Microstructure and oxidation behavior of CoCrxCuFeMnNi high-entropy alloys fabricated by vacuum hot-pressing sintering

Ren, Bo; Zhao, Runze; Jiang, Aiyun; Yu, Yuan

doi:10.1016/j.micron.2022.103291

Cited by 16 publications

(4 citation statements)

References 40 publications

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“…Our previous research has shown that [27,30,31] CoCr x-CuFeMnNi (x = 0, 0.5, 1.0, 1.5, 2.0, mol) and Co x CrCu-FeMnNi (x = 0.5, 1.0, 1.5, 2.0, mol) alloy systems formed metastable supersaturated solid solutions with FCC or FCC + BCC structure after mechanical alloying. After aging treatment at 800°C or hot pressing sintering at 950°C, the FCC phase was transformed into FCC1 and FCC2 phases, and the BCC phase was transformed into intermetallic compound ρ phase.…”

Section: Microstructurementioning

confidence: 99%

“…Powder metallurgy (including vacuum hot pressing sintering and spark plasma sintering) is a relatively mature alloy preparation process, which has the advantages of near-net forming and restraining component segregation; thus, it has been widely used in the preparation of HEAs. [25][26][27][28][29] In the present work, CoCrCuFeMnNi x HEAs were prepared by vacuum hot pressing sintering process. The effects of Ni element on the microstructure of the alloy system and the corrosive behavior in 3.5% NaCl solution were studied by XRD, SEM, EDS, polarization corrosion, and impedance spectroscopy, to provide a reference for further research and application of HEAs.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and corrosion properties of CoCrCuFeMnNi_x high‐entropy alloys prepared by powder metallurgy

Zhao

Jiang

Ren

et al. 2023

Materials & Corrosion

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CoCrCuFeMnNix (x = 0.5, 1.0, 1.5, 2.0 mol, named Ni0.5, Ni1.0, Ni1.5, and Ni2.0, respectively) high‐entropy alloys (HEAs) were prepared by powder metallurgy. The effects of Ni content on its microstructure and corrosion resistance in a 3.5% NaCl solution were studied. The HEAs with low Ni content consisted of FCC1 primary phase, FCC2 secondary phase, and a few σ phases. While the Ni2.0 alloy was composed of the FCC phase and a small amount of σ phase. The results of polarization corrosion in 3.5% NaCl solution show that the increase of Ni content led to the increase of corrosion potential of the alloy and the decrease of corrosion current density and average corrosion rate. Among them, Ni2.0 alloy had the best corrosion resistance. The electrochemical impedance spectroscopy analysis showed that the increase in Ni content promoted the increase of the polarization resistance of the alloy RCPE and the thickness of the passive film, thus improving the corrosion resistance of the alloys.

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Section: Microstructurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructure and corrosion properties of CoCrCuFeMnNi_x high‐entropy alloys prepared by powder metallurgy

Zhao

Jiang

Ren

et al. 2023

Materials & Corrosion

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“…HEA systems containing Co, Cr, Cu, Fe, Mn, and Ni have been widely studied. Their preparation and processing technologies mainly include arc melting [1,2], induction melting [9], thermal mechanical processing [10,11], mechanical alloying [12][13][14], hot pressing sintering [15,16], plasma sintering [17], laser surface cladding [18], water atomization [12], etc. In the alloy systems studied, the CoCrFeMnNi alloy has a single FCC solid solution phase, good thermodynamic stability, and excellent ductility, which was reported by Cantor [1], Otto [19], and Gali [20].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Alloying Behavior and Thermal Stability of CoCrCuFeMnNix High-Entropy Alloy Powders Prepared via MA

et al. 2023

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CoCrCuFeMnNix (x = 0, 0.5, 1.0, 1.5, 2.0 mol, named as Ni0, Ni0.5, Ni1.0, Ni1.5, and Ni2.0, respectively) high-entropy alloy powders (HEAPs) were prepared via mechanical alloying (MA), and XRD, SEM, EDS, and vacuum annealing were used to study the alloying behavior, phase transition, and thermal stability. The results indicated that the Ni0, Ni0.5, and Ni1.0 HEAPs were alloyed at the initial stage (5–15 h), the metastable BCC + FCC two-phase solid solution structure was formed, and the BCC phase disappeared gradually with the prolonging of ball milling time. Finally, a single FCC structure was formed. Both Ni1.5 and Ni2.0 alloys with high nickel content formed a single FCC structure during the whole mechanical alloying process. The five kinds of HEAPs showed equiaxed particles in dry milling, and the particle size increased with an increase in milling time. After wet milling, they changed into lamellar morphology with thickness less than 1 μm and maximum size less than 20 μm. The composition of each component was close to its nominal composition, and the alloying sequence during ball milling was Cu→Mn→Co→Ni→Fe→Cr. After vacuum annealing at 700~900 °C, the FCC phase in the HEAPs with low Ni content transformed into FCC2 secondary phase, FCC1 primary phase, and a minor σ phase. The thermal stability of HEAPs can be improved by increasing Ni content.

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“…The cost of preparing high-entropy alloys by additive manufacturing is too high and energy intensive. Although powder metallurgy including discharged plasma sintering (SPS) and hot press sintering can solve the above problems [14][15] , but there are still inadequate for improving dense density, promoting particle rearrangement, and enhancing microstructure uniformity. In recent years, Xie et al [16] proposed an advanced sintering technique called hot oscillating pressing (HOP), which had been applied to a variety of materials with uniform organization, high-density and excellent properties at lower temperatures.…”

Section: Introductionmentioning

confidence: 99%

Hot oscillating pressing sintered AlCoCrFeNi/nanodiamond high-entropy alloy composites

Gao,

Wu,

Ren

et al. 2023

Preprint

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In this work, AlCoCrFeNi/nanodiamond high-entropy alloy composites (HEA/diamond) were prepared for the first time by hot oscillating pressing (HOP) using nanodiamond as the reinforcing phase, and the evolution of microstructure and properties at different sintering temperatures were investigated. The microstructures of the HOPed HEA/diamond high-entropy alloy composites all consisted of the FCC phase, BCC phase and nanocarbide phase uniformly distributed in the interstices of the particles. With the increase in sintering temperature, the original powder particle boundaries in the composites gradually disappeared, the density progressively increased, and the microstructure defects decreased. At 1100°C, the dense density of the material reached its maximum, 99.7%. Moreover, the FCC phase volume fraction and carbide content further increased without significant microstructure coarsening. The hardness and corrosion resistance of the HOPed samples were better than the hot pressing (HP) samples at the same sintering temperature. Especially at lower sintering temperatures (1000°C and below), the microstructure uniformity of the composite material was significantly improved because the original particle boundaries and pores became smaller, and a small number of nanocarbides were uniformly distributed in the powder interstices. The performance of HEA/diamond was greatly enhanced by the carbide pinned reinforcement. The hardness reached a maximum of 566.48 HV1, and the corrosion current density and corrosion rate reached a minimum of 2.916 µm/cm2 and 0.013 mm/year, respectively, which was better than other alloys reported. However, at high temperatures (at 1100°C), the performance decreased due to a large amount of graphitization of diamond to generate carbides, which weakened the interfacial bonding. The results showed that high-density, high-performance HEA/diamond composites could be obtained by HOP at appropriate sintering temperatures.

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Microstructure and oxidation behavior of CoCrxCuFeMnNi high-entropy alloys fabricated by vacuum hot-pressing sintering

Cited by 16 publications

References 40 publications

Microstructure and corrosion properties of CoCrCuFeMnNi_x high‐entropy alloys prepared by powder metallurgy

Microstructure and corrosion properties of CoCrCuFeMnNi_x high‐entropy alloys prepared by powder metallurgy

Mechanical Alloying Behavior and Thermal Stability of CoCrCuFeMnNix High-Entropy Alloy Powders Prepared via MA

Hot oscillating pressing sintered AlCoCrFeNi/nanodiamond high-entropy alloy composites

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Microstructure and oxidation behavior of CoCrxCuFeMnNi high-entropy alloys fabricated by vacuum hot-pressing sintering

Cited by 16 publications

References 40 publications

Microstructure and corrosion properties of CoCrCuFeMnNix high‐entropy alloys prepared by powder metallurgy

Microstructure and corrosion properties of CoCrCuFeMnNix high‐entropy alloys prepared by powder metallurgy

Mechanical Alloying Behavior and Thermal Stability of CoCrCuFeMnNix High-Entropy Alloy Powders Prepared via MA

Hot oscillating pressing sintered AlCoCrFeNi/nanodiamond high-entropy alloy composites

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Microstructure and corrosion properties of CoCrCuFeMnNi_x high‐entropy alloys prepared by powder metallurgy

Microstructure and corrosion properties of CoCrCuFeMnNi_x high‐entropy alloys prepared by powder metallurgy