In situ study on the compression deformation of MoNbTaVW high-entropy alloy

Zhang, Congyan; Yue, Binbin; Bhandari, Uttam; Starovoytov, Oleg N.; Yang, Yan; Young, David P.; Yan, Jinyuan; Hong, Fang; Yang, Shizhong

doi:10.1016/j.jallcom.2021.159557

Cited by 8 publications

(5 citation statements)

References 55 publications

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“…principal elements in equal or near-equal molar ratios [1,2]. Due to the distinct alloying strategy, HEAs demonstrate many remarkable properties such as high tensile strength [3], good ductility [4], outstanding cryogenic fracture toughness [5], soft magnetism [6], and excellent resistance to fatigue, wear, corrosion, and oxidation [7][8][9][10], which makes them attractive in a series of applications like transportation, aerospace, and nuclear industries [11][12][13][14][15][16][17]. Over recent years, HEAs have been widely investigated with regard to their mechanical properties, which depend strongly on their crystallographic structure [12,13,18].…”

Section: Introductionmentioning

confidence: 99%

Thermo-elastic behavior of hexagonal Sc–Ti–Zr–Hf high-entropy alloys

Huang¹,

Cheng²,

Лю³

et al. 2022

J. Phys. D: Appl. Phys.

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Recent advance in tuning the long-standing strength-ductility tradeoff draw attention to high-entropy alloys (HEAs), and the appearance of the hexagonal close-packed (hcp) structure is emphasized. However, few studies have explored the elastic moduli of the hcp HEAs, which is of prime importance to improve the understanding of the outstanding mechanical properties. In this work, we focus on a set of equiatomic rare-earth-free HEAs with the hcp structure, i.e., ScTiZr, ScTiHf, ScZrHf, TiZrHf, and ScTiZrHf, and their thermo-elastic properties are studied using quantum mechanical first-principles methods. It is found that for all considered HEAs, the hexagonal axial ratio shows a weak dependence on the temperature effect, and the thermal expansion coefficient remains almost unchanged above room temperature. From the calculated temperature dependent single-crystal elastic constants, we analyzed the mechanical stability, elastic anisotropy, and derived polycrystalline moduli. Results indicate that the present HEAs exhibit rather high elastic isotropy and large elastic softening resistance. The ab initio predicted Young’s modulus, shear modulus, and specific modulus do not obey the rule of mixture, which indicates that there exists a strong intrinsic hardening effect in all of the considered HEAs. The calculated results are in good agreement with the available experimental measurements.

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Section: Introductionmentioning

confidence: 99%

Thermo-elastic behavior of hexagonal Sc–Ti–Zr–Hf high-entropy alloys

Huang¹,

Cheng²,

Лю³

et al. 2022

J. Phys. D: Appl. Phys.

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“…At present, bulk RHEAs are commonly produced by liquid metallurgy (arc melting, induction melting, and laser melting), [65,223,234] field-assisted PM (SPS, high-pressure consolidation, and hot isostatic pressing), [67,69,227,[235][236][237][238][239][240][241][242][243][244] and deposition techniques for thin films. Due to the high melting temperatures of refractory metals, the differences in their atomic size and chemistry, and sensitivity to trace oxygen impurity, mixing all elements uniformly by melting and casting is quite challenging.…”

Section: Bcc Refractory High-entropy Alloys and Compositesmentioning

confidence: 99%

“…However, it is in doubt whether the stabilized structure is induced by its high configurational entropy or the GB pining effect of in situ formed second phase particles. It is believed that oxyphilic composition elements such as Ta preferentially react with oxygen to form Ta oxide particles before [65,[223][224][225][226][227][228][229][230][231][232][233][234] MA combined with SPS, [67,69,227,[235][236][237][238][239][240][241][242][243][244] magnesiothermal synthesis combined with SPS, and nitridation synthesis combined with SPS route. The second-phase dispersed structure and the metal (BCC)-ceramic (FCC) interconnected structure are recently produced by our group.…”

Section: Bcc Refractory High-entropy Alloys and Compositesmentioning

confidence: 99%

“…Figure 14. Schematic diagram of the representative microstructure of RHEAs synthesized by arc melting,[65,[223][224][225][226][227][228][229][230][231][232][233][234] MA combined with SPS,[67,69,227,[235][236][237][238][239][240][241][242][243][244] magnesiothermal synthesis combined with SPS, and nitridation synthesis combined with SPS route. The second-phase dispersed structure and the metal (BCC)-ceramic (FCC) interconnected structure are recently produced by our group.…”

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confidence: 99%

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Powder Metallurgy Route to Ultrafine‐Grained Refractory Metals

Zhang

et al. 2023

Advanced Materials

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Ultrafine‐grained (UFG) refractory metals are promising materials for applications in aerospace, microelectronics, nuclear energy, and many others under extreme environments. Powder metallurgy (PM) allows to produce such materials with well‐controlled chemistry and microstructure at multiple length scales and near‐net shape manufacturing. However, sintering refractory metals to full density while maintaining a fine microstructure is still challenging due to the high sintering temperature and the difficulty to separate the kinetics of densification versus grain growth. Here an overview of the sintering issues, microstructural design rules, and PM practices towards UFG and nanocrystalline refractory metals are sought to be provided. The previous efforts shall be reviewed to address the processing challenges, including the use of fine/nanopowders, second‐phase grain growth inhibitors, and field‐assisted sintering techniques. Recently, pressureless two‐step sintering has been successfully demonstrated in producing dense UFG refractory metals down to ≈300 nm average grain size with a uniform microstructure and this technological breakthrough shall be reviewed. PM progresses in specific materials systems shall be next reviewed, including elementary metals (W and Mo), refractory alloys (W‐Re), refractory high‐entropy alloys, and their composites. Last, future developments and the endeavor towards UFG and nanocrystalline refractory metals with exceptionally uniform microstructure and improved properties are outlined.

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“…The yield strength of NbMoTaW RHEA at 1600 °C is 405 MPa, and the working temperature limit of 1600 °C is much higher than that of nickel-based high temperature alloys about 1300 °C. In Xia’s study 17 , the thermal stability of MoNbTaVW RHEA thin film was studied, and the experimental results show the body-centered cubic solid solution phase of MoNbTaVW RHEA is still very stable up to 1800 K. In Zhang’s experimental study 18 , the plastic deformation mechanism of MoNbTaVW RHEA under high pressure was observed. It was found the active dislocation growth is mainly responsible for the high strength in the MoNbTaVW RHEA.…”

Section: Introductionmentioning

confidence: 99%

How atoms of polycrystalline Nb20.6Mo21.7Ta15.6W21.1V21.0 refractory high-entropy alloys rearrange during the melting process

Shih

2022

Sci Rep

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The melting mechanism of single crystal and polycrystalline Nb20.6Mo21.7Ta15.6W21.1V21.0 refractory high entropy alloys (RHEAs) were investigated by the molecular dynamics (MD) simulation using the second-nearest neighbor modified embedded-atom method (2NN MEAM) potential. For the single crystal RHEA, the density profile displays an abrupt drop from 11.25 to 11.00 g/cm3 at temperatures from 2910 to 2940 K, indicating all atoms begin significant local structural rearrangement. For polycrystalline RHEAs, a two-stage melting process is found. In the first melting stage, the melting of the grain boundary (GB) regions firstly occurs at the pre-melting temperature, which is relatively lower than the corresponding system-melting point. At the pre-melting temperature, most GB atoms have enough kinetic energies to leave their equilibrium positions, and then gradually induce the rearrangement of grain atoms close to GB. In the second melting stage at the melting point, most grain atoms have enough kinetic energies to rearrange, resulting in the chemical short-ranged order changes of all pairs.

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In situ study on the compression deformation of MoNbTaVW high-entropy alloy

Cited by 8 publications

References 55 publications

Thermo-elastic behavior of hexagonal Sc–Ti–Zr–Hf high-entropy alloys

Thermo-elastic behavior of hexagonal Sc–Ti–Zr–Hf high-entropy alloys

Powder Metallurgy Route to Ultrafine‐Grained Refractory Metals

How atoms of polycrystalline Nb20.6Mo21.7Ta15.6W21.1V21.0 refractory high-entropy alloys rearrange during the melting process

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