Lattice distortion in a strong and ductile refractory high-entropy alloy

Lee, Chanho; Song, Gian; Gao, Michael C.; Feng, Rui; Chen, Peiyong; Brechtl, Jamieson; Chen, Yan; An, Ke; Guo, Wei; Poplawsky, Jonathan D.; Li, Song; Samaei, Arash; Chen, Wei; Hu, Alice; Choo, Hahn; Liaw, P. K.

doi:10.1016/j.actamat.2018.08.053

Cited by 354 publications

(123 citation statements)

References 69 publications

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“…They also have good stability against radiation damage, hence deemed potential materials for advanced reactor applications (10,11). Refractory HEAs are promising candidates for high-temperature applications, e.g., for aero-engines, due to their thermal stability at elevated temperatures (3,12,13). Superconductivity has also been reported in Ta-Nb-Hf-Zr-Ti HEA, thus extending their possible applications beyond structural materials (14).…”

Section: Introductionmentioning

confidence: 99%

Cooperative deformation in high-entropy alloys at ultralow temperatures

et al. 2020

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High-entropy alloys exhibit exceptional mechanical properties at cryogenic temperatures, due to the activation of twinning in addition to dislocation slip. The coexistence of multiple deformation pathways raises an important question regarding how individual deformation mechanisms compete or synergize during plastic deformation. Using in situ neutron diffraction, we demonstrate the interaction of a rich variety of deformation mechanisms in high-entropy alloys at 15 K, which began with dislocation slip, followed by stacking faults and twinning, before transitioning to inhomogeneous deformation by serrations. Quantitative analysis showed that the cooperation of these different deformation mechanisms led to extreme work hardening. The low stacking fault energy plus the stable face-centered cubic structure at ultralow temperatures, enabled by the high-entropy alloying, played a pivotal role bridging dislocation slip and serration. Insights from the in situ experiments point to the role of entropy in the design of structural materials with superior properties.

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Section: Introductionmentioning

confidence: 99%

Cooperative deformation in high-entropy alloys at ultralow temperatures

et al. 2020

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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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confidence: 99%

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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“…Alloys of the NbTaV -(Ti, W, Mo) system, that have a disordered BCC structure, have been proposed as high temperature materials that offer high strength, ductility and oxidation resistance [15,16]. The alloy TiVNbTa shows excellent compressive mechanical properties at room temperature (y = 1273 MPa) and at elevated temperatures (y drops to 688 MPa at 900 • C) [17]. Variations of the TiVCrZrNb system have also been proposed as high temperature, structural materials which exhibit low densities and high hardness [18].…”

mentioning

confidence: 99%

“…In this work, we start with the well characterised BCC alloy, TiVNbTa, as this material consists of a single phase, disordered, BCC microstructure, with exceptionally high strength and significant plastic flow in compression at elevated temperatures [17]. The composition is modified by replacing the high activation element, Nb in TiVNbTa with Zr and Cr, to produce TiVZrTa and TiVCrTa; two low activation alloys that have low thermal neutron absorption cross-sections making them suitable for both advanced fission and fusion applications.…”

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confidence: 99%

Short communication: ‘Low activation, refractory, high entropy alloys for nuclear applications’

Kareer

Waite

et al. 2019

Journal of Nuclear Materials

102

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Two new, low activation high entropy alloys (HEAs) TiVZrTa and TiVCrTa are studied for use as in-core, structural nuclear materials for in-core nuclear applications. Low-activation is a desirable property for nuclear reactors, in an attempt to reduce the amount of high level radioactive waste upon decommissioning, and for consideration in fusion applications. The alloy TiVNbTa is used as a starting composition to develop two new HEAs; TiVZrTa and TiVCrTa. The new alloys exhibit comparable indentation hardness and modulus, to the TiVNbTa alloy in the as-cast state. After heavy ion implantation the new alloys show an increased irradiation resistance.

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Lattice distortion in a strong and ductile refractory high-entropy alloy

Cited by 354 publications

References 69 publications

Cooperative deformation in high-entropy alloys at ultralow temperatures

Cooperative deformation in high-entropy alloys at ultralow temperatures

Beating Thermal Coarsening in Nanoporous Materials via High‐Entropy Design

Short communication: ‘Low activation, refractory, high entropy alloys for nuclear applications’

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