A critical review of the mechanical properties of CoCrNi-based medium-entropy alloys

Xu, Dingfeng; Wang, Mingliang; Li, Tianxin; Wei, Xiangsai; Lu, Yiping

doi:10.20517/microstructures.2021.10

Cited by 16 publications

(14 citation statements)

References 150 publications

(269 reference statements)

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“…A fine grain size is known to help with slip homogenization, promoting ductility, and also leads directly to strengthening via the Hall–Petch relationship. Enhanced work hardening in the alloy due to twinning also extends the necking stage, thereby enhancing ductility 29 . Alloyed carbide particles are expected also be present in the form of fine particles dispersed in the matrix phase.…”

Section: Resultsmentioning

confidence: 99%

“…HEAs have also shown the potential to exhibit enhanced combinations of strength and ductility. Excellent ductility can be achieved in fcc HEAs, albeit with limited strength, whereas high strength but limited ductility has been reported for bcc HEAs Different attempts have been carried out, therefore, to further enhance the strength-ductility combinations in HEAs by design of HEAs containing both fcc and bcc solid-solution phases, where some promising results have already been achieved 27 – 29 . Development of HEAs strengthened by interstitial solid-solutions has also been explored.…”

Section: Introductionmentioning

confidence: 99%

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Microstructural evolution and mechanical characterization of a WC-reinforced CoCrFeNi HEA matrix composite

Hussain

Mehmood

Karim

et al. 2022

Sci Rep

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High entropy alloys (HEAs) are a relatively new class of material that have shown the potential to exhibit excellent combinations of mechanical properties. Various microstructural modifications have been explored to further enhance their mechanical properties for use in demanding structural applications. The main focus of the present work is an investigation of the effect of adding varying amounts of hard ceramic material (WC) to a tough HEA matrix (CoCrFeNi) by arc melting under an argon atmosphere, including microstructural changes, and evaluation of the WC additions on mechanical properties. X-ray diffraction analysis of the HEA-WC composites showed the presence of both fcc and carbide phases. Scanning electron microscope investigations, including energy dispersive spectroscopy, reveal that chromium diffuses from the matrix and interacts with WC to form an alloyed carbide phase. The amount of alloyed carbide was found to increase with increasing amount of WC addition to the HEA matrix. Mechanical characterization revealed that hardness and yield strength of the HEA-WC composites increase with increasing amount of the carbide phase in the matrix. The hardness of HEA-20wt.% WC sample was found to be as high as 3.3 times (593 HV) the hardness of the base HEA (180 HV), while the yield strength increased from 278 MPa for the base HEA to 1098 MPa for the CoCrFeNi-20 wt.% WC composite. The investigated composites also showed excellent values of ductility (~ 50% strain for CoCrFeNi-10 wt% WC and ~ 20% strain for CoCrFeNi-20 wt% WC). It is therefore believed that ceramic-reinforced high entropy matrix composites have the potential to provide outstanding combinations of mechanical properties for demanding structural applications.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructural evolution and mechanical characterization of a WC-reinforced CoCrFeNi HEA matrix composite

Hussain

Mehmood

Karim

et al. 2022

Sci Rep

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“…Along with the development of high-entropy alloys, researchers have also focused on medium-entropy alloys, such as the equi-atomic CoCrNi series of alloys that exhibit an excellent strength-ductility trade-off [ 11 ]. Fundamental understanding of CoCrNi MEAs shows their development potential [ 12 ], especially the exceptional mechanical properties in the cryogenic environment [ 13 , 14 ] and impressive performance in wear and corrosion resistance [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Improvement of Corrosion and Wear Resistance of CoCrNiSi0.3 Medium-Entropy Alloy by Sputtering CrN Film

et al. 2023

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In this study, Co, Cr, and Ni were selected as the equal-atomic medium entropy alloy (MEA) systems, and Si was added to form CoCrNiSi0.3 MEA. In order to further improve its wear and corrosion properties, CrN film was sputtered on the surface. In addition, to enhance the adhesion between the soft CoCrNiSi0.3 substrate and the super-hard CrN film, a Cr buffer layer was pre-sputtered on the CoCrNiSi0.3 substrate. The experimental results show that the CrN film exhibits a columnar grain structure, and the film growth rate is about 2.022 μm/h. With the increase of sputtering time, the increase in CrN film thickness, and the refinement of columnar grains, the wear and corrosion resistance improves. Among all CoCrNiSi0.3 MEAs without and with CrN films prepared in this study, the CoCrNiSi0.3 MEA with 3 h-sputtered CrN film has the lowest wear rate of 2.249 × 10−5 mm3·m−1·N−1, and the best corrosion resistance of Icorr 19.37 μA·cm–2 and Rp 705.85 Ω·cm2.

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“…Cobalt, chromium and nickel are wildly used to produce alloys with good corrosion resistance. Other elements are selected and added into CoCrNi alloy to change the microstructures and enhance the mechanical properties, such as CoCrFeMnNi alloy [ 11 ]. Co–CrFeNiSn has good passivation in sodium chloride solution compared with stainless steels [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

The Effects of Niobium and Molybdenum on the Microstructures and Corrosion Properties of CrFeCoNiNbxMoy Alloys

2022

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The present work systematically investigated the effects of niobium and molybdenum on the microstructures and corrosion properties of high-entropy CrFeCoNiNbxMox and CrFeCoNiNbxMo1−x alloys, the maximum content of (Nb + Mo) was 20 at.%. All of the alloys were prepared by arc melting under an argon atmosphere. In CrFeCoNiNbxMox alloys (x = 0.15, 0.3 and 0.5), increasing Nb and Mo content would change the microstructure of the alloy from a hypoeutectic structure (x ≤ 0.3) to a hypereutectic one (x = 0.5). All of the CrFeCoNiNbxMo1−x alloys (x = 0.25, 0.5 and 0.75) had a hypereutectic microstructure. Only two phases were analyzed in these alloys, which were face-centered cubic (FCC) and hexagonal close packing (HCP). Increasing the content of Nb and Mo increases the hardness of the alloys by the effects of the solid solution strengthening and formation of the HCP phase. The potentiodynamic polarization curves of these alloys were also measured in 1 M sulfuric acid and 1 M sodium chloride solutions to evaluate the corrosion resistance of these alloys. The CrFeCoNiNb0.3Mo0.3 alloy had the smallest corrosion rate (0.0732 mm/yr) in 1 M deaerated H2SO4 solution, and the CrFeCoNiNb0.15Mo0.15 alloy had the smallest corrosion rate (0.0425 mm/yr) in 1 M deaerated NaCl solution. However, the CrFeCoNiNb0.5Mo0.5 alloy still had the best combination of corrosion resistance and hardness in the present study.

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A critical review of the mechanical properties of CoCrNi-based medium-entropy alloys

Cited by 16 publications

References 150 publications

Microstructural evolution and mechanical characterization of a WC-reinforced CoCrFeNi HEA matrix composite

Microstructural evolution and mechanical characterization of a WC-reinforced CoCrFeNi HEA matrix composite

Improvement of Corrosion and Wear Resistance of CoCrNiSi0.3 Medium-Entropy Alloy by Sputtering CrN Film

The Effects of Niobium and Molybdenum on the Microstructures and Corrosion Properties of CrFeCoNiNbxMoy Alloys

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