the stacking-fault energy of CrMnFeCoNi increases due to C alloying. Using our extensive set of first-principles computed solution energies, correlations between them and local environments around the C atoms are investigated. This analysis reveals, e.g., that the local valence-electron concentration around a C atom is well correlated with its solution energy.

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Section: A Stacking-fault Energymentioning

confidence: 99%

Impact of interstitial C on phase stability and stacking-fault energy of the CrMnFeCoNi high-entropy alloy

Ikeda

Tanaka

Neugebauer

et al. 2019

Phys. Rev. Materials

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“…The advantage of this method is that it is possible to calculate several alloy compositions with less effort than the one required for an experimental determination of the same alloys. So far, the systems CoCrFeMnNi [9,10,13,14], AlCoCrCuFeNi, and AlCoCrFeNi [15] have been investigated regarding their SFE. A comprehensive list can be found in Reference [12].…”

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confidence: 99%

From High-Manganese Steels to Advanced High-Entropy Alloys

Haase

Barrales‐Mora

2019

Metals

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Arguably, steels are the most important structural material, even to this day. Numerous design concepts have been developed to create and/or tailor new steels suited to the most varied applications. High-manganese steels (HMnS) stand out for their excellent mechanical properties and their capacity to make use of a variety of physical mechanisms to tailor their microstructure, and thus their properties. With this in mind, in this contribution, we explore the possibility of extending the alloy design concepts that haven been used successfully in HMnS to the recently introduced high-entropy alloys (HEA). To this aim, one HMnS steel and the classical HEA Cantor alloy were subjected to cold rolling and heat treatment. The evolution of the microstructure and texture during the processing of the alloys and the resulting properties were characterized and studied. Based on these results, the physical mechanisms active in the investigated HMnS and HEA were identified and discussed. The results evidenced a substantial transferability of the design concepts and more importantly, they hint at a larger potential for microstructure and property tailoring in the HEA. several core effects (high-entropy effect, sever lattice distortion effect, sluggish diffusion effect, cocktail effect) of HEAs have been proposed [5], a clear design strategy is still missing.The underlying physical mechanisms active in HMnS have already been studied for several decades [1,2,6], and therefore are comparatively well understood. One of the most important parameters when designing HMnS is the tailoring of their stacking fault energy (SFE). This property controls the dissociation distance of partial dislocations and determines whether TRIP and/or TWIP is activated/suppressed during plastic deformation. The role of the SFE during plastic deformation and subsequent heat treatment in metals has been studied for decades, and its effect is relatively well-known for face-centered cubic (fcc) metals [7]. In fcc HEAs, the mechanisms of microstructure formation have been found to occur in a similar way to the same class of alloys with comparable SFE [8]. For instance, the Cantor alloy (CoCrFeMnNi) with an estimated SFE between 18.3-27.3 mJ/m 2 [9,10] has been shown to develop the TWIP effect, depending on the processing conditions [11]. Evidently, the determination of the SFE in HEAs is fundamental, because this property indicates the possible acting mechanisms for microstructure development. However, as with steels, the complex chemistry of HEAs leads to almost unlimited combinations that make a systematic determination of this property difficult. Nevertheless, to accelerate the development of these alloys, several research groups have made use of ab initio calculations, e.g., [12]. The advantage of this method is that it is possible to calculate several alloy compositions with less effort than the one required for an experimental determination of the same alloys. So far, the systems CoCrFeMnNi [9,10,13,14], AlCoCrCuFeNi, and AlCoCrFeNi [15] have been investig...

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“…The stacking fault energy (SFE) of materials is one of the most important factors in determining the dominant plastic deformation mechanisms. By using a first-principles approach, Kivy and Asle Zaeem [109] recently calculated the generalized stacking fault energy (GSFE) of CoCrFeNi-based single phase MPE alloys to investigate the effect of Cu, Ti, Mo, Mn, Al elements on their plastic deformation mechanisms. With randomly distributed alloy systems, possible variations in formation energies were obtained.…”

Section: Plastic Deformationmentioning

confidence: 99%

“…This study demonstrated that relatively high amounts of Al, or the presence of Cu and Mn, endorse martensitic transformation and dislocation mediated slip as plastic deformation mechanisms. Alternatively, mechanical twining and dislocation glide in alloys containing Mo or Ti, and dislocation gliding for alloys with a low amount of Al would be the plastic deformation mechanisms [109]. In another study, SFEs for a series of solid solution alloys (SSAs) were studied by first-principles calculations [110].…”

Section: Plastic Deformationmentioning

confidence: 99%

“…(a) fcc supercell structure used for calculating generalized stacking fault energy curves and surface energies of CoCrFeNi-based single phase MPE alloys. (b) Calculated GSFE curves for CoCrFeNi and CoCrFeNiAl0.3Ti0.1 by considering two different fault planes shown in (a); subset pictures show twin boundary formation for these two cases (this figure is from Reference[109]). …”

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confidence: 99%

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A Review of Multi-Scale Computational Modeling Tools for Predicting Structures and Properties of Multi-Principal Element Alloys

Kivy

Hong

Zaeem

2019

Metals

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Multi-principal element (MPE) alloys can be designed to have outstanding properties for a variety of applications. However, because of the compositional and phase complexity of these alloys, the experimental efforts in this area have often utilized trial and error tests. Consequently, computational modeling and simulations have emerged as power tools to accelerate the study and design of MPE alloys while decreasing the experimental costs. In this article, various computational modeling tools (such as density functional theory calculations and atomistic simulations) used to study the nano/microstructures and properties (such as mechanical and magnetic properties) of MPE alloys are reviewed. The advantages and limitations of these computational tools are also discussed. This study aims to assist the researchers to identify the capabilities of the state-of-the-art computational modeling and simulations for MPE alloy research.

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Generalized stacking fault energies, ductilities, and twinnabilities of CoCrFeNi-based face-centered cubic high entropy alloys

Cited by 154 publications

References 49 publications

Impact of interstitial C on phase stability and stacking-fault energy of the CrMnFeCoNi high-entropy alloy

Impact of interstitial C on phase stability and stacking-fault energy of the CrMnFeCoNi high-entropy alloy

From High-Manganese Steels to Advanced High-Entropy Alloys

A Review of Multi-Scale Computational Modeling Tools for Predicting Structures and Properties of Multi-Principal Element Alloys

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