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Effect of Y2O3-Al2O3 sintering additive content on the properties of porous Si3N4 ceramics prepared by digital light processing using Polymethyl methacrylate as pore-forming agent

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Ceramics International 2025年

作者： Wu, Ya-Ru Huang, Hai-Lu Tian, Chong Wu, Jia-Min Liu, Chun-Lei Guo, Lin Cai, Wei-Hao Yang, Ling-Hao Liu, Zhi-Wei Zhang, Yang-Ze Luo, Zhi-Cong Su, Sen Shi, Yu-Sheng State Key Laboratory of Materials Processing and Die & Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan430074 China Engineering Research Center of Ceramic Materials for Additive Manufacturing Ministry of Education Wuhan430074 China Wenzhou Key Laboratory of Microwave Communication Materials and Devices Wenzhou Advanced Manufacturing Institute of HUST Wenzhou325035 China

Porous Si3N4 ceramics have been widely used in aerospace and military industry due to their excellent mechanical properties. Digital light processing (DLP) technology offers an effective route to prepare porous Si3N4 ceramics. In this paper, porous Si3N4 ceramics were successfully fabricated by DLP technology using Polymethyl methacrylate (PMMA) as pore-forming agent, and the effects of the sintering additive (Y2O3-Al2O3) content on the properties of Si3N4 ceramic slurry, green bodies and sintered parts were systematically studied. With the increase of sintering additive content from 2 wt% to 14 wt%, the viscosity of the Si3N4 slurry decreased and the cure depth of that increased. It was found that Y2O3 in sintering additives could induce the growth of β-Si3N4 grain and the fracture mode of Si3N4 ceramics changed from transgranular fracture to intergranular fracture gradually. Additionally, the porosity of porous Si3N4 ceramics first decreased and then increased, while the bulk density, flexural strength of the sintered samples first increased and then decreased with the increase of the sintering additive content. When the content of Y2O3-Al2O3 sintering additives was 10 wt%, the flexural strength of the Si3N4 ceramics reached the maximum value of 459.38 MPa. This research is of great significance for the mechanical property improvement of porous Si3N4 ceramics prepared by DLP. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Machinability

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Microstructure and mechanical properties of extruded Mg-Sn alloys with a heterogeneous grain structure

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Journal of Magnesium and Alloys 2024年

作者： Tong, Lin Jiang, Jing Bi, Guangli Li, Yuandong Chen, Tijun Zhang, Xiaoru Fang, Daqing State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology Lanzhou730050 China School of Material Science and Engineering Lanzhou University of Technology Lanzhou730050 China State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an710049 China

The high-strength Mg-7Sn alloys (wt.%) with a heterogeneous grain structure were prepared by low-temperature extrusion (230 °C) with the extrusion ratio of 9:1 (9E230) and 17:1 (17E230). The two extruded alloys contained fine dynamic recrystallization (DRX) grains (FG) and coarse unDRX grains (CG). The difference in deformability between CG and FG leads to the formation of heterogeneous grain structure. The average grain size and basal texture intensities increased while the volume fraction of CG decreased with increasing extrusion ratio. Tensile testing results indicated that the extruded 17E230 alloy exhibited higher tensile strengths than 9E230 alloy, whose tensile yield strength (σ0.2), ultimate tensile strengths (σb), and elongation to failure (Εf) were 231.1 MPa, 319.5MPa, and 12.54 % respectively. The high tensile strengths of the extruded alloy mainly originated from grain refinement, texture strengthening, precipitation strengthening from a great number of nano-scale Mg2Sn phases, solid solution strengthening and hetero-deformation induced (HDI) strengthening, while the good ductility of the alloy was also mainly attributed to grain refinement, activation of the non-basal slip systems and HDI hardening. © 2024

关键词： Tensile strength

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Design and Strengthening Mechanism of Silver-Carbon Synergistic Reinforced Al Matrix Composites

SSRN

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SSRN 2023年

作者： Li, Junguo Yang, Xuebin Li, Peibo Zhang, Yang Luo, Guoqiang Shen, Qiang Sun, Yi State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Chaozhou Branch of Chemistry and Chemical Engineering Guangdong Laboratory Chaozhou521000 China Hubei Longzhong Laboratory Hubei Xiangyang441000 China

Owing to inadequate interface contact between carbon and aluminum, enhancing the Al/C interface is crucial for the fabrication of high-performance Al matrix composites. This study selected polyvinyl butyral (PVB) with excellent dispersion properties as the carbon source. Simultaneously introducing silver to achieve synergistic reinforcement between silver and carbon in Al matrix composites, offering a novel reinforcement approach for Al matrix composites. The Al-16Ag-C composite is fabricated through the in-situ pyrolysis of PVB followed by hot pressing sintering. Subsequently, the effect of temperature on the microstructural evolution and mechanical properties of the composite is investigated. Microstructural characterization demonstrates the formation of two alloy phases, namely Ag2Al and Al4C3, within the Al-16Ag-C composite. The alloy phases, distributed at the grain boundaries, enhance the material’s strength by impeding dislocation motion, increasing dislocation density within the matrix, and limiting grain growth. The Al-16Ag-C composite, sintered at 630 °C, exhibits a remarkable ultimate tensile strength of 481 MPa and an elongation of 22.25%, representing a significant enhancement compared to pure Al. © 2023, The Authors. All rights reserved.

关键词： Polyvinyl butyral

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Towards intelligent design optimization: Progress and challenge of design optimization theories and technologies for plastic forming

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Chinese Journal of Aeronautics 2021年第2期34卷 104-123页

作者： Heng LI Jingchao YANG Guangyao CHEN Xin LIU Zhao ZHANG Guangjun LI Wenhui LIU State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Poly technical UniversityXi'an 710072China Chengdu Aircraft Industry(Group)Corporation Ltd. Chengdu 610092China High Temperature Wear Resistant Materials and Preparation Technology of Hunan Province National Defence Science and Technology Laboratory Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and ConversionSchool of Materials Science and EngineeringHunan University of Science and TechnologyXiangtan 411201China

Plastic forming is one of enabling and fundamental technologies in advanced manufacturing chains. Design optimization is a critical way to improve the performance of the forming system, exploit the advantages of high productivity, high product quality, low production cost and short time to market and develop precise, accurate, green, and intelligent(smart) plastic forming technology. However, plastic forming is quite complicated, relating to multi-physics field coupling,multi-factor influence, multi-defect constraint, and triple nonlinear, etc., and the design optimization for plastic forming involves multi-objective, multi-parameter, multi-constraint, nonlinear,high-dimensionality, non-continuity, time-varying, and uncertainty, etc. Therefore, how to achieve accurate and efficient design optimization of products, equipment, tools/dies, and processing as well as materials characterization has always been the research frontier and focus in the field of engineering and manufacturing. In recent years, with the rapid development of computing science, data science and internet of things(Io T), the theories and technologies of design optimization have attracted more and more attention, and developed rapidly in forming process. Accordingly, this paper first introduced the framework of design optimization for plastic forming. Then, focusing on the key problems of design optimization, such as numerical model and optimization algorithm,this paper summarized the research progress on the development and application of the theories and technologies about design optimization in forming process, including deterministic and uncertain optimization. Moreover, the applicability of various modeling methods and optimization algorithms was elaborated in solving the design optimization problems of plastic forming. Finally, considering the development trends of forming technology, this paper discusses some challenges of design optimization that may need to be solved and faced in forming pr

关键词： advanced manufacturing Design optimization Deterministic optimization(DOP) Intelligent design optimization(IDO) Plastic forming Uncertain optimization(UOP)

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Self-Adaptive Control System for Additive Manufacturing Using Double Electrode Micro Plasma Arc Welding

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Chinese Journal of Mechanical Engineering 2021年第3期34卷 285-298页

作者： Nan Li Ding Fan Jiankang Huang Shurong Yu Wen Yuan Miaomiao Han School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of TechnologyLanzhou 730050China School of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050China

Wire arc additive manufacturing(WAAM)has been investigated to deposit large-scale metal parts due to its high deposition efficiency and low material ***,in the process of automatically manufacturing the high-quality metal parts by WAAM,several problems about the heat build-up,the deposit-path optimization,and the stability of the process parameters need to be well *** overcome these issues,a new WAAM method based on the double electrode micro plasma arc welding(DE-MPAW)was *** circuit principles of different metal-transfer models in the DE-MPAW deposition process were analyzed *** effects between the parameters,wire feed rate and torch stand-off distance,in the process of WAAM were investigated *** addition,a real-time DE-MPAW control system was developed to optimize and stabilize the deposition process by self-adaptively changing the wire feed rate and torch stand-off ***,a series of tests were performed to evaluate the control system’s *** results show that the capability against interferences in the process of WAAM has been enhanced by this self-adaptive adjustment ***,the deposition paths about the metal part’s layer heights in WAAM are ***,the appearance of the WAAM-deposited metal layers is also improved with the use of the control system.

关键词： Double electrode microplasma arc welding Additive manufacturing Wire feed rate Torch stand-off distance Self-adaptive adjustment

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Influence of rotation tool-induced friction regime transformation on heat generation and material flow during friction stir welding: a computational fluid dynamics study

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The International Journal of advanced Manufacturing technology 2025年 1-16页

作者： Qiao, Junnan Shi, Qingyu Chen, Shujun Yang, Chengle Han, Yang Chen, Gaoqiang State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment Department of Mechanical Engineering Tsinghua University Beijing China Key Laboratory for Advanced Materials Processing Technology Ministry of Education Beijing China CRRC Technology Innovation (Beijing) Co. Ltd Beijing China Engineering Research Center of Advanced Manufacturing Technology for Automotive Components Ministry of Education Beijing University of Technology Beijing China

This study employs computational fluid dynamics (CFD) simulations, incorporating an advanced shear stress boundary condition at the tool-workpiece interface, to investigate the influence of tool rotation speed on the interface friction regime, material flow, and heat generation. Experimental measurements of the temperature cycle curve, the shape of plastic deformation zone, and the deposition position of marking material validate the simulation accuracy. The simulation results indicate a transition in the friction mechanism from sliding to sticking as the tool rotation speed increases. At higher tool rotation speeds, the total heat generation depends on the strength of the material itself. Therefore, tool rotation speeds in a certain range will not significantly affect the heat generation. Regardless of the tool rotation speed, the material flow from the front of the metal through the pin’s influence zone consistently follows a straight-through pattern. However, at higher tool rotation speeds, some materials flowing through the shoulder’s influence zone from the front of the metal rotate around the tool multiple times, exhibiting a multi-turn flow pattern. The deposition position of marking materials also changes from a symmetric to an asymmetric distribution when the friction regime transitions from sliding to sticking.

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Mechanism of high temperature oxidation of Inconel 625 superalloy with various solution and ageing heat treatment processes

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Transactions of Nonferrous Metals Society of China 2024年第11期34卷 3662-3676页

作者： Jiang-kun FAN Hong-ci YANG Pei-zhe ZHANG Jia-yu LI Zhan-jie JING Fu-long CHEN De-gui LIU Bin TANG Hong-chao KOU Jin-shan LI State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China National&Local Joint Engineering Research Center for Precision Thermoforming Technology of Advanced Metal Materials Xi’an 710072China Chongqing Innovation Center Northwestern Polytechnical UniversityChongqing 401135China AVIC Manufacturing Technology Institute Beijing 100024China

The high-temperature oxidation behaviour of the Inconel 625 alloy at 950℃ was investigated after different ageing *** effect of heat treatment on the oxidation behaviour of the alloy was analysed by characterizing the structure and elemental distribution before and after *** results reveal that the two ageing treatments at 650℃ for 500 h and at 750℃ for 400 h both reduced the oxidation mass *** oxidation at 950℃,an outer Cr_(2)O_(3) layer and inner Al_(2)O_(3) are identified as the main oxidation ***,Nb_(2)O_(5) andδ(Ni_(3)Nb)phases precipitated after *** ageing treatments cause the rapid generation of a dense Cr_(2)O_(3) layer on the surface,which prevents the diffusion of oxygen into the matrix,reduce the Al_(2)O_(3) inward growth depth,and improve the oxidation resistance of the alloy.

关键词： Inconel 625 alloy ageing treatment oxidation behaviour oxidation film kinetics

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First-principles study on lattice structures and electronic properties of Al/Al2S3 interface

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MRS Communications 2025年 1-6页

作者： Zhao, Qing-shan Li, Wen-xiang Xue, Hong-tao Tang, Fu-ling State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals Lanzhou University of Technology Lanzhou China School of Mechanical Engineering Lanzhou Petrochemical University of Vocational Technology Lanzhou China School of Materials Science and Engineering Lanzhou University of Technology Lanzhou China

The interfacial crystal structures and electrical properties of the collector fluids Al and Al2S3 were studied. For the semi-coherent interface whose lattice matching degree is only 7.99%, the binding energy of the interface is − 1.287 J /m2 when the interface distance is 2.448 Å. It was found that the accumulation of electrons from Al to Al2S3 promoted the formation of a stable interface that exhibited metallic conductivity. After the interface is formed, electrons need to overcome the energy barrier of 1.71 eV to enter Al2S3, which increases the difficulty of fluid collection. The formation of the Al/Al2S3 interface leads to the decline in the conductivity of the current collector and the stability of the Al current collector

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Rationally Designing Anti-Poisoning Polymer Electrolyte by Electronegativity Modulation: Towards Efficient Ammonia-Cracked Hydrogen Fuel Cells

SSRN

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SSRN 2023年

作者： Shuai, Jiaqi Zhao, Shengqiu Liao, Yucong Wu, Fanglin Wang, Rui Wang, Letian Shen, Chunhui Tang, Haolin State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Department of Polymer Materials & Engineering School of Material Science & Engineering Wuhan University of Technology Wuhan430070 China Hubei Key Laboratory of Fuel Cells Wuhan University of Technology Wuhan430070 China

Ammonia as a hydrogen enrichment medium has tremendous advantages over pure hydrogen in terms of transportation and utilization. The high-efficiency anti-ammonia-poisoning membrane electrode assembly (MEA) is pivotal for the practical implementation of ammonia-resistant proton exchange membrane fuel cells (PEMFCs). As for the polymer electrolyte, which is an integral part of the proton exchange membrane (PEM) and catalytic layer (CL) binder in the MEA, structural design is an effective way to improve its resistance to ammonia poisoning. Herein, an in-depth study of sulfonimides with superacidic structures reveals that the proton dissociation energies can be altered by tuning the terminal groups with different electronegativity and enhancing the competitive adsorption of protons on Pt. Four perfluorinated backbone sulfonimides (PFSI-x (x= TSM, MSA, ESA, and iPSA)) with distinct charge delocalization were fabricated by grafting different electronegative monomers onto the perfluorosulfonyl fluoride (PFSF). The results show that PFSI-TSM possesses a higher electrostatic potential (2.69 eV) and the lowest activation energy (12.07 KJ/mol). Meanwhile, the performance of the PFSI-TSM PEM fuel cell is 40.6% higher than the PFSA at 80°C, 100% relative humidity (RH) under 100 ppm NH3, with a maximum power density of 635.2 mW/cm2. The underlying reason for enhanced performance is in virtue of the more electronegative end groups render the superacid electrolyte with higher acidity and pKa values, which change the direction of the acid dissociation equilibrium reaction on the Pt surface, enhance the competitive adsorption of protons in the MEA and reduces the probability of ammonia adsorption poisoning. The insights in charge delocalization and proton ionization construct the structure-property relationship which would provide the guidance for a rational design of PEM for ammonia-resistant fuel cells. © 2023, The Authors. All rights reserved.

关键词： Electronegativity

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Long lifespan Li-Se battery: Advances, challenges and prospects

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Journal of Energy Chemistry 2025年 102卷 712-733页

作者： Hongyan Li Thomas L. Madanu Tarek Barakat Wen-Da Dong Alexandru Vlad Xikun Zhang Cheng-Bin Jin Yu Li Bao-Lian Su College of Materials and Chemistry China Jiliang University Hangzhou 310018 Zhejiang China Laboratory of Inorganic Materials Chemistry (CMI) Namur Institute of Structured Matter (NISM) University of Namur 61 rue de Bruxelles B-5000 Namur Belgium State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430074 Hubei China Institute of Condensed Matter and Nanosciences Molecular Chemistry Materials and Catalysis Université catholique de Louvain Louvain-la-Neuve Belgium

Lithium-selenium (Li-Se) batteries have attracted increasing attention as one of the next-generation battery systems due to much higher electronic conductivity and comparable volumetric capacity of Se compared to the popular sulfur cathode. However, its practical application still faces great challenges, especially the rapid capacity decay triggered by the loss of active Se species. A comprehensive review to uncover the in-depth failure mechanism and provide targeted solutions to promote the stable operation of Li-Se batteries is urgently needed. This review systematically summarizes the strategies in the new perspective, focusing on the optimization of Se utilization in Li-Se batteries by keeping a high Se maintenance in the cathode and accelerating the electrochemical kinetics of lithium polyselenides (LiPSe) conversion. On the basis of structural design and Li 2 Se active material introduction to accommodate volume expansion, blocking shuttle transport of LiPSe by physical/chemical adsorption, bonding Se with polymers or cathode electrolyte interphase (CEI) construction, and catalytic design to accelerate the conversion of LiPSe, different strategies for improving the utilization of Se have been evaluated and discussed. To address the inevitable loss of Se, prospects on inactive Se reactivation and Li protection are detailedly proposed and analyzed referring to the chemistry and corrosion science. Additionally, the perspectives on the future design and comprehensive parameter evaluations for the optimization of Li-Se batteries are recommended. This review comprehensively explains the causes and solutions of capacity fading and provides potential efforts for lifespan expansion of batteries, shedding light on the future development of Li-Se batteries.

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