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Strength-ductility balance of AZ31 magnesium alloy via accumulated extrusion bonding combined with two-stage artificial cooling Author links open overlay panel

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Journal of Magnesium and Alloys 2023年第5期11卷 1549-1555页

作者： Tingzhuang Han Guangsheng Huang Heng Li Lifei Wang Hua Zhang Fusheng Pan State Key Laboratory of Solidification Processing School of Materials Science&EngineeringNorthwestern Polytechnical UniversityXi'an 710072PR China Shaanxi Key Lab oratory of High-Performance Precision Forming Technology and Equipment Northwestern Polytechnical UniversityXi'an 710072PR China State Key Laboratory of Mechanical Transmission College of Materials Science and EngineeringChongqing UniversityChongqing 400044PR China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024PR China Institute for Advanced Studies in Precision Materials Yantai UniversityYantai 264005PR China

AZ31 Mg alloy with heterogeneous bimodal grain structure(smaller grain size of 5-20µm and coarser grain size of 100-200µm)was subjected to accumulated extrusion bonding(AEB)at 250℃combined with two-stage artificial cooling in this work,*** water cooling and artificial *** microstructure developed consecutively as a result of discontinuous dynamic recrystallization(DDRX)for the AEBed samples.{10-12}tensile twinning also played an important role for the AEB with local water cooling at the initial extrusion stage in the *** water cooling could further reduce the DRXed grain size to~2.1µm comparing that without water *** the grain growth rate was reduced by artificial cooling out of extrusion *** the combination of two-stage cooling,the fine DRXed grains at sizing band were almost retained with average grain size of~2.3µm after the sheet out of extrusion die,and the unDRXed grains with high residual dislocation density accumulation were also *** tensile tests results indicated that a good strength-ductility balance with a high ultimate tensile strength(319 MPa vs.412 MPa)and fracture elongation(19.9%vs.30.3%)were *** strength enhancement was mainly owing to the grain refinement and local residual plastic strain reserved by the artificial *** excellent ductility originated from fine DRXed microstructure and ED-tilt double peak texture.

关键词： Magnesium alloy Accumulated extrusion bonding Local water cooling Artificial cooling Microstructure Mechanical properties

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Study on the effect of tempering on the impact abrasive wear performance of 45Si2MnCr2Mo ultra-high strength steel 10

Study on the effect of tempering on the impact abrasive wear...

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2023 10th International Conference on advanced Manufacturing technology and Materials Engineering, AMTME 2023

作者： Yang, Ming Chen, Xiaohua Wang, Zidong Pan, Peng Beijing National Innovation of Lightweight Ltd Beijing Beijing100083 China State Key Laboratory for Advanced Forming Technology and Equipment China Academy of Machinery and Technology Beijing100083 China School of Materials Science and Engineering University of Science and Technology Beijing100083 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing100083 China

In this paper, three-body impact abrasive wear tests of 45Si2MnCr2Mo ultra-high strength steel (UHSS) at different tempering temperatures were carried out by using the MLD-10 impact abrasive wear machine. The effects of different tempering temperatures on the wear weight loss and the depth of the hardened layer of UHSS were investigated. The results show that the weight reduction rate of the steels tempered at 150 and 220 °C decreases at first and then increases with time, but the steels tempered at 290 and 360 °C gradually increase with time. The surface and subsurface areas of UHSS are strengthened by work hardening after wear. The wear performance of UHSS should consider the change of weight reduction rate with time rather than just considering short-term weight loss. UHSS tempered at 150 °C has the best comprehensive surface hardness, hardening percentage, and effective hardened layer depth, and the wear process is more uniform. © Published under licence by IOP Publishing Ltd.

关键词： High strength steel

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Impact mechanism of gas temperature in metal powder production via gas atomization

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Chinese Physics B 2021年第5期30卷 437-451页

作者： Peng Wang Jing Li Xin Wang Bo-Rui Du Shi-Yuan Shen Xue-Yuan Ge Miao-Hui Wang State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science&TechnologyBeijing 100083China Beijing National Innovation Institute of Lightweight Ltd Beijing 100083China

This paper aims at studying the influence mechanism of gas temperatures(300 K,400 K,500 K,and 600 K)on gas atomization by simulating the integral atomization process of the close-coupled nozzle in vacuum induction gas atomization(VIGA).The primary atomization is simulated by the volume of fluid(VOF)approach,and the second atomization is studied by the discrete phase model(DPM)combined with the instability breakage *** results show that,at an increased gas temperature,the influences of gas-liquid contact angle and gas temperature in the recirculation zone on the primary atomization are virtually ***,increasing the gas temperature will increase the gas-liquid relative velocity near the recirculation zone and decrease the melt film thickness,which are the main reasons for the reduced mass median diameter(MMD,d50)of primary atomized *** the secondary atomization,increasing the gas temperature from 300 K to 600 K results in an increase in the droplet dispersion angle,which is beneficial to the formation of spherical metal *** addition,increasing the gas temperature,the positive effect of gas-liquid relative velocity increase on droplets refinement overweighs the negative influence of the GMR decrease,resulting in the reduced MMD and diameter distribution *** the analysis of the atomization mechanism,the increase in atomization efficiency caused by increasing the temperature of the atomizing gas,including primary atomization and secondary atomization,is mainly due to the increase in the gas drag force difference between the inner and outer sides of the annular liquid film.

关键词： metallic powders VIGA technology argon temperature two-phase flow

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Simulation and experimental study on pressure transfer in sand mold digital extrusion process 2

Simulation and experimental study on pressure transfer in sa...

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2nd International Conference on Mechanical, Electronics, and Electrical and Automation Control, METMS 2022

作者： Jiang, E.B. Cheng, G. Zhang, G.L. Liang, H.T. Gu, Z.X. Wang, X.L. State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Beijing100044 China Beijing Union University Beijing100101 China

ISBN: (数字)9781510654785

ISBN: (纸本)9781510654778

As a new sand mold forming for patternless casting process, a further study is needed in the extrusion-milling technology. Since the extrusion of sand mold can change the strength and gas permeability, it plays a vital role in the control of shape and performance. To study the law of pressure transfer during extrusion, static and dynamic models of sand particles are developed, and the force transfer mechanism between granular particles is revealed. In this study, the extrusion near-shape process of sand mold with 300mm cavity depth is simulated and analyzed by using discrete element method (DEM). The transmission law of force with 300mm cavity depth under single-sided extrusion is obtained. The deeper the depth of the sand mold cavity, the smaller the force on the bottom of the sand mold, and the more defects in strength and uniformity at the bottom. The correctness of the simulation model is verified by testing the strength and gas permeability of the bottom of the sand mold. This present study provides a research basis for the preparation of high-quality sand mold in extrusion cutting process. © 2022 SPIE

关键词： Finite difference method

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Thickness Distribution Prediction of Superplastic forming Parts Based on Machine Learning and Computer Aided Engineering

Thickness Distribution Prediction of Superplastic Forming Pa...

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Artificial Intelligence and Intelligent Manufacturing (AIIM), International Symposium on

作者： Muqi Sun Chengyue Xiong Yuwei Zhou Yongbing Li Xicheng Zhang China Academy of Machinery Science and Technology State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science & Technology Beijing China Beijing National Innovation Institute of Lightweight Ltd. State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science & Technology Beijing China

ISBN: (数字)9798331541729

ISBN: (纸本)9798331541736

In recent years, the high-speed and high-performance needs of aircraft put forward higher requirements for superplastic forming process, in which uneven thickness distribution is one of the important factors affecting the performance of formed parts, and it increases the cost of design and manufacturing. Therefore, this study proposes using neural networks to predict the thickness distribution of superplastic formed parts. We established BP neural network and PSO-BP neural network to predict the thickness distribution of cross-section edges of box-shaped parts. The prediction performance of the two models is compared and the results show that the PSO-BP neural network has a higher prediction accuracy, especially in the area of the round corners. It is demonstrated that the method is feasible and significantly improves the computational efficiency.

关键词： Accuracy Costs Computational modeling Neural networks Fitting Machine learning Predictive models Manufacturing Computational efficiency Computer aided engineering

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Towards smart scanning probe lithography: a framework accelerating nano-fabrication process with in-situ characterization via machine learning

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Microsystems & Nanoengineering 2023年第5期9卷 281-294页

作者： Yijie Liu Xuexuan Li Ben Pei Lin Ge Zhuo Xiong Zhen Zhang State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua UniversityBeijing 100084China Biomanufacturing Center Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Biomanufacturing and Rapid Forming Technology Key Laboratory of Beijing Beijing 100084China ‘Biomanufacturing and Engineering Living Systems’Innovation International Talents Base(111 Base) Beijing 100084China NT-MDT Spectrum Instruments China office Beijing 100053China

Scanning probe lithography(SPL)is a promising technology to fabricate high-resolution,customized and costeffective features at the ***,the quality of nano-fabrication,particularly the critical dimension,is significantly influenced by various SPL fabrication techniques and their corresponding process ***,the identification and measurement of nano-fabrication features are very time-consuming and *** tackle these challenges,we propose a novel framework for process parameter optimization and feature segmentation of SPL via machine learning(ML).Different from traditional SPL techniques that rely on manual labeling-based experimental methods,the proposed framework intelligently extracts reliable and global information for statistical analysis to finetune and optimize process *** on the proposed framework,we realized the processing of smaller critical dimensions through the optimization of process parameters,and performed direct-write nano-lithography on a large ***,data-driven feature extraction and analysis could potentially provide guidance for other characterization methods and fabrication quality optimization.

关键词： lithography process characterization

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Prediction and Analysis of the Force and Shape Parameters in Variable Gauge Rolling

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Chinese Journal of Mechanical Engineering 2022年第4期35卷 79-92页

作者： Yuanming Liu Zhenhua Wang Tao Wang Jie Sun Xianguang Zheng Dianhua Zhang Qingxue Huang College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment Ministry of EducationTaiyuan 030024China TYUT-UOW Joint Research Center Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

Variable gauge rolling is a new process to obtain a plate for which the thickness changes continuously by continuously and dynamically adjusting the roll gap upward and downward in the rolling *** technology is an efective method for producing lightweight,low-cost,and economical ***,variable gauge rolling is an unsteady process,and the changes in the force and deformation parameters are *** this research,based on the minimum energy theory of the variational principle and considering the characteristics of the roll movement and workpiece deformation comprehensively,the internal plastic deformation,friction,shear and tension powers,and the minimum result of the total power functional in upward and downward rolling are obtained with the frst integral and then with a variation of adopting the specifc plastic power and strain rate vector inner *** analytical results of the deformation and force parameters are also established using the variational *** the precision of this model is certifed using the measured values in a medium plate hot rolling plant and the experimental data for Tailor Rolled Blank *** agreement is ***,the variation rule of bite angle,neutral angle,and location neutral points are shown,and the change mechanism of the friction parameter on the stress state efect coefcient is given in variable gauge *** research proposes a new mathematical model for rolling process control that provides a scientifc basis and technical support for obtaining an accurate section shape in variable gauge rolling production.

关键词： Variable gauge rolling Analytical solution Roll separating force Energy method Neutral point

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Study on the Distribution of Frictional Forces on Z-yarn Continuous Implanted Preforms and Their Applications

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Chinese Journal of Mechanical Engineering 2022年第4期35卷 53-66页

作者： Zitong Guo Zhongde Shan Jihua Huang Debo Xue School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Nanjing University of Aeronautics and Astronautics Nanjing 210016China State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Group Co.ltdBeijing 100083China School of Mechanical Engineering Shandong University of TechnologyZibo 255000China

To improve the quality and efciency of Z-directional 3D preform forming,the Z-yarn frictional force distribution model of the preform and its wear mechanism were *** this study,a tensile force measuring device was designed to measure the force required to replace the guide sleeve,which is equivalent to the Z-yarn frictional *** frictional force is proportional to the number of preform layers and is applied to the preform decreased from the corner,edge,sub-edge,and middle in order.A back propagation neural network model was established to predict the friction at diferent positions of the preform with diferent layers,and the error was within 1.9%.The wear of Z-yarn was studied at diferent frictional positions and after diferent times of successive implantation into the *** results showed that with an increase in the number of Z-yarn implantations and frictional forces,the amount of carbon fber bundle hairiness gradually increased,and the tensile fracture strength damage of the fber was increasingly afected by the frictional *** the corner position of the preform,when the number of implantations was 25,the fber fracture strength decreased non-linearly and substantially;in order to avoid fber fracturing in the implantation process,the Z-yarn needs to be replaced in time after 20–25 cycles of continuous *** study solves the problem of difculty in measuring the force required for individual replacements owing to the excessive number of guide sleeves,puts forward the relationship between fber wear,preform position,and implantation times,solves the phenomenon of fracture in the preform during Z-direction fber implantation,and realizes the continuous implantation of fbers.

关键词： Z-yarn implantation BP neural network Z-yarn wear

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Effect of contact forms on the wear of hard silicon surfaces by soft polymers

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Friction 2021年第5期9卷 918-928页

作者： Zhaoxiang ZHANG Xiaohong JIA Fei GUO Zhongde SHAN Yuming WANG State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China Joint Research Center for Rubber and Plastic Seals Tsinghua UniversityBeijing 100084China State Key Laboratory of Advanced Forming Technology&Equipment China Academy of Machinery Science&TechnologyBeijing 100044China

The mechanism of hard surfaces worn by soft polymers is not clearly *** this paper,a new hypothesis has been proposed,it holds that the stress acting on the hard surface under certain working conditions is the main reason for wear of the hard surface by a soft *** hypothesis was investigated by changing the contact form between *** this,friction tests between six polymer spheres and smooth,rough,and inclined monocrystalline silicon surfaces were carried *** results show that for the same tribo-pair,the silicon surface will not be worn in some contact forms,but in other contact forms it will be *** believe the wear of hard surface by a soft polymer is the result of the combined stress state action on the hard surface.

关键词： polymers silicon surface wear combined stress

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Ultrasonic welding of thermoplastic composites with woven mesh energy directors: Enhanced strength and hygrothermal resistance

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Journal of Materials Research and technology 2025年 36卷 9699-9712页

作者： Dongsheng Yue Guoqun Zhao Jiaying Pan Jiaming Liu Dong Quan State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan Shandong 250061 China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) Shandong University Jinan Shandong 250061 China

In ultrasonic welding of thermoplastic composites, energy directors (EDs) based on thermoplastic films often exhibit low heat generation efficiency and uneven temperature distribution at the welding interface, which negatively affect weld quality and joint strength. To address these limitations, this study introduces a novel plain-woven mesh ED for the ultrasonic welding of carbon fiber-reinforced PPS (CF/PPS) composites. The influence of welding amplitude and displacement on the welding process and joint quality was systematically investigated based on a single-lap shear test. Additionally, the moisture absorption behavior and mechanical performance degradation, and failure mechanisms of welded joints exposed to hydrothermal environments were also investigated. The results demonstrate that the uniform distribution of filament crossings and open areas in the mesh ED significantly enhances its deformation capability under ultrasonic vibration, leading to improved heat generation efficiency and more uniform temperature distribution at the welding interface. As a result, superior weld quality was achieved. By optimizing process parameters, a low defect level of 1.1 % and a maximum shear strength of 32.6 MPa was obtained for the welded joints. Furthermore, after aging at 80 °C and 95 % relative humidity for 12 weeks, the joint strength remained unchanged, demonstrating exceptional resistance to hygrothermal aging. These findings highlight the potential of mesh ED to overcome the limitations of traditional film-type ED, significantly enhancing both the performance and durability of ultrasonic-welded thermoplastic composite joints.

关键词： Thermoplastic composites (TPCs) Ultrasonic welding Energy director (ED) Environmental degradation Welding/joining

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