Phase formation and thermal stability of CoCrFeNi and CoCrFeMnNi equiatomic high entropy alloys

Vaidya, M.; Guruvidyathri, K.; Murty, B.S.

doi:10.1016/j.jallcom.2018.09.342

Cited by 130 publications

(19 citation statements)

References 24 publications

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“…As a result, the FeNiCoCr and FeNiCoCrMn alloys, even under the solid solubility extension state of MA, still exhibit a coexistence of FCC and BCC phases. Following SPS at 1000 °C, the nonequilibrium BCC phase in the 50 h as-milled powders transformed into more stable FCC phase under high temperature, which is in agreement with the published studies that the two HEAs usually exhibit a single FCC phase in the homogenized state [13,23]. Note that the secondary phase indexed as M 23 C 6 phase in the two bulk HEAs, will be further studied in hereinafter.…”

supporting

confidence: 88%

“…Among various HEAs' systems, the most deeply studied HEAs are designed based on III-rd to XII-th's transition metals, such as the well-known "Cantor alloy" (equiatomic FeNiCoCrMn HEA) and its derivative alloys (e.g., equiatomic FeNiCoCr HEA) [12,13]. Inspection of the HEA literature reveals that equiatomic FeNiCoCrMn HEA with a single FCC structure could be stabilized at temperatures > 900 °C [14].…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and Mechanical Behavior of FeNiCoCr and FeNiCoCrMn High-Entropy Alloys Fabricated by Powder Metallurgy

Chu

Chen

Жен

et al. 2020

Acta Metall. Sin. (Engl. Lett.)

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The present work reports a systematic investigation on phase evolution, microstructure and microstructure-property relationship of two typical face-centered cubic (FCC) structured high-entropy alloys (HEAs), FeNiCoCr and FeNiCoCrMn, prepared via mechanical alloying (MA) followed by spark plasma sintering (SPS). Following 50 h of MA, the two HEAs consisted of a mixture of FCC and body-centered cubic phases. Following SPS, the bulk FeNiCoCr alloy showed a primary FCC phase with a small amount of Cr 23 C 6 and Cr 2 O 3 contaminants, while the bulk FeNiCoCrMn alloy was composed of a primary FCC phase with some (Cr,Mn) 23 C 6 and MnCr 2 O 4 contaminants. The average grain size of the primary FCC phase in the bulk FeNiCoCr alloy was ~ 416 nm, while that of the primary FCC phase in the bulk FeNiCoCrMn alloy was ~ 547 nm. The yield strength, compressive strength and strain-to-failure of the bulk FeNiCoCr alloy are 1525 MPa, 1987 MPa and 24.4%, respectively, whereas those of the bulk FeNiCoCrMn alloy are 1329 MPa, 1761 MPa and 21.9%, respectively. It suggests that the bulk FeNiCoCrMn exhibited lower strength and plasticity in comparison with the bulk FeNiCoCr alloy. Clearly, the smaller grain size of the primary FCC phase in the FeNiCoCr alloy is mainly responsible for the better mechanical performance.

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supporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Behavior of FeNiCoCr and FeNiCoCrMn High-Entropy Alloys Fabricated by Powder Metallurgy

Chu

Chen

Жен

et al. 2020

Acta Metall. Sin. (Engl. Lett.)

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“…The number of HEA compositions under investigation is increasing steadily due to the evergrowing interest and research efforts in this field, particularly driven by their superb properties [12]. Notable among the exceptional mechanical properties are high strength at elevated temperatures, excellent cryogenic toughness [13][14][15][16], high wear resistance [17][18][19], good thermal stability [20][21][22], excellent fracture toughness [14,23,24] and superior corrosion resistance [25]. Thus far, CoCrFeMnNi is the most studied HEA [26][27][28][29][30] and is also called as 'Cantor alloy' named after Cantor et al [2] for their first studies of the alloy.…”

Section: Introductionmentioning

confidence: 99%

Constitutive modelling of hot deformation behaviour of a CoCrFeMnNi high-entropy alloy

Patnamsetty

Saastamoinen

Somani

et al. 2020

Science and Technology of Advanced Materials

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Models describing the constitutive flow behaviour of a metallic material are desired for appropriate process design and realization of defect-free components. In this study, constitutive equations based on the hyperbolic-sinusoidal Arrhenius-type model have been developed to define the hot deformation characteristics of a CoCrFeMnNi high-entropy alloy. The experimental true stress-true strain data were generated over a wide temperature (1023-1423 K) and strain rates (10 −3-10 s −1) ranges. The impact of strain rate and temperature on deformation behaviour was further characterized through a temperature compensated strain rate parameter, i.e. Zener-Hollomon parameter. Additionally, a mathematical relation was employed to express the influence of various material constants on true-strain ranging from 0.2 to 0.75. Typical third order polynomial relations were found to be appropriate to fit the true-strain dependency of these material constants. The accuracy of the developed constitutive equations was evaluated by using the average absolute relative error (AARE) and correlation coefficient (R); the obtained values were 7.63% and 0.9858, respectively, suggesting reasonable predictions. These results demonstrate that the developed constitutive equations can predict the flow stress behaviour of the alloy with a good accuracy over a wide range of temperature and strain rate conditions and for large strains.

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“…Traditional alloys, such as steel, aluminum, and magnesium alloys, are generally composed of one or two major metal elements, to which other constituent elements are added to modify the properties. In 2004, a new alloy design strategy was proposed by Yeh et al [1] and Cantor et al [2], which yields high-entropy alloys (HEAs). These novel alloys typically comprise five or more elements, each of which accounts for between 5at% and 35at%.…”

Section: Introductionmentioning

confidence: 99%

First-principles calculations of structural, elastic and electronic properties of (TaNb)0.67(HfZrTi)0.33 high-entropy alloy under high pressure

Nong

Wang

Zhu

2020

Int J Miner Metall Mater

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To clarify the effect of pressure on a (TaNb) 0.67 (HfZrTi) 0.33 alloy composed of a solid solution with a single body-centered-cubic crystal structure, we used first-principles calculations to theoretically investigate the structural, elastic, and electronic properties of this alloy at different pressures. The results show that the calculated equilibrium lattice parameters are consistent with the experimental results, and that the normalized structural parameters of lattice constants and volume decrease whereas the total enthalpy difference ΔE and elastic constants increase with increasing pressure. The (TaNb) 0.67 (HfZrTi) 0.33 alloy exhibits mechanical stability at high pressures lower than 400 GPa. At high pressure, the bulk modulus B shows larger values than the shear modulus G, and the alloy exhibits an obvious anisotropic feature at pressures ranging from 30 to 70 GPa. Our analysis of the electronic structures reveals that the atomic orbitals are occupied by the electrons change due to the compression of the crystal lattices under the effect of high pressure, which results in a decrease in the total density of states and a wider electron energy level. This factor is favorable for zero resistance.

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Phase formation and thermal stability of CoCrFeNi and CoCrFeMnNi equiatomic high entropy alloys

Cited by 130 publications

References 24 publications

Microstructure and Mechanical Behavior of FeNiCoCr and FeNiCoCrMn High-Entropy Alloys Fabricated by Powder Metallurgy

Microstructure and Mechanical Behavior of FeNiCoCr and FeNiCoCrMn High-Entropy Alloys Fabricated by Powder Metallurgy

Constitutive modelling of hot deformation behaviour of a CoCrFeMnNi high-entropy alloy

First-principles calculations of structural, elastic and electronic properties of (TaNb)0.67(HfZrTi)0.33 high-entropy alloy under high pressure

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