Precipitation kinetics, microstructure, and equilibrium state of A2 and B2 phases in multicomponent Al2.75CoCrFeNi alloy

Aizenshtein, M.; Strumza, Einat; Brosh, Eli; Hayun, Shmuel

doi:10.1007/s10853-020-04487-9

Cited by 22 publications

(5 citation statements)

References 23 publications

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“…0 CoCrFeNi. Recently, Aizenshtein et al (2020) verified experimentally that single BCC-B2 phase is stable at 1300 • C in alloy Al 2 . 75 CoCrFeNi while it coexists with BCC-A2 at 1200 • C. The research reported in Abuzaid and Sehitoglu (2018) shows that Al 0 .…”

Section: Microstructure Analysis After Isothermal Annealing Experimentsmentioning

confidence: 90%

Phase Equilibria in the Al–Co–Cr–Fe–Ni High Entropy Alloy System: Thermodynamic Description and Experimental Study

et al. 2020

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In this paper we present and discuss phase equilibria in the quaternary Al-Cr-Fe-Ni and the quinary Al-Co-Cr-Fe-Ni alloy systems based on experimental data from DTA/DSC, SEM/EDS, and SEM/EBSD on as-cast and isothermally annealed samples. These data as well as literature data were used for developing a new Al-Co-Cr-Fe-Ni thermodynamic description by the CALPHAD approach. Considerable efforts in this direction have been made already and commercial databases for high entropy alloys are available, e.g., TCHEA4 and PanHEA. We focus on comparing our new thermodynamic database with computations using TCHEA4 for two section planes, i.e., quaternary Al x CrFe 2 Ni 2 and quinary Al x CoCrFeNi, where x is the stochiometric coefficient. According to our new thermodynamic description a single-phase field BCC-B2 is stable over a wider temperature range in both section planes, giving rise to dual-phase microstructures along solid state phase transformation pathways. In the section plane Al x CoCrFeNi the two-phase field BCC-B2 + σ predicted by the new database is stable between 600 and 800 • C, while in TCHEA4 this phase field extends to nearly 1000 • C. Furthermore, our new database showed that the solidification interval with primary BCC-B2 phase in quinary as well as quaternary section planes is narrow, being in a good agreement with presented micro-segregation measurements. Additionally, computed phase fields and phase-field boundaries in the quinary section plane correspond well to the experimental results reported in the literature.

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Section: Microstructure Analysis After Isothermal Annealing Experimentsmentioning

confidence: 90%

Phase Equilibria in the Al–Co–Cr–Fe–Ni High Entropy Alloy System: Thermodynamic Description and Experimental Study

et al. 2020

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“…In previous work, we found that the composition of the B2 phase depended on temperature between 900 and 1200 °C [15]. Table 4 summarizes the data and other published data on the composition of the A2 and B2 phases in the Al x CoCrFeNi system.…”

Section: Characterization Of Heat-treated Al 275 Cocrfeni Alloysmentioning

confidence: 79%

Synthesis of A2 and B2 Phases in AlxCoCrFeNi Multi-component System

Aizenshtein

Hayun

2020

Metallogr. Microstruct. Anal.

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The two phases of the Al x CoCrFeNi multi-component system, A2 (Im3m, bcc) and B2 (Pm3m, primitive) do not appear as single phases in the entire range studied to date (0 < x < 3). To measure the thermochemical properties of alloys and improve the accuracy of thermodynamic models, single phases need to be synthesized and characterized. Toward this end, we first study the mixture of A2 and B2 phases in the Al 2.75 CoCrFeNi multi-component alloy. After determining the composition of each phase, we attempted to synthesis each individual phase. The "B2" alloy is rich in Al, Ni, and Co and consists of a single primitive structure with a nonuniform composition. The "A2" alloy is a Cr-and Fe-rich alloy of compositional uniformity on the microscale, but that phase separates on the nanoscale into Al-Ni-Co-rich, nanometer-sized B2 precipitates in an A2 matrix rich in Cr and Fe. This result reveals the profound impact of Al on the stabilization of the B2 phase in the Al x CoCrFeNi system. Although the B2 alloy is adequate for thermochemical study, further efforts are required to synthesize an A2 alloy. In this case, the Al content should be less than 10 at.% and the Ni content should be about 1 at.%. These low contents of Al and Ni should prevent the formation of stable "Al-Ni-like" B2 ordered intermetallics.

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“…The composition distribution and crystal structure of the A2 and B2 phases are consistent with References. [30][31][32] The Ni 0.6 and Ni 0.8 HEAs present the dendritic microstructure consisting of the dark region and the bright inter-dendritic region. According to Figures 1 and 2 and Table 2, the dark dendritic and bright interdendritic regions in Ni 0.6 and Ni 0.8 HEAs correspond to the FCC phase and the A2/B2 phase, respectively.…”

Section: Microstructure Evolutionmentioning

confidence: 99%

Effects of Ni content on the corrosion behavior of Al_0.5CoCrFeNi_x high entropy alloys in acid and alkaline media

Dong

Jia

Zhang

et al. 2022

Materials & Corrosion

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The present work investigates the influence of Ni content on the microstructure evolution of Al 0.5 CoCrFeNi x high-entropy alloys followed by the study on their corrosion behavior in acid and alkaline solutions, respectively. The microscopic characterization demonstrates that the transformation from a BCC single-phase to a triple-phase (BCC + FCC + B2) structure occurs with the increase of Ni content. The corrosion behavior of Al 0.5 CoCrFeNi x high-entropy alloys was evaluated by electrochemical measurements coupled with morphology analysis. It is found that the corrosion on Al 0.5 CoCrFeNi 0 high-entropy alloy in both acid and alkaline media

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Precipitation kinetics, microstructure, and equilibrium state of A2 and B2 phases in multicomponent Al2.75CoCrFeNi alloy

Cited by 22 publications

References 23 publications

Phase Equilibria in the Al–Co–Cr–Fe–Ni High Entropy Alloy System: Thermodynamic Description and Experimental Study

Phase Equilibria in the Al–Co–Cr–Fe–Ni High Entropy Alloy System: Thermodynamic Description and Experimental Study

Synthesis of A2 and B2 Phases in AlxCoCrFeNi Multi-component System

Effects of Ni content on the corrosion behavior of Al_0.5CoCrFeNi_x high entropy alloys in acid and alkaline media

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Precipitation kinetics, microstructure, and equilibrium state of A2 and B2 phases in multicomponent Al2.75CoCrFeNi alloy

Cited by 22 publications

References 23 publications

Phase Equilibria in the Al–Co–Cr–Fe–Ni High Entropy Alloy System: Thermodynamic Description and Experimental Study

Phase Equilibria in the Al–Co–Cr–Fe–Ni High Entropy Alloy System: Thermodynamic Description and Experimental Study

Synthesis of A2 and B2 Phases in AlxCoCrFeNi Multi-component System

Effects of Ni content on the corrosion behavior of Al0.5CoCrFeNix high entropy alloys in acid and alkaline media

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Effects of Ni content on the corrosion behavior of Al_0.5CoCrFeNi_x high entropy alloys in acid and alkaline media