Effect of grain size on critical twinning stress and work hardening behavior in the equiatomic CrMnFeCoNi high-entropy alloy

Wagner, Christian; Laplanche, Guillaume

doi:10.1016/j.ijplas.2023.103651

Cited by 38 publications

(2 citation statements)

References 92 publications

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“…This heat treatment yielded a nearly untextured microstructure with a coarse grain size of ∼250 μm. 26 Rectangular electrodes (0.4 mm × 0.4 mm × 1.3 cm, length × width × height) were then cut from the recrystallized HEA and encapsulated in glass capillaries. 17 The microelectrode surface was ground with 1000-mesh sandpaper for 30 s and then polished with 3 and 1 μm diamond suspensions to a mirror finish.…”

Section: Fabrication Of Microelectrode From a Bulk Cantormentioning

confidence: 99%

Revealing Dynamic Surface and Subsurface Reconstruction of High-Entropy Alloy Electrocatalysts during the Oxygen Evolution Reaction at the Atomic Scale

Luan,

Escalera-López,

Hagemann

et al. 2024

ACS Catal.

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High-entropy alloys (HEAs) represent a promising material systems in the search for next-generation high-performance oxygen evolution reaction (OER) electrocatalysts. Developing HEA electrocatalysts requires a thorough understanding of surface and subsurface reconstruction during the OER and their effects on activity and stability. However, it is difficult for most characterization techniques to resolve the atomic-scale elemental distribution of multiple elements and their surface composition. Herein, we combine atom probe tomography and transmission electron microscopy with online and offline inductively coupled plasma mass spectrometry to unveil the surface and subsurface reconstructions of a model CrMnFeCoNi Cantor alloy electrocatalyst during the OER. We reveal that the Cantor alloy suffers from dissolution once in contact with the electrolyte, whereby the surface is deficit in Cr, Mn, and Co before the OER. At the onset of the OER cycling, the Cantor alloy surface is activated by forming an ∼5 nm amorphous NiFe-rich (oxy)hydroxide. Below the surface (oxy)hydroxide, an ∼3 nm Cr-rich oxide layer and an oxygen-rich layer (∼3–5 nm) are formed in the subsurfaces, which impede the outward diffusion of Mn, Fe, Co, and Ni to the surface, retarding their continuous dissolution from the bulk, while Cr dissolution occurs steadily. As the OER proceeds, the Cr-rich oxide layer collapses due to steady Cr dissolution, which results in the exfoliation of the amorphous (oxy)hydroxide layer. Simultaneously, the fastest diffusing Mn segregates to the surface, forming a Mn-rich oxide, which leads to a deterioration in the OER activity. Our atomic-scale data advance the fundamental understanding of how concerted thermodynamically and kinetically driven elementary processes occur for different elements in HEAs during the OER. More importantly, our study highlights the importance of establishing the structure–activity–stability correlations of HEA electrocatalysts during the OER in order to validate the hypothesis of synergistic effects in enhancing their activity and stability.

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Section: Fabrication Of Microelectrode From a Bulk Cantormentioning

confidence: 99%

Revealing Dynamic Surface and Subsurface Reconstruction of High-Entropy Alloy Electrocatalysts during the Oxygen Evolution Reaction at the Atomic Scale

Luan,

Escalera-López,

Hagemann

et al. 2024

ACS Catal.

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show abstract

“…The deformation twin, surrounded by the stacking faults, can be observed and increased with the strain due to the low stacking fault energy (SFE) of the cantor alloy [17]. The essential strain for twinning drops from 24.5% at ambient temperature to 11% at cryogenic temperature, along with an elevated work hardening rate [18]. Twin boundaries have the ability to effectively impede dislocation motion and enhance the cantor alloy's strength and ductility.…”

Section: Introductionmentioning

confidence: 99%

Review on the Tensile Properties and Strengthening Mechanisms of Additive Manufactured CoCrFeNi-Based High-Entropy Alloys

Wu,

Wang,

Jia

et al. 2024

Metals

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The advent of high-entropy alloys (HEAs) provides new possibilities for the metallurgical community. CoCrFeNi-based alloys have been widely recognized to demonstrate superior mechanical properties, amongst the high-entropy alloy systems; in particular, they possess an outstanding tensile ductility and work-hardening capacity. Additive manufacturing (AM) uses a layer-by-layer material deposition approach to build parts directly from computer-aided design models, which are capable of producing near-net-shape HEAs with superior mechanical properties, surpassing traditional manufacturing methods that require a time-consuming post-treatment process, such as cutting, milling, and molding. Moreover, the rapid solidification inherent in AM processes induces the formation of high-density dislocations, which are capable of enhancing the mechanical properties of HEAs. This review comprehensively investigates and summarizes the diverse strengthening mechanisms within CoCrFeNi-based alloys produced using AM technologies, with a specific focus on their influence on tensile properties. A correlation is established between the AM processing parameters and the resultant phases and microstructures, as well as the mechanical properties of CoCrFeNi-based HEAs, which provide guidelines to achieve a superior strength–ductility synergy.

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Coupling effects of temperature and strain rate on the mechanical behavior and microstructure evolution of a powder-plasma-arc additive manufactured high-entropy alloy with multi-heterogeneous microstructures

Wang,

Guo,

Jiao

et al. 2024

Acta Materialia

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Effect of grain size on critical twinning stress and work hardening behavior in the equiatomic CrMnFeCoNi high-entropy alloy

Cited by 38 publications

References 92 publications

Revealing Dynamic Surface and Subsurface Reconstruction of High-Entropy Alloy Electrocatalysts during the Oxygen Evolution Reaction at the Atomic Scale

Revealing Dynamic Surface and Subsurface Reconstruction of High-Entropy Alloy Electrocatalysts during the Oxygen Evolution Reaction at the Atomic Scale

Review on the Tensile Properties and Strengthening Mechanisms of Additive Manufactured CoCrFeNi-Based High-Entropy Alloys

Coupling effects of temperature and strain rate on the mechanical behavior and microstructure evolution of a powder-plasma-arc additive manufactured high-entropy alloy with multi-heterogeneous microstructures

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