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Tribological Behaviors and Statistical Experimental Design of Sintered and Age-Hardened Aluminum–Copper Based Composites

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Lubricants 2025年第4期13卷 172-172页

作者： Popescu, Ileana Nicoleta Alhalaili, Badriyah Anghelina, Florina Violeta Nicolicescu, Claudiu Vidu, Ruxandra Faculty of Materials Engineering and Mechanics Valahia University of Targoviste Targoviste130004 Romania Valahia University of Targoviste Targoviste130004 Romania American Romanian Academy of Arts and Sciences Citrus HeightsCA95611 United States Nanotechnology and Advanced Materials Program Kuwait Institute for Scientific Research P.O. Box 24885 Safat 13109 Kuwait Department of Engineering and Management of the Technological Systems Faculty of Mechanics University of Craiova Drobeta-Turnu Severin220037 Romania Faculty of Materials Science and Engineering National University of Science and Technology POLITEHNICA Bucharest Bucharest060042 Romania

This paper reports on the influence of various processing parameters and different SiCp proportions on the outcome of mechanical, tribological, microstructural, and microcompositional investigations of Al-Cu based composites used as potential brake friction materials for eco-friendly vehicle parts. The composites were obtained by powder metallurgy, and then the sintered composite was treated at 515 ± 5 °C/6 h, quenched in water, and artificially aged at different temperatures and times. The microstructural and microcompositional investigations of the composites were made using an environmental scanning electron microscopy (ESEM), energy-dispersive X-ray spectroscopy (EDS). After analyzing the microstructures in correlation with the results of the hardness tests, the optimal proportion of SiCp and optimal heat treatment parameters were determined. The composite samples with the best properties were chosen for tribological investigation. The friction and wear tests of samples were made under dry sliding conditions using a "pin on disc" machine, at a contact pressure of 0.35 to 1.15 MPa, 2 to 4.5 m/s relative speed, and the prediction of tribological behavior was made using a linear factorial design approach. © 2025 by the authors.

关键词： Sintering

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Strengthening Mechanism of Cold-Rolled Co-Based Super Alloy for Diaphragm Valves under Room Temperature Tensile Loading

Journal of Korean Institute of Metals and Materials

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Journal of Korean Institute of Metals and materials 2025年第5期63卷 319-329页

作者： Park, Jung-Hyun Song, Noh-Geon Choi, Jae-Ho Kang, Doo-Hong Lee, Kee-Ahn Department of Materials Science and Engineering Inha University Incheon22212 Korea Republic of Program in Semiconductor Convergence Inha University Incheon22212 Korea Republic of CN-1 Corp. Hwaseong18487 Korea Republic of Asflow Corp Hwaseong18514 Korea Republic of

Cold-rolled Co-Cr-Ni alloy (Elgiloy) and Co-Ni-Cr alloy (SPRON 510) can be considered for diaphragm valve materials in gas valve systems. In this study, the effect of direct aging (DA) heat treatment on the tensile properties of Co-based alloys was investigated and the influence of microstructural changes on the tensile behavior was examined. The Co-Cr-Ni Elgiloy alloy exhibited a hexagonal close packed (HCP) phase formation through strain induced martensite transformation (SIMT) in both as-rolled and DA conditions, promoting finer grains due to increased sub-structured and recrystallized grains. In contrast, the Co-Ni-Cr SPRON 510 alloy showed a face centered cubic (FCC) single phase with a higher precipitates fraction and dislocation density. Both Co-based alloys showed improved hardness and strength after DA treatment, with the Co-Cr-Ni alloy demonstrating higher tensile strength and the Co-Ni-Cr alloy exhibiting higher yield strength and elongation. The Co-Cr-Ni alloy revealed fine shallow dimples and cleavage fracture mode, while Co-Ni-Cr showed larger dimples and river patterns on tensile fracture surfaces. The Co-Cr-Ni alloy’s deformation behavior was dominated by active SIMT due to low stacking fault energy (SFE), while the Co-Ni-Cr alloy primarily formed deformation twins due to higher SFE. The high tensile strength of the Co-Cr-Ni alloy was dominated by hardening effects due to a relatively fine grain size and SIMT behavior, while the high yield strength of the Co-Ni-Cr alloy was dominated by deformation twin, dislocation density, Taylor factor and high precipitate fraction. Copyright © The Korean Institute of Metals and materials.

关键词： Tensile strength

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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 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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Low voltage graphene interface engineered organic ferroelectric tunnel junction devices

arXiv

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arXiv 2025年

作者： Natani, S. Khajanji, P. Cheng, L. Eshraghi, K. Zhang, Z. Shipley, W. Tao, A. Bandaru, P.R. Department of Mechanical Engineering University of California San Diego La Jolla CA United States Program in Materials Science University of California San Diego La Jolla CA United States Applied Materials Santa ClaraCA United States

It has been indicated 1 that the path forward for the widespread usage of ferroelectric (FE) materials may be considerably facilitated through the reduction of programming voltages to on-chip logic compatible values o... 详细信息

关键词： Ferroelectric devices

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CREASE-2D Analysis of Small Angle X-ray Scattering Data from Supramolecular Dipeptide Systems

arXiv

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arXiv 2025年

作者： Gupta, Nitant Akepati, Sri V.V.R. Bianco, Simona Shah, Jay Adams, Dave J. Jayaraman, Arthi Department of Chemical and Biomolecular Engineering University of Delaware NewarkDE19716 United States Data Science Program University of Delaware NewarkDE19716 United States School of Chemistry University of Glasgow GlasgowG12 8QQ United Kingdom Department of Materials Science and Engineering University of Delaware NewarkDE19716 United States

In this paper, we extend a recently developed machine-learning (ML) based CREASE-2D method to analyze the entire two-dimensional (2D) scattering pattern obtained from small angle X-ray scattering measurements of supramolecular dipeptide micellar systems. Traditional analysis of such scattering data would involve use of approximate or incorrect analytical models to fit to azimuthally-averaged 1D scattering patterns that can miss the anisotropic arrangements. Analysis of the 2D scattering profiles of such micellar solutions using CREASE-2D allows us to understand both isotropic and anisotropic structural arrangements that are present in these systems of assembled dipeptides in water and in the presence of added solvents/salts. CREASE-2D outputs distributions of relevant structural features including ones that cannot be identified with existing analytical models (e.g., assembled tubes’ cross-sectional eccentricity, tortuosity, orientational order). The representative three-dimensional (3D) real-space structures for the optimized values of these structural features further facilitate visualization of the structures. Through this detailed interpretation of these 2D SAXS profiles we are able to characterize the shapes of the assembled tube structures as a function of dipeptide chemistry, solution conditions with varying salts and solvents, and relative concentrations of all components. This paper demonstrates how CREASE-2D analysis of entire SAXS profiles can provide an unprecedented level of understanding of structural arrangements which has not been possible through traditional analytical model fits to the 1D SAXS data. © 2025, CC BY-NC-SA.

关键词： X ray scattering

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Bioactivity and cytotoxicity of LiF-modified bioactive glass ceramics for bone regeneration

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Ceramics International 2025年

作者： Selli, Neslihan Tamsü Başaran, Neslihan Kesmez, Ömer Yavaş, Adem Demir, Feride Ertürk, A. Tamer Department of Materials Science and Engineering Gebze Technical University Kocaeli Gebze41400 Turkey Department of Chemistry Faculty of Science Akdeniz University Antalya07058 Turkey Food Technology Program Food Processing Department Çine Vocational School Aydin Adnan Menderes University Aydin Turkey Agricultural Biotechnology and Food Safety Research and Application Center Aydin Adnan Menderes University Aydin Turkey Mechanical Engineering Department Kocaeli University Umuttepe Campus Kocaeli Izmit41001 Turkey

Bioactive glasses and glass-ceramics have drawn significant attention due to their excellent bone-bonding capabilities and biocompatibility. This study investigates the effects of lithium fluoride (LiF) addition on the microstructure, mechanical properties, and biocompatibility of novel bioactive glass compositions. Glasses with varying LiF contents (1, 2, and 3 wt%) were synthesized using the melt-quenching method and subsequently heat-treated to obtain bioactive glass-ceramics. X-ray diffraction (XRD) analysis revealed an increase in the intensity of hydroxyapatite, fluorapatite, and diopside phases with increasing LiF content, suggesting enhanced crystallization. Vickers hardness measurements showed a significant improvement, with the highest hardness (730 MPa) observed in the K3 composition. Scanning Electron Microscopy (SEM) was used to examine the microstructural morphology, while Energy-Dispersive X-ray Spectroscopy (EDX) was employed to analyze the elemental composition of the samples. Furthermore, in vitro bioactivity assessments in simulated body fluid (SBF) confirmed the apatite-forming ability of all compositions. Cytotoxicity evaluations demonstrated enhanced cell viability in LiF-containing compositions, with K3 exhibiting the highest biocompatibility. The findings suggest that LiF addition optimizes crystallization, mechanical performance, and biocompatibility, making these modified bioactive glass-ceramics promising candidates for biomedical applications. © 2025

关键词： Energy dispersive spectroscopy

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Impact of Quantum Well Thickness on Efficiency Loss in InGaN/GaN LEDs: Challenges for Thin-Well Designs

arXiv

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arXiv 2025年

作者： Li, Xuefeng Pant, Nick Rahman, Sheikh Ifatur Armitage, Rob Rajan, Siddharth Kioupakis, Emmanouil Feezell, Daniel University of New Mexico AlbuquerqueNM87106 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Lumileds LLC San JoseCA95131 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

We investigate the impact of quantum well (QW) thickness on efficiency loss in c-plane InGaN/GaN LEDs using a small-signal electroluminescence (SSEL) technique. Multiple mechanisms related to efficiency loss are independently examined, including injection efficiency, carrier density vs. current density relationship, phase space filling (PSF), quantum confined stark effect (QCSE), and Coulomb enhancement. An optimal QW thickness of around 2.7 nm in these InGaN/GaN LEDs was determined for quantum wells having constant In composition. Despite better control of deep-level defects and lower carrier density at a given current density, LEDs with thin QWs still suffer from an imbalance of enhancement effects on the radiative and intrinsic Auger-Meitner recombination coefficients. The imbalance of enhancement effects results in a decline in internal quantum efficiency (IQE) and radiative efficiency with decreasing QW thickness at low current density in LEDs with QW thicknesses below 2.7 nm. We also investigate how LED modulation bandwidth varies with quantum well thickness, identifying the key trends and their implications for device performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Semiconductor quantum wells

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Development of Flexible Sendust Composite Sheets with Enhanced Magnetic Permeability for Microwave Absorbers and Antennas

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IEEE Transactions on Magnetics 2025年

作者： Whalen, Matthew P. Plouff, David T. Shevchenko, Nicholas B. Mirotznik, Mark Xiao, John Q. University of Delaware Quantum Science and Engineering Program NewarkDE19716 United States University of Delaware Department of Physics and Astronomy NewarkDE19716 United States University of Delaware Center for Composite Materials NewarkDE19716 United States University of Delaware Department of Electrical and Computer Engineering NewarkDE19716 United States

The demand for high-frequency soft magnetic composites with elevated permeability and flexibility is growing for applications in microwave absorbers and magnetodielectric antennas. However, balancing high permeability with mechanical flexibility remains challenging. This study presents flexible Sendust (FeSiAl) composite sheets, fabricated with a hot-pressing technique that aligns flakes within an acrylic rubber and epoxy resin matrix. The alignment significantly enhances relative permeability at high frequencies, achieving single-layer film properties of μr' = 14.8 and μr"= 20.4 at 1 GHz, alongside high saturation magnetization (118 eμg) and high hesitivity (44.7 kΩ m-1), outperforming commonly used materials such as NiZn ferrite. Our method supports customizable thickness without sacrificing permeability, establishing a versatile platform for advanced conformal microwave absorber and antenna applications. © 2025 IEEE.

关键词： Saturation magnetization

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Electrostatic self-assembled ceramic magnetic Ti3C2Tx nanocomposites reinforced with hollow Fe3O4 particles for strong and broadband absorption of electromagnetic waves

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Ceramics International 2025年

作者： Guo, Jiang Sun, Yukun Chen, Zhuoran Zhang, Huaguang AlMasoud, Najla Qiu, Hua Guo, Zhanhu Yu, Qifeng Ren, Juanna Alomar, Taghrid S. Zhu, Jianfeng School of Materials Science and Engineering Key Laboratory of Materials and Technology for Unearthed Cultural Heritage Conservation Ministry of Education Shaanxi University of Science & Technology Xi'an710021 China Oil&Gas Technology Research Institute Changqing Oilfield Company Xi'an710018 China Department of Chemistry College of Science Princess Nourah bint Abdulrahman University P.O. Box 84428 Riyadh11671 Saudi Arabia Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical Engineering Northwestern Polytechnical University Shaanxi Xi'an710072 China Department of Mechanical and Construction Engineering Faculty of Engineering and Environment Northumbria University Newcastle Upon TyneNE1 8ST United Kingdom College of Materials Science and Engineering Taiyuan University of Science and Technology Taiyuan030024 China

Developing materials with strong and broadband electromagnetic wave absorption (EWA) is one of the efficient ways to address the electromagnetic (EM) pollution. In this work, Fe3O4/Ti3C2Tx ceramic composites with a unique heterogeneous structure were constructed by electrostatic self-assembly of lamellar Ti3C2Tx and hollow Fe3O4 (HFO) particles. Altering the content of HFO and Ti3C2Tx successfully tuned the EM parameters. To be specific, when the mass ratio of HFO to Ti3C2Tx is 1:2, effective absorption bandwidth (EAB) is 4.8 GHz at 2.2 mm. Reflection loss (RL) even reaches -57.17 dB at 1.8 mm when HFO to Ti3C2Tx is 2:1. The satisfying EWA performance results from the special heterogeneous structure of the Fe3O4/Ti3C2Tx composites, which significantly optimizes the impedance matching and enhances magnetic and electric losses. Notably, at an incidence angle of 15°, HF/T-2 composites exhibit the largest RCS reduction value (18.73 dB m2) in the computer simulation technology simulation confirming the excellent EWA performance of Fe3O4/Ti3C2Tx ceramic composites. This work provides a new way to prepare magnetic MXene ceramic composites with strong and broadband EWA performance. © 2025 The Author(s)

关键词： Reflection

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Surface Modification of Cu Native Oxide: Ag Displacement for Homogeneous Layering

Surface Modification of Cu Native Oxide: Ag Displacement for...

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International Conference on Electronics Packaging (ICEP)

作者： Shubhayan Mukherjee Akitsu Shigetou Shih-kang Lin Department of Materials Science and Engineering National Cheng Kung University Tainan Taiwan National Institute for Materials Science Ibaraki Japan Hierarchical Green-Energy Materials (Hi-GEM) Research Centre National Cheng Kung University Tainan Taiwan Program on Smart and Sustainable Manufacturing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan Taiwan

ISBN: (数字)9784991191190

ISBN: (纸本)9798331514747

Cu's electrical and thermal conductivity makes it a vital material in various industrial applications, but its susceptibility to oxidation under ambient conditions can compromise performance, particularly in the semiconductor industry. This study presents an innovative surface modification technique to inhibit the growth of native oxide on Cu prior to Ag coating to enhance a galvanic replacement (GR) reaction under good adhesion between Ag and Cu. Ag-coated Cu electrodes are effective in removing the surface oxide on Cu and acting as deformable and low-resistance Cu interconnects. The surface modification process utilizes vacuum ultraviolet (VUV) treatment in an ethanol atmosphere, forming a stable, hydroxylated surface layer that minimizes reoxidation before Ag deposition. X-ray photoelectron spectroscopy (XPS) confirmed the effective suppression of reoxidation, and scanning electron microscopy (SEM) revealed a homogeneous Ag coating with optimal surface coverage. This methodology significantly enhances the oxidation resistance of Cu.

关键词： Scanning electron microscopy Surface resistance Ethanol Atmosphere Thermal conductivity Oxidation Coatings Copper Surface treatment Thermal stability

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