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Whole-process modeling of titanium disc forming for gradient distributions of temperature and deformation

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Chinese Journal of Aeronautics 2020年第12期33卷 3550-3563页

作者： Hongwei LI Bin CHEN Mei ZHAN Jing HE Xinxin SUN Xin ZHANG State key laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710072China Shaanxi key laboratory of High-Performance Precision forming Technology and equipment Northwestern Polytechnical UniversityXi'an 710072China

Gradient distributions of temperature and deformation(GDTD)are crucial for achieving dual-performance discs of titanium alloys which is required by the service environment of ***,heating,cooling and deforming sequence in the whole process of the titanium disc forming,which leads to difficulties for achieving GDTD due to a lot of *** solve this problem,a whole-process model of the titanium disc forming for GDTD has been *** the model,heating and cooling via heat radiation,conduction and convection,and deforming by local loading with mold chilling are all *** on heating and cooling as well as deforming were carried out by using a furnace and the Gleeble-3500 *** experimental data are used to determine thermal parameters and constitutive relations of the IMI834 titanium alloy,and then to verify the reliability of the *** the model was used to simulate the evolution rules of temperature and deformation of the titanium *** results show that the heating surface,furnace temperature,billet profile and loading rate play the core role for the control of GDTD,and thus a set of parameters were ***,this work provides a base for developing a new forming technology of the dual-performance titanium discs with the approach of local heating and local loading.

关键词： Gradient distributions of temperature and deformation Heat conduction Heat radiation Mold chilling Titanium disc Whole-process modelling

Effects of carbon content on the microstructure and tensile properties of a low-density steel

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International Journal of Minerals,Metallurgy and Materials 2025年第02期 391-401页

作者： Yongxuan Shang Mingyu Fan Shuyong Jiang Zhongwu Zhang key laboratory of Superlight Materials and Surface Technology Ministry of Education College of Materials Science and Chemical Engineering Harbin Engineering University State key laboratory of Metal Material for Marine equipment and Application Iron & Steel Research Institute of Ansteel Group Corporation

Carbon can change the phase components of low-density steels and influence the mechanical properties. In this study, a new method to control the carbon content and avoid the formation of δ-ferrite by decarburization treatment was proposed. The microstructural changes and mechanical characteristics with carbon content induced by decarburization were systematically examined. Crussard–Jaoul(C–J) analysis was employed to examine the work hardening characteristics during the tensile test. During decarburization by heat treatments, the carbon content within the austenite phase decreased, while Mn and Al were almost unchanged; this made the steel with full austenite transform into the austenite and ferrite dual phase. Meanwhile,(Ti,V)C carbides existed in both matrix phase and the mole fraction almost the same. In addition, the formation of other carbides restrained. Carbon loss induced a decrease in strength due to the weakening of the carbon solid solution. For the steel with the single austinite, the deformation mode of austenite was the dislocation planar glide, resulting in the formation of microbands. For the dual-phase steel, the deformation occurred by the dislocation planar glide of austenite first, with the increase in strain, the cross slip of ferrite took place, forming dislocation cells in ferrite. At the late stage of deformation, the work hardening of austinite increased rapidly, while that of ferrite increased slightly.

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Effect of void size and Mg contents on plastic deformation behaviors of Al-Mg alloy with pre-existing void:Molecular dynamics study

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Chinese Physics B 2022年第6期31卷 580-588页

作者： Ning Wei Ai-Qiang Shi Zhi-Hui Li Bing-Xian Ou Si-Han Zhao Jun-Hua Zhao jiangsu key laboratory of Advanced Food Manufacturing equipment and Technology Jiangnan UniversityWuxi 214122China China Aerodynamics Research and Development Center Mianyang 621000China National laboratory for Computational Fluid Dynamics Beijing 100191China National Graphene Products Quality Supervision and Inspection Center Special Equipment Safety Supervision Inspection Institute of Jiangsu ProvinceWuxi 214174China

The plastic deformation properties of cylindrical pre-void aluminum-magnesium(Al-Mg)alloy under uniaxial tension are explored using molecular dynamics simulations with embedded atom method(EAM)*** factors of Mg content,void size,and temperature are *** results show that the void fraction decreases with increasing Mg in the plastic deformation,and it is almost independent of Mg content when Mg is beyond 5%.Both Mg contents and stacking faults around the void affect the void *** phenomena are explained by the dislocation density of the sample and stacking faults distribution around the *** variation trends of yield stress caused by void size are in good agreement with the Lubarda ***,temperature effects are explored,the yield stress and Young’s modulus obviously decrease with *** results may enrich and facilitate the understanding of the plastic mechanism of Al-Mg with defects or other alloys.

关键词： Al-Mg alloys molecular dynamics nanovoid plastic deformation

BP neural network model for material distribution prediction based on variable amplitude anti-blocking screening DEM simulations

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International Journal of Agricultural and Biological Engineering 2023年第4期16卷 190-199页

作者： Zheng Ma Yongle Zhu Zhiping Wu Souleymane Nfamoussa Traore Du Chen Licheng Xing School of Agricultural Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina key laboratory of Modern Agricultural equipment and Technology Ministry of Education&Jiangsu ProvinceJiangsu UniversityZhenjiang 212013JiangsuChina key laboratory for Theory and Technology of Intelligent Agricultural Machinery and equipment Jiangsu UniversityZhenjiang 212013JiangsuChina College of Engineering China Agricultural UniversityBeijing 100083China jiangsu World Agricultural Machinery Co. Ltd.Picheng Industrial ParkDanyang 212311JiangsuChina

The material feeding changing of combine harvester is easy to cause accumulation and blockage of the vibrating screen,which seriously affects the harvest *** order to alleviate such accumulation and blockages on the vibrating screen surface,the guide chute rotation angle of the improved variable amplitude screening mechanism was selected as the target variable,and EDEM-RecurDyn was employed to simulate the anti-blocking process of the variable amplitude under a changing feeding quantity(0.5 kg/s abnormal,0.2 kg/s normal)of materials(rice grain and stem mixture).A BP(an error back propagation algorithm)neural network was designed and the prediction model of the material distribution was subsequently constructed on the variable screening surface under different chute angles during abnormal *** results revealed a continuous decrease in the quality and time of the material blockage at the front end of the screen surface with the increasing guide chute *** the guide chute angle of 20°-45°and adjustment time of 3-6 s,the blocked and accumulated materials at the front-end screen surface was be moved back to Grid 6 for ***,overtime,the screen surface materials continued to move back under the chute angle of 40°-45°,which had a great impact on the screening *** the guide chute angle of 30°-35°and adjustment time of 4 s,the materials on the screen surface were evenly distributed in Grid *** was able to alleviate the accumulation and blockage of the screen surface *** R of the material distribution prediction model(BP neural network)on the screen surface was determined as 0.97,indicating the high reliability and accuracy of the material distribution model on the screen surface based on the BP neural *** work provides an important reference for the variable amplitude intelligent control of screen surface material anti-blocking.

关键词： variable amplitude material distribution EDEM-RecurDyn BP neural network

Microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with different prestrain levels

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Journal of Materials Science & Technology 2024年第4期171卷 80-93页

作者： Y.H.Zhang H.Li Z.W.Yang X.Liu Q.F.Gu State key laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi key laboratory of High-Performance Precision forming Technology and equipment Northwestern Polytechnical UniversityXi’an 710072China

Ni_(47)Ti_(44)Nb_(9)shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation *** application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to ***-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA ***,microstructure evolution and deformation mechanisms of Ni_(47)Ti_(44)Nb_(9)SMA subjected to vari-ous prestrain levels are still *** this end,microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with prestrain levels of 8%-16%at-28℃(M_(s)+30℃)were *** results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16%.Whereas stageⅡand stageⅢend at prestrains of∼8%and∼12%,*** stageⅡ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the NiTi matrix andβ-Nb *** stageⅢ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(001)compound twins are introduced as a result of the(001)deformation twinning in stress-induced ***{20-1}martensite twins are gradually introduced in stageⅣ.Correspondingly,after subsequent unloading and heating,a higher density of{114}austenite twins form in the specimen with a larger prestrain of 16%.With increasing prestrain from 8%to 16%,the recoverable strainε_(re)^(T)upon heating increases first and then ***ε_(re)^(T)obtains a maximum of 7.03%at 10%prestrain and de-creases to 6.17%at 16%*** increase ofε_(re)^(T)can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(001)compound *** the decrease ofε_(re)^(T)is mainly associated with the irrecoverable strain by{20−1}martensite *** effe

关键词： Ni_(47)Ti_(44)Nb_(9)shape memory alloy Wide transformation hysteresis Thermomechanical loading Microstructure evolution Shape memory behaviors Stress-induced martensitic transformation Deformation twinning

Determination of Elastoplastic Mechanical Properties of the Weld and Heat Affected Zone Metals in Tailor-Welded Blanks by Nanoindentation Test

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 911-918页

作者： MA Xiangdong GUAN Yingping YANG Liu key laboratory of Advanced forming & Stamping Technology and Science of Ministry of Education Yanshan University

The elastoplastic mechanical properties of the weld and heat affected zone metals have comparatively major impact on the forming process of tailor-welded blanks. A few scholars investigated the elastoplastic mechanical properties of the weld and heat affected zone, but they only simply assumed that it was a uniform distribution elastoplastic material different from the base materials. Four types of tailor-welded blanks which consist of ST12 and 304 stainless steel plates are selected as the research objects, the elastoplastic mechanical properties of the tailor-welded blanks weld and heat affected zone metals are obtained based on the nanoindentation tests, and the Erichsen cupping tests are conducted by combining numerical simulation with physical experiment. The nanoindentation tests results demonstrate that the elastoplastic mechanical properties of the weld and heat affected zone metals are not only different from the base materials, but also varying between the weld metals and the heat affected zone metals. Comparing the Erichsen cupping test resulted from numerical with that from experimental method, it is found that the numerical value of Erichsen cupping test which consider the elastoplastic mechanical properties of the weld and heat affected zone metals have a good agreement with the experimental result, and the relative error is only 4.8%. The proposed research provides good solutions for the inhomogeneous elastoplastic mechanical properties of the tailor-welded blanks weld and heat affected zone metals, and improves the control performance of tailor-welded blanks forming accuracy.

关键词： tailor-welded blanks elastoplastic mechanical properties nanoindentation test Erichsen cupping test

Direct-Ink-Writing Printed Strain Rosette Sensor Array with Optimized Circuit Layout

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Chinese Journal of Mechanical Engineering 2023年第4期36卷 205-211页

作者： Peishi Yu Lixin Qi Zhiyang Guo Yu Liu Junhua Zhao jiangsu key laboratory of Advanced Food Manufacturing equipment and Technology School of Mechanical EngineeringJiangnan UniversityWuxi 214122China jiangsu province Engineering Research Center of Micro-Nano Additive and Subtractive Manufacturing Institute of Advanced TechnologyJiangnan UniversityWuxi 214122China

The full-field multiaxial strain measurement is highly desired for application of structural monitoring but still challenging,especially when the manufacturing and assembling for largearea sensing devices is quite *** with the traditional procedure of gluing commercial strain gauges on the structure surfaces for strain monitoring,the recently developed Direct-Ink-Writing(DIW)technology provides a feasible way to directly print sensors on the ***,there are still crucial issues in the design and printing strategies to be probed and ***,in this work,we propose an integrated strategy from layered circuit scheme to rapid manufacturing of strain rosette sensor array based on the DIW *** from the innovative design with simplified circuit layout and the advantages of DIW for printing multilayer structures,here we achieve optimization design principle for strain rosette sensor array with scalable circuit layout,which enable a hierarchical printing strategy for multiaxial strain monitoring in large scale or multiple *** strategy is highly expected to adapt for the emerging requirement in various applications such as integrated soft electronics,nondestructive testing and small-batch medical devices.

关键词： Direct-ink-writing Strain rosette sensor array Layered circuit scheme Printing strategy

Synthesis and Structural Characterization of Two Lead（Ⅱ） Complexes of Bis（3,5-dimethylpyrazolyl）methane

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Chinese Journal of Chemistry 2006年第6期24卷 811-816页

作者：李巧云张文华李红喜任志刚张勇郎建平 key laboratory of Organic Synthesis of jiangsu province School of Chemistry and Chemical EngineeringSuzhou University Suzhou Jiangsu 215123 China jiangsu laboratory of Advanced Functional Materials Changshu Institute of TechnologyChangshu Jiangsu 215500 China

Reactions of lead（Ⅱ） nitrate or perchlorate with bis（3,5-dimethylpyrazolyl）methane （dmpzm）, produced two new Pb（Ⅱ） chelated complexes [Pb（dmpzm）2X2] （X=NO3^- 1, ClO4^- 2）. Both compounds were structurally characterized by elemental analysis, IR spectroscopy, thermal analysis, and single crystal X-ray diffraction. Both compounds are mononuclear with a distorted square antiprismatic PbN4O4 coordination geometry incorporating a pair of O,O＇-bidentate anions and N,N＇-bidentate dmpzm ligands. In the crystals of 1 or 2, the methyl or methylene groups of dmpzm ligand interact with the oxygen atoms of nitrates or perchlorates to afford intra- and intermolecular hydrogen bonding, thereby forming a two-dimensional network 1 or a three-dimensional structure 2.

关键词： lead(Ⅱ) compound synthesis crystal structure bis(3,5-dimethylpyrazolyl)methane

Defect-induced electron rich nanodomains in CoSe_(0.5)S_(1.5)/GA realize fast ion migration kinetics as sodium-ion capacitor anode

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Journal of Energy Chemistry 2023年第12期87卷 583-593,I0014页

作者： Tianlin Li Danyang Zhao Binghui Du Qing Yin Yongzhi Li Xiaolan Xue Fuxiang Wei Jiqiu Qi Yanwei Sui China University of Mining and Technology Xuzhou 221116JiangsuChina jiangsu province Engineering laboratory of High-Efficient Energy Storage Technology and equipment School of Materials Science and PhysicsChina University of Mining and TechnologyXuzhou 221116JiangsuChina

Optimizing charge migration and alleviating volume expansion in anode materials are the key to improve the electrochemical performance for sodium-ion storage ***,a hierarchical porous conducting matrix confining defect-rich selenium doped cobalt dichalcogenide(CoSe_(0.5)S_(1.5)/GA)is constructed as a promising SICs anode based on the guidance of theoretical calculation *** increased defect concentration significantly enhanced the disorder degree of the compound and presented electron aggregation around the S atoms,which effectively modulated the electronic structure,further enabling high rate and ultra-capacity sodium ***,strong interfacial coupling could construct spatial constraint to alleviate volume expansion as well as maintain electrode integrity and *** CoSe_(0.5)S_(1.5)/GA electrode can deliver a high capacity of 310.1 mA h g^(-1)after 2000 cycles at 1 A g^(-1),and the CoSe_(0.5)S_(1.5)/GA//AC sodium ion capacitor can exhibit an outstanding energy density of 237.5 W h kg^(-1).A series of characterization and theoretical calculation convincingly reveal that the defect moieties can regulate the Na^(+)storage and diffusion kinetics,which prove that our defect manufacture coupling with space-confined strategy can provide deep insights into the development of high-performance Na^(+)storage devices.

关键词： Sodium-ion capacitors Defect manufacture Electron accumulation Carrier kinetic