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Sun J, Li H, Chen Y, An X. Bidirectional Phase Transformations in Multi-Principal Element Alloys: Mechanisms, Physics, and Mechanical Property Implications. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2407283. [PMID: 39158938 DOI: 10.1002/advs.202407283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Revised: 08/08/2024] [Indexed: 08/20/2024]
Abstract
The emergence of multi-principal element alloys (MPEAs) heralds a transformative shift in the design of high-performance alloys. Their ingrained chemical complexities endow them with exceptional mechanical and functional properties, along with unparalleled microscopic plastic mechanisms, sparking widespread research interest within and beyond the metallurgy community. In this overview, a unique yet prevalent mechanistic process in the renowned FeMnCoCrNi-based MPEAs is focused on: the dynamic bidirectional phase transformation involving the forward transformation from a face-centered-cubic (FCC) matrix into a hexagonal-close-packed (HCP) phase and the reverse HCP-to-FCC transformation. The light is shed on the fundamental physical mechanisms and atomistic pathways of this intriguing dual-phase transformation. The paramount material parameter of intrinsic negative stacking fault energy in MPEAs and the crucial external factors c, furnishing thermodynamic, and kinetic impetus to trigger bidirectional transformation-induced plasticity (B-TRIP) mechanisms, are thorougly devled into. Furthermore, the profound significance of the distinct B-TRIP behavior in shaping mechanical properties and creating specialized microstructures c to harness superior material characteristics is underscored. Additionally, critical insights are offered into key challenges and future striving directions for comprehensively advancing the B-TRIP mechanism and the mechanistic design of next-generation high-performing MPEAs.
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Affiliation(s)
- Jiayi Sun
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
- Sydney Nano Institute (Sydney Nano), The University of Sydney, Sydney, NSW, 2006, Australia
| | - Heqing Li
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Yujie Chen
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Xianghai An
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
- Sydney Nano Institute (Sydney Nano), The University of Sydney, Sydney, NSW, 2006, Australia
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2
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Glazyrin K, Spektor K, Bykov M, Dong W, Yu JY, Yang S, Lee JL, Divinski SV, Hanfland M, Yusenko KV. High-Entropy Alloys and Their Affinity with Hydrogen: From Cantor to Platinum Group Elements Alloys. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2401741. [PMID: 38889243 PMCID: PMC11336920 DOI: 10.1002/advs.202401741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 05/08/2024] [Indexed: 06/20/2024]
Abstract
Properties of high-entropy alloys are currently in the spotlight due to their promising applications. One of the least investigated aspects is the affinity of these alloys to hydrogen, its diffusion, and reactions. In this study, high pressure is applied at ambient temperature and stress-induced diffusion of hydrogen is investigated into the structure of high-entropy alloys (HEA) including the famous Cantor alloy as well as less known, but nevertheless important platinum group (PGM) alloys. By applying X-ray diffraction to samples loaded into diamond anvil cells, a comparative investigation of transition element incorporating HEA alloys in Ne and H2 pressure-transmitting media is performed at ambient temperature. Even under stresses far exceeding conventional industrial processes, both Cantor and PGM alloys show exceptional resistance to hydride formation, on par with widely used industrial grade Cu-Be alloys. The observations inspire optimism for practical HEA applications in hydrogen-relevant industry and technology (e.g., coatings, etc), particularly those related to transport and storage.
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Affiliation(s)
| | - Kristina Spektor
- Deutsches Elektronen‐Synchrotron (DESY)Notkestr. 8522607HamburgGermany
| | - Maxim Bykov
- Institute of Inorganic ChemistryUniversity of Cologne50939CologneGermany
| | - Weiwei Dong
- Deutsches Elektronen‐Synchrotron (DESY)Notkestr. 8522607HamburgGermany
- Beijing Synchrotron Radiation Facility (BSRF), Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China
| | - Ji‐Hun Yu Yu
- Powder Materials DivisionKorea Institute of Materials Science51508ChangwonSouth Korea
| | - Sangsun Yang
- Powder Materials DivisionKorea Institute of Materials Science51508ChangwonSouth Korea
| | - Jai‐Sung Lee Lee
- Department of Materials Science and Chemical EngineeringHanyang UniversityAnsan15588South Korea
| | | | - Michael Hanfland
- ESRF ‐ The European Synchrotron71 Av. des Martyrs38000GrenobleFrance
| | - Kirill V. Yusenko
- Bundesanstalt für Materialforschung und ‐ prüfung (BAM)12489BerlinGermany
- Institute of Geology, Mineralogy and Geophysics, Faculty of GeosciencesRuhr‐University BochumUniversitätsstrasse 15044801BochumGermany
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3
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Jiang D, Yuan Z, Zhu Z, Yao M. NiCoCrFeY High Entropy Alloy Nanopowders and Their Soft Magnetic Properties. MATERIALS (BASEL, SWITZERLAND) 2024; 17:534. [PMID: 38276473 PMCID: PMC10821190 DOI: 10.3390/ma17020534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024]
Abstract
High entropy alloy nanopowders were successfully prepared by liquid-phase reduction methods and their applications were preliminarily discussed. The prepared high entropy alloy nanopowders consisted of FeNi alloy spherical powders and NiFeCoCrY alloy spherical powders with a particle size of about 100 nm. The powders have soft magnetic properties, the saturation magnetization field strength were up to 5000 Qe and the saturation magnetization strength Ms was about 17.3 emu/g. The powders have the excellent property of low high-frequency loss in the frequency range of 0.3-8.5 GHz. When the thickness of the powders coating was 5 mm, the powders showed excellent absorption performance in the Ku band; and when the thickness of the powders coating was 10 mm; the powders showed good wave-absorbing performance in the X band. The powders have good moulding, and the powders have large specific surface area, so that the magnetic powder core composites could be prepared under low pressure and without coating insulators, and the magnetic powder cores showed excellent frequency-constant magnetization and magnetic field-constant magnetization characteristics. In the frequency range of 1~100 KHz; the μm of the magnetic powder core heat-treated at 800 °C reached 359, the μe was about 4.6 and the change rate of μe with frequency was less than 1%, meanwhile; the magnetic powder core still maintains constant μe value under the action of the external magnetic field from 0 to 12,000 A/m. The high entropy alloy nanopowders have a broad application prospect in soft magnetic composites.
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Affiliation(s)
| | - Zhifen Yuan
- School of Physics and Material Science, Nanchang University, Nanchang 330031, China; (D.J.); (Z.Z.); (M.Y.)
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4
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Han Y, Wang L, Cao K, Zhou J, Zhu Y, Hou Y, Lu Y. In Situ TEM Characterization and Modulation for Phase Engineering of Nanomaterials. Chem Rev 2023; 123:14119-14184. [PMID: 38055201 DOI: 10.1021/acs.chemrev.3c00510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Solid-state phase transformation is an intriguing phenomenon in crystalline or noncrystalline solids due to the distinct physical and chemical properties that can be obtained and modified by phase engineering. Compared to bulk solids, nanomaterials exhibit enhanced capability for phase engineering due to their small sizes and high surface-to-volume ratios, facilitating various emerging applications. To establish a comprehensive atomistic understanding of phase engineering, in situ transmission electron microscopy (TEM) techniques have emerged as powerful tools, providing unprecedented atomic-resolution imaging, multiple characterization and stimulation mechanisms, and real-time integrations with various external fields. In this Review, we present a comprehensive overview of recent advances in in situ TEM studies to characterize and modulate nanomaterials for phase transformations under different stimuli, including mechanical, thermal, electrical, environmental, optical, and magnetic factors. We briefly introduce crystalline structures and polymorphism and then summarize phase stability and phase transformation models. The advanced experimental setups of in situ techniques are outlined and the advantages of in situ TEM phase engineering are highlighted, as demonstrated via several representative examples. Besides, the distinctive properties that can be obtained from in situ phase engineering are presented. Finally, current challenges and future research opportunities, along with their potential applications, are suggested.
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Affiliation(s)
- Ying Han
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR 999077, China
| | - Liqiang Wang
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR 999077, China
| | - Ke Cao
- School of Advanced Materials and Nanotechnology, Xidian University, Xi'an, Shaanxi 710026, China
| | - Jingzhuo Zhou
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR 999077, China
| | - Yingxin Zhu
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR 999077, China
| | - Yuan Hou
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR 999077, China
| | - Yang Lu
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR 999077, China
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5
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Chen W, Hilhorst A, Bokas G, Gorsse S, Jacques PJ, Hautier G. A map of single-phase high-entropy alloys. Nat Commun 2023; 14:2856. [PMID: 37208345 PMCID: PMC10199023 DOI: 10.1038/s41467-023-38423-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 05/02/2023] [Indexed: 05/21/2023] Open
Abstract
High-entropy alloys have exhibited unusual materials properties. The stability of equimolar single-phase solid solution of five or more elements is supposedly rare and identifying the existence of such alloys has been challenging because of the vast chemical space of possible combinations. Herein, based on high-throughput density-functional theory calculations, we construct a chemical map of single-phase equimolar high-entropy alloys by investigating over 658,000 equimolar quinary alloys through a binary regular solid-solution model. We identify 30,201 potential single-phase equimolar alloys (5% of the possible combinations) forming mainly in body-centered cubic structures. We unveil the chemistries that are likely to form high-entropy alloys, and identify the complex interplay among mixing enthalpy, intermetallics formation, and melting point that drives the formation of these solid solutions. We demonstrate the power of our method by predicting the existence of two new high-entropy alloys, i.e. the body-centered cubic AlCoMnNiV and the face-centered cubic CoFeMnNiZn, which are successfully synthesized.
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Affiliation(s)
- Wei Chen
- Institute of Condensed Matter and Nanoscicence (IMCN), UCLouvain, Chemin Etoiles 8, Louvain-la-Neuve, 1348, Belgium
| | - Antoine Hilhorst
- Institute of Mechanics, Materials and Civil Engineering (iMMC), IMAP, UCLouvain, Place Sainte Barbe 2, Louvain-la-Neuve, 1348, Belgium
| | - Georgios Bokas
- Institute of Condensed Matter and Nanoscicence (IMCN), UCLouvain, Chemin Etoiles 8, Louvain-la-Neuve, 1348, Belgium
| | - Stéphane Gorsse
- Univ. Bordeaux, CNRS, Bordeaux INP, ICMCB, UMR 5026, Pessac, 33600, France
| | - Pascal J Jacques
- Institute of Mechanics, Materials and Civil Engineering (iMMC), IMAP, UCLouvain, Place Sainte Barbe 2, Louvain-la-Neuve, 1348, Belgium
| | - Geoffroy Hautier
- Institute of Condensed Matter and Nanoscicence (IMCN), UCLouvain, Chemin Etoiles 8, Louvain-la-Neuve, 1348, Belgium.
- Thayer School of Engineering, Dartmouth College, Thayer Drive 15, Hanover, NH, 03755, USA.
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6
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Pei Z, Zhao S, Detrois M, Jablonski PD, Hawk JA, Alman DE, Asta M, Minor AM, Gao MC. Theory-guided design of high-entropy alloys with enhanced strength-ductility synergy. Nat Commun 2023; 14:2519. [PMID: 37130855 PMCID: PMC10154317 DOI: 10.1038/s41467-023-38111-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 04/14/2023] [Indexed: 05/04/2023] Open
Abstract
Metallic alloys have played essential roles in human civilization due to their balanced strength and ductility. Metastable phases and twins have been introduced to overcome the strength-ductility tradeoff in face-centered cubic (FCC) high-entropy alloys (HEAs). However, there is still a lack of quantifiable mechanisms to predict good combinations of the two mechanical properties. Here we propose a possible mechanism based on the parameter κ, the ratio of short-ranged interactions between closed-pack planes. It promotes the formation of various nanoscale stacking sequences and enhances the work-hardening ability of the alloys. Guided by the theory, we successfully designed HEAs with enhanced strength and ductility compared with other extensively studied CoCrNi-based systems. Our results not only offer a physical picture of the strengthening effects but can also be used as a practical design principle to enhance the strength-ductility synergy in HEAs.
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Affiliation(s)
- Zongrui Pei
- National Energy Technology Laboratory, Albany, OR, 97321, USA.
- ORISE, 100 ORAU Way, Oak Ridge, TN, 37830, USA.
| | - Shiteng Zhao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
- Tianmushan Laboratory, Xixi Octagon City, Yuhang District, Hangzhou, 310023, China
| | - Martin Detrois
- National Energy Technology Laboratory, Albany, OR, 97321, USA
| | | | - Jeffrey A Hawk
- National Energy Technology Laboratory, Albany, OR, 97321, USA
| | - David E Alman
- National Energy Technology Laboratory, Albany, OR, 97321, USA
| | - Mark Asta
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Andrew M Minor
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Michael C Gao
- National Energy Technology Laboratory, Albany, OR, 97321, USA.
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7
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Phase stability and possible superconductivity of new 4d and 5d transition metal high-entropy alloys. J SOLID STATE CHEM 2023. [DOI: 10.1016/j.jssc.2023.123881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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8
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Deng C, Wu P, Li H, Zhu H, Chao Y, Tao D, Chen Z, Hua M, Liu J, Liu J, Zhu W. Engineering polyhedral high entropy oxide with high-index facets via mechanochemistry-assisted strategy for efficient oxidative desulfurization. J Colloid Interface Sci 2023; 629:569-580. [PMID: 36179577 DOI: 10.1016/j.jcis.2022.09.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/01/2022] [Accepted: 09/11/2022] [Indexed: 11/21/2022]
Abstract
High entropy oxides are promising catalysts for numerous catalytic oxidation processes with oxygen as the oxidant. However, most of them often show bulk morphologies, which hinders the full exposure of active sites. In this work, a unique 26-faceted polyhedral high entropy oxide MnNiCuZnCoOx-1000 (P-HEO) with highly active site exposure is fabricated via a mechanochemistry-assisted strategy. By employing such a strategy, the supersaturation of P-HEO during the crystal growth process is effectively reduced to form high-index facets, which is proved to be beneficial to the formation of high-index facets. Characterization results indicate that more oxygen vacancies are generated in P-HEO compared with the bulk counterparts. Density functional theory calculations reveal that the high-index facets {-211} can facilitate adsorption and activation of O2 because of the higher adsorption energy -2.23 eV compared with that of (111) surfaces (-1.79 eV), which induces significantly enhanced activity for organic sulfides oxidation. Interestingly, the synthesized P-HEO with high-index facets shows a 98.4% removal rate of dibenzothiophene from model oil within 8 h at 120 °C, which is much higher than that of the bulk counterparts (33.5%).
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Affiliation(s)
- Chang Deng
- School of Chemistry and Chemical Engineering, Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | - Peiwen Wu
- School of Chemistry and Chemical Engineering, Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China.
| | - Hongping Li
- School of Chemistry and Chemical Engineering, Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | - Haonan Zhu
- School of Chemistry and Chemical Engineering, Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | - Yanhong Chao
- School of Chemistry and Chemical Engineering, Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China; College of Chemical Engineering and Environment, State Key Laboratory of Heavy Oil Processing, China University of Petroleum-Beijing, Beijing 102249, China
| | - Duanjian Tao
- College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, China
| | - Ziran Chen
- Department of Architecture and Environment Engineering, Sichuan Vocational and Technical College, Suining, Sichuan 629000, China
| | - Mingqing Hua
- School of Chemistry and Chemical Engineering, Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China.
| | - Jixing Liu
- School of Chemistry and Chemical Engineering, Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | - Jianjun Liu
- School of Chemistry and Chemical Engineering, Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | - Wenshuai Zhu
- School of Chemistry and Chemical Engineering, Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China; College of Chemical Engineering and Environment, State Key Laboratory of Heavy Oil Processing, China University of Petroleum-Beijing, Beijing 102249, China.
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9
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Lu S, Sun X, Tian Y, An X, Li W, Chen Y, Zhang H, Vitos L. Theory of transformation-mediated twinning. PNAS NEXUS 2022; 2:pgac282. [PMID: 36712941 PMCID: PMC9830949 DOI: 10.1093/pnasnexus/pgac282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/03/2022] [Indexed: 12/12/2022]
Abstract
High-density and nanosized deformation twins in face-centered cubic (fcc) materials can effectively improve the combination of strength and ductility. However, the microscopic dislocation mechanisms enabling a high twinnability remain elusive. Twinning usually occurs via continuous nucleation and gliding of twinning partial dislocations on consecutive close-packed atomic planes. Here we unveil a completely different twinning mechanism being active in metastable fcc materials. The transformation-mediated twinning (TMT) is featured by a preceding displacive transformation from the fcc phase to the hexagonal close-packed (hcp) one, followed by a second-step transformation from the hcp phase to the fcc twin. The nucleation of the intermediate hcp phase is driven by the thermodynamic instability and the negative stacking fault energy of the metastable fcc phase. The intermediate hcp structure is characterized by the easy slips of Shockley partial dislocations on the basal planes, which leads to both fcc and fcc twin platelets during deformation, creating more twin boundaries and further enhancing the prosperity of twins. The disclosed fundamental understanding of the complex dislocation mechanism of deformation twinning in metastable alloys paves the road to design novel materials with outstanding mechanical properties.
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Affiliation(s)
- Song Lu
- To whom correspondence should be addressed:
| | - Xun Sun
- To whom correspondence should be addressed:
| | - Yanzhong Tian
- Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 10819, China
| | - Xianghai An
- School of Aerospace, Mechanical & Mechatronic Engineering, The University of Sydney, Camperdown Sydney, NSW 2006, Australia
| | - Wei Li
- Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology, Brinellvägen 23, Stockholm, SE-10044, Sweden
| | - Yujie Chen
- School of Aerospace, Mechanical & Mechatronic Engineering, The University of Sydney, Camperdown Sydney, NSW 2006, Australia,School of Mechanical Engineering, University of Adelaide, Adelaide, SA 5005, Australia
| | | | - Levente Vitos
- Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology, Brinellvägen 23, Stockholm, SE-10044, Sweden,Department of Physics and Astronomy, Division of Materials Theory, Uppsala University, Uppsala, Box 516, SE-75121, Sweden,Research Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Budapest H-1525, Hungary
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10
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Chulist R, Pukenas A, Chekhonin P, Hohenwarter A, Pippan R, Schell N, Skrotzki W. Phase Transformation Induced by High Pressure Torsion in the High-Entropy Alloy CrMnFeCoNi. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8407. [PMID: 36499904 PMCID: PMC9736661 DOI: 10.3390/ma15238407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/13/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
The forward and reverse phase transformation from face-centered cubic (fcc) to hexagonal close-packed (hcp) in the equiatomic high-entropy alloy (HEA) CrMnFeCoNi has been investigated with diffraction of high-energy synchrotron radiation. The forward transformation has been induced by high pressure torsion at room and liquid nitrogen temperature by applying different hydrostatic pressures and large shear strains. The volume fraction of hcp phase has been determined by Rietveld analysis after pressure release and heating-up to room temperature as a function of hydrostatic pressure. It increases with pressure and decreasing temperature. Depending on temperature, a certain pressure is necessary to induce the phase transformation. In addition, the onset pressure depends on hydrostaticity; it is lowered by shear stresses. The reverse transformation evolves over a long period of time at ambient conditions due to the destabilization of the hcp phase. The effect of the phase transformation on the microstructure and texture development and corresponding microhardness of the HEA at room temperature is demonstrated. The phase transformation leads to an inhomogeneous microstructure, weakening of the shear texture, and a surprising hardness anomaly. Reasons for the hardness anomaly are discussed in detail.
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Affiliation(s)
- Robert Chulist
- Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 30-059 Krakow, Poland
| | - Aurimas Pukenas
- Institute of Solid State and Materials Physics, Technische Universität Dresden, D-01062 Dresden, Germany
| | - Paul Chekhonin
- Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany
| | - Anton Hohenwarter
- Chair of Materials Physics, Department of Materials Science, Montanuniversität Leoben, Jahnstraße 12, 8700 Leoben, Austria
| | - Reinhard Pippan
- Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstraße 12, 8700 Leoben, Austria
| | - Norbert Schell
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Max-Planck-Strasse 1, D-21502 Geesthacht, Germany
| | - Werner Skrotzki
- Institute of Solid State and Materials Physics, Technische Universität Dresden, D-01062 Dresden, Germany
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11
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Ultrahigh-temperature melt printing of multi-principal element alloys. Nat Commun 2022; 13:6724. [DOI: 10.1038/s41467-022-34471-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 10/26/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractMulti-principal element alloys (MPEA) demonstrate superior synergetic properties compared to single-element predominated traditional alloys. However, the rapid melting and uniform mixing of multi-elements for the fabrication of MPEA structural materials by metallic 3D printing is challenging as it is difficult to achieve both a high temperature and uniform temperature distribution in a sufficient heating source simultaneously. Herein, we report an ultrahigh-temperature melt printing method that can achieve rapid multi-elemental melting and uniform mixing for MPEA fabrication. In a typical fabrication process, multi-elemental metal powders are loaded into a high-temperature column zone that can be heated up to 3000 K via Joule heating, followed by melting on the order of milliseconds and mixing into homogenous alloys, which we attribute to the sufficiently uniform high-temperature heating zone. As proof-of-concept, we successfully fabricated single-phase bulk NiFeCrCo MPEA with uniform grain size. This ultrahigh-temperature rapid melt printing process provides excellent potential toward MPEA 3D printing.
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12
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Huang C, Yao Y, Chen S. Phase Volume Fraction-Dependent Strengthening in a Nano-Laminated Dual-Phase High-Entropy Alloy. ACS OMEGA 2022; 7:29675-29683. [PMID: 36061647 PMCID: PMC9435032 DOI: 10.1021/acsomega.2c02027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
A recently synthesized FCC/HCP nano-laminated dual-phase (NLDP) CoCrFeMnNi high entropy alloy (HEA) exhibits excellent strength-ductility synergy. However, the underlying strengthening mechanisms of such a novel material is far from being understood. In this work, large-scale atomistic simulations of in-plane tension of the NLDP HEA are carried out in order to explore the HCP phase volume fraction-dependent strengthening. It is found that the dual-phase (DP) structure can significantly enhance the strength of the material, and the strength shows apparent phase volume fraction dependence. The yield stress increases monotonously with the increase of phase volume fraction, resulting from the increased inhibition effect of interphase boundary (IPB) on the nucleation of partial dislocations in the FCC lamella. There exists a critical phase volume fraction, where the flow stress is the largest. The mechanisms for the volume fraction-dependent flow stress include volume fraction-dependent phase strengthening effect, volume fraction-dependent IPB strengthening effect, and volume fraction-dependent IPB softening effect, that is, IPB migration and dislocation nucleation from the dislocation-IPB reaction sites. This work can provide a fundamental understanding for the physical mechanisms of strengthening effects in face-centered cubic HEAs with a nanoscale NLDP structure.
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Affiliation(s)
- Cheng Huang
- Institute
of Advanced Structure Technology, Beijing
Institute of Technology, Beijing 100081, China
- Beijing
Key Laboratory of Lightweight Multifunctional Composite Materials
and Structures, Beijing Institute of Technology, Beijing 100081, China
| | - Yin Yao
- Institute
of Advanced Structure Technology, Beijing
Institute of Technology, Beijing 100081, China
- Beijing
Key Laboratory of Lightweight Multifunctional Composite Materials
and Structures, Beijing Institute of Technology, Beijing 100081, China
| | - Shaohua Chen
- Institute
of Advanced Structure Technology, Beijing
Institute of Technology, Beijing 100081, China
- Beijing
Key Laboratory of Lightweight Multifunctional Composite Materials
and Structures, Beijing Institute of Technology, Beijing 100081, China
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13
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Severe Plastic Deformation and Phase Transformations in High Entropy Alloys: A Review. CRYSTALS 2021. [DOI: 10.3390/cryst12010054] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This review discusses an area of expertise that is at the intersection of three large parts of materials science. These are phase transformations, severe plastic deformation (SPD), and high-entropy alloys (HEA). First, SPD makes it possible to determine the borders of single-phase regions of existence of a multicomponent solid solution in HEAs. An important feature of SPD is that using these technologies, it is possible to obtain second-phase nanoparticles included in a matrix with a grain size of several tens of nanometers. Such materials have a very high specific density of internal boundaries. These boundaries serve as pathways for accelerated diffusion. As a result of the annealing of HEAs subjected to SPD, it is possible to accurately determine the border temperature of a single-phase solid solution area on the multicomponent phase diagram of the HEA. Secondly, SPD itself induces phase transformations in HEAs. Among these transformations is the decomposition of a single-phase solid solution with the formation of nanoparticles of the second phase, the formation of high-pressure phases, amorphization, as well as spinodal decomposition. Thirdly, during SPD, a large number of new grain boundaries (GBs) are formed due to the crystallites refinement. Segregation layers exist at these new GBs. The concentration of the components in GBs differs from that in the bulk solid solution. As a result of the formation of a large number of new GBs, atoms leave the bulk solution and form segregation layers. Thus, the composition of the solid solution in the volume also changes. All these processes make it possible to purposefully influence the composition, structure and useful properties of HEAs, especially for medical applications.
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14
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Recent Advances in Additive Manufacturing of High Entropy Alloys and Their Nuclear and Wear-Resistant Applications. METALS 2021. [DOI: 10.3390/met11121980] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Alloying has been very common practice in materials engineering to fabricate metals of desirable properties for specific applications. Traditionally, a small amount of the desired material is added to the principal metal. However, a new alloying technique emerged in 2004 with the concept of adding several principal elements in or near equi-atomic concentrations. These are popularly known as high entropy alloys (HEAs) which can have a wide composition range. A vast area of this composition range is still unexplored. The HEAs research community is still trying to identify and characterize the behaviors of these alloys under different scenarios to develop high-performance materials with desired properties and make the next class of advanced materials. Over the years, understanding of the thermodynamics theories, phase stability and manufacturing methods of HEAs has improved. Moreover, HEAs have also shown retention of strength and relevant properties under extreme tribological conditions and radiation. Recent progresses in these fields are surveyed and discussed in this review with a focus on HEAs for use under extreme environments (i.e., wear and irradiation) and their fabrication using additive manufacturing.
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15
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Huang C, Yao Y, Peng X, Chen S. Plastic deformation and strengthening mechanism of FCC/HCP nano-laminated dual-phase CoCrFeMnNi high entropy alloy. NANOTECHNOLOGY 2021; 32:505724. [PMID: 34555821 DOI: 10.1088/1361-6528/ac2980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
FCC-structured CoCrFeMnNi high entropy alloy (HEA) has attracted abroad interests for years because of its excellent mechanical properties, except for strength. Recent experiments have reported a kind of nano-laminated dual-phase (NLDP) FCC/HCP structure that can strengthen the HEA. However, it is still unknown why the HEA can be strengthened by this kind of NLDP structure. Here, we employ molecular dynamics simulations to study the atomistic strengthening mechanism of the NLDP HEA. Dislocation-assisted multiple plastic deformation mechanisms in both FCC and HCP single phase HEAs are observed, and amorphization is also found in the plasticity of HCP phase, which are consistent with the previous experimental characterizations. The HCP phase possesses higher strength because of its higher stacking fault energy, higher Peierls-Nabarro stress and less active dislocation slip systems. It is also found that the introduction of HCP phase can enhance the mechanical properties, including yield stress, yield strain and plastic flow stress, of the NLDP HEAs, which also show volume fraction dependence. And the phase boundary plays crucial roles in the deformation and strengthening of the NLDP HEAs. The plastic deformation of the NLDP HEAs can be divided into two stages, i.e. stage I (plasticity only appears in FCC lamella) and stage II (plasticity in both FCC and HCP lamellas). With the increase of volume fraction, the lamella thickness of FCC matrix phase decreases, leading to continuous strengthening of yield properties and flow stress of stage I because of suppressed dislocation nucleation and confined dislocation motion in FCC matrix phase by the phase boundary. While there is no monotonous relationship between the flow stresses of stage II and the increasing volume fraction of HCP phase, which can be attributed to the competitive mechanisms between strengthening effect of phase boundary on the dislocation motion in FCC phase and softening effect of phase boundary on the dislocation motion in HCP phase. The results should be helpful for understanding the underlying physical mechanism of strengthening of HEAs with NLDP structure.
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Affiliation(s)
- Cheng Huang
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Yin Yao
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Xianghe Peng
- College of Aerospace Engineering, Chongqing University, Chongqing 400044, People's Republic of China
| | - Shaohua Chen
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, People's Republic of China
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16
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Pei Z, Dutta B, Körmann F, Chen M. Hidden Effects of Negative Stacking Fault Energies in Complex Concentrated Alloys. PHYSICAL REVIEW LETTERS 2021; 126:255502. [PMID: 34241525 DOI: 10.1103/physrevlett.126.255502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
Negative stacking fault energies (SFEs) are found in face-centered cubic high-entropy alloys with excellent mechanical properties, especially at low temperatures. Their roles remain elusive due to the lack of in situ observation of nanoscale deformation. Here, the polymorphism of Shockley partials is fully explored, assisted by a new method. We show negative SFEs result in novel partial pairs as if they were in hexagonal close-packed alloys. The associated yield stresses are much higher than those for other mechanisms at low temperatures. This generalizes the physical picture for all negative-SFE alloys.
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Affiliation(s)
- Zongrui Pei
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Biswanath Dutta
- Department of Materials Science and Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Fritz Körmann
- Department of Materials Science and Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands and Computational Materials Design, Max-Planck-Institut für Eisenforschung GmbH, D-40237 Düsseldorf, Germany
| | - Mingwei Chen
- Department of Materials Science and Engineering and Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, Maryland 21218, USA
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17
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Microstructure, Hardness, and Elastic Modulus of a Multibeam-Sputtered Nanocrystalline Co-Cr-Fe-Ni Compositional Complex Alloy Film. MATERIALS 2021; 14:ma14123357. [PMID: 34204382 PMCID: PMC8235313 DOI: 10.3390/ma14123357] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/12/2021] [Accepted: 06/14/2021] [Indexed: 12/02/2022]
Abstract
A nanocrystalline Co-Cr-Ni-Fe compositional complex alloy (CCA) film with a thickness of about 1 micron was produced by a multiple-beam-sputtering physical vapor deposition (PVD) technique. The main advantage of this novel method is that it does not require alloy targets, but rather uses commercially pure metal sources. Another benefit of the application of this technique is that it produces compositional gradient samples on a disk surface with a wide range of elemental concentrations, enabling combinatorial analysis of CCA films. In this study, the variation of the phase composition, the microstructure (crystallite size and defect density), and the mechanical performance (hardness and elastic modulus) as a function of the chemical composition was studied in a combinatorial Co-Cr-Ni-Fe thin film sample that was produced on a surface of a disk with a diameter of about 10 cm. The spatial variation of the crystallite size and the density of lattice defects (e.g., dislocations and twin faults) were investigated by X-ray diffraction line profile analysis performed on the patterns taken by synchrotron radiation. The hardness and the elastic modulus were measured by the nanoindentation technique. It was found that a single-phase face-centered cubic (fcc) structure was formed for a wide range of chemical compositions. The microstructure was nanocrystalline with a crystallite size of 10–27 nm and contained a high lattice defect density. The hardness and the elastic modulus values measured for very different compositions were in the ranges of 8.4–11.8 and 182–239 GPa, respectively.
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18
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Wang H, Chen D, An X, Zhang Y, Sun S, Tian Y, Zhang Z, Wang A, Liu J, Song M, Ringer SP, Zhu T, Liao X. Deformation-induced crystalline-to-amorphous phase transformation in a CrMnFeCoNi high-entropy alloy. SCIENCE ADVANCES 2021; 7:7/14/eabe3105. [PMID: 33789894 PMCID: PMC8011962 DOI: 10.1126/sciadv.abe3105] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 02/11/2021] [Indexed: 05/23/2023]
Abstract
The Cantor high-entropy alloy (HEA) of CrMnFeCoNi is a solid solution with a face-centered cubic structure. While plastic deformation in this alloy is usually dominated by dislocation slip and deformation twinning, our in situ straining transmission electron microscopy (TEM) experiments reveal a crystalline-to-amorphous phase transformation in an ultrafine-grained Cantor alloy. We find that the crack-tip structural evolution involves a sequence of formation of the crystalline, lamellar, spotted, and amorphous patterns, which represent different proportions and organizations of the crystalline and amorphous phases. Such solid-state amorphization stems from both the high lattice friction and high grain boundary resistance to dislocation glide in ultrafine-grained microstructures. The resulting increase of crack-tip dislocation densities promotes the buildup of high stresses for triggering the crystalline-to-amorphous transformation. We also observe the formation of amorphous nanobridges in the crack wake. These amorphization processes dissipate strain energies, thereby providing effective toughening mechanisms for HEAs.
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Affiliation(s)
- Hao Wang
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - Dengke Chen
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Xianghai An
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia.
| | - Yin Zhang
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Shijie Sun
- Laboratory of Fatigue and Fracture for Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Yanzhong Tian
- Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China
- Research Center for Metal Wires, Northeastern University, Shenyang 110819, China
| | - Zhefeng Zhang
- Laboratory of Fatigue and Fracture for Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Anguo Wang
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - Jinqiao Liu
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - Min Song
- State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China
| | - Simon P Ringer
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - Ting Zhu
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
| | - Xiaozhou Liao
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia.
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Guan S, Liang H, Wang Q, Tan L, Peng F. Synthesis and Phase Stability of the High-Entropy Carbide (Ti 0.2Zr 0.2Nb 0.2Ta 0.2Mo 0.2)C under Extreme Conditions. Inorg Chem 2021; 60:3807-3813. [PMID: 33616408 DOI: 10.1021/acs.inorgchem.0c03319] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
As a novel ultrahigh temperature ceramic, the stability of a high-entropy transition metal carbide under extreme conditions is of great concern to its application. Despite the intense research, the available high-pressure experimental results are few so far. Here, we synthesized the nanocrystalline (Ti0.2Zr0.2Nb0.2Ta0.2Mo0.2)C by a high-pressure solid-state reaction successfully. Meanwhile, synchrotron radiation X-ray diffraction experiments were carried out to explore the phase stability and mechanical response under high pressure. The single cubic B1 phase structure of the high-entropy carbide is retained under extreme hydrostatic pressure. An abnormal cubic-to-cubic phase transition was observed unexpectedly under nonhydrostatic compression. This result reflects the effect of the severe lattice distortion of the initial B1 phase high-entropy carbide and the shear strain caused by deviatoric stress under high nonhydrostatic pressure. The physical mechanism about electronic/magnetic characteristics behind findings is an interesting issue for future studies.
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Affiliation(s)
- Shixue Guan
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P. R. China
| | - Hao Liang
- School of Science, Southwest University of Science and Technology, Mianyang 621010, P. R. China
| | - Qiming Wang
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P. R. China
| | - Lijie Tan
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P. R. China
| | - Fang Peng
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P. R. China
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20
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Lee H, Shabani M, Pataky GJ, Abdeljawad F. Tensile deformation behavior of twist grain boundaries in CoCrFeMnNi high entropy alloy bicrystals. Sci Rep 2021; 11:428. [PMID: 33431909 PMCID: PMC7801446 DOI: 10.1038/s41598-020-77487-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 11/04/2020] [Indexed: 01/29/2023] Open
Abstract
High entropy alloys (HEA) are a class of materials that consist of multiple elemental species in similar concentrations. The use of elements in far from dilute concentrations introduces a multi-dimensional composition design space by which the properties of metallic systems can be tailored. While the mechanical behavior of HEAs has been the subject of active research recently, the role of grain boundaries (GBs) in their deformation behavior remains poorly understood. Motivated by recent experiments on HEAs demonstrating that GBs act as nucleation sites for deformation twins, herein, we leverage atomistic simulations to construct a series of equiatomic CoCrFeMnNi HEA bicrystals with [Formula: see text] and [Formula: see text] symmetric twist GBs and examine their tensile behavior and underlying deformation mechanisms at 77 K. Simulation results reveal that plastic deformation proceeds by the nucleation of partial dislocations from GBs, which then grow with further loading by bowing into the bulk crystals leaving behind stacking faults. Variations in the nucleation stress exist as function of GB character, defined in this work by the twist angle. Our results provide future avenues to explore GBs as a microstructure design tool to develop HEAs with tailored properties.
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Affiliation(s)
- Hyunsoo Lee
- grid.26090.3d0000 0001 0665 0280Department of Mechanical Engineering, Clemson University, Clemson, SC 29634 USA
| | - Mitra Shabani
- grid.26090.3d0000 0001 0665 0280Department of Mechanical Engineering, Clemson University, Clemson, SC 29634 USA
| | - Garrett J. Pataky
- grid.26090.3d0000 0001 0665 0280Department of Mechanical Engineering, Clemson University, Clemson, SC 29634 USA
| | - Fadi Abdeljawad
- grid.26090.3d0000 0001 0665 0280Department of Mechanical Engineering, Clemson University, Clemson, SC 29634 USA ,grid.26090.3d0000 0001 0665 0280Department of Materials Science and Engineering, Clemson University, Clemson, SC 29634 USA
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21
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Ek G, Nygård MM, Pavan AF, Montero J, Henry PF, Sørby MH, Witman M, Stavila V, Zlotea C, Hauback BC, Sahlberg M. Elucidating the Effects of the Composition on Hydrogen Sorption in TiVZrNbHf-Based High-Entropy Alloys. Inorg Chem 2020; 60:1124-1132. [PMID: 33370527 PMCID: PMC7871323 DOI: 10.1021/acs.inorgchem.0c03270] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
A number
of high-entropy alloys (HEAs) in the TiVZrNbHf system
have been synthesized by arc melting and systematically evaluated
for their hydrogen sorption characteristics. A total of 21 alloys
with varying elemental compositions were investigated, and 17 of them
form body-centered-cubic (bcc) solid solutions in the as-cast state.
A total of 15 alloys form either face-centered-cubic (fcc) or body-centered-tetragonal
(bct) hydrides after exposure to gaseous hydrogen with hydrogen per
metal ratios (H/M) as high as 2.0. Linear trends are observed between
the volumetric expansion per metal atom [(V/Z)fcc/bct – (V/Z)bcc/hcp]/(V/Z)bcc/hcp with the valence electron concentration and average
Pauling electronegativity (χp) of the alloys. However,
no correlation was observed between the atomic size mismatch, δ,
and any investigated hydrogen sorption property such as the maximum
storage capacity or onset temperature for hydrogen release. The effect of the composition on hydrogen
sorption has been
studied on high-entropy alloys based on TiVZrNbHf. Most alloys crystallize
in body-centered-cubic solid solutions and form fluorite-type metal
hydrides. The desorption behavior of three selected metal deuterides
was studied with in situ neutron diffraction coupled with gravimetric
analysis. It was found that when Zr is added to TiVNb, deuterium first
jumps from tetrahedral interstitial sites to octahedral sites before
leaving the structure.
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Affiliation(s)
- Gustav Ek
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala SE-75120, Sweden
| | - Magnus M Nygård
- Department for Neutron Materials Characterization, Institute for Energy Technology, P.O. Box 40, Kjeller NO-2027, Norway
| | - Adriano F Pavan
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala SE-75120, Sweden
| | - Jorge Montero
- Institut de Chimie et des Matériaux Paris Est, Université de Paris Est, CNRS, UPEC, Thiais 94320, France
| | - Paul F Henry
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala SE-75120, Sweden.,ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Magnus H Sørby
- Department for Neutron Materials Characterization, Institute for Energy Technology, P.O. Box 40, Kjeller NO-2027, Norway
| | - Matthew Witman
- Sandia National Laboratories, Livermore, California 94551, United States
| | - Vitalie Stavila
- Sandia National Laboratories, Livermore, California 94551, United States
| | - Claudia Zlotea
- Institut de Chimie et des Matériaux Paris Est, Université de Paris Est, CNRS, UPEC, Thiais 94320, France
| | - Bjørn C Hauback
- Department for Neutron Materials Characterization, Institute for Energy Technology, P.O. Box 40, Kjeller NO-2027, Norway
| | - Martin Sahlberg
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala SE-75120, Sweden
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Mouralova K, Benes L, Zahradnicek R, Bednar J, Zadera A, Fries J, Kana V. WEDM Used for Machining High Entropy Alloys. MATERIALS 2020; 13:ma13214823. [PMID: 33126700 PMCID: PMC7662231 DOI: 10.3390/ma13214823] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/24/2020] [Accepted: 10/26/2020] [Indexed: 11/16/2022]
Abstract
Unconventional wire electrical discharge machining technology (WEDM) is a key machining process, especially for machining newly emerging materials, as there are almost no restrictions (only at least minimal electrical conductivity) in terms of demands on the mechanical properties of the workpiece or the need to develop new tool geometry. This study is the first to present an analysis of the machinability of newly developed high entropy alloys (HEAs), namely FeCoCrMnNi and FeCoCrMnNiC0.2, using WEDM. The aim of this study was to find the optimal setting of machine parameters for the efficient production of parts with the required surface quality without defects. For this reason, an extensive design of experiments consisting of 66 rounds was performed, which took into account the influence of five input factors in the form of pulse off time, gap voltage, discharge current, pulse on time, and wire speed on cutting speed and the quality of the machined surface and its subsurface layer. The analysis of topography, morphology, subsurface layers, chemical composition analysis (EDX), and lamella analysis using a transmission electron microscope (TEM) were performed. An optimal setting of the machine parameters was found, which enables machining of FeCoCrMnNi and FeCoCrMnNiC0.2 with the required surface quality without defects.
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Affiliation(s)
- Katerina Mouralova
- Faculty of Mechanical Engineering, Brno University of Technology, 616 69 Brno, Czech Republic; (R.Z.); (J.B.); (A.Z.); (V.K.)
- Correspondence:
| | - Libor Benes
- Faculty of Mechanical Engineering, Czech Technical University in Prague, 166 07 Prague, Czech Republic;
| | - Radim Zahradnicek
- Faculty of Mechanical Engineering, Brno University of Technology, 616 69 Brno, Czech Republic; (R.Z.); (J.B.); (A.Z.); (V.K.)
| | - Josef Bednar
- Faculty of Mechanical Engineering, Brno University of Technology, 616 69 Brno, Czech Republic; (R.Z.); (J.B.); (A.Z.); (V.K.)
| | - Antonin Zadera
- Faculty of Mechanical Engineering, Brno University of Technology, 616 69 Brno, Czech Republic; (R.Z.); (J.B.); (A.Z.); (V.K.)
| | - Jiří Fries
- Department of Production Machines and Design, Technical University of Ostrava, 708 33 Ostrava, Czech Republic;
| | - Vaclav Kana
- Faculty of Mechanical Engineering, Brno University of Technology, 616 69 Brno, Czech Republic; (R.Z.); (J.B.); (A.Z.); (V.K.)
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23
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Jiang L, Hu YJ, Sun K, Xiu P, Song M, Zhang Y, Boldman WL, Crespillo ML, Rack PD, Qi L, Weber WJ, Wang L. Irradiation-Induced Extremes Create Hierarchical Face-/Body-Centered-Cubic Phases in Nanostructured High Entropy Alloys. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002652. [PMID: 32820560 DOI: 10.1002/adma.202002652] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 07/12/2020] [Indexed: 05/07/2023]
Abstract
A nanoscale hierarchical dual-phase structure is reported to form in a nanocrystalline NiFeCoCrCu high-entropy-alloy (HEA) film via ion irradiation. Under the extreme energy deposition and consequent thermal energy dissipation induced by energetic particles, a fundamentally new phenomenon is revealed, in which the original single-phase face-centered-cubic (FCC) structure partially transforms into alternating nanometer layers of a body-centered-cubic (BCC) structure. The orientation relationship follows the Nishiyama-Wasser-man relationship, that is, (011)BCC || ( 1¯1¯1)FCC and [100]BCC || [ 11¯0]FCC . Simulation results indicate that Cr, as a BCC stabilizing element, exhibits a tendency to segregate to the stacking faults (SFs). Furthermore, the high densities of SFs and twin boundaries in each nanocrystalline grain serve to accelerate the nucleation and growth of the BCC phase during irradiation. By adjusting the irradiation parameters, desired thicknesses of the FCC and BCC phases in the laminates can be achieved. This work demonstrates the controlled formation of an attractive dual-phase nanolaminate structure under ion irradiation and provides a strategy for designing new derivate structures of HEAs.
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Affiliation(s)
- Li Jiang
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Yong-Jie Hu
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Kai Sun
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Pengyuan Xiu
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Miao Song
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Yanwen Zhang
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Walker L Boldman
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA
| | - Miguel L Crespillo
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA
| | - Philip D Rack
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Liang Qi
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - William J Weber
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Lumin Wang
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
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24
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Lee C, Kim G, Chou Y, Musicó BL, Gao MC, An K, Song G, Chou YC, Keppens V, Chen W, Liaw PK. Temperature dependence of elastic and plastic deformation behavior of a refractory high-entropy alloy. SCIENCE ADVANCES 2020; 6:eaaz4748. [PMID: 32917694 PMCID: PMC11206460 DOI: 10.1126/sciadv.aaz4748] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
Single-phase solid-solution refractory high-entropy alloys (HEAs) show remarkable mechanical properties, such as their high yield strength and substantial softening resistance at elevated temperatures. Hence, the in-depth study of the deformation behavior for body-centered cubic (BCC) refractory HEAs is a critical issue to explore the uncovered/unique deformation mechanisms. We have investigated the elastic and plastic deformation behaviors of a single BCC NbTaTiV refractory HEA at elevated temperatures using integrated experimental efforts and theoretical calculations. The in situ neutron diffraction results reveal a temperature-dependent elastic anisotropic deformation behavior. The single-crystal elastic moduli and macroscopic Young's, shear, and bulk moduli were determined from the in situ neutron diffraction, showing great agreement with first-principles calculations, machine learning, and resonant ultrasound spectroscopy results. Furthermore, the edge dislocation-dominant plastic deformation behaviors, which are different from conventional BCC alloys, were quantitatively described by the Williamson-Hall plot profile modeling and high-angle annular dark-field scanning transmission electron microscopy.
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Affiliation(s)
- Chanho Lee
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996-2100, USA
| | - George Kim
- Department of Mechanical, Materials, and Aerospace Engineering, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Yi Chou
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Brianna L Musicó
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996-2100, USA
| | - Michael C Gao
- National Energy Technology Laboratory/Leidos Research Support Team, Albany, OR 97321, USA
| | - Ke An
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Gian Song
- Division of Advanced Materials Engineering and Institute for rare metals, Kongju National University, Cheonan, Chungnam 330-717, Republic of Korea
| | - Yi-Chia Chou
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Veerle Keppens
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996-2100, USA
| | - Wei Chen
- Department of Mechanical, Materials, and Aerospace Engineering, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Peter K Liaw
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996-2100, USA.
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25
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Tian F, Lin DY, Gao X, Zhao YF, Song HF. A structural modeling approach to solid solutions based on the similar atomic environment. J Chem Phys 2020; 153:034101. [PMID: 32716184 DOI: 10.1063/5.0014094] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A solid solution is one of the important ways to enhance the structural and functional performance of materials. In this work, we develop a structural modeling approach to solid solutions based on the similar atomic environment (SAE). We propose a similarity function associated with any type of atom cluster to describe quantitatively the configurational deviation from the desired solid-solution structure that is fully disordered or contains short-range order (SRO). In this manner, the structural modeling for solid solutions is transferred to a minimization problem in the configuration space. Moreover, we strive to enhance the practicality of this approach. The approach and implementation are demonstrated by cross validations with the special quasi-random structure method. We apply the SAE method to the typical quinary CoCrFeMnNi high-entropy alloy, continuous binary Ta-W alloy, and ternary CoCrNi medium-entropy alloy with SRO as prototypes. In combination with ab initio calculations, we investigate the structural properties and compare the calculation results with experiments.
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Affiliation(s)
- Fuyang Tian
- Institute for Applied Physics, Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science, University of Science and Technology Beijing, Beijing 100083, China
| | - De-Ye Lin
- CAEP Software Center for High Performance Numerical Simulation, Beijing 100088, China
| | - Xingyu Gao
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
| | - Ya-Fan Zhao
- CAEP Software Center for High Performance Numerical Simulation, Beijing 100088, China
| | - Hai-Feng Song
- CAEP Software Center for High Performance Numerical Simulation, Beijing 100088, China
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26
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Alshataif YA, Sivasankaran S, Al-Mufadi FA, Alaboodi AS, Ammar H. Synthesis, structure, and mechanical response of Cr0.26Fe0.24Al0.5 and Cr0.15Fe0.14Al0.30Cu0.13Si0.28 nanocrystallite entropy alloys. ADV POWDER TECHNOL 2020. [DOI: 10.1016/j.apt.2020.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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27
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Chang X, Zeng M, Liu K, Fu L. Phase Engineering of High-Entropy Alloys. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1907226. [PMID: 32100909 DOI: 10.1002/adma.201907226] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 12/22/2019] [Indexed: 06/10/2023]
Abstract
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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Affiliation(s)
- Xuejiao Chang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Mengqi Zeng
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Keli Liu
- Institute for Advanced Studies, Wuhan University, Wuhan, 430072, China
| | - Lei Fu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
- Institute for Advanced Studies, Wuhan University, Wuhan, 430072, China
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28
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Mechanical and Magnetic Properties of the High-Entropy Alloys for Combinatorial Approaches. CRYSTALS 2020. [DOI: 10.3390/cryst10030200] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This review summarizes the state of high-entropy alloys and their combinatorial approaches, mainly considering their magnetic applications. Several earlier studies on high-entropy alloy properties, such as magnetic, wear, and corrosion behavior; different forms, such as thin films, nanowires, thermal spray coatings; specific treatments, such as plasma spraying and inclusion effects; and unique applications, such as welding, are summarized. High-entropy alloy systems that were reported for both their mechanical and magnetic properties are compared through the combination of their Young’s modulus, yield strength, remanent induction, and coercive force. Several potential applications requiring both mechanical and magnetic properties are reported.
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29
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Qin G, Chen R, Liaw PK, Gao Y, Wang L, Su Y, Ding H, Guo J, Li X. An as-cast high-entropy alloy with remarkable mechanical properties strengthened by nanometer precipitates. NANOSCALE 2020; 12:3965-3976. [PMID: 32016212 DOI: 10.1039/c9nr08338c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
High-entropy alloys (HEAs) with good ductility and high strength are usually prepared by a combination of forging and heat-treatment processes. In comparison, the as-cast HEAs typically do not reach strengths similar to those of HEAs produced by the forging and heat-treatment processes. Here we report a novel equiatomic-ratio CoCrCuMnNi HEA prepared by vacuum arc melting. We observe that this HEA has excellent mechanical properties, i.e., a yield strength of 458 MPa, and an ultimate tensile strength of 742 MPa with an elongation of 40%. Many nanometer precipitates (5-50 nm in size) and domains (5-10 nm in size) are found in the inter-dendrite and dendrite zones of the produced HEA, which is the key factor for its excellent mechanical properties. The enthalpy of mixing between Cu and Mn, Cr, Co, or Ni is higher than those of mixing between any two of Cr, Co, Ni and Mn, which leads to the separation of Cu from the CoCrCuMnNi HEA. Furthermore, we reveal the nanoscale-precipitate-phase-forming mechanism in the proposed HEA.
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Affiliation(s)
- Gang Qin
- National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, 150001, China.
| | - Ruirun Chen
- National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, 150001, China.
| | - Peter K Liaw
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996, USA
| | - Yanfei Gao
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996, USA
| | - Liang Wang
- National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, 150001, China.
| | - Yanqing Su
- National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, 150001, China.
| | - Hongsheng Ding
- National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, 150001, China.
| | - Jingjie Guo
- National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, 150001, China.
| | - Xiaoqing Li
- Department of Materials Science and Engineering, KTH - Royal Institute of Technology, 10044 Stockholm, Sweden
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30
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Wang X, Liu X. High pressure: a feasible tool for the synthesis of unprecedented inorganic compounds. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00477d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
After a simple classification of inorganic materials synthesized at high-temperature and high-pressure, this tutorial reviews the important research results in the field of high-temperature and high-pressure inorganic synthesis in the past 5 years.
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Affiliation(s)
- Xuerong Wang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry
- College of Chemistry
- Jilin University
- Changchun 130012
- P. R. China
| | - Xiaoyang Liu
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry
- College of Chemistry
- Jilin University
- Changchun 130012
- P. R. China
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31
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Element Effects on High-Entropy Alloy Vacancy and Heterogeneous Lattice Distortion Subjected to Quasi-equilibrium Heating. Sci Rep 2019; 9:14788. [PMID: 31616021 PMCID: PMC6794270 DOI: 10.1038/s41598-019-51297-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/29/2019] [Indexed: 12/01/2022] Open
Abstract
We applied Simmons–Balluffi methods, positron measurements, and neutron diffraction to estimate the vacancy of CoCrFeNi and CoCrFeMnNi high-entropy alloys (HEAs) using Cu as a benchmark. The corresponding formation enthalpies and associated entropies of the HEAs and Cu were calculated. The vacancy-dependent effective free volumes in both CoCrFeNi and CoCrFeMnNi alloys are greater than those in Cu, implying the easier formation of vacancies by lattice structure relaxation of HEAs at elevated temperatures. Spatially resolved synchrotron X-ray measurements revealed different characteristics of CoCrFeNi and CoCrFeMnNi HEAs subjected to quasi-equilibrium conditions at high temperatures. Element-dependent behavior revealed by X-ray fluorescence (XRF) mapping indicates the effect of Mn on the Cantor Alloy.
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32
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Cheng B, Lou H, Sarkar A, Zeng Z, Zhang F, Chen X, Tan L, Prakapenka V, Greenberg E, Wen J, Djenadic R, Hahn H, Zeng Q. Pressure-induced tuning of lattice distortion in a high-entropy oxide. Commun Chem 2019. [DOI: 10.1038/s42004-019-0216-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Abstract
As a new class of multi-principal component oxides with high chemical disorder, high-entropy oxides (HEOs) have attracted much attention. The stability and tunability of their structure and properties are of great interest and importance, but remain unclear. By using in situ synchrotron radiation X-ray diffraction, Raman spectroscopy, ultraviolet–visible absorption spectroscopy, and ex situ high-resolution transmission electron microscopy, here we show the existence of lattice distortion in the crystalline (Ce0.2La0.2Pr0.2Sm0.2Y0.2)O2−δ HEO according to the deviation of bond angles from the ideal values, and discover a pressure-induced continuous tuning of lattice distortion (bond angles) and band gap. As continuous bending of bond angles, pressure eventually induces breakdown of the long-range connectivity of lattice and causes amorphization. The amorphous state can be partially recovered upon decompression, forming glass–nanoceramic composite HEO. These results reveal the unexpected flexibility of the structure and properties of HEOs, which could promote the fundamental understanding and applications of HEOs.
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33
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Lee JI, Tsuchiya K, Tasaki W, Oh HS, Sawaguchi T, Murakami H, Hiroto T, Matsushita Y, Park ES. A strategy of designing high-entropy alloys with high-temperature shape memory effect. Sci Rep 2019; 9:13140. [PMID: 31511574 PMCID: PMC6739314 DOI: 10.1038/s41598-019-49529-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 08/27/2019] [Indexed: 11/28/2022] Open
Abstract
Shape memory effect, the ability to recover a pre-deformed shape on heating, results from a reversible martensitic transformation between austenite and martensite phases. Here, we demonstrate a strategy of designing high-entropy alloys (HEAs) with high-temperature shape memory effect in the CrMnFeCoNi alloy system. First, we calculate the difference in Gibbs free energy between face-centered-cubic (FCC) and hexagonal-close-packed (HCP) phases, and find a substantial increase in thermodynamic equilibrium temperature between the FCC and HCP phases through composition tuning, leading to thermally- and stress-induced martensitic transformations. As a consequence, the shape recovery temperature in non-equiatomic CrMnFeCoNi alloys can be increased to 698 K, which is much higher than that of conventional shape memory alloys (SMAs) and comparable to that of B2-based multi-component SMAs containing noble metals (Pd, Pt, etc.) or refractory metals (Zr, Hf, etc.). This result opens a vast field of applications of HEAs as a novel class of cost-effective high-temperature SMAs.
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Affiliation(s)
- Je In Lee
- International Center for Young Scientists, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan.
- School of Materials Science and Engineering, Pusan National University, Busan, 46241, Republic of Korea.
| | - Koichi Tsuchiya
- International Center for Young Scientists, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan.
- Research Center for Structural Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan.
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tenodai, Tsukuba, Ibaraki, 305-8577, Japan.
| | - Wataru Tasaki
- Research Center for Structural Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tenodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Hyun Seok Oh
- Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Takahiro Sawaguchi
- Research Center for Structural Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan
| | - Hideyuki Murakami
- Research Center for Structural Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan
- Department of Nanoscience and Nanoengineering, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku-ku, 169-8555, Japan
| | - Takanobu Hiroto
- Materials Analysis Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan
| | - Yoshitaka Matsushita
- Materials Analysis Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan
| | - Eun Soo Park
- Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
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34
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Comparing Cyclic Tension-Compression Effects on CoCrFeMnNi High-Entropy Alloy and Ni-Based Superalloy. CRYSTALS 2019. [DOI: 10.3390/cryst9080420] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An equal-molar CoCrFeMnNi, face-centered-cubic (fcc) high-entropy alloy (HEA) and a nickel-based superalloy are studied using in situ neutron diffraction experiments. With continuous measurements, the evolution of diffraction peaks is collected for microscopic lattice strain analyses. Cyclic hardening and softening are found in both metallic systems. However, as obtained from the diffraction-peak-width evolution, the underneath deformation mechanisms are quite different. The CoCrFeMnNi HEA exhibits distinct lattice strain and microstructure responses under tension-compression cyclic loadings.
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35
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Zhao YF, Zhang JY, Wang YQ, Wu K, Liu G, Sun J. Unusual plastic deformation behavior of nanotwinned Cu/high entropy alloy FeCoCrNi nanolaminates. NANOSCALE 2019; 11:11340-11350. [PMID: 31166340 DOI: 10.1039/c9nr00836e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Compared with coarse-grained FeCoCrNi-based high entropy alloys (HEAs), their nanocrystalline (NC) siblings with ultra-high strength often suffer from notably reduced deformability. Here, to enhance the deformability of these NC HEAs without losing their high strength, we design equal layered nanotwinned (NT) Cu/HEA (HEA = FeCoCrNi) crystalline/crystalline nanolaminates (C/CNLs) with coherent crystalline/crystalline interfaces (CCIs). In contrast to the tenet that in conventional bimetal C/CNLs, the soft/ductile phase plays the dominant major role, we discover that in NT Cu/HEA C/CNLs, the hard HEA phase unusually makes more contribution to the plastic deformation. The underlying reason is that the soft NT Cu layers without dislocation pile-up serve as the dislocation donator and export abundant dislocations that transmit across the coherent CCIs into the hard HEA accepter, and thus trigger their great deformability. The size-dependent hardness was explained based on dislocation-based models considering the stability of extremely small nanotwins with thickness less than ∼10 nm. These findings provide a new pathway to achieve great deformability of strong alloys with high lattice friction stresses in ultra-strong metallic composites: control the size of NT soft phases to suppress dislocation pile-up in conjunction with coherent CCIs to facilitate continuity of dislocation slip.
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Affiliation(s)
- Y F Zhao
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
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36
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Prediction of Strength and Ductility in Partially Recrystallized CoCrFeNiTi 0.2 High-Entropy Alloy. ENTROPY 2019; 21:e21040389. [PMID: 33267103 PMCID: PMC7514873 DOI: 10.3390/e21040389] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 03/28/2019] [Indexed: 12/05/2022]
Abstract
The mechanical behavior of a partially recrystallized fcc-CoCrFeNiTi0.2 high entropy alloys (HEA) is investigated. Temporal evolutions of the morphology, size, and volume fraction of the nanoscaled L12-(Ni,Co)3Ti precipitates at 800 °C with various aging time were quantitatively evaluated. The ultimate tensile strength can be greatly improved to ~1200 MPa, accompanied with a tensile elongation of ~20% after precipitation. The temporal exponents for the average size and number density of precipitates reasonably conform the predictions by the PV model. A composite model was proposed to describe the plastic strain of the current HEA. As a consequence, the tensile strength and tensile elongation are well predicted, which is in accord with the experimental results. The present experiment provides a theoretical reference for the strengthening of partially recrystallized single-phase HEAs in the future.
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37
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Abstract
High-entropy alloys (HEAs) present excellent mechanical properties. However, the exploitation of chemical properties of HEAs is far less than that of mechanical properties, which is mainly limited by the low specific surface area of HEAs synthesized by traditional methods. Thus, it is vital to develop new routes to fabricate HEAs with novel three-dimensional structures and a high specific surface area. Herein, we develop a facile approach to fabricate nanoporous noble metal quasi-HEA microspheres by melt-spinning and dealloying. The as-obtained nanoporous Cu30Au23Pt22Pd25 quasi-HEA microspheres present a hierarchical porous structure with a high specific surface area of 69.5 m2/g and a multiphase approximatively componential solid solution characteristic with a broad single-group face-centered cubic XRD pattern, which is different from the traditional single-phase or two-phase solid solution HEAs. To differentiate, these are named quasi-HEAs. The synthetic strategy proposed in this paper opens the door for the synthesis of porous quasi-HEAs related materials, and is expected to promote further applications of quasi-HEAs in various chemical fields.
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38
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Effect of FeCoNiCrCu 0.5 High-entropy-alloy Substrate on Sn Grain Size in Sn-3.0Ag-0.5Cu Solder. Sci Rep 2019; 9:3658. [PMID: 30842519 PMCID: PMC6403290 DOI: 10.1038/s41598-019-40268-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/11/2019] [Indexed: 11/28/2022] Open
Abstract
High-entropy alloys (HEAs) are well known for their excellent high-temperature stability, mechanical properties, and promising resistance against oxidation and corrosion. However, their low-temperature applications are rarely studied, particularly in electronic packaging. In this study, the interfacial reaction between a Sn-3.0Ag-0.5Cu solder and FeCoNiCrCu0.5 HEA substrate was investigated. (Cu0.76, Ni0.24)6Sn5 intermetallic compound was formed the substrate at the interface between the solder and the FeCoNiCrCu0.5 HEA substrate. The average Sn grain size on the HEA substrate was 246 μm, which was considerably larger than that on a pure Cu substrate. The effect of the substrate on Sn grain size is due to the free energy required for the heterogeneous nucleation of Sn on the FeCoNiCrCu0.5 substrate.
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39
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Zhang F, Lou H, Cheng B, Zeng Z, Zeng Q. High-Pressure Induced Phase Transitions in High-Entropy Alloys: A Review. ENTROPY 2019; 21:e21030239. [PMID: 33266954 PMCID: PMC7514720 DOI: 10.3390/e21030239] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 02/22/2019] [Accepted: 02/26/2019] [Indexed: 11/28/2022]
Abstract
High-entropy alloys (HEAs) as a new class of alloy have been at the cutting edge of advanced metallic materials research in the last decade. With unique chemical and topological structures at the atomic level, HEAs own a combination of extraordinary properties and show potential in widespread applications. However, their phase stability/transition, which is of great scientific and technical importance for materials, has been mainly explored by varying temperature. Recently, pressure as another fundamental and powerful parameter has been introduced to the experimental study of HEAs. Many interesting reversible/irreversible phase transitions that were not expected or otherwise invisible before have been observed by applying high pressure. These recent findings bring new insight into the stability of HEAs, deepens our understanding of HEAs, and open up new avenues towards developing new HEAs. In this paper, we review recent results in various HEAs obtained using in situ static high-pressure synchrotron radiation x-ray techniques and provide some perspectives for future research.
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Affiliation(s)
- Fei Zhang
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China
- State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
| | - Hongbo Lou
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China
| | - Benyuan Cheng
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China
- China Academy of Engineering Physics, Mianyang 621900, China
| | - Zhidan Zeng
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China
| | - Qiaoshi Zeng
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China
- Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing 211189, China
- Correspondence: ; Tel.: +86-021-8017-7102
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40
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Jo YH, Choi WM, Kim DG, Zargaran A, Sohn SS, Kim HS, Lee BJ, Kim NJ, Lee S. FCC to BCC transformation-induced plasticity based on thermodynamic phase stability in novel V 10Cr 10Fe 45Co xNi 35-x medium-entropy alloys. Sci Rep 2019; 9:2948. [PMID: 30814569 PMCID: PMC6393512 DOI: 10.1038/s41598-019-39570-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 01/21/2019] [Indexed: 11/09/2022] Open
Abstract
We introduce a novel transformation-induced plasticity mechanism, i.e., a martensitic transformation from fcc phase to bcc phase, in medium-entropy alloys (MEAs). A VCrFeCoNi MEA system is designed by thermodynamic calculations in consideration of phase stability between bcc and fcc phases. The resultantly formed bcc martensite favorably contributes to the transformation-induced plasticity, thereby leading to a significant enhancement in both strength and ductility as well as strain hardening. We reveal the microstructural evolutions according to the Co-Ni balance and their contributions to a mechanical response. The Co-Ni balance plays a leading role in phase stability and consequently tunes the cryogenic-temperature strength-ductility balance. The main difference from recently-reported metastable high-entropy dual-phase alloys is the formation of bcc martensite as a daughter phase, which shows significant effects on strain hardening. The hcp phase in the present MEA mostly acts as a nucleation site for the bcc martensite. Our findings demonstrate that the fcc to bcc transformation can be an attractive route to a new MEA design strategy for improving cryogenic strength-ductility.
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Affiliation(s)
- Y H Jo
- Center for High Entropy Alloys, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - W M Choi
- Center for High Entropy Alloys, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - D G Kim
- Center for High Entropy Alloys, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - A Zargaran
- Graduate Institute of Ferrous Technology, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - S S Sohn
- Center for High Entropy Alloys, Pohang University of Science and Technology, Pohang, 790-784, Korea.
| | - H S Kim
- Center for High Entropy Alloys, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - B J Lee
- Center for High Entropy Alloys, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - N J Kim
- Graduate Institute of Ferrous Technology, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - S Lee
- Center for High Entropy Alloys, Pohang University of Science and Technology, Pohang, 790-784, Korea
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41
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Bu Y, Li Z, Liu J, Wang H, Raabe D, Yang W. Nonbasal Slip Systems Enable a Strong and Ductile Hexagonal-Close-Packed High-Entropy Phase. PHYSICAL REVIEW LETTERS 2019; 122:075502. [PMID: 30848647 DOI: 10.1103/physrevlett.122.075502] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Indexed: 06/09/2023]
Abstract
Linear defects, referred to as dislocations, determine the strength, formability, and toughness of crystalline metallic alloys. The associated deformation mechanisms are well understood for traditional metallic materials consisting of one or two prevalent matrix elements such as steels or aluminum alloys. In the recently developed high-entropy alloys (HEAs) containing multiple principal elements, the relationship between dislocations and the mechanical behavior is less understood. Particularly HEAs with a hexagonal close-packed (hcp) structure can suffer from intrinsic brittleness due to their insufficient number of slip systems. Here we report on the surprisingly high formability of a novel high-entropy phase with hcp structure. Through in situ tensile testing and postmortem characterization by transmission electron microscopy we reveal that the hcp phase in a dual-phase HEA (Fe_{50}Mn_{30}Co_{10}Cr_{10}, at. %) activates three types of dislocations, i.e., ⟨a⟩, ⟨c⟩, and ⟨c+a⟩. Specifically, nonbasal ⟨c+a⟩ dislocations occupy a high line fraction of ∼31% allowing for frequent double cross slip which explains the high deformability of this high-entropy phase. The hcp structure has a c/a ratio of 1.616, i.e., below the ideal value of 1.633. This modest change in the structure parameters promotes nonbasal ⟨c+a⟩ slip, suggesting that ductile HEAs with hcp structure can be designed by shifting the c/a ratio into regimes where nonbasal slip systems are activated. This simple alloy design principle is particularly suited for HEAs due to their characteristic massive solid solution content which readily allows tuning the c/a ratio of hcp phases into regimes promoting nonbasal slip activation.
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Affiliation(s)
- Yeqiang Bu
- School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
- Center for X-mechanics, Zhejiang University, Hangzhou 310027, China
| | - Zhiming Li
- Max-Planck-Institut für Eisenforschung, Max-Planck-Straβe 1, 40237 Düsseldorf, Germany
| | - Jiabin Liu
- School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
- Center for X-mechanics, Zhejiang University, Hangzhou 310027, China
| | - Hongtao Wang
- Institute of Applied Mechanics, Zhejiang University, Hangzhou 310027, China
- Center for X-mechanics, Zhejiang University, Hangzhou 310027, China
| | - Dierk Raabe
- Max-Planck-Institut für Eisenforschung, Max-Planck-Straβe 1, 40237 Düsseldorf, Germany
| | - Wei Yang
- Institute of Applied Mechanics, Zhejiang University, Hangzhou 310027, China
- Center for X-mechanics, Zhejiang University, Hangzhou 310027, China
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Elemental Phase Partitioning in the γ-γ″ Ni 2CoFeCrNb 0.15 High Entropy Alloy. ENTROPY 2018; 20:e20120910. [PMID: 33266634 PMCID: PMC7512494 DOI: 10.3390/e20120910] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/15/2018] [Accepted: 11/16/2018] [Indexed: 11/20/2022]
Abstract
The partitioning of the alloying elements into the γ″ nanoparticles in a Ni2CoFeCrNb0.15 high entropy alloy was studied by the combination of atom probe tomography and first-principles calculations. The atom probe tomography results show that the Co, Fe, and Cr atoms incorporated into the Ni3Nb-type γ″ nanoparticles but their partitioning behaviors are significantly different. The Co element is much easier to partition into the γ″ nanoparticles than Fe and Cr elements. The first-principles calculations demonstrated that the different partitioning behaviors of Co, Fe and Cr elements into the γ″ nanoparticles resulted from the differences of their specific chemical potentials and bonding states in the γ″ phase.
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Zhang F, Tong Y, Jin K, Bei H, Weber WJ, Zhang Y. Lattice Distortion and Phase Stability of Pd-Doped NiCoFeCr Solid-Solution Alloys. ENTROPY 2018; 20:e20120900. [PMID: 33266624 PMCID: PMC7512485 DOI: 10.3390/e20120900] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 11/16/2022]
Abstract
In the present study, we have revealed that (NiCoFeCr)100−xPdx (x= 1, 3, 5, 20 atom%) high-entropy alloys (HEAs) have both local- and long-range lattice distortions by utilizing X-ray total scattering, X-ray diffraction, and extended X-ray absorption fine structure methods. The local lattice distortion determined by the lattice constant difference between the local and average structures was found to be proportional to the Pd content. A small amount of Pd-doping (1 atom%) yields long-range lattice distortion, which is demonstrated by a larger (200) lattice plane spacing than the expected value from an average structure, however, the degree of long-range lattice distortion is not sensitive to the Pd concentration. The structural stability of these distorted HEAs under high-pressure was also examined. The experimental results indicate that doping with a small amount of Pd significantly enhances the stability of the fcc phase by increasing the fcc-to-hcp transformation pressure from ~13.0 GPa in NiCoFeCr to 20–26 GPa in the Pd-doped HEAs and NiCoFeCrPd maintains its fcc lattice up to 74 GPa, the maximum pressure that the current experiments have reached.
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Affiliation(s)
- Fuxiang Zhang
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831, USA
- Correspondence: ; Tel.: +01-865-574-0835
| | - Yang Tong
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831, USA
| | - Ke Jin
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831, USA
| | - Hongbin Bei
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831, USA
| | - William J. Weber
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831, USA
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Yanwen Zhang
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831, USA
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Zhuang YX, Zhang XL, Gu XY. Effect of Annealing on Microstructure and Mechanical Properties of Al 0.5CoCrFeMo xNi High-Entropy Alloys. ENTROPY 2018; 20:e20110812. [PMID: 33266536 PMCID: PMC7512363 DOI: 10.3390/e20110812] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 10/16/2018] [Accepted: 10/19/2018] [Indexed: 11/16/2022]
Abstract
The effect of annealing temperature on the microstructure, phase constituents and mechanical properties of Al0.5CoCrFeMoxNi high-entropy complex alloys has been investigated at a fixed annealing time (10 h). The 600 °C-annealing has no obvious effect on their microstructures, while the annealing at 800–1200 °C enhances the precipitation of (Al,Ni)-rich ordered BCC phase or/and (Cr,Mo)-rich σ phase, and thereby greatly affects the microstructure and mechanical properties of the alloys. All the annealed Al0.5CoCrFeNi alloys are composed of FCC and (Al,Ni)-rich ordered BCC phases; the phase constituent of the Al0.5CoCrFeMo0.1Ni alloy changes from FCC + BCC (600 °C) to FCC + BCC + σ (800 °C) and then to FCC + BCC (1100 °C); the phase constituents of the Al0.5CoCrFeMo0.2Ni and Al0.5CoCrFeMo0.3Ni alloys change from FCC + BCC + σ to FCC + BCC with the annealing temperature rising from 600 to 1200 °C; while all the annealed Al0.5CoCrFeMo0.4Ni and Al0.5CoCrFeMo0.5Ni alloys consist of FCC, BCC and σ phases. The phase constituents of most of the alloys investigated are in good agreement with the calculated results from Thermo-Calc program. The alloys annealed at 800 °C under current investigation conditionshave relative fine precipitations and microstructure, and thereby higher hardness and yield stress.
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Dong Z, Schönecker S, Li W, Chen D, Vitos L. Thermal spin fluctuations in CoCrFeMnNi high entropy alloy. Sci Rep 2018; 8:12211. [PMID: 30111892 PMCID: PMC6093928 DOI: 10.1038/s41598-018-30732-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/09/2018] [Indexed: 11/09/2022] Open
Abstract
High entropy alloys based on 3d transition metals display rich and promising magnetic characteristics for various high-technology applications. Understanding their behavior at finite temperature is, however, limited by the incomplete experimental data for single-phase alloys. Here we use first-principles alloy theory to investigate the magnetic structure of polymorphic CoCrFeMnNi in the paramagnetic state by accounting for the longitudinal spin fluctuations (LSFs) as a function of temperature. In both face-centered cubic (fcc) and hexagonal close-packed (hcp) structures, the LSFs induce sizable magnetic moments for Co, Cr and Ni. The impact of LSFs is demonstrated on the phase stability, stacking fault energy and the fcc-hcp interfacial energy. The hcp phase is energetically preferable to the fcc one at cryogenic temperatures, which results in negative stacking fault energy at these conditions. With increasing temperature, the stacking fault energy increases, suppressing the formation of stacking faults and nano-twins. Our predictions are consistent with recent experimental findings.
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Affiliation(s)
- Zhihua Dong
- Applied Materials Physics, Department of Materials Science and Engineering, KTH-Royal Institute of Technology, Stockholm, SE, 10044, Sweden.
| | - Stephan Schönecker
- Applied Materials Physics, Department of Materials Science and Engineering, KTH-Royal Institute of Technology, Stockholm, SE, 10044, Sweden.
| | - Wei Li
- Applied Materials Physics, Department of Materials Science and Engineering, KTH-Royal Institute of Technology, Stockholm, SE, 10044, Sweden
| | - Dengfu Chen
- College of Materials Science and Engineering, Chongqing University, Chongqing, 400030, P.R. China
| | - Levente Vitos
- Applied Materials Physics, Department of Materials Science and Engineering, KTH-Royal Institute of Technology, Stockholm, SE, 10044, Sweden. .,Department of Physics and Astronomy, Division of Materials Theory, Uppsala University, Box 516, SE, 75121, Uppsala, Sweden. .,Research Institute for Solid State Physics and Optics, Wigner Research Center for Physics, P.O. Box 49, H-1525, Budapest, Hungary.
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Li X, Irving DL, Vitos L. First-principles investigation of the micromechanical properties of fcc-hcp polymorphic high-entropy alloys. Sci Rep 2018; 8:11196. [PMID: 30046064 PMCID: PMC6060180 DOI: 10.1038/s41598-018-29588-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 07/09/2018] [Indexed: 11/25/2022] Open
Abstract
High-entropy alloys offer a promising alternative in several high-technology applications concerning functional, safety and health aspects. Many of these new alloys compete with traditional structural materials in terms of mechanical characteristics. Understanding and controlling their properties are of the outmost importance in order to find the best single- or multiphase solutions for specific uses. Here, we employ first-principles alloy theory to address the micro-mechanical properties of five polymorphic high-entropy alloys in their face-centered cubic (fcc) and hexagonal close-packed (hcp) phases. Using the calculated elastic parameters, we analyze the mechanical stability, elastic anisotropy, and reveal a strong correlation between the polycrystalline moduli and the average valence electron concentration. We investigate the ideal shear strength of two selected alloys under shear loading and show that the hcp phase possesses more than two times larger intrinsic strength than that of the fcc phase. The derived half-width of the dislocation core predicts a smaller Peierls barrier in the fcc phase confirming its increased ductility compared to the hcp one. The present theoretical findings explain a series of important observations made on dual-phase alloys and provide an atomic-level knowledge for an intelligent design of further high-entropy materials.
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Affiliation(s)
- Xiaoqing Li
- Department of Materials Science and Engineering, KTH-Royal Institute of Technology, 10044, Stockholm, Sweden.
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina, 27695, USA.
- Research Institute for Solid State Physics and Optics, Wigner Research Center for Physics, P.O. Box 49, Budapest, H-1525, Hungary.
| | - Douglas L Irving
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina, 27695, USA
| | - Levente Vitos
- Department of Materials Science and Engineering, KTH-Royal Institute of Technology, 10044, Stockholm, Sweden
- Research Institute for Solid State Physics and Optics, Wigner Research Center for Physics, P.O. Box 49, Budapest, H-1525, Hungary
- Department of Physics and Astronomy, Division of Materials Theory, Uppsala University, Box 516, SE-75120, Uppsala, Sweden
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47
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Bönisch M, Wu Y, Sehitoglu H. Twinning-induced strain hardening in dual-phase FeCoCrNiAl 0.5 at room and cryogenic temperature. Sci Rep 2018; 8:10663. [PMID: 30006547 PMCID: PMC6045582 DOI: 10.1038/s41598-018-28784-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 06/21/2018] [Indexed: 11/09/2022] Open
Abstract
A face-centered-cubic (fcc) oriented FeCoCrNiAl0.5 dual-phase high entropy alloy (HEA) was plastically strained in uniaxial compression at 77K and 293K and the underlying deformation mechanisms were studied. The undeformed microstructure consists of a body-centered-cubic (bcc)/B2 interdendritic network and precipitates embedded in 〈001〉-oriented fcc dendrites. In contrast to other dual-phase HEAs, at both deformation temperatures a steep rise in the stress-strain curves occurs above 23% total axial strain. As a result, the hardening rate associated saturates at the unusual high value of ~6 GPa. Analysis of the strain partitioning between fcc and bcc/B2 by digital image correlation shows that the fcc component carries the larger part of the plastic strain. Further, electron backscatter diffraction and transmission electron microscopy evidence ample fcc deformation twinning both at 77K and 293K, while slip activity only is found in the bcc/B2. These results may guide future advancements in the design of novel alloys with superior toughening characteristics.
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Affiliation(s)
- M Bönisch
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206W. Green St., Urbana, IL, 61801, USA
| | - Y Wu
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206W. Green St., Urbana, IL, 61801, USA
| | - H Sehitoglu
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206W. Green St., Urbana, IL, 61801, USA.
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Abstract
Twinning is a fundamental mechanism behind the simultaneous increase of strength and ductility in medium- and high-entropy alloys, but its operation is not yet well understood, which limits their exploitation. Since many high-entropy alloys showing outstanding mechanical properties are actually thermodynamically unstable at ambient and cryogenic conditions, the observed twinning challenges the existing phenomenological and theoretical plasticity models. Here, we adopt a transparent approach based on effective energy barriers in combination with first-principle calculations to shed light on the origin of twinning in high-entropy alloys. We demonstrate that twinning can be the primary deformation mode in metastable face-centered cubic alloys with a fraction that surpasses the previously established upper limit. The present advance in plasticity of metals opens opportunities for tailoring the mechanical response in engineering materials by optimizing metastable twinning in high-entropy alloys. Twinning has been experimentally seen in high-entropy alloys, but understanding how it operates remains a challenge. Here, the authors show that twinning can be a primary deformation mechanism in three well-known medium- and high-entropy alloys that have unstable face-centered cubic lattices.
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49
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Coury FG, Clarke KD, Kiminami CS, Kaufman MJ, Clarke AJ. High Throughput Discovery and Design of Strong Multicomponent Metallic Solid Solutions. Sci Rep 2018; 8:8600. [PMID: 29872065 PMCID: PMC5988724 DOI: 10.1038/s41598-018-26830-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/14/2018] [Indexed: 11/09/2022] Open
Abstract
High Entropy Alloys (HEAs) are new classes of structural metallic materials that show remarkable property combinations. Yet, often times interesting compositions are still found by trial and error. Here we show an "Effective Atomic Radii for Strength" (EARS) methodology, together with different semi-empirical and first-principle models, can be used to predict the extent of solid solution strengthening to discover and design new HEAs with unprecedented properties. We have designed a Cr45Ni27.5Co27.5 alloy with a yield strength over 50% greater with equivalent ductility than the strongest HEA (Cr33.3Ni33.3Co33.3) from the CrMnFeNiCo family reported to date. We show that values determined by the EARS methodology are more physically representative of multicomponent concentrated solid solutions. Our methodology permits high throughput, property-driven discovery and design of HEAs, enabling the development of future high-performance advanced materials for extreme environments.
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Affiliation(s)
- Francisco G Coury
- Center for Advanced Non-Ferrous Structural Alloys, George S. Ansell Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO, 80401, USA
| | - Kester D Clarke
- Center for Advanced Non-Ferrous Structural Alloys, George S. Ansell Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO, 80401, USA
| | - Claudio S Kiminami
- Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rodovia Washington Luís, km 235, São Carlos, SP, 13565-905, Brazil
| | - Michael J Kaufman
- Center for Advanced Non-Ferrous Structural Alloys, George S. Ansell Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO, 80401, USA
| | - Amy J Clarke
- Center for Advanced Non-Ferrous Structural Alloys, George S. Ansell Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO, 80401, USA.
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50
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Niu C, LaRosa CR, Miao J, Mills MJ, Ghazisaeidi M. Magnetically-driven phase transformation strengthening in high entropy alloys. Nat Commun 2018; 9:1363. [PMID: 29636478 PMCID: PMC5893566 DOI: 10.1038/s41467-018-03846-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 03/16/2018] [Indexed: 11/09/2022] Open
Abstract
CrCoNi alloy exhibits a remarkable combination of strength and plastic deformation, even superior to the CrMnFeCoNi high-entropy alloy. We connect the magnetic and mechanical properties of CrCoNi, via a magnetically tunable phase transformation. While both alloys crystallize as single-phase face-centered-cubic (fcc) solid solutions, we find a distinctly lower-energy phase in CrCoNi alloy with a hexagonal close-packed (hcp) structure. Comparing the magnetic configurations of CrCoNi with those of other equiatomic ternary derivatives of CrMnFeCoNi confirms that magnetically frustrated Mn eliminates the fcc-hcp energy difference. This highlights the unique combination of chemistry and magnetic properties in CrCoNi, leading to a fcc-hcp phase transformation that occurs only in this alloy, and is triggered by dislocation slip and interaction with internal boundaries. This phase transformation sets CrCoNi apart from the parent quinary, and its other equiatomic ternary derivatives, and provides a new way for increasing strength without compromising plastic deformation. Medium entropy alloy CoCrNi has better mechanical properties than high entropy alloys such as CrMnFeCoNi, but why that is remains unclear. Here, the authors show that a nanostructured phase at lattice defects in CoCrNi causes its extraordinary properties, while it is magnetically frustrated and suppressed in CrMnFeCoNi.
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Affiliation(s)
- Changning Niu
- Materials Science and Engineering, Ohio State University, 2041 College Rd, Columbus, OH, 43210, USA
| | - Carlyn R LaRosa
- Materials Science and Engineering, Ohio State University, 2041 College Rd, Columbus, OH, 43210, USA
| | - Jiashi Miao
- Materials Science and Engineering, Ohio State University, 2041 College Rd, Columbus, OH, 43210, USA
| | - Michael J Mills
- Materials Science and Engineering, Ohio State University, 2041 College Rd, Columbus, OH, 43210, USA
| | - Maryam Ghazisaeidi
- Materials Science and Engineering, Ohio State University, 2041 College Rd, Columbus, OH, 43210, USA.
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