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Analytical and Experimental Studies of the Improved Conductance-Stability and Stretchability of the Liquid Metal-Embedded Composites Based on a Novel Continuous Annular-Shaped Branch Channels

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SSRN 2023年

作者： Li, Jing Wang, Xi Guo, Shu Chen, Shuang Luo, Yiwen Zhao, Shiyan School of Mechanical Engineering Hubei Modern Manufacturing Quality Engineering Key Laboratory Hubei University of Technology Hubei Wuhan430068 China School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Sichuan Chengdu611731 China School of Vehicle and Energy Yanshan University Hebei Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao066004 China

Stretchable and conductance-stable composites are critical for progress in flexible electronics. Tremendous efforts have focused on engineering electrical conductors from liquid metal-embedded elastomers. While these elastomers enable elastic compliance and deformability, the embedded liquid metal is vulnerable to puncture that cause undesired electrical failure, and most of the conductive elastomers are strain sensitive with degenerative conductance upon deformations. Here, we combined analytical and numerical analyses with experimental studies to investigate effects of the innovatively designed continuous annular-shaped branch channels, inspired by the Tesla valve, on the performances of the LM-embedded conductive composite. Theoretically, in the process of mechanical deformations, the as-proposed continuous annular-shaped architecture can dissipate the pressure energy of the fluidic LM to enhance the fracture toughness of the composite, while the LM flow could be accelerated as the deformation was removed to maintain the percolated conductive path, leading to excellent conductive stability. Experimentally, the as-fabricated composite conductor with continuous annular-shaped branch channels can be stretched up to ~80% (more than two times higher than conventional LM-embedded composite), and upon fully activating the conductive pathway, a very high conductivity of ~4×104 S·m-1 and conductance change of less than 2% under varied deformations, including stretching, flexing, twisting and compressing, are realized. It is believed that this novel design strategy will extend the understanding and application opportunities of LM as functional materials in the development of flexible electronics. © 2023, The Authors. All rights reserved.

关键词： Liquid metals

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Calculation of the Crss Ratios of Ti80 Alloy and its Application in Accurate Simulation of Texture in Pilger Cold Rolling

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SSRN 2023年

作者： He, Shengtong Zeng, Weidong Zhao, Zibo Xu, Jianwei Zhou, Dadi State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'An710072 China Defense Technologies Innovation Center of Precision Forging and Ring Rolling School of Materials Science and Engineering Northwestern Polytechnical University Xi'An710072 China Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment Northwestern Polytechnical University Xi'An710072 China Institute of Metal Research Chinese Academy of Sciences Shenyang110016 China

The accurate critical resolved shear stress (CRSS) ratios of different slip systems and deformation history are vital for the texture simulation and controlling for Ti80 alloy pipe during Pilger cold rolling process. In this work, a method to calculate the CRSS ratio based on the statistics of activated slip systems was proposed, which could effectively eliminate the error of activated slip systems proportion caused by texture. No twinning was observed in the deformation of Ti80 alloy, and the activated slip systems of {0002}, {100}, {101} and {112} were observed through uniaxial in-situ tensile test combined with EBSD at room temperature. And the CRSS ratio of Ti80 alloy has been calculated as τBasal: τPrism: τPyram: τPyram=1:0.8:3.5:6. Based on visco-plastic self-consistent (VPSC) model and the calculated CRSS, the texture with shear strain and without shear strain was simulated respectively in the Pilger cold rolling process. The texture component was [0001] ‖ TD, and ‖ AD when the traditional velocity gradient neglecting shear strain was adopted in simulation. However, the shear strain in ZR direction would cause the texture to rotate 30 ° around the [0001] axis. Compared with that only considering the velocity gradient in the normal strain direction, the rolling texture can be more accurately predicted when considering the history of velocity gradient in all directions. © 2023, The Authors. All rights reserved.

关键词： Textures

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Deformation Mechanism of the Tooth Material Filling for Precision forging of Spur Gears 13th

Deformation Mechanism of the Tooth Material Filling for Prec...

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13th International Conference on the technology of Plasticity, ICTP 2021

作者： Feng, Wei Feng, Zengjie Zhou, Mengjuan Mao, Ling Jia, Xiangyang School of Materials Science and Engineering Wuhan University of Technology 430070 Wuhan Hubei China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan Hubei430070 China Hubei Engineering Research Center for Green Precision Material Forming 430070 Wuhan Hubei China

ISBN: (纸本)9783030753801

Spur gears are an important transmission part used widely in many industries. Precision forging of spur gears has a lot of advantages compared with the conventional mechanical cutting method. However, it is very difficult to fill the corner well and the forging load is also very large, especially in the final forming stage during the precision forging of spur gears. So, a three-dimensional (3D) finite element (FE) model for precision forging of spur gears was built by DEFORM-3D software. The stress and strain states in different forming stages and positions of billet have been studied. Also, the Lode parameter μσ was calculated, and the metal flow line method was used to reveal the deformation mechanism of the tooth material. Results show that the Lode parameter of the tooth shape is negative at the beginning of the tooth filling and is positive at the final stage of the tooth filling. Also, the stress state changes from two-directional compressive stress and one-directional tensile stress to three-directional compressive stress. © 2021, The Minerals, Metals & Materials Society.

关键词： Spur gears

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A Stretchable and Conductance-Stable Composite Based on a Liquid Metal-Embedded Elastomer with Continuous Annular-Shaped Branch Channels

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SSRN 2023年

作者： Li, Jing Chen, Shuang Guo, Shu Luo, Yiwen Zheng, Zhong Li, Xiuhong Zhao, Shiyan School of Mechanical Engineering Hubei Modern Manufacturing Quality Engineering Key Laboratory Hubei University of Technology Hubei Wuhan430068 China School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Sichuan Chengdu611731 China School of Vehicle and Energy Yanshan University Hebei Qinhuangdao066004 China Key Laboratory of Advanced Forging and Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao066004 China

Stretchable and conductance-stable composites are critical for progress in flexible electronics. Tremendous efforts have focused on engineering electrical conductors from liquid metal-embedded elastomers. While these elastomers enable elastic compliance and deformability, the embedded liquid metal is vulnerable to puncture that cause undesired electrical failure, and most of the conductive elastomers are strain sensitive with degenerative conductance upon deformations. Here, we report a versatile and practical approach to prepare stretchable LM-embedded elastomeric conductors with continuous annular-shaped branch channels. In the process of mechanical deformations, the annular-shaped branch channels can dissipate the pressure energy of the fluidic LM to enhance the fracture toughness of the composite, while the LM flow could be accelerated as the deformation was removed to maintain the percolated conductive path, leading to excellent conductive stability. The as-proposed composite conductor can be stretched up to ~80% (two times higher than conventional LM-embedded composite), and upon fully activating the conductive pathway, a very high conductivity of ~4×104 S·m-1 and conductance change of less than 2% under varied deformations, including stretching, flexing, twisting and compressing, are realized. It is believed that this novel design strategy will extend the application opportunities of LM as functional materials in the development of flexible electronics. © 2023, The Authors. All rights reserved.

关键词： Liquid metals

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Workability Optimization and Microstructure Regulation for a Multi-Angular Extrusion Process of Az80 Magnesium Alloy

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SSRN 2023年

作者： Su, Zexing Sun, Chaoyang Qian, Lingyun Liu, Chengzhi Zhang, Li Liu, Yanlian School of Mechanical Engineering North University of China Taiyuan030051 China Shanxi Key Laboratory of Advanced Metal Materials for Special Environments North University of China Taiyuan030051 China School of Mechanical Engineering University of Science and Technology Beijing Beijing100083 China Beijing Key Laboratory of Lightweight Metal Forming Beijing100083 China

Engineering stability control of microstructure evolution and precision forming is a key technical issue for the high-performance manufacturing of magnesium alloy components. In this paper, a fine-grain processing window was proposed for the workability optimization and microstructure control of AZ80 magnesium alloy. The hot activation energy map (AEM) and processing map (PM) were established to analyze the hot-working properties and microstructural mechanisms, respectively. The internal state variable (ISV) based finite element (FE) model was introduced to predict the evolutions of grain size and microstructure homogeneity with processing parameters during multi-angular extrusion process. The fine-grain processing window was used to form a magnesium alloy plate. Fine microstructure and good forming performance were obtained with the optimized processing parameters at the complete DRX domain. forming at the processing instability domain shows flow defects and microstructure heterogeneity. The above research can be applied to the processing parameter optimization and microstructure regulation during hot forming processes of magnesium alloy. © 2023, The Authors. All rights reserved.

关键词： Magnesium alloys

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Revealing the Macroscale Texture in an Additive Manufactured Co-Cr-Mo Alloy by Neutron Diffraction

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SSRN 2023年

作者： Tang, Shengyang Luzin, Vladimir Yang, Chao Zhang, Weiwen Wang, Zhi Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of Technology Guangzhou510640 China National Engineering Research Center of Near-net-shape Forming for Metallic Materials South China University of Technology Guangzhou510640 China Lucas HeightsNSW2234 Australia School of Engineering The University of Newcastle CallaghanNSW2308 Australia College of Materials Science and Engineering

We firstly revealed the texture from macroscale of an additive manufactured Co-Cr-Mo alloy, which was produced by laser-based powder bed fusion (PBF-L) using a hatch rotation of 72° between the layers. The results show that the texture observed from the local area (microscale) was superposed. Furthermore, the overall bulk texture (macroscale) is not a simple algebraical sum of individual layers. The Goss texture component was observed in bulk. Instead of 5-fold symmetry texture in bulk, the texture is orthorhombic/tetragonal symmetry. Since this phenomenon occurs due to the manufacturing parameters, which shows the potential that the texture of PBF-L alloys can be tuned for optimizing the microstructure and properties. © 2023, The Authors. All rights reserved.

关键词： Chromium alloys

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Microstructural Evolution and Hot-Compressive Behavior of Waspaloy Forged Bolts: Experimental and Finite Element Simulation

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SSRN 2023年

作者： Su, Ru Li, Jixiao Wu, Dayong Hu, Fuhong Liang, Xueze Shen, Qingyuan Tian, Wenguang Wang, Yalong Ma, Haikun Narayanaswamy, Balaji Dong, Huicong Wang, Qian Hebei Key Laboratory of Material Near-Net Forming Technology School of Materials Science and Engineering Hebei University of Science and Technology Shijiazhuang050018 China Oriental Bluesky Titanium Technology Co. Ltd Yantai264670 China China Astronautics Standards Institute Beijing100071 China School of Engineering Deakin University Geelong Australia State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing100083 China

This study aims to present the optimum technological parameters of hot forging process of aerospace bolt. Deformation Temperature and strain rate were determined according to relevant conditions for commercial bolt production. Deformation behavior and evolution of microstructure of Waspaloy were investigated using hot isothermal compression tests. The results show that the flow stresses show sufficient sensitivity to the deformation parameters and decreased with increase in deformation temperatures and decrease in strain rates. At high strain rates of 5-10 s-1. Flow curves exhibit a pronounced flow softening. At low strain rates of 0.01-0.1 s-1, the curves demonstrate a dynamic equilibrium. Constitute models of Waspaloy is established and the hot deformation energy is calculated as 446.824 kJ/mol. Microstructures showed that at low temperature (1000-1040°C), grain refinement of DRX is the main mechanism of microstructural evolution, while grain growth kinetics is the dominant mechanism at high temperature (1080-1120°C). DRX kinetics model of this superalloy is established. Also, constitutive and dynamic recrystallization models are brought into the Deform-3D software for validation. The results reveal that the simulation results match well with the experimental results. The study can provide guidance on optimizing technological parameters and predict the microstructure for commercial bolt forging. © 2023, The Authors. All rights reserved.

关键词： Finite element method

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Improvement of Magnetic Properties and Hardness by Doing Mo to a Medium Entropy Alloy

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SSRN 2023年

作者： Xiang, Zhaolong Wang, Engang Wang, Tao An, Bailing Xin, Yan Lu, Jun Niu, Rongmei Han, Ke Li, Xi Shanghai Key Lab of Advanced High-temperature Materials and Precision Forming Shanghai Jiao Tong University Shanghai200240 China National High Magnetic Field Laboratory Florida State University TallahasseeFL32310 United States Northeastern University Shenyang110819 China State Key Laboratory of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology Wuhan430074 China

In most technologies for improving material properties, the enhancement of one type of properties usually leads to the degradation of other properties. In this study, we demonstrated that we were able to simultaneously improve hardness, coercivity, and remanence by doping a FeCrCo Medium Entropy Alloy (MEA) with Mo in order to engineer the α→α1 + α2 spinodal decomposition of the MEA. Scanning Transmission Electron Microscopy (STEM) demonstrated that, in samples doped with Mo, decomposition led to an increase in the volume fraction of the α1 phase. Decomposition also led to an enhancement in the composition gap between the α1 and α2 phases, as well as to greater and greater lattice mismatch between the two phases at each stage of decomposition. Our first-principles calculations and Magnetic Force Microscopy (MFM) showed that the saturation magnetization gap between the α1 and α2 phases gradually increased, while the size of the magnetic domain decreased. Despite the fact that the magnetic moment of Mo atom was antiparallel to those of Co and Fe atoms in both α1 and α(according to first-principles calculations), Mo doping actually enhanced rather than diminished the magnetic properties of FeCrCo MEA while at the same time also increasing hardness. © 2023, The Authors. All rights reserved.

关键词： Spinodal decomposition

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Process Optimization of A356 Aluminum Alloy Wheel Hub Fabricated by Low-Pressure Die Casting with Simulation and Experimental Coupling Methods

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SSRN 2023年

作者： Bi, Jiang Dong, Guojiang Zhang, Liping Ma, Shaozhong Zhang, Dongsheng Wang, Ji Li, Wen Xu, Zuo Li, Shide Starostenkov, Mikhail Dmitrievich Yanshan University China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao066004 China CITIC Daika Co. Ltd. Qinhuangdao066004 China Hebei Key Laboratory of Special Delivery Equipment Yanshan University Qinhuangdao066004 China State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao066004 China General Physics Department Altai State Technical University Leninst. 46 Barnaul656099 Russia

The aluminum alloy wheel hub is mainly produced by low-pressure die casting process (LPDC), which casting quality is related to the process parameters. In this paper, the LPDC process of the A356 alloy wheel hub was simulated by ProCAST software, and the forming quality of the wheel hub under different cooling processes has been studied. The result indicated that the liquid aluminum exhibited different solidification characteristics under three cooling processes of 300 L/min for 150 s, 400 L/min for 140 s and 500 L/min for 130 s, and the wheels showed a sequential solidification state under the condition of 400 L/min for 140 s. By comparing the tensile properties of the rim under 300 L/min for 150 s and 400 L/min for 140 s cooling processes, it was found that the latter had higher tensile strength and elongation, which were 178.9 MPa and 6.6%, respectively. The reduction of casting defects, microstructure refinement and uniform distribution of eutectic Si particles in the wheel hub are the main reasons for the improvement of mechanical properties. © 2023, The Authors. All rights reserved.

关键词： Microstructure

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In situ synthesis of a porous high-Mn and high-Al steel by a novel two-step pore-forming technique in vacuum sintering

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Journal of Materials Science & technology 2020年第4期39卷 82-88页

作者： Chuanbing Zhuang Zhigang Xu Shangyu Huang Yu Xia Chuanbin Wang Qiang Shen Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China State Key Lab of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei Engineering Research Center for Green Precision Materials Forming Wuhan University of TechnologyWuhan 430070China

In this work, a novel in-situ two-step pore-forming process in vacuum sintering(ITPVS) technique combining low-temperature processing to produce open pores through the interdiffusion among the intrinsic components in the base steel, and subsequent high-temperature processing to further improve the porosities by the sublimation of Mn via previously formed open pores, was proposed to produce a lab-scale porous Fe Mn Al steel. For the first time, a high-Mn and high-Al steel with open and overall porosities of ~59.6 vol.% and ~63.7 vol.%(percent in volume, vol.%) was synthesized by isothermal holding of the quaternary elemental Fe/Mn/Al/C powder mixture at 640℃ for 1 h and the subsequent sintering at 1200℃ for 1 h. Elemental Al partly incorporated into/reacted with α-Fe and α-Mn after sintering at640℃ for 1 h, leading to the overall and open porosities promoting by ~26.6 vol.% and ~25.6 vol.%. After sintering at 1200℃, Fe Mn Al steel with increased porosities mainly comprising of austenite and α-Fe obtained. The compression strength and corresponding strain of the 1200℃-sintered porous specimen without crack on the surface was ~75 MPa and ~25%. The ITPVS technique takes advantage of using the intrinsic components like Al, Mn and Fe in steels to produce porous structure. This is beneficial to avoiding the contamination of the Fe Mn Al steel matrix caused by the employment of the foreign pore-forming agents.

关键词： Porous metal High manganese steel Two-stage sintering Reaction-diffusion Sublimation method

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