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SSRN 2025年

作者： Li, Huanqing Zhao, Yuhong Song, Zhuo Tian, Xiaolin Dong, Ruifeng Zhang, Yuntao Hou, Hua School of Materials Science and Engineering MOE jointly Collaborative Innovation Center for High-performance Al/Mg based Materials Shanxi Key Laboratory of Intelligent Casting and Advanced Forming for New Materials North University of China Taiyuan030051 China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology Beijing Beijing100083 China School of Materials Science and Engineering Taiyuan University of Science and Technology Taiyuan030024 China Institute of Materials Intelligent Technology Liaoning Academy of Materials Shenyang110004 China

Modulating serrated grain boundaries (SGB) has the potential to enhance fracture properties in materials. This work investigates the crack behavior at SGB during loading through high-resolution transmission electron microscopy, quasi in-situ electron backscatter diffraction and phase field crystal simulations. Experimental results demonstrate the presence of abundant SGBs in the transition zone of rolled pure magnesium, with nano-crack initiation and propagation at these boundaries driven by basal or prismatic slip at varying angles between the grains. Additionally, large shear strains are observed in the SGB bending regions, and portions of these regions that align with the loading direction impede crack propagation. Previous studies have suggested that a loading direction perpendicular to the grain boundary (GB) promotes intergranular fracture. However, our research demonstrates that the influence of the angle between GB and the loading direction on crack propagation is localized, with previous conclusions valid only within a strain range of 10-27%. Beyond this critical strain, cracks predominantly transgranular propagate in a brittle manner, with a weaker effect in the loading direction. Furthermore, when the angle between SGB and the loading direction is less than 65°, the proportion of the SGB parallel to the loading direction increases, thereby inhibiting intergranular fracture. Additionally, SGB curvature significantly impacts crack extension, with an optimal curvature of approximately 0.151 1/nm for double-serrated grain boundaries that effectively suppresses nano-crack propagation. This work may provide insights into enhancing material fracture strength through the control of SGB. © 2025, The Authors. All rights reserved.

关键词： Crack propagation

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Material flow characteristics and deformation law during dual directional hot forging of the steel-aluminium spur gear

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Procedia Manufacturing 2020年 50卷 425-428页

作者： Wei Feng Xiangyang Jia Biao Liu Ming Gao School of Materials Science and Engineering Wuhan University of Technology Wuhan Hubei 430070 China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan Hubei 430070 China Hubei Engineering Research Center for Green Precision Material Forming Wuhan Hubei 430070 China

To study the material forming characteristic and deformation law during dual directional hot forging (DDHF) of the steel-aluminum spur gear, a thermo-mechanical coupled finite element model (FEM) was built using DEFORM-3D software. Billet was designed into two parts—core cylinder and outer ring. 20CrMnTi steel and pure aluminum are selected as the materials of the outer ring and core cylinder, respectively. The steel outer ring formed the teeth of the spur gear and heated 1000°C, while the aluminum core formed the center of the spur gear and heated 400°C. The heated steel-aluminum billet was deformed under biaxial forging pressure. The FE simulation was carried out and the metal forming characteristic and flow law were analyzed. The simulation results show that the core pure aluminum has bigger deformation in the middle part and extruding the steel ring forming part of the teeth. The final forging temperature of billet increases and the forming load decreases with the increasing the forging speed.

关键词： Spur gears dual directional hot forging steel-aluminum materials thermo-mechanical coupled FEM deformation characteristic

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Study on relationship of intellectualization between hydraulic mobile machinery and hydraulic components 7

Study on relationship of intellectualization between hydraul...

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7th International Conference on Advances in Construction Machinery and Vehicle Engineering, ICACMVE 2019

作者： Xu, Yangzeng Liu, Siyuan Shanghai Hydraulics Pneumatics and Seal Industry Association Shanghai200000 China Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Hebei.Qinhuangdao066004 China MOE Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University China

ISBN: (纸本)9781728139050

This paper analyses the current situation of insufficient intellectualization of hydraulic system and component in the process of intellectualization of Engineering robots, and puts forward the way to develop hydraulic intelligent components. At the present the hydraulic intelligent components are still in the initiation period, the main requirements and means of product development are put forward in this paper. Emphasis is laid on the feasibility of implicit state space method as the core theory of hydraulic intelligent components, and a control algorithm of hydraulic components based on implicit state equation is proposed, which can realize the function of autonomous control. A parameter identification method based on the inverse operation of the above control algorithm is proposed, which can be used to construct a model-based intelligent fault diagnosis system for grey box identification, and for future use in the hydraulic technology. Fault diagnosis of hydraulic system and components are prospected. Hydraulic intelligent components are to be an agent. It continues to develop in application in intelligent construction machinery, and will inevitably open up a new practical application market in the development of digital twin technology. © 2019 IEEE.

关键词： State space methods

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Optimization of Casting Process of Headstock Based on Numerical Simulation

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Journal of Physics: Conference Series 2021年第2期1802卷

作者： Yifei Wang Zhongde Shan Haoqin Yang Xueliang Zhang Mengmeng Zhao State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Group Co. Ltd Beijing 100083 China

In this paper, the casting process optimization design of a certain type of headstock is carried out by numerical simulation technology of casting process. Designed the pouring plan based on theoretical calculation; based on the numerical simulation results, quantitatively designed the riser size, and rationally arranged the pouring riser system based on the equilibrium solidification theory, which can reduce the shrinkage porosity and shrinkage defects in the casting process and increase the process yield; Finally, a sand core production plan is provided based on the precision machining technology of the moldless casting mold, which provides a new idea for the process plan design of complex spindle box castings.

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Influence of Intermetallics and Solute Solution on the Performance of the Heat Treated Hvdc Alsimgmncu Alloys at Nano-Scale

SSRN

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SSRN 2022年

作者： Liu, Fei Qin, Jun Zhao, Haidong Jiang, Yuanhang Zheng, Huiting Chen, Bo National Engineering Research Center of Near-net Shape Forming for Metallic Materials South China University of Technology Guangzhou510641 China Key Laboratory of Advanced Civil Engineering Materials Ministry of Education School of Materials Science and Engineering Tongji University Shanghai201804 China Department of Gastrointestinal Surgery Renji Hospital School of Medicine Shanghai Jiao Tong University Shanghai200127 China London Centre for Nanotechnology University College London LondonWC1H 0AH United Kingdom

A method to calculate solute solution in Al alloy castings, based on the serial block-face scanning electron microscopy (SBFSEM) measurement at nano-scale, was proposed. For the high vacuum die casting (HVDC) Al-10Si-0.4MgMn-0.6Cu alloy, it reveals that the solute fractions of the Si, Mg and Cu in the Al matrix reaches about 0.39 wt.%, 0.15 wt.%, and 0.10 wt.%, respectively, under the as-cast condition. After it was heat treated via T5 process, larger nano-scale precipitation phases with low density and non-uniform distribution were formed in the α-Al matrix. After T6-treated, the narrow neck regions of the seaweed-like α-Fe phase particles were fragmented as well, but could not dissolve into the α-Al matrix. The solute fractions of the Si, Mg and Cu in the α-Al matrix increases to 0.75 wt.%, 0.23 wt.%, and 0.43 wt.%, respectively. Hence, finer nano-scale precipitation phases with high density and uniform distribution are formed in the Al matrix. Consequently, the ultimate tensile strength, yield strength and elongation of the T6-treated alloy simultaneously increase of about 15%, 52% and 63%, respectively. It presents that the solute solution during high pressure die casting solidification has decisive effect on the mechanical properties before and after heat treatment. © 2022, The Authors. All rights reserved.

关键词： Scanning electron microscopy

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Optimization design and application of material transfer device based on DEM 7

Optimization design and application of material transfer dev...

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7th International Conference on Advances in Construction Machinery and Vehicle Engineering, ICACMVE 2019

作者： Xu, Yangsheng Zhang, Chunhui Zhao, Jingyi Li, Wenlei Qin, Yalu Lin, Jishen Port Machinery Co. Ltd. Hebei Port Group Qinhuangdao066004 China Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Qinhuangdao066004 China

ISBN: (纸本)9781728139050

Aimed at the problems of plugging material, off-load of the boom belt, scattering material and wear of equipment, the model of material transfer process is analyzed theoretically, providing theoretical basis for the design of the head hopper and the curve chute in the material transfer device. The optimization design of traditional transfer device is carried out through 3D modeling and discrete element method (DEM) simulation analysis. The results show that the optimized transfer device has a good field application effect and effectively solves transfer point common problems of such as plugging material, scattering material and off-load of the boom belt, providing reference for the design and application of similar products? © 2019 IEEE.

关键词： 3D modeling

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The Growth Restriction Effect of Ticn Nanoparticles on Al-Zr Alloys: An Integrated Study by in Situ X-Radiography and Numerical Modeling

SSRN

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SSRN 2021年

作者： Jia, Yiwang Song, Dongfu Zhou, Nan Zheng, Kaihong Fu, Yanan Shu, Da Institute of Materials and Processing Guangdong Academy of Science Guangzhou510650 China Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application Guangzhou510650 China Shanghai Synchrotron Radiation Facility Shanghai Institute of Applied Physics CAS Shanghai201204 China Shanghai Key Lab of Advanced High-temperature Materials and Precision Forming School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai200240 China

Ex situ and in situ synchrotron X-radiography study of Al-Zr alloys with addition of Al-5Ti-1B and TiCN nanoparticles (TiCNnp ) were carried out at different cooling rates. Al-Zr alloy can be effectively refined by TiCNnp as compared with Al-5Ti-1B which has Zr poisoning effect. The influence of cooling rate on the nucleation and growth of grains has been studied quantitatively. The results show that the grain size was decreased and the growth rate was increased with the increase of cooling rate. At the same cooling rate, the grain size with addition of 0.5% TiCNnp was smaller than that with the addition of 0.5% Al-5Ti-1B. The blocking factor f of TiCNnp increases with increasing cooling rate. Based on the free growth model, a new numerical model considering the growth restriction effect of nanoparticles was established. The growth of grain was inhibited by the combining effect of solute and nanoparticles. The growth rate of grain is reduced due to part of the solid/liquid interface coated by nanoparticles. The blocking factor f is linearly decreased with the coverage ratio f which is proportional to the critical grain radius. The grain size decreases with increasing cooling rate and decreasing f . This study is especially beneficial for Al alloys that have poisoning phenomenon inoculated by traditional refiner such as Al-Zr, Al-Si and Al-Sc alloys. © 2021, The Authors. All rights reserved.

关键词： Nanoparticles

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Higher-Order Kinematics Modeling of 3-RRS Parallel Mechanism Based on CGA

Research Square

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Research Square 2020年

作者： Wang, Chang Zhao, Tie-Shi Li, Er-Wei Zhao, Yan-Zhi Bian, Hui Geng, Ming-Chao Parallel Robot and Mechatronic System Laboratory Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of National Education Yanshan University Qinhuangdao066004 China School of Mechanical Engineering Hebei University of Architecture Zhangjiakou075000 China

Higher-order kinematics of mechanisms has been applied in servo motor control, human-robot interaction and machinery life design fields, etc. The representations of acceleration and jerk by screws have been fully developed by researchers with the methods of the differential of the matrix representation of SE(3) group. Clifford algebra, which is tighter and with higher computational efficiency than the matrix method, is another representation of the motions of rigid bodies. It has been used in position kinematics, grub task motion planning, and robot vision for its convenience of geometric representations and calculations. As far as we know, the work of higher-order kinematics of mechanisms based on Clifford algebra is rare. First, after recalling the based theory of motion representation in conformal geometric algebra (CGA), the mathematical relationships between flag and motor are built. Second, a method for the higher-order kinematics modeling of serial chain mechanisms is proposed. Finally, the higher-order kinematics of the 3-RRS parallel mechanism is built to prove the correctness of the algorithm. This work further enriches the application of CGA for the higher-order kinematics modeling of parallel mechanisms. © 2020, CC BY.

关键词： Kinematics

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High-quality manufacturing method ofcomplicated castings based on multi-materialhybrid moulding process

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China Foundry 2018年第5期15卷 343-350页

作者： Li-min Liu Zhong-de Shan Feng Liu Dun Lan State Key Laboratory of Advanced Forming Technologyand EquipmentChina Academy of Machinery Science and Technology Group Co.Ltd.Beijing 100083China

A multi-material hybrid patternless moulding process for complicated castings has been proposed. Moulding sands used in the hybrid moulding process include silica sand, ceramic sand, chromite sand, zircon sand, and steel shot sand. Experimental method was used to study the effects of moulding sands on the temperature field, mechanical properties, and dimensional precision of the iron castings. Under the condition that the wall thickness on different sides of the casting is the same, when the wall thickness is greater than 10 mm, the heat storage capacity of the moulding sands from strong to weak is steel shot sand, zircon sand, chromite sand, ceramic foundry sand, and silica sand. Tensile strength of the obtained castings from high to low is zircon sand, chromite sand, steel shot sand, ceramic sand, and silica sand. Contraction rate of the obtained castings from high to low is steel shot sand, zircon sand, chromite sand, silica sand, and ceramic sand. Therefore, steel shot sand and zircon sand can be used as chilled sand, and even can be used instead of cold iron when the casting wall thickness is greater than 10 mm. Zircon sand and chromite sand can be used to obtain high mechanical properties, and silica sand and ceramic sand can be selected to obtain high dimensional precision of the castings. Finally, a typical iron casting piece was tested by experiment using the hybrid moulding process. Excellent performances of iron castings confirm the feasibility of the hybrid moulding process.

关键词： hybrid patternless moulding process hybrid moulding process thermal physical parameters temperature field mechanical properties dimensional precision

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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...

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Artificial Intelligence and Electromechanical Automation (AIEA), International Conference on

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

ISBN: (数字)9781728182889

ISBN: (纸本)9781728182896

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.

关键词： Grinding Ball Steel Microstructure Hardness Impact Toughness IMPACT TOUGHNESS grinding ball Microstructure Soundness hardness Vanadium Mechanical properties Alloying elements ultimate tensile strength MO ADDITIONS Spring steels martensitic structure Ball Device Component

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