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Design strategies of high-performance lead-free electroceramics for energy storage applications

Rare Metals 2024年第3期43卷 853-878页

作者： Biao Guo Fei Jin Li Li Zi-Zhao Pan Xin-Wei Xu Hong Wang Department of Materials Science and Engineering College of EngineeringSouthern University of Science and TechnologyShenzhen518055China School of Microelectronics and State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an710049China

A greater number of compact and reliable electrostatic capacitors are in demand due to the Internet of Things boom and rapidly growing complex and integrated electronic systems,continuously promoting the development of high-energy-density ceramic-based *** significant successes have been achieved in obtaining high energy densities in lead-based ferroelectric ceramics,the utilization of lead-containing ceramies has been restricted due to environmental and health hazards of ***-free ferroelectric ceramics have garnered tremendous attention and are expected to replace lead-based ceramics in the near ***,the energy density of lead-free ceramics is still lagging behind that of lead-containing ***,severely limiting their *** efforts have been made to enhance the energy storage performance of lead-free ceramics using multi-scale design strategies,and exciting progress has been achieved in the past *** review briefly discusses the energy storage mechanism and fundamental characteristics of a dielectric capacitor,summarizes and compares the state-of-the-art design strategies for high-energy-density lead-free ceramics,and highlights several critical issues and requirements for industrial *** prospects and challenges of lead-free ceramics for energy storage applications are also discussed.

关键词： Dielectric materials Lead-free ceramic Environment friendly Energy storage Design strategy

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Experimental investigation and optimization of cutting parameters during dry turning process of copper alloy

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Journal of engineering and Applied science 2023年第1期70卷 145页

作者： Tefera, Aklilu Getachew Sinha, Devendra Kumar Gupta, Gaurav Department of Mechanical Engineering School of Mechanical Chemical and Materials Engineering Centre of Advanced Manufacturing Engineering Adama Science and Technology University Adama Ethiopia Mechanical Engineering Department Amity School of Engineering Noida India

Increasing the quality and productivity of machined components are the main issues of machining operations in metalworking industries. The copper alloys CuZr and CuCrZr generally find applications for current-carrying structural components, seam welder wheels, shafts, and bearings flash. The manufacturing of these components is still facing challenges in the form of machining process characteristics. One of the most common machining operations for removing material is turning that produces reasonably good surface finish quality, which is influenced by different factors (speed of cut, rate of feed, tool geometry, cutting fluid, cutting tool, etc.). This research has focused on experimental study and optimization of the cutting parameters viz. cutting speed, depth of cut, and feed, for best surface finish, material removal rate, tool tip temperature as well as surface morphology during dry turning of C15000 and C18150 copper alloy using High-Speed Steel (HSS) tool The plan and design of experiment has been performed through orthogonal Taguchi L9. array. The optimum cutting settings were discovered by using the Taguchi technique and using the performance index by applying a Grey Relational Grade (GRG). The best cutting parameters for both materials were a cutting speed 1200 rpm, feed rate 0.06 mm/rev, and depth of cut 1.25 mm. The optimum factors obtained from GRA for all responses (surface roughness, MRR, and tool temperature) at the best level of cutting parameters are the same for both materials. These cutting parameters values yielded the experimental result for each response like surface roughness, MRR, and tool tip temperature (2.5 µm,12,475 mm3/min, and 74 °C) for grade C15000 whereas (2.39 µm, 2590mm3/min and 68 °C) for grade C18150. The optimization of cutting parameters plays a vital role in the improvement of surface finish which minimizes mechanical failures caused by wear, corrosion, and thereby increasing the productivity of the products. This investigati

关键词： Surface roughness

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Cold sintered BaTiO_(3)–poly(ether imide)nanocomposites with superior comprehensive performances

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Journal of Advanced Ceramics 2024年第9期13卷 1453-1460页

作者： Xinyi Li Li Li Mingming Si Xiaoqian Tai Hong Wang Jing Guo State Key Laboratory for Mechanical Behavior of Materials&School of Materials Science and Engineering Xi’an Jiaotong UniversityXi’an 710049China Guangdong Provisional Key Laboratory of Functional Oxide Materials and Devices Southern University of Science and TechnologyShenzhen 518055China Department of Materials Science and Engineering&Shenzhen Engineering Research Center for Novel Electronic Information Materials and Devices Southern University of Science and TechnologyShenzhen 518055China

With the rapid development of the electronics industry,the demand for dielectric materials with high permittivities,low losses,and excellent electrical breakdown strengths prepared via low-temperature fabrication techniques is ***,we propose a one-step cold sintering process route to improve the comprehensive performance of BaTiO_(3)−based ceramics by integrating polyetherimide(PEI).Dense BaTiO_(3)–PEI nanocomposites can be prepared via a cold sintering process at 250℃ using Ba(OH)_(2)∙8H_(2)O and H_(2)TiO_(3) as the transient liquid *** grain growth of BaTiO_(3) is inhibited,and thin PEI layers less than 10 nm in size are located at the grain *** dissolution‒precipitation process triggered by the transient liquid phase and viscous flow assisted by PEI dominates the cold sintering mechanism of the(1−x)BaTiO_(3)–xPEI *** dielectric properties are stable over a broad temperature range up to 200℃.Compared with BaTiO_(3),80%BaTiO_(3)–20%PEI has superior performance,with a relative permittivity of 163 and a low dielectric loss of 0.014,and the electrical breakdown strength is increased by 80.65%compared with BaTiO_(3).Overall,the cold sintering process provides a potential way to develop dielectric nanocomposites with excellent comprehensive performance.

关键词： cold sintering process(CSP) dielectrics BaTiO_(3) ceramic-polymer composites

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Unconventional dislocation starvation behavior of medium-entropy alloy single crystal pillars containing pre-existing dislocations

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Journal of materials science & Technology 2023年第11期142卷 60-75页

作者： Luling Wang Bin Liu Jianqiu Zhou Yang Cao Feng Zhang Yonghao Zhao Department of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 210009China Nano and Heterogeneous Materials Center School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China School of Mechanical Engineering Nanjing Institute of TechnologyNanjing 211167China

The excellent dislocation storage ability of bulk multi-principal element alloys(MPEAs)has been widely *** date,however,the underlying mechanisms of dislocation escape behavior in small-size facecentered cubic(FCC)MPEAs have rarely been ***,we quantitatively control the initial dislocation densities(-10^(15) m^(-2) and -10^(16) m^(-2))by large-scale molecular dynamics(MD)simulations and perform uniaxial compression simulations to compare the dislocation starvation behavior of CrCoNi with pure Cu single crystal pillars(SCPs).The analysis reveals that the CrCoNi SCPs with low initial dislocation density(-10^(15) m^(-2))can continuously accommodate mobile dislocations,and the critical dimension for dislocation starvation is about 30 *** particular,the CrCoNi SCPs with chemical short-range ordering(SRO)exhibit better dislocation storage and multiplication abilities than the random solid solution(RSS)samples even when the initial dislocation density is ***,the presence of a large number of pre-existing dislocation locks governs the strong dislocation multiplication ability of the small-size RSS CrCoNi SCPs,in obvious contrast to the deformation of all pure Cu SCPs which is completely dominated by intermittent mobile dislocation *** importantly,we reveal the fundamental physics for the good dislocation storage of CrCoNi SCPs at small sizes from the perspective of chemical *** new phenomena reported in this work provide a unique atomic-scale perspective for understanding the microscopic physical origin of the mechanical behavior of MPEAs and the discovery of extremely slow dislocation escape behavior in small-scaled pillars,providing a reliable basis for the development of the dislocation starvation model.

关键词： Molecular dynamics Medium entropy alloy Single crystal pillar Dislocation starvation Chemical short-range order Size effect

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Oscillatory Hall effect from magnetoelectronic coupling in flexoelectronic silicon

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Physical Review B 2024年第8期109卷 L081113-L081113页

作者： Paul C. Lou Ravindra G. Bhardwaj Anand Katailiha W. P. Beyermann Sandeep Kumar Department of Mechanical Engineering University of California Riverside California 92521 USA Department of Physics and Astronomy University of California Riverside California 92521 USA Materials Science and Engineering Program University of California Riverside California 92521 USA

Magnetoelectronic coupling can be defined as cross-domain coupling between electronic and magnetic properties, where modulation in magnetic properties changes the electronic properties. In this Letter, explicit experimental evidence of magnetoelectronic coupling is presented, which is uncovered from the oscillatory Hall effect response in Hall measurement. The strain gradient in a MgO (1.8 nm)/p-Si (∼400 nm) freestanding sample leads to transfer of electrons (∼5×1018cm−3) from valence to conduction band due to flexoelectronic charge separation in the p-Si layer. The resulting flexoelectronic polarization gives rise to the temporal magnetic moment from dynamical multiferroicity. The external magnetic field changes the net temporal magnetic moment, which causes modulations in charge carrier concentration and oscillatory Hall effect. The period of oscillatory Hall response is 1.12 T, which is attributed to the magnitude of the temporal magnetic moment. The discovery of the oscillatory Hall effect adds another member to the family of Hall effects.

关键词： Hall effect Doped semiconductors Electronically polarized systems Flexoelectrics Multiferroics Hall bar

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High-strength and thermally stable TiB_(2)-modified Al-Mn-Mg-Er-Zr alloy fabricated via selective laser melting

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International Journal of Minerals,Metallurgy and materials 2024年第10期31卷 2221-2232页

作者： Jiang Yu Yaoxiang Geng Yongkang Chen Xiao Wang Zhijie Zhang Hao Tang Junhua Xu Hongbo Ju Dongpeng Wang School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China National Engineering Research Center of Near-Net Shape Forming for Metallic Materials Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic MaterialsSouth China University of TechnologyGuangzhou 510640China CEMMPRE-Centre for Mechanical Engineering Materials and Processes Department of Mechanical EngineeringUniversity of CoimbraRua Luís Reis SantosCoimbra 3030-788Portugal

To increase the processability and plasticity of the selective laser melting(SLM)fabricated Al-Mn-Mg-Er-Zr alloys,a novel TiB_(2)-modified Al-Mn-Mg-Er-Zr alloy with a mixture of Al-Mn-Mg-Er-Zr and nano-TiB_(2) powders was fabricated by *** pro-cessability,microstructure,and mechanical properties of the alloy were systematically investigated by density measurement,microstruc-ture characterization,and mechanical properties *** alloys fabricated at 250 W displayed higher relative densities due to a uni-formly smooth top surface and appropriate laser energy *** maximum relative density value of the alloy reached(99.7±0.1)%,demonstrating good *** alloy exhibited a duplex grain microstructure consisting of columnar regions primarily and equiaxed regions with TiB_(2),Al6Mn,and Al3Er phases distributed along the grain *** directly aging treatment at a high tem-perature of 400℃,the strength of the SLM-fabricated TiB_(2)/Al-Mn-Mg-Er-Zr alloy increased due to the precipitation of the secondary Al6Mn *** maximum yield strength and ultimate tensile strength of the aging alloy were measured to be(374±1)and(512±13)MPa,*** SLM-fabricated TiB_(2)/Al-Mn-Mg-Er-Zr alloy demonstrates exceptional strength and thermal stability due to the synergistic effects of the inhibition of grain growth,the incorporation of TiB_(2) nanoparticles,and the precipitation of secondary Al6Mn nanoparticles.

关键词： selective laser melting aluminum alloy processability mechanical properties thermal stability

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Multi-objective optimization of micro crystalline cellulose and montmorillonite filled poly lactic acid bio–composite and its characterizations

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Journal of engineering and Applied science 2024年第1期71卷 191页

作者： Zeleke, Nehemiah Mengistu Sinha, Devendra Kumar Kumar, Santosh Department of Mechanical Engineering School of Mechanical Chemical and Materials Engineering Adama Science and Technology University Adama Ethiopia Center of Excellence Advanced Manufacturing Engineering Adama Science and Technology University Adama Ethiopia Varanasi India

In this research study, the synthesis of poly lactic acid (PLA) based bio composite material factors contributions were investigated through the Taguchi-based grey relational analysis (GRA) technique. Effects of micro crystalline cellulose (MCC) and montmorillonite (MTT) nano clay filler, sorbitol (S) plasticizer, and temperature (T) operating factor on the PLA matrix through melt-mixing preparation method. The tensile strength (TS), Young modulus (YM), flexural strength (FS), flexural modulus (FM), hardness, impact strength (IS), water absorption (WA), and density properties of bio composite material were investigated for each experimental setup (orthogonal array, L16). Additionally, neat PLA and optimal sample structural, thermal, and morphological properties were examined through Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (X-RD), thermal gravimetry analysis/differential thermal gravimetry (TGA/DTG), and DSC and SEM analyses. The obtained result for optimal mechanical and physical properties of MCC/MTT/S/PLA bio composite was MCC at level 3 (6%), MTT at level 4 (9%), S at level 2 (10%), and T at level 4 (175 °C). Analysis of variance (ANOVA) shows that MTT has the greatest significant effect on mechanical and physical properties of MCC/MTT/S/PLA bio composite followed by MCC, T, and S. The confirmation test indicates that the improvement of weighted grey relational grade (GRG) from 0.7896 to 0.846 and the FTIR, XRD, thermal gravimetry/differential scanning calorimetry (TG/DSC), and scanning electron microscopy (SEM) results indicates that the good interaction between PLA and fillers, improvement of thermal and morphological properties of optimal (6MCC/9MTT/10S/175 °C) bio composite samples. Therefore, the multi-response characteristics of MCC/MTT/S/PLA bio composite can be highly improved by this technique. © The Author(s) 2024.

关键词： Fourier transform infrared spectroscopy

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Recent advances using equal-channel angular pressing to improve the properties of biodegradable Mg-Zn alloys

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Journal of Magnesium and Alloys 2023年第7期11卷 2260-2284页

作者： Mohammad Hashemi Reza Alizadeh Terence G.Langdon Department of Materials Science and Engineering Sharif University of TechnologyTehranIran Materials Research Group Department of Mechanical EngineeringUniversity of SouthamptonSouthampton SO171BJUnited Kingdom

Magnesium alloys are of considerable current interest for use as degradable implants due to their unique properties including biodegrad-ability,biocompatibility,low density and adequate mechanical ***,there is a need to further improve these properties either by alloying or through the use of appropriate *** the different biodegradable Mg alloys now in use,the Mg-Zn series are of special interest and have been the subject of many research *** is primarily because Zn is an essential element for the human body in addition to its positive effects in improving the mechanical strength and lowering the degradation rate of the *** properties of Mg-Zn alloys may be further improved both through the addition of third and fourth alloying elements such as Ca,Ag,Sn or Sr and/or by thermo-mechanical processing where the latter is more environmentally and economically *** practice,procedures based on the application of severe plastic deformation(SPD)are especially suited to produce fine-grained microstructures with improved mechanical,degradation and cell ***-channel angular pressing(ECAP)is a popular SPD technique that has the capability of pro-ducing bulk materials that are sufficiently large for use as typical ***,this review is designed to provide a comprehensive summary of the research that has been undertaken on ECAP-processed biodegradable Mg-Zn alloys.

关键词： Bio-degradation ECAP Fine-grained microstructure Mg–Zn alloys Severe plastic deformation

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Repulsion, Acceleration, and Coalescence between Water Droplets on Superhydrophobic Glass by Triboelectrification

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Langmuir 2024年第25期40卷 13219-13226页

作者： Chen, Kuan Ting Wu, Yu Ping Huang, Yu Fang Hsu, Chin Chi Shieh, Jiann Department of Materials Science and Engineering National United University Miaoli36063 Taiwan Department of Mechanical Engineering National United University Miaoli36063 Taiwan

Manipulating the motion of water droplets on surfaces, which is crucial for various applications, such as microfluidics and heat transfer, presents considerable challenges, primarily due to the significant influence of capillary forces. This effect becomes more pronounced when droplets are in close proximity, often resulting in undesired coalescence. Triboelectrification, which involves charging pure water droplets, is a promising approach to enhance the ability to manipulate water droplets. For effective triboelectrification, charges must accumulate within the droplets;this ensures efficient and sustained droplet manipulation while minimizing dissipation. Low-friction, superhydrophobic, insulating surfaces are ideal for this purpose. However, few studies have explored the application of insulating superhydrophobic surfaces to manipulate droplet motion. In this study, we investigated the behavior of water droplets on insulating superhydrophobic quartz surfaces after triboelectrification. The droplets acquired significant charge when dripped onto a superhydrophobic glass surface. Consequently, these charged droplets exhibited behaviors such as repulsion and acceleration from one another, uphill movement, and rapid long-distance transport to specific positions. These advancements in droplet manipulation techniques hold promise for diverse fields such as microfluidics and heat exchangers. © 2024 American Chemical Society.

关键词： Microfluidics

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The Significance of the Critical Stress Ratio in the Formulation of Nonlinear Constant Life Diagrams for CFRP Laminate Life Prediction

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Journal of The Institution of Engineers (India): Series E 2024年第2期105卷 119-128页

作者： Behera, Alok Kale, Sandeep Thawre, Manjusha M. Ballal, Atul Department of Mechanical Engineering Indian Institute of Science Karnataka Bangalore India Department of Metallurgical and Materials Engineering Visvesvaraya National Institute of Technology Nagpur India

The constant life diagram (CLD), a trusted method for life prediction, is generated based on static strength and constant amplitude fatigue data. This study examines the predictive accuracy of various nonlinear CLDs, including the innovative Anisomorphic CLDs, for a [+ 45,− 45]3S carbon fiber reinforced polymer composite laminate fabricated via autoclave curing with a 59% fiber volume. Initial calculations encompassed ultimate tensile strength (UTS) and ultimate compressive strength (UCS) using a constant crosshead speed of 1 mm/min. Subsequently, constant amplitude fatigue experiments were conducted for five stress ratios, encompassing the critical stress ratio (CSR) (χ = UCS/UTS), R = 0.1 and 0.5 (tension–tension), − 1 (tension–compression), and 5 (compression-compression). The predictive accuracy of three top-performing nonlinear CLDs, i.e., asymmetric Gerber, inclined Goodman, and the innovative Anisomorphic CLD, was assessed through necessary stress-life (S–N) curves. Notably, the novel Anisomorphic CLD, utilizing only static and CSR fatigue data, demonstrated optimal accuracy, positioning the maximum amplitude stress for any random fatigue life (Nf) on CSR. Its practical implementation undoubtedly streamlines the process, saving time, money, and effort required for extensive fatigue data generation. © The Institution of Engineers (India) 2024.

关键词： Fatigue of materials

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