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Microstructure evolution and local strengthening mechanisms in CoCrFeMnNi high entropy alloy joints reinforced with Inconel 625

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materials science and engineering: A 2025年 937卷

作者： Shen, Jiajia Yang, Jin Choi, Yeon Taek Gonçalves, Rita Pedro, Rodrigo Santana, D.A. Coury, F.G. Schell, N. Zeng, Zhi Kim, Hyoung Seop Oliveira, J.P. UNIDEMI Department of Mechanical and Industrial Engineering NOVA School of Science and Technology Universidade NOVA de Lisboa Caparica2829-516 Portugal CENIMAT/I3N Department of Materials Science NOVA School of Science and Technology Universidade NOVA de Lisboa Caparica2829-516 Portugal School of Materials Engineering Shanghai University of Engineering Science Shanghai201620 China Pohang790-794 Korea Republic of Graduate Program in Materials Science and Engineering Federal University of São Carlos Rodovia Washington Luís km 235 SP-310 São Carlos São Paulo13565-905 Brazil Helmholtz-Zentrum Hereon Institute of Materials Physics Max-Planck-Str. 1 Geesthacht21502 Germany School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Chengdu611731 China

In the fusion-based welding processes, filler materials are commonly used to adjust and improve the composition of the fusion zone with the aim of optimizing both microstructure and mechanical properties. However, in the field of welding high entropy alloys, the influence of different filler materials on the microstructure and mechanical response is still scarce, owing to the yet incipient usage of welding technologies for these novel, advanced engineering alloys. To bridge this knowledge gap, Inconel 625 filler wire was used during gas metal arc welding of the well-known CoCrFeMnNi high entropy alloy. To systematically analyze the microstructure evolution and mechanical properties of the welded joints, multiscale characterization techniques were employed. It is shown that the different regions of the welded joint possess distinct microstructural features due to the weld thermal cycle, which is further compounded in the fusion zone by the introduction of the filler material. The use of Inconel 625 filler promotes a solid solution strengthening effect in the fusion zone and became the main contributor to the yield strength of this region (302 MPa (via solid solution strengthening) vs 478 MPa (yield stress from tensile experiments). Since Hall-Petch strengthening is predominant in both base material and heat affected zone, but not on the fusion zone due to the large grain structure that developed, the addition of Inconel 625 filler demonstrates to be a feasible approach to increase the typically low fusion zone strength. By coupling microstructural characterization with mechanical property analysis, aided by the calculation of the strengthening mechanisms, we unveil processing, microstructure, property relationships, providing a broader basis for the widespread application of gas metal arc welding for high entropy alloys. © 2025 The Authors

关键词： Tensile testing

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Anomalous elastic softening in ferroelectric hafnia under pressure

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Physical Review B 2025年第6期111卷 064106-064106页

作者： Alejandro Alvarez Niaz Abdolrahim Sobhit Singh Materials Science Program University of Rochester Rochester New York 14627 USA Department of Mechanical Engineering University of Rochester Rochester New York 14627 USA Laboratory for Laser Energetics University of Rochester Rochester New York 14627 USA Center for Coherence and Quantum Optics University of Rochester Rochester New York 14627 USA

This study employs first-principles density-functional theory (DFT) calculations to explore the elastic and mechanical properties of ferroelectric hafnia (HfO2) in its polar orthorhombic Pca21 phase under varying hydrostatic pressure conditions up to 30 GPa. Utilizing a plane-wave basis set and Perdew-Burke-Ernzerhof generalized-gradient approximation for solids in our DFT calculations, we investigate both pure and yttrium-substituted HfO2. Our findings reveal an anomalous reduction in the C33 component of the elastic tensor with increasing pressure, which becomes significant above 15 GPa and signals a potential pressure-driven structural phase transition at higher pressure. The analysis of atomic displacements under pressure sheds light on the unusual mechanical behavior and phase stability of this material. Additionally, we observe a transition from an indirect band gap to a direct band gap with increasing pressure, which could have significant implications for optical applications. The effects of yttrium substitution on the mechanical and electronic properties are further examined, revealing that yttrium substitution softens the elastic response of this material and reduces the electronic band gap. These results enhance our understanding of elastic and mechanical responses of ferroelectric hafnia and its potential for applications in microelectronics, piezoelectric devices, and nonvolatile ferroelectric random-access memories. Further experimental validation is recommended to confirm our predictions and explore the practical implications of the observed phase transitions and electronic behavior of the ferroelectric hafnia under high-pressure conditions.

关键词： Ferroelectricity

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Optimizing dispersion of torrefied spent coffee grounds for enhanced biochar-EVA composite properties through sodium percarbonate-assisted treatment

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Journal of Industrial and engineering Chemistry 2025年

作者： Lee, Kuan-Ting Gabriela, Situmorang Chen, Wei-Hsin Rajendran, Saravanan Selvarajoo, Anurita Department of Chemical and Materials Engineering Tunghai University Taichung407 Taiwan International Master Degree Program on Energy Engineering National Cheng Kung University Tainan701 Taiwan Department of Aeronautics and Astronautics National Cheng Kung University Tainan701 Taiwan Research Center for Smart Sustainable Circular Economy Tunghai University Taichung407 Taiwan Department of Mechanical Engineering National Chin-Yi University of Technology Taichung411 Taiwan Instituto de Alta Investigación Universidad de Tarapacá Arica1000000 Chile Department of Civil Engineering Faculty of Science and Engineering University of Nottingham Malaysia

This study aims to optimize biochar by combining 10 % sodium percarbonate with 90 % spent coffee grounds and torrefying at 300 °C for 30 min. Biochar enhances black color dispersion in a composite when blending the optimal biochar and ethylene vinyl acetate. The maximum carbon content of the optimal biochar is 59.97 %, exhibiting similar dispersion, packing density, pore size, and contact angle to carbon black. The optimal biochar's specific surface area and total pore volume are 7.12 m2·g−1 and 0.0018 cm3·g−1, respectively, 2.9 times and 1.2 times that of untreated torrefied spent coffee grounds with SP treated. The mechanical properties of the composite, which is blended with 15 wt% of the optimal biochar to ethylene vinyl acetate through trade-off analysis, indicate a tensile strength and Young's modulus of 1.03 MPa and 9.69 MPa, respectively. As the amount of blended optimal biochar increases, the tensile strength decreases while Young's modulus increases. Compared with a composite blended with the same 15 wt% of carbon black, the tensile strength and Young's modulus are 0.77 MPa and 9.55 MPa, respectively. In conclusion, the optimal biochar is a potential alternative material that could replace carbon black. This finding aligns with the developmental direction of achieving negative carbon emissions, promoting a circular economy and valorizing waste. © 2025 The Korean Society of Industrial and engineering Chemistry

关键词： Tensile strength

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Optimal sandwich panel's core design for an enhanced impact resistance

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Heliyon 2025年第1期11卷 e41211页

作者： Charkaoui, Assil Hassan, Noha M. Bahroun, Zied Materials Science and Engineering Program College of Arts and Sciences American University of Sharjah P.O. Box 26666 Sharjah United Arab Emirates Department of Industrial Engineering College of Engineering American University of Sharjah P.O. Box 26666 Sharjah United Arab Emirates

Despite the extensive literature revealing various core structures that can enhance the impact resistance of composite panels, a comparative study illustrating the difference in performance of the various cores under same loading conditions is missing. The aim of this study is to determine the optimal core structure and design in terms of energy absorption under low-velocity impact using both numerical simulations and experimental testing for validation. Response surface analysis was used to design the experiments and analyse the panel's behaviour. A total of 160 numerical simulations were conducted by varying the core shape, density, number of layers and panel's thickness. Drop tower tests were performed to experimentally validate the results. Additive manufacturing was used to 3D print the tested structures which simplified the manufacturing process. Results provided insights on time to perforation, stiffness of the panels showcasing an inverse relationship between recoverable strain energy and equivalent plastic strain. The number of layers within the panels were identified as a pivotal factor in the energy distribution and tendency for localized plastic deformation to occur. Both numerical and experimental results revealed the superior energy absorption capabilities of the X-frame core shaped structure. Regression models developed shed light on the relationships between core height, volume fraction, number of layers, and core topology revealing the extent of damage. Multi-objective optimization was used to yield optimal configuration for sandwich panels with highest impact resistance. © 2024

关键词： Additive manufacturing Core geometry Energy absorption Impact resistance Optimization Sandwich panels

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Nanoconfined constructs for electrochemical aptamer-based in vivo biosensing

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Current Opinion in Electrochemistry 2025年 51卷

作者： Huldin, Grayson F. Huang, Junming Fu, Kaiyu X. Department of Chemistry and Biochemistry University of Notre Dame Notre DameIN46556 United States Materials Science and Engineering Program University of Notre Dame Notre DameIN46556 United States Berthiaume Institute for Precision Health University of Notre Dame Notre DameIN46556 United States

In the last two decades, electrochemical aptamer-based (EAB) sensors have grown rapidly due to their high sensitivity, good selectivity, excellent biocompatibility, and flexible architectures among the wide range of biosensing platforms. Yet, achieving continuous, long-term, and in vivo monitoring remains challenging due to obstacles like device miniaturization, signal amplification, and sensor stability. To tackle these hurdles, researchers are leveraging nanostructured electrodes, leading to new EAB designs with improved in vivo biosensing performance. This opinion provides a brief overview of the development and latest progress in nanoconfined constructs for EAB in vivo biosensing. We illustrate fundamental sensing principles, the various nanostructures being explored, and their respective advantages. These nanostructured EABs hold promise for applications spanning disease diagnostics, environmental surveillance, and food safety management. Finally, we address the persistent challenges EABs face and discuss potential future directions, offering insights into how these sensors can continue to evolve and foster more effective healthcare technologies. © 2025 The Author(s)

关键词： Nanorings

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Observation of mechanical kink control and generation via phonons

arXiv

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arXiv 2025年

作者： Qian, Kai Cheng, Nan Serafin, Francesco Sun, Kai Theocharis, Georgios Mao, Xiaoming Boechler, Nicholas Department of Mechanical and Aerospace Engineering University of California San Diego La Jolla CA92093 United States Department of Physics University of Michigan Ann ArborMI48109 United States Department of Physics and Materials Science University of Luxembourg 2 Avenue de l’Universite L Esch-sur-Alzette4365 Luxembourg CNRS Le Mans Université France Program in Materials Science and Engineering University of California San Diego La Jolla CA92093 United States

Kinks (or domain walls) are localized transitions between distinct ground states associated with a topological invariant, and are central to many phenomena across physics, from condensed matter to cosmology. While phonon (i.e., small-amplitude vibration) wave packets have been theorized to deterministically interact with kinks and initiate their movement, this interaction has remained elusive in experiments, where only uncontrollable stochastic kink motion generated by thermal phonons or dislocation glide by low-frequency quasi-static loading have been observed. This is partly because all physical systems that support kinks are, at some level, discrete, making deterministic phonon control of kinks extremely challenging due to the existence of Peierls-Nabarro (PN) barrier. Here, we demonstrate, for the first time, experimental observation of phonon-mediated control and generation of mechanical kinks, which we enable using a topological metamaterial that constitutes an elastic realization of the Kane-Lubensky chain model. Our metamaterial overcomes the PN barrier by supporting a single, topologically protected kink that requires zero energy to form and move. Using simulations that show close agreement with our experimental observations, we also reveal unique dynamics of phonon interplay with highly discrete kinks, including long-duration motion and a continuous family of internal modes, features absent in other discrete nonlinear systems. This work introduces a new paradigm for topological kink control, with potential applications in material stiffness tuning, shape morphing, locomotion, and robust signal transmission. © 2025, CC BY-NC-ND.

关键词： Stochastic systems

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HP40Nb reformer tube exposed to 950 °C – Machine learning informed microstructure evolution and multi-scale mechanical properties

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International Journal of Pressure Vessels and Piping 2025年 216卷

作者： Khan, Adnan Shunmugasamy, Vasanth C. Abuhelaiqa, Mousa Hamer, Wouter J. Laycock, Nicholas J. Mansoor, Bilal Department of Materials Science and Engineering Texas A&M University College StationTX United States Mechanical Engineering Program Texas A&M University at Qatar Doha Qatar Qatar Shell Research and Technology Center QSTP Doha Qatar Shell Global Solutions International B.V. Grasweg 31 Amsterdam1031 HW Netherlands

Austenitic stainless steel tubes extensively employed in energy sector, endure extreme service temperatures over long period of time and are susceptible to creep damage. This study investigates microstructural evolution and mechanical properties of HP40Nb (25Cr35Ni1Nb) steel exposed to 950 °C for up to 1600h, with specimens retrieved at 200h intervals. Advanced multi-scale characterization methods, including scanning electron microscopy, energy dispersive spectroscopy, and micro- and nanoindentation were utilized to analyze transformation of precipitates and resulting impact on mechanical properties. Microstructural changes (precipitate evolution, transformation and coarsening) were quantified using Machine Learning based algorithm and correlated with the mechanical properties. The as-cast microstructure comprised two primary intergranular Cr- and Nb-rich carbides in austenitic matrix. Post 200h exposure at 950 °C, secondary intragranular Cr-rich pepper carbide was observed in the austenite matrix. Following this, segregation of Si around Cr-rich precipitates occurred resulting in dark phases. At 800h, Si migrated to NbC resulting in transformation of NbC to Ni-Nb Silicide phase (G-phase). Transformation of NbC to G-phase and coarsening of the primary Cr-rich carbides was observed towards end of study at 1600h. The microstructural changes resulted in microcracks owing to precipitate transformation, coarsening and thermal coefficient mismatch. It was identified that both Nb and Cr precipitates are susceptible to microcracks post 800h at 950 °C. The study offers improved understanding of microstructural changes occurring in austenitic stainless steels used as reformer tubes during exposure to elevated service temperature. © 2025

关键词： Coarsening

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Characterization of Ureolysis and Microbially Induced Calcium Carbonate Precipitation Under Different Incubation and Reaction Conditions

SSRN

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SSRN 2025年

作者： Joo, Hyun-Woo Fyfe, Matthew H. Verdú, Irene Rahmaninezhad, Seyed Ali Sales, Christopher M. Srubar, Wil V. Hubler, Mija H. Department of Civil Environmental and Architectural Engineering University of Colorado Boulder BoulderCO United States 1111 Engineering Drive – UCB 428 ECOT 441 BoulderCO80309-0422 United States Department of Civil Architectural and Environmental Engineering Drexel University PhiladelphiaPA United States Environmental Department Terracon Consulting Inc. The ColonyTX United States Department of Civil Environmental and Architectural Engineering Materials Science and Engineering Program University of Colorado Boulder BoulderCO United States Department of Biology

This study investigates the ureolysis and microbially induced calcium carbonate precipitation (MICP) characteristics of Sporosarcina pasteurii and Lysinibacillus sphaericus under varying incubation and reaction conditions. A series of batch MICP experiments were conducted to assess the effects of incubation duration and pH, bacterial cell density, and reagent (i.e., urea and calcium ion) concentrations on ureolysis and CaCO3 precipitation characteristics. The findings indicate that both bacteria exhibit higher urease activity after 24 hours of incubation compared to 48 hours, regardless of incubation pH. S. pasteurii exhibits maximum specific urease activity at an alkaline pH (pH 9.0), whereas L. sphaericus reaches peak activity at a neutral pH (pH 7.2). Across six incubation conditions for each bacterium, S. pasteurii exhibits greater sensitivity in specific urease activity, while L. sphaericus maintains a more consistent ureolysis performance. In terms of cell density, a lower OD600 (~0.1) enhances specific urease activity and early-stage mineralization efficiency, whereas a higher OD600 (~1.0) accelerates overall CaCO3 precipitation, enhances terminal-stage mineralization efficiency, and promotes the prolonged presence of vaterite. High reagent concentrations (1.0 and 1.5 M) enhance specific urease activity and CaCO3 precipitation rates and lead to over 93% of vaterite formation, while low reagent concentration (0.3 M) favors calcite-dominant precipitation over time. These findings provide insights into evaluating and optimizing MICP performance under varying incubation and reaction conditions. © 2025, The Authors. All rights reserved.

关键词： Carbonation

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On the mechanism behind the enhanced solubility of glibenclamide in aqueous ionic liquid solution

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Journal of Molecular Liquids 2025年 422卷

作者： Murnikova, Žyginta Klimavicius, Vytautas Mocci, Francesca Laaksonen, Aatto Aidas, Kęstutis Institute of Chemical Physics Faculty of Physics Vilnius University Vilnius10257 Lithuania Department of Chemical and Geological Sciences University of Cagliari Monserrato09042 Italy Department of Materials and Environmental Chemistry Arrhenius Laboratory Stockholm University Stockholm10691 Sweden Energy Engineering Division of Energy Science Luleå University of Technology Luleå97187 Sweden Center of Advanced Research in Bionanoconjugates and Biopolymers "Petru Poni" Institute of Macromolecular Chemistry Iasi700469 Romania State Key Laboratory of Materials-Oriented and Chemical Engineering Nanjing Tech University Nanjing211816 China

The aim of the present study was to dissect the nature of intermolecular interactions leading to the improved solubility of glibenclamide in an aqueous solution of the choline tryptophanate, [Cho][Trp], ionic liquid. To this end, experimental [Figure presented] NMR measurements and computational modeling employing classical molecular dynamics (MD) simulations and combined quantum mechanics/molecular mechanics (QM/MM) models were carried out. Samples of glibenclamide dissolved in water and in an aqueous mixture of [Cho][Trp] were scrutinized both experimentally and computationally. MD simulations revealed that the constituent ions of the ionic liquid condensed around the drug molecule pushing water molecules away. Nevertheless, virtually no specific hydrogen bonding interactions between glibenclamide and the ions were formed. The hydrotropic activity of the [Cho][Trp] ionic liquid thus occurs through the formation of dynamic aggregates between the solute and the ions, which screen the hydrophobic glibenclamide from polar water molecules. Experimental [Figure presented] NMR measurements have shown that the largest changes in chemical shifts were registered for protons in the benzene rings of glibenclamide, implying that these are the main sites of interaction with the ions of the ionic liquid – a conclusion well-corroborated by the results of MD simulations. The good qualitative agreement between the computational QM/MM-based and experimental NMR spectra of glibenclamide in an aqueous solution and in aqueous mixture of [Cho][Trp] provides support to the structural results. © 2025 Elsevier B.V.

关键词： Solubility

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The effect of calcium and barium fluoride on CeF3 doped in gadolinium phosphate scintillating glass

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Ceramics International 2025年

作者： Sarumaha, C.S. Kantuptim, P. Yanagida, T. Intachai, N. Kothan, S. Kim, H.J. Busayaporn, W. Pakawanit, P. Phoovasawat, C. Kaewnuam, E. Kaewkhao, J. Faculty of Science and Technology Muban Chombueng Rajabhat University Ratchaburi 70150 Thailand Nakhon Pathom Rajabhat University Nakhon Pathom73000 Thailand Department of Materials Engineering Faculty of Engineering Kasetsart University Bangkok10900 Thailand Division of Materials Science of Science and Technology Nara Institute of Science and Technology 8916-5 Takayama Ikoma Nara630-0192 Japan Center of Radiation Research and Medical Imaging Department of Radiologic Technology Faculty of Associated Medical Sciences Chiang Mai University Chiang Mai50200 Thailand Department of Physics Kyungpook National University Daegu41566 Korea Republic of Synchrotron Research and Applications Division Synchrotron Light Research Institute 111 University Avenue Muang District Nakhon Ratchasima30000 Thailand Physics Program Faculty of Science and Technology Nakhon Pathom Rajabhat University Nakhon Pathom73000 Thailand

This study concerns alkaline fluorides such as CaF2 and BaF2 contained in gadolinium phosphate glass doped with CeF3, which were synthesized using a melt-quenching technique. Ce3+ was activated in both glasses and a comparative study of their optical, luminescence and scintillation behaviors was conducted. The results found that the higher atomic weight of BaF2 glass makes higher density compared with CaF2 glass, resulting in more integral scintillation efficiency. The quantum yield of BaF2-glass (PLZGdBafCe0.5) is also higher than that of CaF2-glass (PLZGdCafCe0.5). Energy transfer efficiency from Gd3+ to Ce3+ shows similar values, reflecting that the higher photoluminescence intensity of BaF2-glass comes from the efficiency of the luminescence center (Ce3+ ion). Photoluminescence and scintillation decay times were measured and found to be in the range of nanoseconds. XANES measurement was used to confirm the oxidation state and ratio between Ce3+/Ce4+. Moreover, the practical application of the glass scintillator was succeeded by micro-imaging using synchrotron X-ray. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Photoluminescence

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