Atomic Structure Modeling of Multi-Principal-Element Alloys by the Principle of Maximum Entropy

Wang, Shaoqing

doi:10.3390/e15125536

Cited by 85 publications

(30 citation statements)

References 33 publications

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“…However, it is difficult to physically visualize and quantitatively define lattice distortion at the atomic level. Some efforts have been made [6,7] to evaluate the distortion, but with only limited success. The usual approach is to statistically calculate the atomic size difference, but the physical picture how the lattice is distorted is still unclear [7].…”

Section: Introductionmentioning

confidence: 99%

Correlation between lattice distortion and friction stress in Ni-based equiatomic alloys

2017

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Many recent efforts have been made to apply traditional theories for solid solution strengthening to explain the strength increase in concentrated equiatomic alloys (or high-entropy alloys), but always faced the challenge of differentiating solvent from solute atoms. In this report, we conducted a systematical analysis of Ni-based equiatomic alloys with a face-centered cubic structure and found that the lattice distortion in this alloy system could be simply described by the parameter of atomic size mismatch. It was found that lattice friction stresses of these alloys were well correlated with the lattice distortion. Dislocation core width in this Ni-based alloy system was also estimated and compared with that in the pure nickel. The intrinsically high strength in high-entropy alloys was probably resulted from a high lattice friction stress.

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Section: Introductionmentioning

confidence: 99%

Correlation between lattice distortion and friction stress in Ni-based equiatomic alloys

2017

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“…High entropy alloys types. (Recreated from Diao et al[10]) Atoms arrangement in the lattice for (a) FCC FeCoCrNi and (b) FCC CoCrFeMnNi (Source:[11])Mechanical properties of HEAs such as yield and ultimate strength, ductility, hardness and fracture toughness were found to be in the same range or better than conventional metal alloys like stainless steel and nickel-base superalloy [1-4, 9, 10, 12-14].Figure 3shows the toughness versus yield strength Ashby chart of different materials at 77K[10]. High fracture toughness and simultaneous high yield strength of HEAs compared to other materials can be observed from the chart.Figure 4shows the yield strength of different groups of HEAs at different temperatures compared to five conventional metal alloys which shows that the yield strength of HEAs at a range of temperature from cryogenic to high temperature is better or comparable with other presented metal alloys.…”

mentioning

confidence: 99%

Effect of Strain Rate on the Tensile Behavior of CoCrFeNi and CoCrFeMnNi High-Entropy Alloys

Shabani

Indeck

Hazeli

et al. 2019

J. of Materi Eng and Perform

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High entropy alloys (HEAs) are a new class of alloys with the potential to be used in critical load bearing applications instead of conventional alloys. The HEAs studied in this research were CoCrFeNi and CoCrFeMnNi. Both were single-phase face-centered cubic materials. The focus of this study was on the tensile behavior of the two materials at quasi-static and dynamic strain-rates (10 −4 to 10 3 s −1) and the underlying microstructural phenomena driving the behaviors. Electron back-scatter diffraction was performed on both HEAs to study the microstructure before mechanical testing. To study the effect of strain rate, tensile experiments were performed at quasi-static strain rates on hydraulic MTS load frames and dynamic strain-rates on a Split-Hopkinson Pressure Bar. HEAs stressstrain curves, modulus of elasticity, yield strength, ultimate strength, strain-rate sensitivity and work hardening rates were calculated with the data from the tensile experiments. Transmission electron microscopy was performed post-mortem to study the plastic deformation mechanisms activated at different strain rates. The dominant deformation mechanism changed from dislocation slip at quasi-static strain-rates to the addition of deformation nano-twins at dynamic strain-rates. Ultimate strength and ductility both improved with the increase of strain-rate, which can be attributed to the activation of deformation nano-twins in HEAs. CoCrFeNi and CoCrFeMnNi both have low stacking fault energies which encouraged twinning at high strains to accommodate plastic deformation. The strain-rate sensitivity component increased with increasing strain-rate, beginning with negligible strain-rate sensitivity in the quasi-static range to high strain-rate sensitivity in the dynamic range. CoCrFeMnNi showed greater strain-rate sensitivity. CoCrFeNi, with the less configurational entropy, had higher iii mechanical properties and strain hardening rates at different strain-rates compared to CoCrFeMnNi.

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“…In order to understand solute strengthening in HEAs, it is important to understand not only the average misfit ∆V i m , but also its distribution around the mean. Wang [18] employed empirical pair-potentials to study lattice distortions in fcc and bcc HEAs. However, empirical pair-potentials do not take the underlying electronic structure and magnetic effects into account, both of which may cause additional distortion effects.…”

Section: Introductionmentioning

confidence: 99%

Lattice Distortions in the FeCoNiCrMn High Entropy Alloy Studied by Theory and Experiment

Leyson

et al. 2016

Entropy

178

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Lattice distortions constitute one of the main features characterizing high entropy alloys. Local lattice distortions have, however, only rarely been investigated in these multi-component alloys. We, therefore, employ a combined theoretical electronic structure and experimental approach to study the atomistic distortions in the FeCoNiCrMn high entropy (Cantor) alloy by means of density-functional theory and extended X-ray absorption fine structure spectroscopy. Particular attention is paid to element-resolved distortions for each constituent. The individual mean distortions are small on average, <1%, but their fluctuations (i.e., standard deviations) are an order of magnitude larger, in particular for Cr and Mn. Good agreement between theory and experiment is found.

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Atomic Structure Modeling of Multi-Principal-Element Alloys by the Principle of Maximum Entropy

Cited by 85 publications

References 33 publications

Correlation between lattice distortion and friction stress in Ni-based equiatomic alloys

Correlation between lattice distortion and friction stress in Ni-based equiatomic alloys

Effect of Strain Rate on the Tensile Behavior of CoCrFeNi and CoCrFeMnNi High-Entropy Alloys

Lattice Distortions in the FeCoNiCrMn High Entropy Alloy Studied by Theory and Experiment

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