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compositional complexity as a Design Principle for Stabilizing Magnetization Reversal in Corundum-Derived A 4Nb2O9 Phases

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CHEMISTRY OF MATERIALS 2024年第3期36卷 1753-1762页

作者： Martin, Christine Bolletta, Juan Pablo Maignan, Antoine Normandie Univ Lab CRISMAT ENSICAEN UNICAEN F-14050 Caen France

Corundum and related compounds possess interesting properties for functional applications, such as magnetization reversal or linear magneto electricity, depending on their structures and magnetic ground states. In this system, materials corresponding to the A(4)Nb(2)O(9) formula crystallize in two different structures, i.e., Pbcn for Ni4Nb2O9 and P3c1 for A = Co, Fe, and Mn, leading to ferrimagnetism and antiferromagnetism at low temperature, respectively. In this family, the nickel-based compound is special because Ni4Nb2O9 is the only one crystallizing in the orthorhombic structure. The Pbcn and P3c1 structures are both able to adapt to various substitutions of the A-cation, and as soon as Ni is involved, the two structural types are stabilized depending on the Ni/A ratio and A. In this context, the differences reported in the structural and magnetic behaviors of the Ni4-xCoxNb2O9 and Ni4-xZnxNb2O9 series motivated the (Ni/Co/Zn)(4)Nb2O9 study by mapping the magnetization-structure-composition phase diagram. This first step toward compositionally complex materials allows us to identify an unexpected large area of compounds that exhibit ferrimagnetism and magnetization reversal. Moreover, inside this domain, interesting variations of N & eacute;el temperature and compensation temperature are observed, including an increase of T-comp induced by nonmagnetic substituting cations. The originality of these structural and magnetic behaviors makes these materials promising for theoreticians to provide conceptual models, especially since the partial substitution of the magnetic cation by a d(0) one may enhance the magnetization reversal.

关键词： corundum compounds compositional complexity magnetization reversal linear magnetoelectric effect

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compositional complexity dependence of lattice distortion in FeNiCoCrMn high entropy alloy system

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MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING 2021年 823卷 141775-141775页

作者： Thirathipviwat, P. Sato, S. Song, G. Bednarcik, J. Nielsch, K. Han, J. Ibaraki Univ Frontier Res Ctr Appl Atom Sci Tokai Ibaraki 3191106 Japan Leibniz Inst Solid State & Mat Res IFW Dresden Helmholtzstr 20 D-01069 Dresden Germany Ibaraki Univ Grad Sch Sci & Engn 4-12-1 Nakanarusawa Hitachi Ibaraki 3168511 Japan Kongju Natl Univ Div Adv Mat Engn Cheonan 330717 Chungnam South Korea Kongju Natl Univ Inst Rare Met Cheonan 330717 Chungnam South Korea Pavol Jozef Safarik Univ Kosice Inst Phys Kosice 04154 Slovakia DESY Notkestr 8 D-22607 Hamburg Germany Korea Inst Ind Technol KITECH Korea Inst Rare Met Incheon 21999 South Korea

Based on the hypothesis of lattice distortion, compositional complexity of high entropy alloys (HEAs) induces severe lattice distortion. Recent studies on the experimental and theoretical approaches to lattice distortion have been made to evaluate this hypothesis. However, the understanding of this effect is not complete due to their highly complex compositions and limited direct evidence. This work was designed to systematically study the effect of compositional complexity from unary to quinary compositions (Ni, FeNi, FeNiCo, FeNiCoCr and FeNiCoCrMn). To focus on the effect of interactions between constituent elements, the microstructural effect was minimized by controlling similar microstructural features such as grain size and residual strain. The micro lattice strain was evaluated on X-ray line profile analysis using the Williamson-Hall method and the local lattice strain was assessed by using pair distribution function (PDF) method through the total scattering data using the synchrotron X-ray diffraction measurement. Analysis on both the micro and local scales indicates that severe lattice distortion is not evident in FeNiCoCrMn HEA. Lattice strain and solid solution hardening are comparable between FeNiCoCrMn HEA and its sub-alloys. The high compositional complexity of FeNiCoCrMn HEA does not lead to a strong effect on lattice strain and solid solution hardening.

关键词： High entropy alloys compositional complexity Lattice distortion Pair distribution function Line profile analysis Solid solution hardening

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Low thermal conductivity of dense(TiZrHfVNbTa)C_(x) high-entropy carbides by tailoring carbon stoichiometry

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Journal of Advanced Ceramics 2023年第1期12卷 49-58页

作者： Lei CHEN Wen ZHANG Wenyu LU Boxin WEI Sijia HUO Yujin WANG Yu ZHOU Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China Key Laboratory of Advanced Structural–Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150001China

Transition metal carbides are promising candidates for thermal protection materials due to their high melting points and excellent mechanical ***,the relatively high thermal conductivity is still a major obstacle to its application in an ultra-high-temperature insulation *** this work,the low thermal conductivity of dense(TiZrHfVNbTa)Cx(x=0.6-1)high-entropy carbides has been realized by adjusting the carbon *** thermal conductivity gradually decreases from 10.6 W·m^(−1)·K^(−1) at room temperature to 6.4 W·m^(−1)·K^(−1) with carbon vacancies *** to enhanced scattering of phonons and electrons by the carbon vacancies,nearly full-dense(97.9%)(TiZrHfVNbTa)C_(0.6) possesses low thermal conductivity of 6.4 W·m^(−1)·K^(−1),thermal diffusivity of 2.3 mm^(2)·s^(−1),as well as electrical resistivity of 165.5μΩ·*** thermal conductivity of(TiZrHfVNbTa)C_(0.6) is lower than that of other quaternary and quinary high-entropy carbide ceramics,even if taking the difference of porosity into account in some cases,which is mainly attributed to compositional complexity and carbon *** provides a promising route to reduce the thermal conductivity of high-entropy carbides by increasing the number of metallic elements and carbon vacancies.

关键词： high-entropy carbides thermal conductivity compositional complexity carbon vacancies

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Stabilizing Fe-based nanocrystalline alloys via a high-entropy strategy

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JOURNAL OF ALLOYS AND COMPOUNDS 2022年第0期896卷 163138-163138页

作者： Liu, Tao He, Aina Wang, Anding Wang, Xinmin Zhang, Hua Ni, Hongwei Wuhan Univ Sci & Technol State Key Lab Refractories & Met Wuhan 430081 Peoples R China Chinese Acad Sci Ningbo Inst Mat Technol & Engn Key Lab Magnet Mat & Devices Ningbo 315201 Peoples R China Dongguan Univ Technol Sch Mat Sci & Engn Dongguan 523808 Peoples R China Wuhan Univ Sci & Technol Key Lab Ferrous Met & Resources Utilizat Minist Educ Wuhan 430081 Peoples R China

Fe-based nanocrystalline alloys with unique dual-nano-phase structure and superior magnetic softness have aroused tremendous interest, yet they generally suffer from the harsh annealing process due to the poor thermal stability. In this study, a high-entropy strategy was proposed to enhance the soft-magnetic property and nanostructure stability of Fe-based nanocrystalline alloys by adding P and C elements in the FeCuSiBPC alloy system. This alloying approach by complicating the composition will greatly increase the mixing entropy, which significantly increase the frequency factor for the formation of alpha-Fe grains and activation energy for the formation of compounds, which on one hand enhance the competition and soft impingement effects due to the increased number density of alpha-Fe grains, and on the other hand hinder the precipitation of compounds in the intergranular amorphous interphase due to the improved crystallization resistance. These both contribute to a thermodynamically and kinetically stable dual-nano-phase structure with fine alpha-Fe grains embedded in amorphous matrix. Following this strategy of nanostructure stabilization by tuning the compositional complexity, FeCuSiBPC alloy with enlarged processing window and enhanced soft-magnetic properties were successfully obtained. This high-entropy strategy can be applied in a verity of alloy systems to develop high performance nanocrystalline alloys with excellent thermal stability suitable for large-scale industrial processing. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Nanocrystalline alloy compositional complexity High entropy Thermal stability Soft magnetic property

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Single-Source Precursor Synthesis of a compositionally Complex Early Transitional Metal Carbonitride (Ti,Zr,Hf,Nb,Ta)NxC1-x

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ADVANCED ENGINEERING MATERIALS 2024年第18期26卷

作者： Teppala, Dharma Teja Bernauer, Jan Rashid, Aasir Pejic, Milan Zagorac, Dejan Matovic, Branko Ionescu, Emanuel Tech Univ Darmstadt Inst Mat Sci Otto Berndt Str 3 D-64287 Darmstadt Germany Univ Belgrade Vinca Inst Nucl Sci Dept Mat Sci Mike Petrov Alasa 12-14 Vinca 11351 Belgrade Serbia Fraunhofer IWKS Brentanostr 2a D-63755 Alzenau Germany

compositionally complex transitional metal nitrides are possible candidates for ultra-high temperature usage and are known for their superior properties due to the high configuration entropy. It is often difficult to synthesize pure metal nitrides in bulk, due to significant oxygen contamination;hence, they are synthesized mainly as thin films through magnetron sputtering, chemical vapor deposition or surface nitridation of high entropy alloys. The present article reports on a single-phase compositionally complex ceramic, i.e., (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)NxC1-x, that is synthesized for the first time by employing an organometallic precursor route and using a double ammonolysis process. A multidisciplinary approach is performed to study these compositionally complex nitride and carbonitride systems, including experimental and theoretical investigations.

关键词： ammonolysis compositional complexity DFT modeling nitrides

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Microstructural Evolution of compositionally Complex Alloys Under Heavy Ion Irradiation

Microstructural Evolution of Compositionally Complex Alloys ...

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作者： Parkin, Calvin A. The University of Wisconsin - Madison

学位级别：Ph.D., Doctor of Philosophy

To improve the alloy discovery and development process for radiation resistant nuclear structural materials, the new design parameter of an atomically disordered base matrix was investigated experimentally using heavy-ion irradiation. Candidate compositionally complex alloys (CCAs) were compared to less compositionally complex reference materials and conventional structural materials. Cr18Fe27Mn27Ni28, Cr15Fe35Mn15Ni35, and NbTaTiV were irradiated using in-situ transmission electron microscopy (TEM) at 50 K, 500 and 600 °C and compared to structurally similar but less compositionally complex reference materials. The cryogenic temperature irradiation allowed confirmation of a lower primary defect accumulation in CCAs with diffusion limited while higher temperature irradiations with and without a bubble-stabilizing He-environment characterized the extended defect evolution at the early nucleation and incubation stages of void formation. Void swelling was also lower in He-implanted CCAs compared to less complex reference materials, which was linked to faulted interstitial dislocation loop sink strength and stacking-fault energy. Bulk irradiations were performed at 50, 75, 100, 150, and 200 dpa using various temperatures to investigate the influence of compositional complexity and composition on the temperature and dose effect on void swelling. Cr18Fe27Mn27Ni28 and Cr15Fe35Mn15Ni35 both experienced redistribution of Mn with depth, indicating that vacancies exchange preferentially with Mn atoms as they diffuse along the vacancy gradient, while Ni became enriched in the areas near voids in all materials. Voids nucleate before 50 dpa in the plateau region in Cr18Fe27Mn27Ni28 while they nucleate deep beyond the damage peak in Cr15Fe35Mn15Ni35 by 75 dpa, and not in the plateau region until between 75-100 dpa. The swelling increase from 500 to 600 °C was far less in Cr15Fe35Mn15Ni35 than 316H stainless steel at 150 dpa. Cr15Fe35Mn15Ni35 outperformed Cr18Fe27Mn27Ni28 at variou

关键词： compositional complexity High-entropy alloy Irradiation Nuclear energy Stacking fault energy Void swelling

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High entropy ceramics for applications in extreme environments

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JOURNAL OF PHYSICS-MATERIALS 2024年第2期7卷 021001页

作者： Ward, T. Z. Wilkerson, R. P. Musico, B. L. Foley, A. Brahlek, M. Weber, W. J. Sickafus, K. E. Mazza, A. R. Mat Sci & Technol Div Oak Ridge Natl Lab Oak Ridge TN 37831 USA Sigma Div Alamos Natl Lab Los Alamos NM 87545 USA Los Alamos Natl Lab Mat Sci & Technol Div Los Alamos NM 87545 USA Univ Tennessee Dept Mat Sci & Engn Knoxville TN 37996 USA

compositionally complex materials have demonstrated extraordinary promise for structural robustness in extreme environments. Of these, the most commonly thought of are high entropy alloys, where chemical complexity grants uncommon combinations of hardness, ductility, and thermal resilience. In contrast to these metal-metal bonded systems, the addition of ionic and covalent bonding has led to the discovery of high entropy ceramics (HECs). These materials also possess outstanding structural, thermal, and chemical robustness but with a far greater variety of functional properties which enable access to continuously controllable magnetic, electronic, and optical phenomena. In this experimentally focused perspective, we outline the potential for HECs in functional applications under extreme environments, where intrinsic stability may provide a new path toward inherently hardened device design. Current works on high entropy carbides, actinide bearing ceramics, and high entropy oxides are reviewed in the areas of radiation, high temperature, and corrosion tolerance where the role of local disorder is shown to create pathways toward self-healing and structural robustness. In this context, new strategies for creating future electronic, magnetic, and optical devices to be operated in harsh environments are outlined.

关键词： high entropy materials extreme enviornments compositional complexity microelectronics radiation hardness

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The impact of vacancy formation energies on the nucleation and growth of helium (He) bubbles in low-activation multicomponent vanadium-based alloys

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MATERIALS TODAY COMMUNICATIONS 2023年 36卷

作者： Wang, Y. F. Chen, H. Q. Sun, B. R. Li, X. W. Meng, Q. N. Wu, Z. F. Hao, L. Y. Du, J. L. Liu, X. Shen, T. D. Zhang, J. Li, J. Fu, E. G. Peking Univ Sch Phys Dept Tech Phys State Key Lab Nucl Phys & Technol Beijing 100871 Peoples R China Yanshan Univ Clean Nano Energy Ctr State Key Lab Metastable Mat Sci & Technol Qinhuangdao 066004 Peoples R China China Univ Petr Coll New Energy & Mat Beijing 102249 Peoples R China Xiamen Univ Coll Energy Xiamen 361005 Peoples R China Harbin Inst Technol Inst Special Environm Phys Sci Shenzhen 518055 Peoples R China

Generally, the complexity of concentrated solid solution alloys (CSAs) can effectively enhance their radiation tolerance. We studied the effect of helium (He) ion irradiation on body centered cubic (BCC) V, VCr, VCrFe and VCrFeMn alloys with the increase of complexity. The comparison shows the void swelling in terms of the size and density of bubbles in V, VCrFe and VCrFeMn decreases with the increase of the complexity after the same He ion irradiation. However, binary VCr alloy has the smallest void swelling although it has only two types of elements, that is less complexity, which is significantly different from VCrFe and VCrFeMn subjected to the same He ion irradiation. Meanwhile, the irradiated VCr lattice exhibits almost no shrinkage. First-principles calculations reveal that the high vacancy formation energy (VFE) of VCr could prevent He-vacancy clusters from absorbing vacancies to grow. The results suggest that the VFE could play a more important role in enhancing the radiation tolerance under He ion irradiation in addition to the compositional complexity.

关键词： He ion irradiation High entropy alloy Concentrated solid solution alloys Vacancy formation energy compositional complexity

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Effects of temperature on helium cavity evolution in single-phase concentrated solid-solution alloys

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JOURNAL OF NUCLEAR MATERIALS 2021年 557卷 153261-153261页

作者： Liu, Shaofei Lin, Weitong Chen, Da Han, Bin Zhao, Shijun He, Feng Niu, Huan Kai, Ji-jung City Univ Hong Kong Dept Mech Engn Hong Kong Peoples R China Shaanxi Univ Sci & Technol Inst Atom & Mol Sci Xian 710021 Peoples R China Natl Tsing Hua Univ Nucl Sci & Technol Dev Ctr Accelerator Lab Hsinchu Taiwan City Univ Hong Kong Ctr Adv Nucl Safety & Sustainable Dev Hong Kong Peoples R China

Single-phase concentrated solid-solution alloys (SP-CSSAs) have shown great potential as structural ma-terials in advanced reactor systems. Up to date, nevertheless, the synergistic effect of compositional com-plexity and irradiation temperature on helium (He) irradiation-induced cavity formation has not been systematically studied yet. In this work, pure Ni and three prototype face-centered-cubic SP-CSSAs, i.e., NiCo, NiCoCr and NiCoFeCrMn, were irradiated with He + ions at 673, 773, 873 and 973 K. The evolution of He-induced cavities were investigated in detail with transmission electron microscopy. It was found that growth of He cavities was suppressed with increasing compositional complexity at 673 and 773 K. Due to the lower melting temperature, NiCoFeCrMn exhibited the strongest temperature susceptibility in terms of He cavity growth with the increasing temperature. Interestingly, the He cavity growth tended to be enhanced with increasing compositional complexity when the radiation temperature increaseed to 973 K, which can be attributed to the prominent chemical-biased vacancy migration at high temperatures. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Single-phase concentrated solid-solution alloys Helium irradiation Irradiation temperature compositional complexity He cavity

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Microstructure and composition engineering Yb single-filled CoSb_(3) for high thermoelectric and mechanical performances

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Journal of Materiomics 2019年第4期5卷 702-710页

作者： Zhenxing Zhou Matthias T.Agne Qihao Zhang Shun Wan Qingfeng Song Qing Xu Xiaofang Lu Shijia Gu Yuchi Fan Wan Jiang Gerald Jeffrey Snyder Lianjun Wang State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai201620China Department of Materials Science and Engineering Northwestern UniversityEvanstonIL60208USA State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai200050China Center for High Pressure Science and Technology Advanced Research(HPSTAR) Shanghai201203China University of Chinese Academy of Sciences 19 Yuquan RoadBeijing100049China Institute of Functional Materials Donghua UniversityShanghai201620China School of Material Science and Engineering Jingdezhen Ceramic InstituteJindezhen333000China

A broad tunability of the thermoelectric and mechanical properties of CoSb_(3) has been demonstrated by adjusting the composition with the addition of an increasing number of ***,such a strategy may negatively impact processing repeatability and composition *** this work,singleelement-filled skutterudite is engineered to have high thermoelectric and mechanical *** Yb filling fraction is found to increase phonon scattering,whereas cryogenic grinding contributes additional microstructural scattering.A peak zT of 1.55 and an average zT of about 1.09,which is comparable to the reported results of multiple-filled SKDs,are realized by the combination of simple composition and microstructure ***,the mechanical properties of Yb single-filled CoSb_(3) skutterudite are improved by manipulation of the microstructure through cryogenic *** findings highlight the realistic prospect of producing high-performance thermoelectric materials with reduced compositional complexity.

关键词： Skutterudites Thermoelectric material compositional complexity Microstructure engineering Cryogenic grinding

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