Temperature dependent stacking fault energy of FeCrCoNiMn high entropy alloy

Huang, Shuo; Li, Wei; Lu, Song; Tian, Fuyang; Shen, Jiang; Holmström, Erik; Vitos, Levente

doi:10.1016/j.scriptamat.2015.05.041

Cited by 434 publications

(158 citation statements)

References 54 publications

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“…720 ± 30 MPa for the HEA reported in [24]) is reached. This is consistent with the experimentally measured and theoretically estimated stacking fault energy of the alloy being low enough to enable twinning [2,[25][26][27]. We have chosen this alloy as a testbed for a constitutive description for HEAs based on a model that considers dislocation glide and deformation twinning.…”

Section: Introductionsupporting

confidence: 73%

Constitutive modeling of deformation behavior of high-entropy alloys with face-centered cubic crystal structure

Jang

Ahn

Moon

et al. 2017

Materials Research Letters

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A constitutive model based on the dislocation glide and deformation twinning is adapted to facecentered cubic high-entropy alloys (HEAs) as exemplified by the CrMnFeCoNi system. In this model, the total dislocation density is considered as the only internal variable, while the evolution equation describing its variation during plastic deformation is governed by the volume fraction of twinned material. The suitability of the model for describing the strain hardening behavior of HEAs was verified experimentally through compression tests on alloy CrMnFeCoNi and its microstructure characterization by electron backscatter diffraction and X-ray diffraction using synchrotron radiation. IMPACT STATEMENTWe adopted a constitutive model based on dislocation density and twin volume fraction evolution, to analyze the deformation behavior of the high-entropy alloy CrMnFeCoNi theoretically. ARTICLE HISTORY

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Section: Introductionsupporting

confidence: 73%

Constitutive modeling of deformation behavior of high-entropy alloys with face-centered cubic crystal structure

Jang

Ahn

Moon

et al. 2017

Materials Research Letters

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“…A simple way to estimate the SFE is to calculate the energy difference between hexagonal close-packed (hcp) and fcc structures since the hcp/fcc energy difference is the dominant factor that determines the SFE value. 28 The calculated hcp/fcc energy difference (ΔE fcc→hcp ) in the CoCrFeMnNi HEA is −814 J/ mol at 0 K, which means that hcp is a more stable structure than fcc for the CoCrFeMnNi HEA at absolute zero temperature. We believe the higher stability of hcp than fcc yields a low SFE and eventually leads to the easy formation of micro-twins in the HEA during deformations at 77 K. The same quantity (ΔE fcc→hcp ) for the other alloys, Fe-50Ni, Co-50Ni and 100Ni, are 239, 794 and 1930 J/ mol, respectively.…”

Section: Resultsmentioning

confidence: 94%

Understanding the physical metallurgy of the CoCrFeMnNi high-entropy alloy: an atomistic simulation study

et al. 2018

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Although high-entropy alloys (HEAs) are attracting interest, the physical metallurgical mechanisms related to their properties have mostly not been clarified, and this limits wider industrial applications, in addition to the high alloy costs. We clarify the physical metallurgical reasons for the materials phenomena (sluggish diffusion and micro-twining at cryogenic temperatures) and investigate the effect of individual elements on solid solution hardening for the equiatomic CoCrFeMnNi HEA based on atomistic simulations (Monte Carlo, molecular dynamics and molecular statics). A significant number of stable vacant lattice sites with high migration energy barriers exists and is thought to cause the sluggish diffusion. We predict that the hexagonal close-packed (hcp) structure is more stable than the face-centered cubic (fcc) structure at 0 K, which we propose as the fundamental reason for the micro-twinning at cryogenic temperatures. The alloying effect on the critical resolved shear stress (CRSS) is well predicted by the atomistic simulation, used for a design of non-equiatomic fcc HEAs with improved strength, and is experimentally verified. This study demonstrates the applicability of the proposed atomistic approach combined with a thermodynamic calculation technique to a computational design of advanced HEAs.

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“…The line tension parameter α = 0.123 is obtained from the atomistically-measured edge dislocation line tension in the EAM FeNiCr effective matrix, and is close to the coefficient for elemental Al [82]. The dislocation cores in HEAs show large dissociation distances d > 10b, consistent their relatively low stacking fault energies γ SF (low ab initio estimates, and large stacking fault ribbons observed experimentally [100,101,102]). The minimized parameters of Eqs.…”

Section: Fcc High Entropy Alloysmentioning

confidence: 79%

“…Direct calculations of average properties, such as C ij , b, ∆V n , σ 2 ∆Vn , and γ SF are currently feasible (see Refs. [100,101]) and provide the inputs needed for application of the simplified elasticity model. The precise dislocation core structure, direct solute/dislocation core interactions U n (x i , y j , z k ), and dislocation line tension, are all far more challenging, and perhaps prohibitively expensive, to compute.…”

Section: Identification Of Promising Materialsmentioning

confidence: 99%

Solute strengthening in random alloys

et al. 2017

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Random solid solution alloys are a broad class of materials that are used across the entire spectrum of engineering metals, whether as stand-alone materials (e.g. Al-5xxx alloys) or as the matrix in precipitatestrengthening materials (e.g. Ni-based superalloys). As a result, the mechanisms of, and prediction of, strengthening in solid solutions has a long history. Many concepts have been developed and important trends identified but predictive capability has remained elusive. In recent years, a new theory has been developed that builds on one historical model, the Labusch model, in important ways that lead to a well-defined model valid for random solutions with arbitrary numbers of components and compositions. The new theory uses first-principles-computed solute/dislocation interaction energies as input, from which specific predictions emerge for the yield strength and activation volume as a function of alloy composition, temperature, and strain-rate. Being a general model for materials that otherwise have a low Peierls stress, it has broad application and has been successfully applied to Al-X alloys, Mg-Al, twinning in Mg alloys, and recently fcc High-Entropy Alloys. Here, the new theory is presented in a general and systematic manner. Approximations and limiting cases that reduce the complexity and facilitate understanding are introduced, and help relate the new model to various physical features present among the historical array of models. The quantitative predictions of the model in the various materials above is then demonstrated.

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Temperature dependent stacking fault energy of FeCrCoNiMn high entropy alloy

Cited by 434 publications

References 54 publications

Constitutive modeling of deformation behavior of high-entropy alloys with face-centered cubic crystal structure

Constitutive modeling of deformation behavior of high-entropy alloys with face-centered cubic crystal structure

Understanding the physical metallurgy of the CoCrFeMnNi high-entropy alloy: an atomistic simulation study

Solute strengthening in random alloys

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