Selective laser melted equiatomic CoCrFeMnNi high-entropy alloy: Microstructure, anisotropic mechanical response, and multiple strengthening mechanism

Kim, Young-Kyun; Choe, Jungho; Lee, Kee‐Ahn

doi:10.1016/j.jallcom.2019.07.106

Cited by 154 publications

(37 citation statements)

References 57 publications

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“…In our previous study 33 , we confirmed that SLM-built equiatomic CoCrFeMnNi HEA has outstanding room temperature mechanical properties. Furthermore, equiatomic CoCrFeMnNi HEA is known to have high phase stability, which will allow it to be used in high temperatures 34 .…”

supporting

confidence: 75%

“…Furthermore, when compared to oxide dispersion strengthened steels, which are developed by cryo-milling, SLM-built HEA represented excellent high-temperature strength at temperatures greater than 700 °C 70 . In our previous study, it is confirmed that the outstanding room temperature mechanical properties of SLM-built HEA can be attributed to fine grain sizes, dislocation networks and nano-sized oxides, and based on this, the authors presented their interpretation of a multiple strengthening mechanism 33 . However, it was not known until the present that SLM-built HEA has a superior mechanical property up to 700 °C.…”

Section: Discussion Effects Of Dislocation Network and Mn 2 O 3 On Tementioning

confidence: 61%

“…As identified in the STEM image ( (Fig. 5b) 33 . In general, equiatomic CoCrFeMnNi HEA is known to form a Cr-Mn-based oxide or σ-phase of a few μm in size 58,59 .…”

Section: Resultsmentioning

confidence: 80%

“…Also, average dislocation density was calculated from the XRD pattern using convolutional multiple whole profile (CMWP) analysis. The SLM-built HEA has a higher dislocation density of 1.88 × 10 14 m −2 as compared to the homogenized HEA 33 . This is a common tendency found in AM-processed materials, and it is known to be caused by thermal contraction strain that occurs during rapid solidification and cooling 42 .…”

Section: Resultsmentioning

confidence: 96%

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Superior Temperature-Dependent Mechanical Properties and Deformation Behavior of Equiatomic CoCrFeMnNi High-Entropy Alloy Additively Manufactured by Selective Laser Melting

Kim

Yang

Lee

2020

Sci Rep

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The microstructure, temperature-dependent mechanical properties and deformation behaviors of equiatomic CoCrFeMnNi high-entropy alloy (HEA) additively manufactured by selective laser melting (SLM) were investigated. SLM-built HEA had a face-centered cubic (FCC) single-phase random solid solution. In addition, SLM-built HEA was composed of epitaxial growth grains, dislocation network and nano-sized oxides. Room- and high-temperature compression tests confirmed that SLM-built HEA has outstanding mechanical properties in all temperature ranges compared to equiatomic CoCrFeMnNi HEAs reported up to the present. The excellent mechanical properties of SLM-built HEA were achieved with fine grains, high dislocation density and fine precipitates at low temperatures (25 °C to 600 °C), and by high dislocation density and fine precipitates at high temperatures (700 °C or higher). On the other hand, the deformation microstructure showed that slip and deformation twins are the main deformation mechanisms from 25 °C to 600 °C, and slip and partial recrystallization are the main deformation mechanisms above 700 °C. Based on the above findings, this study also discusses correlations among the microstructure, superior mechanical properties and deformation mechanisms of SLM-built equiatomic CoCrFeMnNi HEA.

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supporting

confidence: 75%

Section: Discussion Effects Of Dislocation Network and Mn 2 O 3 On Tementioning

confidence: 61%

“…As identified in the STEM image ( (Fig. 5b) 33 . In general, equiatomic CoCrFeMnNi HEA is known to form a Cr-Mn-based oxide or σ-phase of a few μm in size 58,59 .…”

Section: Resultsmentioning

confidence: 80%

Section: Resultsmentioning

confidence: 96%

See 2 more Smart Citations

Superior Temperature-Dependent Mechanical Properties and Deformation Behavior of Equiatomic CoCrFeMnNi High-Entropy Alloy Additively Manufactured by Selective Laser Melting

Kim

Yang

Lee

2020

Sci Rep

Self Cite

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“…Meanwhile, further developments of deformation twinning in AE-HEA enhance the strain hardening. Contrary to coarse inclusion particles, fine particles could enhance strain hardening by dislocation multiplication around the particles, which is also observed in the present study (Figure 9c) [65][66][67].…”

Section: Discussionsupporting

confidence: 86%

Influence of Manufacturing Conditions on Inclusion Characteristics and Mechanical Properties of FeCrNiMnCo Alloy

Choi

Park

Kim

et al. 2020

Metals

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Three CoCrFeMnNi high-entropy alloys (HEAs) were produced by vacuum induction melting, induction melting under inert gas atmosphere, and melting under inert gas atmosphere followed by air exposure, respectively. The different manufacturing conditions for the three investigated alloys resulted in different levels and types of inclusions. The alloys melted under vacuum or inert gas contained Al2O3 inclusions formed by impurity Al, due to its high oxidation tendency. The molten alloy exposed in air showed an excessive oxidation. During oxidation of the molten alloy in air, impurity Al was initially oxidized, and fine MnCr2O4 inclusions were formed rather than pure Al2O3 inclusions. This difference was analyzed based on thermodynamic calculations. Specifically, the influence of impurity content on the inclusion characteristics was investigated for the three HEAs. Moreover, the inclusion characteristics were found to have an influence on mechanical properties of the alloys also. In air-exposed HEA, smaller inclusions were formed, resulting in a higher dislocation density at the matrix/inclusion interface and thus strengthening of the HEA. Thus, it is proposed that atmospheric conditions could be an important factor to control the inclusion characteristics and to form fine inclusion particles, which could improve the mechanical properties of HEAs.

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Deformation Behavior of 3D‐Printed High‐Entropy Alloys: A Critical Review

Bajaj,

Feng,

et al. 2023

Adv Eng Mater

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The 3D‐printing of high‐entropy alloys (HEAs) is capable of enhancing the design and manufacturing flexibilities for the novel materials. Owing to the rapid solidification, the 3D‐printed HEAs exhibit markedly different microstructures than their conventionally‐manufactured equivalents, leading to peculiar mechanical properties. Many additively‐manufactured HEAs also break down the strength‐ductility trade‐off dilemma. Novel dynamics regarding the simultaneous and sequential nature of deformation mechanisms are emerging through recent intensive research on these materials. Herein the deformation behavior of 3D‐printed HEAs is reviewed and explained on the basis of the latest advances in this area. A comprehensive picture regarding the role of cellular dislocation networks, twinning‐induced plasticity (TWIP), and transformation‐induced plasticity (TRIP) in the monotonic and cyclic deformation of 3D‐printed HEAs is presented. Special emphasis is placed on fatigue characteristics due to the enormous interest in this burgeoning area. The effect of post‐fabrication thermomechanical processing on plasticity is discussed along with the microstructural evolution in the 3D‐printed HEAs. Several innovative developments that carry latent potential for further research are also deliberated in this review. Finally, the present understanding of the deformation behavior of 3D‐printed HEAs is summarized while gauging the future directions.This article is protected by copyright. All rights reserved.

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Selective laser melted equiatomic CoCrFeMnNi high-entropy alloy: Microstructure, anisotropic mechanical response, and multiple strengthening mechanism

Cited by 154 publications

References 57 publications

Superior Temperature-Dependent Mechanical Properties and Deformation Behavior of Equiatomic CoCrFeMnNi High-Entropy Alloy Additively Manufactured by Selective Laser Melting

Superior Temperature-Dependent Mechanical Properties and Deformation Behavior of Equiatomic CoCrFeMnNi High-Entropy Alloy Additively Manufactured by Selective Laser Melting

Influence of Manufacturing Conditions on Inclusion Characteristics and Mechanical Properties of FeCrNiMnCo Alloy

Deformation Behavior of 3D‐Printed High‐Entropy Alloys: A Critical Review

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