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Martensitic transformations in Ti-(16-26 at%) Nb alloys

JOURNAL OF materials science 1996年第16期31卷 4267-4276页

作者： Ahmed, T Rack, HJ Materials Science and Engineering Program Department of Mechanical Engineering Clemson University Clemson USA

Martensitic phase transformations in the solution-treated and water-quenched binary Ti-Nb alloys in the range of 16-26 at % Nb, were examined. An ordered, base-centred orthorhombic martensite was observed for alloys containing up to 23.4 at % Nb. The substructure of this martensite was generally composed of twins and stacking faults, the presence of antiphase boundaries observed in the plates indicating that the martensite underwent ordering during quenching. Both order-disorder and NJ,temperatures were. observed to be affected by total interstitial content, higher contents increasing both temperatures. Increasing the niobium content to above 23.4% resulted in retention of the beta phase, this phase containing either athermal omega or ''diffuse'' omega depending upon niobium and total interstitial concentration. Finally, the microhardness of the Ti-Nb alloys examined was observed to decrease with increase in niobium and decrease in total interstitial content.

关键词： Titanium alloys

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Supplementary information for "Low-loss silicon nitride Kerr-microresonators fabricated with metallic etch masks via metal lift-off"

arXiv

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arXiv 2025年

作者： Colación, Gabriel M. Rukh, Lala Buck, Franco Drake, Tara E. Optical Science & Engineering Program University of New Mexico AlbuquerqueNM87106 United States Center for High Technology Materials University of New Mexico AlbuquerqueNM87106 United States Department of Physics & Astronomy University of New Mexico AlbuquerqueNM87106 United States

Stoichiometric silicon nitride has emerged as a widely used integratedphotonic material owing to its high index of refraction, nonlinear opticalproperties, and broad transparency window spanning visible to mid-IRfrequencies. However, silicon nitride is generally more resistant to reactiveion etching than are typical etch masks made of polymer-based resist. Thisnecessitates resist layers that are significantly thicker than the siliconnitride and results in mask patterns which are tall and narrow. Thesehigh-aspect-ratio patterns inhibit the plasma transport of reactive ionetching, which leads to difficulties in accurately reproducing dimensions andcreating well-defined, vertical waveguide sidewalls. In this work, we overcomethese challenges by developing a metallic etch mask that provides a 30:1nitride-to-metal etch rate ratio, representing a near 20-fold reduction in therequired mask thickness. We demonstrate the quality of this technique byetching microring resonators with near-vertical waveguide sidewalls andintrinsic quality factors of over 1 million. Leveraging the low optical loss ofour resonators, we generate optical frequency combs with more than an octave ofbandwidth and dual dispersive waves. These results establish metal lift-off asa viable and easy-to-implement technique capable of producing low optical losswaveguides. © 2025, CC BY.

关键词： Aspect ratio

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Creating Sodium Ion Channels via De Novo Encapsulation of Ionophores for Enhanced Water Energy Harvesting

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Advanced materials 2025年第20期37卷 e2420636页

作者： Guo, Qing Xing, Zhiwei Guo, Huaxi Lai, Zhuozhi Yi, Jiaming Wu, Di Dai, Zhifeng Zhang, Li Wang, Sai Ma, Shengqian Sun, Qi Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological Engineering Zhejiang University Hangzhou310027 China Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province School of Chemistry and Chemical Engineering Zhejiang Sci-Tech University Hangzhou310018 China Hangzhou Institute of Advanced Studies Zhejiang Normal University Hangzhou311231 China Department of Chemistry University of North Texas 1508 W Mulberry St DentonTX76201 United States

Biological ion channels achieve remarkable permselectivity and cation discrimination through the synergy of their intricate architectures and specialized ionophores within confined nanospaces, enabling efficient energy conversion. Emulating such selectivity in synthetic nanochannels, however, remains a persistent challenge. To address this, a novel host-guest assembly membrane is developed by incorporating sodium-selective ionophores into a β-ketoenamine-linked covalent organic framework (COF). This design confers exceptional permselectivity and Na+ selectivity, achieving Na+/K+ and Na+/Li+ selectivity ratios of 3.6 and 103, respectively, along with near-perfect Na+/Cl− selectivity under a 0.5 M || 0.01 M salinity gradient. Notably, the membrane dynamically switches its permselectivity to favor anion transport in the presence of high-valent cations (e.g., Ca2+), overcoming limitations such as uphill cation diffusion and back currents observed in conventional cation-selective membranes. This adaptive behavior yields a 4.6-fold increase in output power density in Ca2+-rich environments. These findings advance the design of biomimetic nanochannels with unparalleled ion selectivity and enhanced energy conversion efficiency. © 2025 Wiley-VCH GmbH.

关键词： Ionophores

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Meter-scale heterostructure printing for high-toughness fiber electrodes in intelligent digital apparel

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Nature Communications 2025年第1期16卷 1-10页

作者： Lee, Gun-Hee Lee, Yunheum Seo, Hyeonyeob Jo, Kyunghyun Yeo, Jinwook Kim, Semin Bae, Jae-Young Kim, Chul Majidi, Carmel Kang, Jiheong Kang, Seung-Kyun Ryu, Seunghwa Park, Seongjun Medical Research Center Seoul National University Seoul South Korea Departments of Cogno-Mechatronics Engineering and Optics & Mechatronics Engineering Pusan National University Busan South Korea Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Program of Brain and Cognitive Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Graduate School of Semiconductor Technology Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Department of Materials Science and Engineering Seoul National University Seoul South Korea Department of Mechanical Engineering Carnegie Mellon University Pittsburgh PA United States Department of Chemistry Seoul National University Seoul Seoul South Korea School of Transdisciplinary Innovations Seoul National University Seoul South Korea Department of Biomedical Science College of Medicine Seoul National University Seoul South Korea Interdisciplinary Program in Bioengineering College of Engineering Seoul National University Seoul South Korea Department of Transdisciplinary Medicine Seoul National University Hospital Seoul South Korea

Intelligent digital apparel, which integrates electronic functionalities into clothing, represents the future of healthcare and ubiquitous control in wearable devices. Realizing such apparel necessitates developing meter-scale conductive fibers with high toughness, conductivity, stable conductance under deformation, and mechanical durability. In this study, we present a heterostructure printing method capable of producing meter-scale (~50 m) biphasic conductive fibers that meet these criteria. Our approach involves encapsulating deformable liquid metal particles (LMPs) within a functionalized thermoplastic polyurethane matrix. This encapsulation induces in situ assembly of LMPs during fiber formation, creating a heterostructure that seamlessly integrates the matrix’s durability with the LMPs’ superior electrical performance. Unlike rigid conductive materials, deformable LMPs offer stretchability and toughness with a low gauge factor. Through precise twisting using an engineered annealing machine, multiple fiber strands are transformed into robust, electrically stable meter-scale electrodes. This advancement enhances their practicality in various intelligent digital apparel applications, such as stretchable displays, wearable healthcare systems, and digital controls. © The Author(s) 2025.

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When graphite meets Li metal

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National science Review 2020年第10期7卷 1521-1522页

作者： Yu Ding Guihua Yu Materials Science and Engineering Program and Department of Mechanical Engineering The University of Texas at Austin

Wetting, indicating the ability of a liquid to spread out over solid surfaces,is of vital importance in addressing the scientific issues related to energy and environment technologies. The study of wetting encompasses the academic disciplines of surface chemistry, nanotechnology, materials science and energy *** past several decades have witnessed significant progress in achieving desirable wetting performance with water,

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Production of cobalt- and manganese-based oxide nanofibers via solution blow spinning: Structural properties and high-performance oxygen evolution reaction

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Applied Surface science 2025年 703卷

作者： Pereira, Thiago O. Raimundo, Rafael A. Alves, Ricardo F. Morales, Marco A. Simões, Thiago A. Medeiros, Eliton S. Macedo, Daniel A. Dutra, Ricardo P.S. Materials Science and Engineering Postgraduate Program Federal University of Paraíba PB João Pessoa58051-900 Brazil TEMA – Centre for Mechanical Technology and Automation Department of Mechanical Engineering University of Aveiro Aveiro3810-193 Portugal Department of Mechanical Engineering Federal University of Paraíba PB João Pessoa58051-900 Brazil Department of Theoretical and Experimental Physics Federal University of Rio Grande do Norte Natal59078-970 Brazil Cabo de Santo Agostinho PE 54518-430 Brazil Department of Materials Engineering Federal University of Paraíba PB João Pessoa58051-900 Brazil

Cobalt- and manganese-based oxides (Co3O4, MnCo2O4, and CoMn2O4) with nanofiber-like morphology were successfully synthesized via solution blow spinning (SBS) and evaluated as electrocatalysts for the oxygen evolution reaction (OER). The structural, morphological, and surface properties of the prepared materials were investigated through x-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Fourier-transform infrared (FTIR), Raman spectroscopy, x-ray photoelectron spectra (XPS), and magnetic measurements. The magnetic characterization of MnCo2O4, CoMn2O4, and Co3O4 confirmed their phase purity and expected magnetic behavior. MnCo2O4 exhibited ferromagnetic ordering (θ = +145 K) with Hc = 8200 Oe and Ms = 11.9 emu/g at 5 K. CoMn2O4 showed multiple transitions at 178 K, 169 K, and 81 K, suggesting ferrimagnetic ordering. Co3O4 displayed antiferromagnetic behavior with a Néel temperature of 37 K. These results corroborate with the literature, validating the synthesis and characterization. X-ray photoelectron spectroscopy (XPS) analysis confirmed the oxidation states of Co and Mn and the presence of oxygen vacancies in CoMn2O4, MnCo2O4, and Co3O4. The Oads/Olats ratio indicated a higher concentration of oxygen vacancies in CoMn2O4 (1.21), while MnCo2O4 exhibited the highest Mn4+ content (Mn4+/Mn3+ = 0.76). The Co3+/Co2+ ratio was higher in MnCo2O4 (1.94), suggesting enhanced oxidation stability. The electrochemical characterization for OER in 1 M KOH electrolyte of the CoMn2O4, MnCo2O4, and Co3O4 samples displayed overpotentials of 330, 348, and 375 mV, respectively, to achieve a current density of 10 mA cm−2. Cyclic voltammetry and electrochemical impedance spectroscopy further corroborate these findings. The electrodes exhibited great stability maintaining their performance for 20 h. A detailed surface chemistry analysis showed that oxygen vacancy-rich samples exhibited enhanced charge transfer and generated Mn catalytic sites that facilitated

关键词： Fourier transform infrared spectroscopy

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Macromolecule-Enriched Solvation Enabling High-Voltage Sodium-Ion Batteries

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Angewandte Chemie 2025年

作者： Zhiming Zhao Chen Liu Tianxing Lai Zehao Cui Arumugam Manthiram Materials Science and Engineering Program and Walker Department of Mechanical Engineering The University of Texas at Austin Austin TX 78712 USA

Sodium-ion batteries (SIBs) are emerging as a viable alternative for sustainable and cost-effective energy storage, yet their energy density is curtailed by relatively low voltage outputs (< 4 V) due to the lack of high-voltage electrolytes. Here, for the first time, we describe a high-voltage Na + electrolyte featuring a macromolecule-enriched solvation architecture. The vulnerable small molecules in the Na + solvation shell are replaced by macro polyamide (PA) molecules with high thermodynamic resilience, ensuring a wide electrochemical stability window for the electrolytes with suppressed oxidative/reductive decomposition. Concomitantly, the anions engage in H-bonding with the amido groups of PA, which not only stabilizes the anions against hydrolysis, but also delivers a high Na + transference number of 0.93. Importantly, the nitrogen-rich composition of the macromolecule-enriched electrolyte (MEE) fosters the formation of robust nitride interphases that impart enduring stability to both the cathode and anode. As a result, the hard carbon (HC) || NaNi 1/3 Fe 1/3 Mn 1/3 O 2 (NFM) full cells demonstrate significant rechargeability even with an ultrahigh cutoff voltage of 4.4 V. Our approach distinctively avoids the use of fluorinated molecules typically found in (localized-) high-concentration electrolytes, presenting a novel principle that could revolutionize high-voltage electrolyte design.

关键词： Hard carbon anode High-voltage electrolyte Layered oxide cathode Sodium-ion batteries Solvation structure

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Enhanced output performance in paper-based piezoelectric nanogenerators via polarization-engineered Schottky barrier contacts

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Journal of materials Chemistry C 2025年

作者： Wang, Ping Xin, Haoyang Wang, Xiuli Luo, Jingyu Xu, Ruiqi Wang, Zhigang Wang, Zhanhua Zhang, Sufeng Sun, Zixiong Jung, Jong Hoon School of Electronic Information and Artificial Intelligence Shaanxi University of Science and Technology Xi’an 710021 China Engineering Research Center of Eco-friendly Polymeric Materials Ministry of Education Sichuan University Chengdu 610065 China School of Materials Science and Engineering Shaanxi University of Science and Technology Xi’an 710021 China Shandong Provincial Engineering Research Center of Organic Functional Materials and Green Low-Carbon Technology Dezhou University Dezhou 253023 China State Key Laboratory of Polymer Materials Engineering (Sichuan University) Chengdu 610065 China Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development National Demonstration Center for Experimental Light Chemistry Engineering Education China Department of Physics Inha University Incheon 22212 South Korea Program in Semiconductor Convergence Inha University Incheon 22212 South Korea Physics Research Institute Inha University Incheon 22212 South Korea

Cellulose, owing to its abundant natural availability and excellent mechanical properties, is considered an ideal alternative to petroleum-based polymers in the fabrication of piezoelectric nanogenerators (PENGs). In this study, we fabricated PENGs with a matrix composed of 80% cellulose and 20% PVDF by mass, incorporating KNN ceramics with varying components as fillers. The films exhibited a dense structure with uniform distribution of KNN fillers, facilitated by hydrogen bonding between the cellulose, PVDF, and KNN. The piezoelectric output performance was significantly enhanced by the piezoelectric polarization-induced Schottky barrier contact and the additional triboelectric contribution from the interaction between the film and PDMS, as elucidated using band theory and two distinct connection modes. Among the PENGs, the C8P2-KNN46 device demonstrated the highest piezoelectric output, achieving a peak power density (P_D) of 12.81 μW cm⁻² under a 10 N force, surpassing most other paper-based PENGs. Furthermore, the contributions of piezoelectric and triboelectric mechanisms were clearly identified. In addition to its impressive piezoelectric performance, the C8P2-KNN46 PENG exhibited excellent mechanical properties, high hydrophobicity, and long-term reliability. Notably, the device was capable of lighting a 3 V LED with simple bending, highlighting its significant potential for next-generation passive devices. © 2025 The Royal Society of Chemistry.

关键词： Piezoelectric devices

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Three-dimensional construction of hyperuniform, nonhyperuniform, and antihyperuniform disordered heterogeneous materials and their transport properties via spectral density functions

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Physical Review E 2025年第3期111卷 035310-035310页

作者： Wenlong Shi Yang Jiao Salvatore Torquato Materials Science and Engineering Arizona State University Tempe Arizona 85287 USA Department of Physics Arizona State University Tempe Arizona 85287 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Institute of Materials Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Rigorous theories connecting physical properties of a heterogeneous material to its microstructure offer a promising avenue to guide the computational material design and optimization. The spectral density function χ̃V(k), which can be obtained experimentally from scattering data, enables accurate determination of various transport and wave propagation characteristics, including the time-dependent diffusion spreadability S(t) and effective dynamic dielectric constant εe for electromagnetic wave propagation. Moreover, χ̃V(k) determines rigorous upper bounds on the fluid permeability K. Given the importance of χ̃V(k), we present here an efficient Fourier-space based computational framework to construct three-dimensional (3D) statistically isotropic two-phase heterogeneous materials corresponding to targeted spectral density functions. In particular, we employ a variety of analytical functional forms for χ̃V(k) that satisfy all known necessary conditions to construct disordered stealthy hyperuniform, standard hyperuniform, nonhyperuniform, and antihyperuniform two-phase heterogeneous material systems at varying phase volume fractions. We show that by tuning the correlations in the system across length scales via the targeted functions, one can generate a rich spectrum of distinct structures within each of the above classes of materials. Importantly, we present the first realization of antihyperuniform two-phase heterogeneous materials in 3D, which are characterized by autocovariance function χV(r) with a power-law tail, resulting in microstructures that contain clusters of dramatically different sizes and morphologies. We also determine the diffusion spreadability S(t) and estimate the fluid permeability K associated with all of the constructed materials directly from the corresponding spectral densities. Although it is well established that the long-time asymptotic scaling behavior of S(t) only depends on the functional form of χ̃V(k), with the stealthy hyperuniform a

关键词： Spectral density

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Deciphering the Impact of Polysulfide Solvation Structure on Electrical Double Layer Chemistry in Sodium–Sulfur Batteries

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Angewandte Chemie 2025年

作者： Weiqi Yao Min-Hao Pai Arumugam Manthiram Materials Science and Engineering Program & Walker Department of Mechanical Engineering The University of Texas at Austin Austin Texas 78712 USA

Room-temperature sodium–sulfur (RT Na–S) batteries are garnering attention for large-scale energy storage. However, their practical application is hindered by challenges, such as the shuttle effect of sodium polysulfides (NaPS) and dendrite growth. The high solubility of NaPS in the electrolyte is particularly problematic. It disrupts electron transfer and obstructs mass transport in the electrical double layer (EDL) region. The EDL plays a pivotal role in governing the interfacial chemistry between the electrode and electrolyte, significantly impacting the overall electrochemical performance. Through simulations and experimental screening of various solvents, including 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), and tetrahydropyran (THP), along with ethyl 1,1,2,2-tetrafluoroethyl ether (ETFE) as a diluent, the relationship between NaPS solvation structure and EDL chemistry has been elucidated. Our findings reveal that THP-based localized high-concentration electrolyte (LHCE) not only reduces the solubility of NaPS by altering its solvation structure but also promotes the formation of a stable inorganic solid-electrolyte interphase (SEI) and improves compatibility with sodium metal. Consequently, Na–S batteries with LHCE-THP/ETFE exhibit long-term stability over 500 cycles at 1C rate with a capacity decay rate of only 0.07% per cycle. This study provides a methodology for designing electrolytes based on molecular structure, polysulfide solvation properties, and EDL interfacial chemistry.

关键词： Electrical double layer Electrolytes Polysulfide solvation structure Shuttle effect Sodium–sulfur batteries

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