Computational design and initial corrosion assessment of a series of non-equimolar high entropy alloys

Lü, Ping; Saal, James E.; Olson, Gregory B.; Li, Tianshu; Sahu, Sarita; Swanson, Orion J.; Frankel, G. S.; Gerard, Angela Y.; Scully, John R.

doi:10.1016/j.scriptamat.2019.07.003

Cited by 52 publications

(22 citation statements)

References 28 publications

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“…2 By now it has been found that this is probably not the case and many of the alloys do not represent their thermodynamic ground state, but are rather kinetically inhibited from phase decomposition and do so upon annealing. 1,5,6 Thus, in this paper, we understand the term HEA not just as entropymaximizing alloys with equiatomic composition, but rather in the modern sense of multiprincipal-element alloys (MPEA) where concentrations do not need to be equiatomic 3,[7][8][9][10][11] . Their oxide equivalents, either high-entropy ceramics 12 or perovskite oxides 13 , are also a currently very actively researched field.…”

Section: Introductionmentioning

confidence: 99%

Bond Synergy Model for Bond Energies in Alloy Oxides

Chien

Windl

2020

J. Electrochem. Soc.

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In this work we introduce a metal-oxide bond-energy model for alloy oxides based on pure-phase bond energies and bond synergy factors that describe the effect of alloying on the bond energy between cations and oxygen, an important quantity to understand the formation of alloy oxides and their composition. This model is parameterized for binary cation-alloy oxides using density-functional theory energies and is shown to be directly transferable to multi-component alloy oxides. We parameterized the model for alloy oxide energies with metal cations that form the basis of corrosion resistant alloys, including Fe, Ni, Cr, Mo, Mn, W, Co, and Ru. We find that isoelectronic solutes allow quantification of pure-phase bond energies in oxides and the calculated bond energy values give sensible results compared to common experience, including the role of Cr as the passive-layer former in Fe–Ni–Cr alloys for corrosion applications. Additionally, the bond synergy factors give insights into the mutual strengthening and weakening effects of alloying on cation-oxygen bonds and can be related to enthalpy of mixing and charge neutrality constraints. We demonstrate how charge neutrality can be identified and achieved by the oxidation states that the different cations assume depending on alloy composition and the presence of defects.

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Section: Introductionmentioning

confidence: 99%

Bond Synergy Model for Bond Energies in Alloy Oxides

Chien

Windl

2020

J. Electrochem. Soc.

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“…Most corrosion resistant CCAs reported to date contain a high concentration of chromium, and therefore the mechanism for corrosion resistance has been proposed to be similar to that reported for Fe-Cr and Ni-Cr based alloys [8]. A conventional Pitting Resistance Equivalent Number (PREN) type of approach for designing corrosion resistant CCAs has been proposed by several researchers [9]. This conventional approach, however, would result in CCAs with high cost and high density, and inhibit exploitation of the full potential of CCAs -which have been noted as being inherently corrosion resistant (in spite of complex compositions and heterogeneous microstructures) [8,10].…”

Section: Development Of the Corrosion Resistant Alloys With Propertiementioning

confidence: 98%

A low-cost, low-density and corrosion resistant compositionally complex alloy: AlFeMnSi

O’Brien¹,

Esteves²,

Birbilis³

et al. 2020

Preprint

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A new class of compositionally complex alloy, consisting of equiatomic concentrations of Al, Fe, Mn and Si is reported. The alloy was characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Corrosion behavior of the AlFeMnSi alloy, as evaluated using potentiodynamic polarization tests and electrochemical impedance spectroscopy in 0.6 M NaCl solution, was comparable with that of stainless steel (SS) 304L. X-ray photoelectron spectroscopy was used to study the AlFeMnSi surface film. The AlFeMnSi alloy also exhibited a lower cost, lower density, and a higher hardness as compared with SS 304L, rendering it a promising alloy for bespoke applications.

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“…The ICME approach has been utilized by several groups to design HEAs. Lu et al [107] in 2019 applied the ICME approach to design a series of chromium-containing HEAs having a single FCC phase, which shows different corrosion behaviors. They carried out simulations using the CALPHAD approach.…”

Section: Icme As An Enabling Tool For the Development Of Healsmentioning

confidence: 99%

“…They carried out simulations using the CALPHAD approach. Lu et al [107] showed that Ni 38 Fe 20 Cr 6-Mn 18 Co 18 , which has a relatively low concentration of chromium, can have passivity in a saline solution. Lu et al [108] in 2018 also utilized the ICME approach to design a superior corrosion resistant HEA for Figure 9 The entropy of mixing in FCC structure calculated using Thermo-Calc along with TCAL6 database (a), and the ultimate tensile strength (UTS) [101] (b), versus total dissolvable weight percent of alloying elements in FCC matrix for different alloys.…”

Section: Icme As An Enabling Tool For the Development Of Healsmentioning

confidence: 99%

A review of the design of high-entropy aluminum alloys: a pathway for novel Al alloys

et al. 2021

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Aluminum (Al) alloys are of great importance and interest because of their extensive applications in various engineering fields. Lightweighting of our infrastructure has been a driver for more than the last two decades as our need to reduce carbon footprint on a global scale has become an inevitable reality. As a result, we have witnessed much progress in alloy development in Al alloys, especially with the advent of Integrated Computational Materials Engineering (ICME) and other computational tools. However, the limitations of the properties one may attain through alloy development to date have relied on the traditional solvent/solute model, where the matrix is Al with additions of elements (solute) to the matrix. Despite making much progress, we are still lockedin to the strength-ductility curve without any appreciable increase in modulus (stiffness) of the alloy. High Entropy Alloys (HEAs) provide a new paradigm as they differ from conventional alloys in entropy-based mixing logic of various elements, which is different from the solvent/solute model. HEAs offer the opportunity to move out of the strength-ductility curve as well as the opportunity to increase the alloy's modulus. In this paper, we present a retrospective view of Al alloys, followed with an understanding of the principles of HEAs, and lastly, with the idea of applying high entropy concept to conventional Al alloys to develop a novel Al alloy category, which we have coined HEAl. Preliminary results with a commentary on potential future opportunities are also given.

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Computational design and initial corrosion assessment of a series of non-equimolar high entropy alloys

Cited by 52 publications

References 28 publications

Bond Synergy Model for Bond Energies in Alloy Oxides

Bond Synergy Model for Bond Energies in Alloy Oxides

A low-cost, low-density and corrosion resistant compositionally complex alloy: AlFeMnSi

A review of the design of high-entropy aluminum alloys: a pathway for novel Al alloys

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