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

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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Prediction and optimisation of gasoline quality in petroleum refining: The use of machine learning model as a surrogate in optimisation framework

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CAAI Transactions on Intelligence Technology 2024年第5期9卷 1185-1198页

作者： Husnain Saghir Iftikhar Ahmad Manabu Kano Hakan Caliskan Hiki Hong School of Chemical and Materials Engineering National University of Sciences and TechnologyIslamabadPakistan Department of Systems Science Kyoto UniversityKyotoJapan Department of Mechanical Engineering Faculty of Engineering and Natural SciencesUsak UniversityUsakTurkey Department of Mechanical Engineering Kyung Hee UniversityYonginRepublic of Korea

Hardware-based sensing frameworks such as cooperative fuel research engines are conventionally used to monitor research octane number (RON) in the petroleum refining industry. Machine learning techniques are employed to predict the RON of integrated naphtha reforming and isomerisation processes. A dynamic Aspen HYSYS model was used to generate data by introducing artificial uncertainties in the range of ±5% in process conditions, such as temperature, flow rates, etc. The generated data was used to train support vector machines (SVM), Gaussian process regression (GPR), artificial neural networks (ANN), regression trees (RT), and ensemble trees (ET). Hyperparameter tuning was performed to enhance the prediction capabilities of GPR, ANN, SVM, ET and RT models. Performance analysis of the models indicates that GPR, ANN, and SVM with R2 values of 0.99, 0.978, and 0.979 and RMSE values of 0.108, 0.262, and 0.258, respectively performed better than the remaining models and had the prediction capability to capture the RON dependence on predictor variables. ET and RT had an R2 value of 0.94 and 0.89, respectively. The GPR model was used as a surrogate model for fitness function evaluations in two optimisation frameworks based on genetic algorithm and particle swarm method. Optimal parameter values found by the optimisation methodology increased the RON value by 3.52%. The proposed methodology of surrogate-based optimisation will provide a platform for plant-level implementation to realise the concept of industry 4.0 in the refinery.

关键词： genetic algorithms mach in ne learning multi-objective optimisation

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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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Revealing the oxidation growth mechanism and crack evolution law of novel Si-HfO_(2)/Yb_(2)Si_(2)O_(7)/Yb_(2)SiO_(5)environmental barrier coatings during thermal cycling

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Journal of Advanced Ceramics 2024年第10期13卷 1677-1696页

作者： Ruixiang Liu Wenping Liang Qiang Miao Hui Zhao Xiaofeng Zhang Meng Zhang Rongxue Yan Brindha Ramasubramanian Seeram Ramakrishna College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Mechanical Engineering National University of SingaporeSingapore 117575Singapore National Engineering Laboratory for Modern Materials Surface Engineering Technology Institute of New MaterialsGuangdong Academy of SciencesGuangzhou 510651China

The development of Si-HfO_(2)/Yb_(2)Si_(2)O_(7)/Yb_(2)SiO_(5)environmental barrier coatings(EBCs)aims to improve the operational temperature and longevity of ceramic matrix composites(CMCs)in turbine ***,several critical questions remain unanswered,including the oxidation mechanism of Si-HfO_(2)bond coating,the compatibility of its mixed thermally grown oxide(m-TGO)with adjacent layers during thermal cycling,and the evolution pattern of vertical mud-cracks that impact the overall performance in *** plasma spraying physical vapor deposition(PS-PVD),we fabricated these EBCs on a CMC substrate,and thermal cycling tests at 1400,1450,and 1500℃ revealed that their durability reached 200 h.m-TGO growth followed a parabolic model,with the oxygen diffusion activation energy being 133.69 kJ/mol between 1400 and 1450℃ and 101.47 kJ/mol from 1450 to 1500℃,emphasizing that the transport of molecular oxygen is key to controlling the oxidation of m-TGO in this EBC *** residual stresses and stored elastic strain energy build up between m-TGO and adjacent layers,especially around the cristobalite phase transition temperature,causing interlaminar crack formation in later thermal cycles,the stored elastic strain energy remains lower than that of the silicon oxide-thermally grown oxide(SiO_(2)-TGO)formed in Si bond coating *** addition to[110]dislocations,(001)twinning and interaction zones between twinning and dislocations were discovered for the first time,driving the bifurcation of mud ***,controlling the mud-crack density is vital for protection of Yb_(2)SiO_(5)layer,as bifurcated mud-crack tips may converge with adjacent mud-cracks.

关键词： environmental barrier coatings(EBCs) thermal cycling oxidation crack propagation defects

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Low-cost chemical surface smoothing of CO2 laser-etched acrylic using WELD ON 4 acrylic solvent cement

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International Journal of Advanced Manufacturing Technology 2025年第5期138卷 2245-2255页

作者： Moncada, Luis H. Safaripour, Samira Hutter, Tanya Walker Department of Mechanical Engineering The University of Texas at Austin AustinTX78712 United States Materials Science and Engineering Program and Texas Materials Institute The University of Texas at Austin AustinTX78712 United States

With the increasing use of micro-manufactured devices and the demand for low-cost fabrication techniques, this study presents a simple and scalable surface polishing method for laser etched acrylic using WELD-ON 4 acrylic solvent cement, a solvent typically used for bonding thermoplastics. The method’s effectiveness was evaluated by treating acrylic samples up to three times and analyzing changes in transparency, surface roughness average (Ra), luminescence, and wettability. Results show that even a single treatment significantly improved surface smoothness, reduced light scattering, and brought contact angle and optical clarity closer to those of unetched acrylic. After three treatments, the surface became isotropic, with laser-etched lines disappearing. Specifically, a 60% reduction in Ra was observed in the direction perpendicular to the etched lines, while the parallel direction initially showed a similar trend, followed by a slight increase attributed to the formation of surface irregularities caused by the re-solidification of dissolved acrylic. Contact angle measurements indicated that the surface remained hydrophilic, with controllable wettability based on the number of treatments. Overall, this method provides a low-cost, cleanroom-free solution for improving the surface finish of laser-fabricated acrylic components. Its compatibility with complex or recessed geometries makes it particularly suitable for microfluidic devices and other precision applications requiring both optical clarity and controlled surface properties. © The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature 2025.

关键词： Carbon dioxide lasers

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Atomistic simulations of twin facets associated with three-dimensional{1011}twins in magnesium

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Journal of Magnesium and Alloys 2025年第2期13卷 626-639页

作者： Qiyu Zeng Mingyu Gong Houyu Ma Yao Shen Jian-feng Nie Jian Wang Yue Liu State Key Lab of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Center for High-resolution Electron Microscopy(CHEM) School of Physical Science and TechnologyShanghai Tech UniversityShanghai 201210China Department of Materials Science and Engineering Monash UniversityVictoria 3800Australia Department of Mechanical&Materials Engineering University of Nebraska-LincolnLincolnNE 68583USA

Twinning is a deformation mechanism that creates three-dimensional(3D)twin domains through the migration of twin *** occurs via the nucleation and glide of twinning disconnections(TDs),which can pile up to create twin facets.A comprehensive under-standing of twin facets associated with 3D twins,including their atomic structures and energies,is crucial for understanding deformation *** this study,we propose a molecular statics/dynamics(MS/MD)approach to determine characteristic twin facets enclosing 3D non-equilibrium/equilibrium{1011}twin domains,which has been much less studied than the counterpart{1012}twin *** stability of different TD pile-up arrangement with varying line senses informs the morphology of 3D non-equilibrium twins,which are bounded by{1010}_(T)||{1013}_(M),{1011}_(T)||{0002}_(M)and{1013}_(T)||{1013}_(M)coherent facets associated with pile-up of edge TDs,and discrete non-edge TDs aligned along CTBs with their line senses parallel to<4513>,<1101>,<5416><2113>or<1012>*** of semi-coherent facets of equilibrium twins is accompanied by rearrangement of TDs around misfit dislocations.3D equilibrium{1011}twins may comprise{1011}_(T)||{0002}_(M),{1457}_(T)||{3419}_(M),{1657}_(T)||{5617}_(M),{1433}_(T)||{3413}_(M),{0110}_(T)||{0111}_(M)and{0221}_(T)||{0221}_(M)semi-coherent facets in<1210>,<4513>,<1101>,<5416>,<2113>and<1012>axes,respectively.

关键词： Twinning Twin boundary Twinning disconnection Molecular dynamics

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TiO_(2)@C catalyzed hydrogen storage performance of Mg-Ni-Y alloy with LPSO and ternary eutectic structure

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Journal of Magnesium and Alloys 2024年第2期12卷 767-778页

作者： Wenjie Song Wenhao Ma Shuai He Wei Chen Jianghua Shen Dalin Sun Qiuming Wei Xuebin Yu College of Mechanical and Electrical Engineering Shaanxi University of Science and TechnologyXi’anShaanxi 710021China Department of Materials Science Fudan UniversityShanghai 200438China School of Aeronautics Northwestern Polytechnical UniversityXi’anShaanxi 710072China Department of Mechanical Engineering&Engineering Science the University of North Carolina at CharlotteCharlotteNorth Carolina 28223United States of America

A designed Mg_(88.7)Ni_(6.3)Y_(5)hydrogen storage alloy containing 14H type LPSO(long-period stacking ordered)and ternary eutectic structure was prepared by regulating the alloy composition and *** hydrogen storage performance of the alloy was improved by adding nano-flower-like TiO_(2)@C *** decomposition of the LPSO structure during hydrogenation led to the formation of plenty of nanocrystals which provided abundant interphase boundaries and activation *** nanoscale TiO_(2)@C catalyst was uniformly dispersed on the surface of alloy particles,and the"hydrogen overflow''effect of TiO_(2)@C accelerated the dissociation and diffusion of hydrogen on the surface of the alloy *** a result,the in-situ endogenous nanocrystals of the LPSO structure decomposition and the externally added flower-like TiO_(2)@C catalyst uniformly dispersed on the surface of the nanoparticles played a synergistic catalytic role in improving the hydrogen storage performance of the Mg-based *** the addition of the TiO_(2)@C catalyst,the beginning hydrogen desorption temperature was reduced to 200℃.Furthermore,the saturated hydrogen absorption capacity of the sample was 5.32 wt.%,and it reached 4.25 wt.%H_(2) in 1 min at 200℃and 30 bar.

关键词： Hydrogen storage Mg LPSO TiO_(2)@C Synergistic catalysis

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Corrosion behavior of severely plastically deformed Mg and Mg alloys

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Journal of Magnesium and Alloys 2022年第10期10卷 2607-2648页

作者： Ahmad Bahmani Mehrab Lotfpour Milad Taghizadeh Woo-Jin Kim Department of Advanced Materials and Renewable Energy Iranian Research Organization for Science and TechnologyTehran ***Iran Department of Mechanical Engineering University of NevadaRenoNV 89557USA Department of Mechanical Engineering Clemson UniversityClemsonSC 29634USA Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

Magnesium(Mg)alloys have several advantages,such as low density,high specific strength and ***,they also suffer weak points,such as high corrosion,low formability and easy ignition,which makes their applications *** studies have been conducted to overcome these disadvantages and further improve the advantages of Mg *** plastic deformation(SPD)is one of the most important techniques and has great effects on the microstructure refinement of Mg alloys and improvements in their strength and *** researchers have studied the corrosion behavior of SPD-processed Mg alloys in recent ***,these studies have reported some controversial effects of SPD on the corrosion of Mg alloys,which makes the research roadmap ***,it is important to review the literature related to the corrosion properties of Mg alloys prepared by SPD and understand the mechanisms controlling their corrosion *** grain refinement by SPD improves the corrosion properties of pure Mg and Mg alloys,but control of the processing conditions is a key factor for achieving this goal because texture,dislocation density,size and morphology of secondary phase also importantly affects the corrosion properties of Mg *** grain size in the fine grain-size range can decrease the corrosion rate due to the increased barrier effect of grain boundaries against corrosion and the formation of a stable passivation layer on the surface of fine *** texture reduces the corrosion rate because basal planes with the highest atomic planar density are more corrosion resistant than other *** dislocation density after SPD deteriorates the corrosion resistance of the interior grains and thus proper annealing after SPD is *** fine and uniform distribution of secondary phase particles during SPD is important to minimize the micro-galvanic corrosion effect and retain small grains during annealing treatment f

关键词： Magnesium alloys Corrosion Severe plastic deformation Grain size Secondary phase Dislocation density

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Evolution of nonmetallic inclusions in 80-t 9CrMoCoB large-scale ingots during electroslag remelting process

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International Journal of Minerals,Metallurgy and materials 2024年第7期31卷 1525-1539页

作者： Shengchao Duan Min Joo Lee Yao Su Wangzhong Mu Dong Soo Kim Joo Hyun Park School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China Department of Materials Science and Chemical Engineering Hanyang UniversityAnsan 15588Rep.of Korea Department of Materials Science and Engineering KTH Royal Institute of TechnologyBrinellvägen 23Stockholm 10044Sweden Department of Engineering Science and Mathematics Division of Materials ScienceLuleåUniversity of Technology97187 LuleåSweden Casting&Forging Business Unit Nuclear Business GroupDoosan EnerbilityChangwon 51711Rep.of Korea

In combination with theoretical calculations,experiments were conducted to investigate the evolution behavior of nonmetallic inclusions(NMIs)during the manufacture of large-scale heat-resistant steel ingots using 9CrMoCoB heat-resistant steel and CaF_(2)–CaO–Al_(2)O_(3)–SiO_(2)–B_(2)O_(3)electroslag remelting(ESR)-type slag in an 80-t industrial ESR *** main types of NMI in the consumable electrode comprised pure alumina,a multiphase oxide consisting of an Al_(2)O_(3)core and liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO shell,and M_(23)C_(6)carbides with an MnS *** Al_(2)O_(3)and MnS inclusions had higher precipitation temperatures than the M_(23)C_(6)-type carbide under equilibrium and nonequilibrium solidification ***,inclusions can act as nucleation sites for carbide layer *** ESR process completely removed the liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO oxide and MnS inclusion with a carbide shell,and only the Al_(2)O_(3)inclusions and Al_(2)O_(3)core with a carbide shell occupied the remelted *** M_(23)C_(6)-type carbides in steel were determined as Cr_(23)C_(6)based on the analysis of transmission electron microscopy *** substitution of Cr with W,Fe,or/and Mo in the Cr_(23)C_(6)lattice caused slight changes in the lattice parameter of the Cr_(23)C_(6)***,Cr_(21.34)Fe_(1.66)C_(6),(Cr_(19)W_(4)C_(6),Cr_(18.4)Mo_(4.6)C_(6),and Cr_(16)Fe_(5)Mo_(2)C_(6)can match the fraction pattern of Cr_(23)C_(6)*** Al_(2)O_(3)inclusions in the remelted ingot formed due to the reduction of CaO,SiO_(2),and MnO components in the liquid *** increased Al content in liquid steel or the higher supersaturation degree of Al_(2)O_(3)precipitation in the remelted ingot than that in the electrode can be attributed to the evaporation of CaF_(2)and the increase in CaO content in the ESR-type slag.

关键词： nonmetallic inclusion heat-resistant steel electroslag remelting M_(23)C_(6) carbide MnS inclusion supersaturation degree

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Advances in doping strategies for sodium transition metal oxides cathodes:A review

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Frontiers in Energy 2024年第2期18卷 141-159页

作者： Zhijing ZHANG Haoze ZHANG Yaopeng WU Wei YAN Jiujun ZHANG Yun ZHENG Lanting QIAN Department of Chemical Engineering Waterloo Institute of NanotechnologyUniversity of WaterlooWaterloo ON N2L 3G1Canada School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China Institute of New Energy Materials Science and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China

The electrochemistry of cathode materials for sodium-ion batteries differs significantly from lithium-ion batteries and offers distinct ***,the progress of commercializing sodium-ion batteries is currently impeded by the inherent inefficiencies exhibited by these cathode materials,which include insufficient conductivity,slow kinetics,and substantial volume changes throughout the process of intercalation and deintercalation ***,numerous methodologies have been utilized to tackle these challenges,encompassing structural modulation,surface modification,and elemental *** paper aims to highlight fundamental principles and strategies for the development of sodium transition metal oxide ***,it emphasizes the role of various elemental doping techniques in initiating anionic redox reactions,improving cathode stability,and enhancing the operational voltage of these cathodes,aiming to provide readers with novel perspectives on the design of sodium metal oxide cathodes through the doping approach,as well as address the current obstacles that can be overcome/alleviated through these dopant strategies.

关键词： sodium-ion batteries transition metal cathode doping strategy

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