Compositional dependence of phase formation and mechanical properties in three CoCrFeNi-(Mn/Al/Cu) high entropy alloys

Zhu, Ze; Ma, Kai; Wang, Q.; Shek, C.H.

doi:10.1016/j.intermet.2016.09.003

Cited by 99 publications

(24 citation statements)

References 57 publications

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“…These analyses confirm that an fcc (A1) structure is present in all samples. This contrasts the prediction criteria of Guo et al [13] and Zhu et al [14] for x = 1.5. Table 4 A correlation in phase presence can be found between x = 0.2 and 0.8 alloys.…”

Section: Phase Determinationcontrasting

confidence: 93%

“…The calculated valence electron concentration according to the chemical composition summarized in Table 3 is 7.3 for x = 0.2, 6.8 for x = 0.8, and 6.5 for x = 1.5. In accordance with previous studies for both x = 0.8 and 1.5, a bcc structure can be predicted, while x = 0.2 fulfills the criterion given by Guo et al for a mixed bcc+fcc structure [13] and the criterion given by Zhu et al for a bcc structure [14].…”

Section: Chemical Composition Of the Cast Samplessupporting

confidence: 91%

“…Guo et al [13] used the valence electron concentration (VEC) for the prediction of a preferred crystal structure in HEA where VEC < 6.87 (bcc), VEC = 6.87-8.0 (bcc+fcc), and VEC > 8.0 (fcc). Zhu et al [14] shifted the bcc+fcc region to VEC = 7.3-8.1. Based on the molar ratio, the VEC is calculated according to Equation (1), with the atomic concentration c i and the valence electron concentration (VEC) i for alloying element i:…”

Section: Introductionmentioning

confidence: 99%

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The Phase Composition and Microstructure of AlxCoCrFeNiTi Alloys for the Development of High-Entropy Alloy Systems

Lindner

Löbel

Mehner

et al. 2017

Metals

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Abstract:Alloying aluminum offers the possibility of creating low-density high-entropy alloys (HEAs). Several studies that focus on the system AlCoCrFeNiTi differ in their phase determination. The effect of aluminum on the phase composition and microstructure of the compositionally complex alloy (CCA) system Al x CoCrFeNiTi was studied with variation in aluminum content (molar ratios x = 0.2, 0.8, and 1.5). The chemical composition and elemental segregation was measured for the different domains in the microstructure. The crystal structure was determined using X-ray diffraction (XRD) analysis. To identify the spatial distribution of the phases found with XRD, phase mapping with associated orientation distribution was performed using electron backscatter diffraction. This made it possible to correlate the chemical and structural conditions of the phases. The phase formation strongly depends on the aluminum content. Two different body-centered cubic (bcc) phases were found. Texture analysis proved the presence of a face-centered cubic (fcc) phase for all aluminum amounts. The hard η-(Ni, Co) 3 Ti phase in the x = 0.2 alloy was detected via metallographic investigation and confirmed via electron backscatter diffraction. Additionally, a centered cluster (cc) with the A12 structure type was detected in the x = 0.2 and 0.8 alloys. The correlation of structural and chemical properties as well as microstructure formation contribute to a better understanding of the alloying effects concerning the aluminum content in CCAs. Especially in the context of current developments in lightweight high-entropy alloys (HEAs), the presented results provide an approach to the development of new alloy systems.

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Section: Phase Determinationcontrasting

confidence: 93%

Section: Chemical Composition Of the Cast Samplessupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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The Phase Composition and Microstructure of AlxCoCrFeNiTi Alloys for the Development of High-Entropy Alloy Systems

Lindner

Löbel

Mehner

et al. 2017

Metals

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“…The two alloys, Al43 Co 22 Cr 33 Fe 7 Ni 5 and Al 47 Co 20 Cr 18 Cu 5 Fe 5 Ni 5 , with the highest hardness tend to have more Al content and little Cu. It is known that Cu can promote the formation of FCC phase in HEAs and decrease strength and hardness; Al, when combined with Ni, tends to form a BCC ordered phase due to the high formation enthalpy of these two elements.…”

mentioning

confidence: 99%

Machine learning assisted design of high entropy alloys with desired property

et al. 2019

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“…Zhu et al studied CoCrFeNiAl and CoCrFeNiCu HEA system and analyzed the influence of varying each element in these two alloy systems. The result from Zhu's paper could be a good reference for a wide range of HEA design [49].…”

Section: Addition Of Other Elementsmentioning

confidence: 91%

UQ eSpace

Chen¹

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The cost-effective iron-based eutectic high entropy alloys (HEAs) that contain four compositions, Fe, Ni, Cr, Mo was prepared by arc melting by Yin et al.[1]. Precipitate strengthening was done to improve the ductility and strength trade-off of Fe45Ni25Cr25Mo5(at. %). The chosen alloy is a hypo-eutectic high entropy alloy mainly contains single FCC phase and eutectic phase (σ phase + FCC phase). The as-cast alloys (hardness = 202HV) were aging treated under 600℃-1000℃ with aging time from 1 to 96 hours. Cr-Mo riched needle-like precipitates formed at the eutectic phase boundary during aging, the hardness of this alloy reaches 300HV under 900℃-48Hours aging. However, the hardness drops to 250HV, when overaging took place under 1000 ℃ aging. For further improving the mechanical properties, minor elements Ti and Al were added with 1 to 5at.% during sample preparation. Sample with 2% Ti-Al addition(Hardness = 260HV) had the optimum balanced hardness and ductility, which was then aging treated under 700-900℃ for 2-96Hours. The hardness raised to 534HV since similar needle-like precipitate formed in FCC matrix with a smaller size(~5μm).

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Compositional dependence of phase formation and mechanical properties in three CoCrFeNi-(Mn/Al/Cu) high entropy alloys

Cited by 99 publications

References 57 publications

The Phase Composition and Microstructure of AlxCoCrFeNiTi Alloys for the Development of High-Entropy Alloy Systems

The Phase Composition and Microstructure of AlxCoCrFeNiTi Alloys for the Development of High-Entropy Alloy Systems

Machine learning assisted design of high entropy alloys with desired property

UQ eSpace

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