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Novel multi-axis differential velocity sideways extrusion process for 3D curved profiles: Feasibility and forming mechanisms studies

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International Journal of Machine Tools and Manufacture 2025年

作者： Yutong Sun Junquan Yu Guoqun Zhao Xiqing Ge State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan Shandong 250061 PR China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) Shandong University Jinan Shandong 250061 PR China

3D curved profiles or extrudates are widely used in industry; however, their flexible manufacturing with very few processing steps remains a great challenge. In this study, a novel extrusion-bending integrated process, termed multi-axis differential velocity sideways extrusion (MX-DVSE), was developed to form controlled 3D curved extrudates within a single operation, and its forming mechanics was clarified by experiments and finite element modelling. The MX-DVSE equipment was set up, and a set of dies was designed to perform a series of experiments in which two pairs of opposing punches were moved at different velocities. During the MX-DVSE process, the superposition of the velocity gradients generated by the four extrusion velocities induces the bending deformation of the extrudates with a controllable bending radius and deflection angle. The bending radius is determined by velocity gradient, velocity gradient ratio, and extrusion ratio. The bending radius decreased with an increase in the deviation of the velocity gradients from 1, reduction in the velocity gradient ratio, and increase in the extrusion ratio. The velocity gradient and velocity gradient ratio can be unified into a proposed indicator, termed the bending radius control factor, which exhibits a monotonic relationship with the bending radius. The deflection angle depends on the extrusion velocity and the velocity gradient. The bending plane of the extrudate was close to the direction of the velocity gradient, which deviated from 1 or the direction of the maximum velocity. This is reflected in another proposed indicator: the deflection angle control factor. The feasibility of the MX-DVSE technique was further verified by considering the specific shape and size of 3D curved extrudates as the forming targets. The experimental results show that MX-DVSE can form 3D curved extrudates with acceptable dimensional accuracy, and the proposed control factors for the bending radius and deflection angle can accurat

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Microstructural and Mechanical Characteristics in Ni-Mn-Ga Alloys under a Magnetic Field-Assisted Directional Solidification

SSRN

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SSRN 2021年

作者： Hou, Long Yang, Siyuan Yu, Xing Fautrelle, Yves Li, Zongbin Cong, Daoyong Ren, Zhongming Zhu, Yanyan Li, Xi Shanghai Key Lab of Advanced High-temperature Materials and Precision Forming Shanghai Jiao Tong University Shanghai200240 China State Key Laboratory of Advanced Special Steels Shanghai University Shanghai200072 China EPM-Madylam ENSHMG BP 38402 St Martin d’Heres Cedex France Key Laboratory for Anisotropy and Texture of Materials Northeastern University Shenyang110819 China Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing100083 China Shanghai Key Lab of Advanced High-temperature Materials and Precision Forming

In the present work, the effect of a transverse magnetic field-assisted directional solidification (MFADS) on the microstructures in Ni-Mn-Ga alloys has been investigated. The results show that the magnetic field is capable of inducing transversal macro segregation perpendicular to magnetic field, causing the emergence of martensite clusters in austenite matrix. Moreover, the magnetic field alleviates the micro segregation on a dendritic scale and promotes the preferred growth of austenite dendrites. On the basis of above investigation, several special samples are designed using the MFADS to study the crystallographic evolution and mechanical behavior during thermal/stress induced martensite transformation. The martensite cluster in austenite matrix is used to investigate the martensite transformation and growth under cooling-heating cycles. The crystallographic relationship and phase boundary microstructure between martensite and austenite have been characterized. In addition, the micro segregation on a dendritic scale can significantly influence the martensite variant distribution, corresponding to the performance during compressive circles based on the analysis about deformation gradient tensor. The stress-induced super elasticity is closely dependent on orientation, well explained from the perspective of different resolved shear stress factors and correspondence variant pair formation transformation strain. The crystallographic evolution has been characterized during in-situ stress-induced transformation. The findings not only deepen the understanding of martensite transformation and mechanical behavior under a thermal/stress field in Ni-Mn-Ga alloys, but also propose a promising strategy to obtain microstructure-controllable functional alloys by MFADS. © 2021, The Authors. All rights reserved.

关键词： Solidification

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Isogeometric topology optimization based on energy penalization for symmetric structure

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Frontiers of Mechanical Engineering 2020年第1期15卷 100-122页

作者： Xianda XIE Shuting WANG Ming YE Zhaohui XIA Wei ZHAO Ning JIANG Manman XU School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Guangzhou Huagong Motor Vehicle Inspection Technology Co. Ltd.Guangzhou 510640China National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510641China Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing South China University of TechnologyGuangzhou 510641China

We present an energy penalization method for isogeometric topology optimization using moving morphable components(ITO–MMC),propose an ITO–MMC with an additional bilateral or periodic symmetric constraint for symmetric structures,and then extend the proposed energy penalization method to an ITO–MMC with a symmetric *** energy penalization method can solve the problems of numerical instability and convergence for the ITO–MMC and the ITO–MMC subjected to the structural symmetric constraint with asymmetric *** optimization problems of asymmetric,bilateral symmetric,and periodic symmetric structures are discussed to validate the effectiveness of the proposed energy penalization *** with the conventional ITO–MMC,the energy penalization method for the ITO–MMC can improve the convergence rate from 18.6%to 44.5%for the optimization of the asymmetric *** the ITO–MMC under a bilateral symmetric constraint,the proposed method can reduce the objective value by 5.6%and obtain a final optimized topology that has a clear boundary with decreased *** the ITO–MMC under a periodic symmetric constraint,the proposed energy penalization method can dramatically reduce the number of iterations and obtain a speedup of more than 2.

关键词： topology optimization moving morphable component isogeometric analysis energy penalization method symmetric constraint

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Modulating dislocation reactions through preferential hydrogen segregation in bcc metals

arXiv

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arXiv 2024年

作者： Hou, Jie Peng, Ducheng Kong, Xiang-Shan Deng, Huiqiu Hu, Wangyu Chen, Cheng Song, Jun College of Materials Science and Engineering Hunan University Changsha410082 China State key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Shandong Jinan250061 China School of Physics and Electronics Hunan University Changsha410082 China School of Aeronautics Northwestern Polytechnical University Shaanxi Xi’an710072 China Department of Mining and Materials Engineering McGill University MontrealQCH3A 0C5 Canada

The interaction between dislocations is fundamental to plastic deformation, work hardening, and defect accumulation. While extensive research has focused on the impact of solutes on individual dislocations, how solutes affect dislocation-dislocation reactions remains largely unexplored. Here, using atomistic simulations of iron as a model bcc system, we demonstrate that hydrogen solutes enable two /2 screw dislocations to react and form a edge dislocation junction, a process that is otherwise unfavorable in hydrogen-free environments. This phenomenon arises from the preferential segregation of hydrogen around the dislocation, which reduces the energy of the reaction product. The resulting dislocation demonstrates remarkable stability and transforms into a vacancy-type dislocation loop under strain. These vacancy-type dislocation loops can accumulate during continuous deformation and dislocation reactions, serving as precursors for the initiation of structural damage, such as cracking and blistering. Our findings highlight the pivotal role of hydrogen in dislocation reactions, uncover a novel defect accumulation mechanism crucial for interpreting recent experimental observations, and represent a significant advance in understanding hydrogen-induced damage in bcc metals. Copyright © 2024, The Authors. All rights reserved.

关键词： Screw dislocations

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Modeling mechanical properties and plastic strain for hot forming-quenching AA6061 aluminum alloy parts

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International Journal of Lightweight Materials and Manufacture 2020年第1期3卷 66-72页

作者： Li, Huanhuan Hu, Zhili Chen, Yizhe Sun, Qian Zhou, Xianyan Hubei Key Laboratory of Advanced Technology of Automobile Parts Wuhan University of Technology Wuhan430070 China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of Technology Wuhan430070 China Hubei Province Material Green Precision Forming Engineering Technology Research Center Wuhan University of Technology Wuhan430070 China Department of Mechanical Engineering Imperial College London Exhibition Road LondonSW7 2AZ United Kingdom

The hot forming-quenching integrated process (HFQ) has proved to be an effective forming method, achieving good formability and excellent mechanical properties simultaneously for aluminum alloys parts. However, the relationship between the mechanical properties and plastic deformation in the part formed by the HFQ process remains unclear. An analytical model of mechanical properties and plastic strain for an HFQ-formed 6061 aluminum alloys part was established by curve fitting of experimental data. The mechanical properties were evaluated by tensile and micro-hardness tests, and the plastic strain distribution in the HFQ process was analyzed by an automatic strain measuring system. The tensile strength and Vickers hardness showed a linear function for the HFQ-formed 6061 aluminum alloys part, and the relationship between Vickers hardness and plastic strain also presented a linear mathematical function model. The proposed analytical model reveals the mechanical properties of the HFQ-formed 6061 aluminum alloys part quickly and accurately in a non-destructive way. Furthermore, the microstructural characteristics of the HFQ-formed aluminum alloys parts were observed by scanning electron microscopy and transmission electron microscopy to clarify the strengthening mechanism. Disperse and dense Mg2Si precipitates significantly increased with increasing plastic strain during hot forming. The results showed that the improvement in strength was mainly attributable to the increase in precipitates caused by dislocation tangle and lattice distortion after HFQ forming. © 2020 The Authors

关键词： Plastic deformation

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Achieving Hierarchical and Multi-Scale Structure Onto Cu Substrate with Superhydrophobicity and Enhanced Anti-Corrosion Via Electrochemical Etching and Heat Treatment Mechanism

SSRN

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SSRN 2022年

作者： Ye, Yuze Kang, Zhixin Wang, Fen Long, Yan Guo, Tao Chen, Dexin Kong, Jing Xu, Lin Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials School of Mechanical & Automotive Engineering South China University of Technology 381 Wushan Guangzhou510640 China Guangdong Industry Polytechnic 152 Xingangxi Guangzhou510300 China Institute of Advanced Wear & Corrosion Resistant and Functional Materials Jinan University 601 Huangpu Avenue West Guangzhou510632 China Zhuhai Institute of Advanced Technology Chinese Academy of Sciences 2 Hagongda Zhuhai519085 China

In this work, superhydrophobic surfaces with hierarchical and multi-scale micro/nanostructure was fabricated by a simple method without damaging the substrate material. Electrochemical etching and heat treatment were taken to adhere the robust electroplated Ni with the excellent hydrophobic material of polydimethylsiloxane (PDMS) to provide a double-layer protection for the bare Cu substrate. The as-prepared superhydrophobic surface exhibited a high contact angle (CA) of 158.5° and a low slide angle (SA) of 2.4°. Electrochemical corrosion test results showed the corrosion current density of superhydrophobic surface was about 4 orders of magnitude lower than that of bare Cu in 3.5 wt.% NaCl solution, indicating that the superhydrophobic surface had superior corrosion resistance. We also discussed the corrosion resistance mechanism of superhydrophobic surface with hierarchical and multi-scale micro/nanostructure. In addition, good mechanochemical and self-cleaning properties provide effective support for the practical application of superhydrophobic surface. © 2022, The Authors. All rights reserved.

关键词： Corrosion resistance

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Influence of Hydrogen Ingress and Capture on the Mechanical Properties of Spray Formed 2195 Aluminum Alloy

SSRN

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SSRN 2024年

作者： Yang, Xiao-Xu Jiang, Yun-Ze Li, Guo-Ai Shen, Xiao-Yu Lai, Xiao-Ming Wang, Xiao-Ya Jiang, Jian-Tang Zhen, Liang School of Materials Science and Engineering Harbin Institute of Technology Harbin150001 China Jiangsu Haoran Spray Forming Alloy Co. Ltd. Zhenjiang212000 China Beijing Institute of Aeronautical Materials Beijing100095 China Beijing Engineering Research Center of Advanced Aluminum Alloys and Application Beijing100095 China Beijing Spacecrafts Co. Ltd. Beijing100094 China Shenzhen518055 China National Key Laboratory of Precision Hot Processing of Metals Harbin Institute of Technology Harbin150001 China

The current research has focused on the hydrogen capturing and its impact on the mechanical properties of spray-formed 2195 (SF2195) aluminum alloy. Microstructure characterization, thermal desorption spectra (TDS) and hydrogen trapping of characteristic microstructure, are used to investigate the generation, migration and trapping of hydrogen. The retention of moisture in the carrier gas is believed to induce high concentration of hydrogen and the amorphous Al2O3 layer within the SF2195 billet, and the local retention of carrier gas brings about pores with the Al2O3 layer on the inner wall. High concentration of hydrogen is captured in the hot-rolled alloy while around 60% of the hydrogen can be eliminated during the solution-quenching. Particles of T1 phase trap large quantity of hydrogen and the high-density dislocations developed from the pre-stretch promote the migration of hydrogen towards dispersoids and precipitates. The presence of hydrogen and Al2O3 layers contribute to the reduced plasticity of SF2195 alloy. The spreading of flattened pores can induce intensified hydrogen damage effect in local regions and thus contribute to the unusually decreased ductility along the thickness direction in the T8 aged alloy. © 2024, The Authors. All rights reserved.

关键词： Hydrogen

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Improving Mechanical and Wear Properties of Multiphase M50 Steel by Tailoring Bainite Morphology

SSRN

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SSRN 2022年

作者： Du, Yuchen Qian, Dongsheng Ren, Haichao Wu, Min Wang, Feng Hubei key Laboratory of Advanced Technology for Automotive Components Wuhan430070 China School of Materials Science and Engineering Wuhan University of Technology Wuhan430070 China Hubei Engineering Research Center for Green Precision Material Forming Wuhan430070 China Aecc Guizhou Liyang Aviation Power Co. Ltd. Guizhou557300 China

The bainite/martensite multiphase microstructure has shown excellent strength-toughness matching compared with the traditional martensitic microstructure. The ratio of martensite to bainite has always been the focus of performance optimization for the multiphase microstructure. However, the effect of bainite morphology on mechanical properties and wear properties remains unknown. In this work, the microstructure, mechanical and wear properties of M50 steel with different bainite morphologies have been investigated. The austempering parameters were designed to obtain the similar bainite fraction (around 10%) and different bainite morphologies. The microstructure characterization shows that the properly introduced lower bainite can significantly refine the lath structure due to the significant microstructure segmentation effect. When the bundle width and length of lower bainite are respectively 0.107 μm and 3.758 μm, the finest lath microstructure is obtained considering the balance of martensite growth space. As well, the mechanical properties results show that the toughness increases without loss of strength under the tailored bainite. The high temperature wear performance shows that the multiphase microstructure with tailored bainite results in the decrease of friction coefficient by 42% and a decline of wear loss by 37.9% due to the optimized lubrication layer. This work provides a novel perspective to further improve the mechanical and wear properties of multiphase M50 steel by finely tailoring the bainite morphology on the basis of fixed bainite content. © 2022, The Authors. All rights reserved.

关键词： Bainite

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An In-Situ Study on Surface Coloring Mechanism of a 12cr Ferrite/Martensite Stainless Steel During Vacuum Heat Treatment

SSRN

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SSRN 2023年

作者： Wu, Yinze Xia, Shuang Bai, Qin Sun, Wenqiang Wang, Baoshun Zhou, Zhu Liu, Tingguang School of Materials Science and Engineering Shanghai University Shanghai200444 China Key Laboratory for Microstructures Shanghai University Shanghai200444 China State Key Laboratory of Advanced Special Steel Shanghai University Shanghai200444 China Zhejiang Jiuli Hi-Tech Metals Co. Ltd. Huzhou313028 China Engineering Research Center of High Performance Nuclear Power Pipe Forming of Zhejiang Province Huzhou313028 China National Center for Materials Service Safety University of Science and Technology Beijing Beijing100083 China

Color changes during oxidation of a 12Cr ferrite/martensite stainless steel were investigated in-situ by using a high vacuum (5×10-3 Pa) heating stage. The color of the oxide film changed from initial metallic silver to brown, then consecutively to purple, liberty blue, blue-gray and finally to azure blue during the 90 min heat treatment at 690 ℃ in high vacuum. In contrast to the above changes, during oxidation at 1130 ℃, the color changes from metallic silver to brown, then to various blue and finally changed back to metallic silver. The color as a result thin-film interference mainly depended on the oxide film thickness. The significant reduction of the thickness of the HV1130 sample is owing to the volatilization of oxide, which is a result of the reaction of the already formed Cr2O3 with residual oxygen to generate CrO3 gas, which evaporated from the surface at 1130 ℃. Ferrite grains have a much lower oxidation kinetics than that of martensite. © 2023, The Authors. All rights reserved.

关键词： Stainless steel

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The effects of v and Mo addition on microstructure and mechanical properties of 60SI2CR spring steel for grinding balls

The effects of v and Mo addition on microstructure and mecha...

引用

2020 International Conference on Artificial Intelligence and Electromechanical Automation, AIEA 2020

作者： Zuo, Lingli Pan, Peng Chen, Yunbo Jiang, Qingwei Zhang, Tianxiang Zhang, Yang Qi, Yesi Beijing National Innovation Institute of Lightweight Ltd. State Key Laboratory of Advanced Forming Technology and Equipment Beijing China Yunnan Kungang Wear Resistant Material Science Co. Ltd. Yuxi China

ISBN: (纸本)9781728182889

Effects of V and Mo micro-alloy elements on the microstructure and mechanical properties of 60Si2Cr grinding ball steel were studied by means of optical microscope, scanning electron microscope, tensile test, impact test and Rockwell hardness test. Results show that by adding 0.12wt%Mo to 60Si2Cr grinding ball steel, less cementite can be precipitated from the matrix than adding 0.08wt%V, so that the hardness of wear-resistant steel ball is higher. The addition of V can refine the needle-like martensite structure, which is conducive to the improvement of impact toughness. The best comprehensive mechanical properties can be obtained by adding 0.12wt%Mo and 0.08wt%V simultaneously, with the ultimate tensile strength (UTS) of 2 277.7 MPa, the yield strength (YS) of 1 753 MPa, the near surface hardness (SH) of 62 HRC, the core hardness (CH) of 60.7 HRC, and the impact energy of 54.3 J/cm^2. The results show that the addition of 0.08wt% V and 0.14wt%Mo to 60Si2Cr grinding ball steel can effectively improve the impact toughness and hardness. © 2020 IEEE.

关键词： Microstructure

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