Enhanced strength–ductility synergy in ultrafine-grained eutectic high-entropy alloys by inheriting microstructural lamellae

Shi, Peijian; Ren, Weili; Zheng, Tianxiang; Ren, Zhongming; Hou, Xueling; Peng, Jianchao; Hu, Pengfei; Gao, Yanfei; Zhong, Yunbo; Liaw, Peter K.

doi:10.1038/s41467-019-08460-2

Cited by 641 publications

(141 citation statements)

References 35 publications

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“…The originally proposed idea behind high‐entropy alloy (HEA) with multiprinciple elements is maximizing the configuration entropy to stabilize a solid‐solution alloy without undesired ordered intermetallics . Many studies have suggested that HEAs uniquely possesses combined desirable properties such as a high strength and ductility paired with high fracture toughness, fatigue resistance, and creep resistance . HEAs also show promising properties in harsh environments resisting corrosion, and irradiation attacks.…”

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Beating Thermal Coarsening in Nanoporous Materials via High‐Entropy Design

et al. 2019

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produced by dealloying have outstanding physical properties due to their unique structure with open porous networks, [3][4][5] the undesirable coarsening phenomenon leads to degradation of physical properties over time, even at room temperature. [6][7][8] The originally proposed idea behind high-entropy alloy (HEA) with multiprinciple elements is maximizing the configuration entropy to stabilize a solid-solution alloy without undesired ordered intermetallics. [9][10][11] Many studies have suggested that HEAs uniquely possesses combined desirable properties such as a high strength and ductility paired with high fracture toughness, [12][13][14] fatigue resistance, [15] and creep resistance. [16] HEAs also show promising properties in harsh environments resisting corrosion, [17][18][19] and irradiation [20] attacks. Atomic size differences between constituting elements in HEA increase the activation energy for grain growth, and sluggish diffusion kinetics has considered as the main reason for the exceptional high strength and structural stability of HEAs at high temperatures. [21,22] The rationale behind it, the multiprinciple elements cause larger fluctuations in lattice potential energy (LPE), providing many low-LPE sites that hinder atomic diffusion. [23] Grain growth and ligament coarsening rely on the same physical background of surface diffusion. In that context, the high-entropy design in nanoporous materials has a potential for achieving an exceptional stability against the coarsening.Controlling the feature sizes of 3D bicontinuous nanoporous (3DNP) materials is essential for their advanced applications in catalysis, sensing, energy systems, etc., requiring high specific surface area. However, the intrinsic coarsening of nanoporous materials naturally reduces their surface energy leading to the deterioration of physical properties over time, even at ambient temperatures. A novel 3DNP material beating the universal relationship of thermal coarsening is reported via high-entropy alloy (HEA) design. In newly developed TiVNbMoTa 3DNP HEAs, the nanoporous structure is constructed by very fine nanoscale ligaments of a solid-solution phase due to enhanced phase stability by maximizing the configuration entropy and suppressed surface diffusion. The smallest size of 3DNP HEA synthesized at 873 K is about 10 nm, which is one order of magnitude smaller than that of conventional porous materials. More importantly, the yield strength of ligament in 3DNP HEA approaches its theoretical strength of G/2π of the corresponding HEA alloy even after thermal exposure. This finding signifies the key benefit of high-entropy design in nanoporous materials-exceptional stability of size-related physical properties. This high-entropy strategy should thus open new opportunities for developing ultrastable nanomaterials against its environment.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.

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Beating Thermal Coarsening in Nanoporous Materials via High‐Entropy Design

et al. 2019

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“…The strength–ductility balance is of great significance. Based on this, Liaw et al architected an FCC/B2 dual‐phase heterogenous lamella AlCoCrFeNi 2.1 HEAs, where the phase structure played an important role in the improvement of mechanical properties 144. During the tensile deformation process, the soft FCC matrix could not plastically deform freely in the presence of the hard B2 phase.…”

Section: Property Adjusting Of Phase Engineered Heasmentioning

confidence: 99%

Phase Engineering of High‐Entropy Alloys

et al. 2020

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High‐entropy alloys (HEAs) are based on five or more principal elements with equal or nearly equal molar fractions and possess many significant advantages over traditional alloys, including high strength and hardness, excellent corrosion resistance, outstanding thermal stability, and irradiation resistance. Phase structure plays a vital role in determining the property of HEAs. For further enhancing the performance of HEAs in various application fields, a controllable synthesis with desired phases is required. In this review, the diverse phase structures of HEAs and the related properties are first introduced. Then, alternative tuning strategies to promote the desired phase structure of HEAs are focused upon. Property adjusting of phase‐engineered HEAs is also discussed in depth. Lastly, some insights into the challenges and future prospects in this rapidly emerging research field are provided.

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“…To overcome this drawback, precipitation hardening [7,8], interstitial solute strengthening [9,10], heterogeneous grain structure [11,12] or multi-phase structure [13] have been applied. Especially, body-centered cubic (BCC) plus FCC dual-phase (DP) or multi-phase HEAs can achieve excellent strength-ductility combinations [14].…”

Section: Introductionmentioning

confidence: 99%

Tailored microstructures and strengthening mechanisms in an additively manufactured dual-phase high-entropy alloy via selective laser melting

Luo

Wang

2020

Sci. China Mater.

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Dual-phase high-entropy alloys (DP-HEAs) with excellent strength-ductility combinations have attracted scientific interests. In the present study, the microstructures of AlCrCuFeNi 3.0 DP-HEA fabricated via selective laser melting (SLM) are rationally adjusted and controlled. The mechanisms engendering the hierarchical microstructures are revealed. It is found that the AlCrCuFeNi 3.0 fabricated by SLM at the scanning speed of 400 mm s −1 falls into the eutectic coupled zone, and increasing the scanning speed will make this composition deviate away from the eutectic coupled zone due to the increased cooling rate. The enrichment of Cr and Fe solutes with large growth restriction values ahead of the solid/ liquid interface can develop a constitutional supercooling zone, thus facilitating the heterogeneous nucleation and nearequiaxed grain formation. The synergy of the near-eutectic DP nano-structures and near-equiaxed grains instead of columnar ones effectively suppresses cracking for the as-built DP-HEA.During the tensile deformation, the intergranular back stress hardening similar to the grain-boundary strengthening is discovered. Meanwhile, the near-eutectic microstructures comprised of soft face-centered cubic and hard ordered bodycentered cubic (B2) DP nano-structures lead to plastic strain incompatibility within grains, thus producing the intragranular back stress. The Cr-rich nano-precipitates inside the B2 phase are found to be sheared by dislocation gliding and can complement the back stress. Additionally, multiple strengthening mechanisms are physically evaluated, and the back stress strengthening contributes obviously to the high performances of the as-built DP-HEA.

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Enhanced strength–ductility synergy in ultrafine-grained eutectic high-entropy alloys by inheriting microstructural lamellae

Cited by 641 publications

References 35 publications

Beating Thermal Coarsening in Nanoporous Materials via High‐Entropy Design

Beating Thermal Coarsening in Nanoporous Materials via High‐Entropy Design

Phase Engineering of High‐Entropy Alloys

Tailored microstructures and strengthening mechanisms in an additively manufactured dual-phase high-entropy alloy via selective laser melting

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