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Microstructure evolution during continuous cooling process in Ti microalloyed steel

Journal of Physics: Conference Series 2021年第1期2044卷

作者： Songjun Chen Liejun Li Zhengwu Peng Xiangdong Huo Jixiang Gao Guangdong key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of Technology Guangzhou 510640 China School of Material Science and Technology Jiangsu University Zhenjiang 212013 China Guangdong Polytechnic Normal University Guangzhou 510640 PR China

The phase transformation law and microstructure evolution of austenite in Ti microalloyed steel under different continuous cooling rates (0.1-30°C/s) after a two-stage deformation were studied based on the Gleeble-3800 Thermo-Mechanical Simulator. The continuous cooling transformation (CCT) curve was obtained by thermal expansion method combining with microstructures. The results showed that the Ac1 and Ac3 of the steel were 835°C and 902°C, respectively. With the increase of cooling rate, the austenite phase transition temperature decreased, from 778.5-712.2°C at 0.1°C/s to 633.7-488.7°C/s at 30°C/s. Accordingly, the austenite transformation structure changed from polygonal ferrite and pearlite to granular bainite. In addition, with the increase of cooling rate, the ferrite transformation was inhibited, and the transformation region of granular bainite was increased.

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Three-dimensional printing technology of zinc alloy fused and deposition

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Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science) 2018年第7期52卷 1364-1369页

作者： Yang, Li-Ning Shan, Zhong-De Rong, Wen-Juan Liu, Feng Yang, Shuo State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Beijing100044 China

A new three-dimensional printing technology based on fused and deposition was proposed in order to solve the high cost and low efficiency problems of the existing additive manufacturing technologies for metal parts. The technology is suitable for medium and low melting point metal material. The principle of the technology was introduced. The three-dimensional printing process of zinc alloy was conducted by using the self-developed equipment in order to analyze the effects of nozzle height, scanning speed and lapping rate on the forming effect. The width of single track was inversely proportional to height. When the nozzle height was 25~35 mm and the scanning speed was 8 mm/s, the single track quality was better. The surface quality of the deposited monolayer was better when the overlap ratio was 35%~40%. The density of the zinc alloy can be more than 97% by using the three-dimensional printing technology based on fused and deposition, and the density of the formed part can be enhanced by increasing the melting temperature, the temperature of the substrate, annealing temperature and annealing time. The technology can be used to realize the forming of the inner flow channel die with complex shape, which can reduce the processing difficulty and improve the forming efficiency. The tensile strength of zinc alloy solid was 198 MPa, the yield strength was 140 MPa, and the elongation was 0.453%, which were equivalent to those of conventional squeeze casting process. The microstructure of the zinc alloy solid was more refined. © 2018, Zhejiang University Press. All right reserved.

关键词： Deposition

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Impact tensile cracking behavior of oxide scale in Q235 strip iron 2

Impact tensile cracking behavior of oxide scale in Q235 stri...

引用

2nd International Conference on Material Engineering and advanced Manufacturing technology, MEAMT 2018

作者： Wang, Shang Li, Wenpei Wang, Xiaochen Ai, Rui Yang, Quan Shan, Zhongde Institute of Engineering Technology University of Science and Technology Beijing Beijing100083 China State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Beijing100083 China

Scanning electron microscopy (SEM) is used to observe the fracture surface morphology of Q235 steel. The cracking law/crack rule principle of strip surface under tension is studied via universal tensile testing machine. The results show that the thickness of the scale is relatively uniform, about 10 μm, and the structure is dense and well attached to the matrix. Tensile experiments show that as the strain increases, the cracks increase slowly in the initial stage, rapidly in the middle period, and slowly in the final period. When the strain exceeds 0.15%, the cracks are difficult to increase. In order to avoid direct erosion of the abrasive on the substrate, a reasonable range of tension setting should be 0.15%-0.18% in the pretreatment process without acid descaling. © 2018 The Authors, published by EDP Sciences.

关键词： Tensile testing

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Simulation of temperature field of A356 aluminum alloy in freeze casting

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Journal of Physics: Conference Series 2020年第1期1600卷

作者： Haoqin Yang Zhongde Shan Yifei Wang Limin Liu State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Group Co. Ltd. Beijing 100044 China

In this paper, the temperature change curve of the casting and frozen sand mould during the solidification process of the A356 aluminum alloy in the frozen sand mould is tested. According to the actual temperature change curve of the casting surface and the sand mould surface, the interface heat transfer coefficient between the frozen sand mould and the A356 aluminum alloy could be reversed analysis. The results show that when the casting temperature is lower than 550 °C, the interface heat transfer coefficient remains about 750 W.(m2.K)-1; When the casting temperature is between 550 °C and 610 °C, the interface heat transfer coefficient increases significantly; when the casting temperature is higher than 610 °C, the interface heat transfer coefficient reaches the maximum value, which is about 2300W. (m2.K) -1. At this time, this study simulates the solidification temperature field of aluminum alloy hub parts in the frozen sand mould according to the interface heat transfer coefficient calculated by inverse analysis, and the temperature field of resin sand mould casting was used as for comparison. The results show that: under the same solidification time, the temperature field of A356 aluminum alloy hub parts in frozen sand mould is lower than that of resin sand casting, freezing casting can realize the high-speed solidification process of different parts of complex castings.

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High Temperature Deformation Mechanisms in WC-Ni 3Al Cermets

SSRN

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SSRN 2019年

作者： Zhang, Minai Dupuy, Alexander D. Li, Jingmao Wang, Xin Qu, Shengguan Schoenung, Julie M. Li, Xiaoqiang Guangdong Key Laboratory for Advanced Metallic Materials Fabrication and Forming South China University of Technology Guangzhou510640 China Department of Materials Science and Engineering University of California Irvine92697 United States

The microstructure and mechanical properties of WC-Ni3 composites were examined after compression in the temperature range of 650-900 ℃. At these temperatures, antiphase boundaries were generated in the Ni3Al binder phase. Due to this mechanism, the WC-10%Ni3Al sample exhibits high compressive strengths of ~1300-1650 MPa at elevated temperatures. TEM analysis indicates that plastic accommodation during the deformation process is primarily due to deformation of both the WC and the Ni3Al binder. Yield loci slip mode analysis was used to confirm that dislocations, stacking faults, and even twins can exist on the prismatic plane {01‾10} in WC at high temperatures. This type of combined strengthening from both the matrix and binder provides a new strategy to improve the high-temperature mechanical properties of cemented carbides. Moreover, Ni3Al becomes a promising alternative intermetallic to Co as a binder. © 2019, The Authors. All rights reserved.

关键词： Binary alloys

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Strain-Rate Dependent Deformation Behavior in WC-10 wt%Ni 3Al Cermet Micropillars under Uniaxial Compression

SSRN

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SSRN 2019年

作者： Zhang, Minai Wang, Xin Dupuy, Alexander D. Schoenung, Julie M. Li, Xiaoqiang Guangdong Key Laboratory for Advanced Metallic Materials Fabrication and Forming South China University of Technology Guangzhou510640 China Department of Materials Science and Engineering University of California Irvine92697 United States

The strain-rate dependent deformation behavior in WC-10%Ni3Al cermet micropillars was studied by in-situ uniaxial compression. The results show that compression at high strain rates exhibits a relatively smooth stress-strain response compared with that at low strain rates. Microstructural characterization suggests that at high strain rates, grain boundary sliding is the dominant mechanism of deformation, while at low strain rates, dislocation annihilation plays a dominant role. The strain rate sensitivity index also varies with strain rate, confirming that the dominant deformation mechanisms have changed. © 2019, The Authors. All rights reserved.

关键词： Cermets

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Effects of structural parameters on hydraulic performance of flow regulator

Effects of structural parameters on hydraulic performance of...

引用

CSAA/IET International Conference on Aircraft Utility Systems, AUS 2018

作者： Li, Yong Zong, Xuemei Yuan, Xiaoming Zhao, Shiyi State Key Laboratory of Intelligent Manufacturing of Advanced Construction Machinery Jiangsu Xuzhou Construction Machinery Research Institute Xuzhou Construction Machinery Group Co. Ltd. Xuzhou China Hebei Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Key Laboratory of Advanced Forging and Stamping Technology and Science Yanshan University Qinhuangdao Hebei China

ISBN: (纸本)9781785617911

In order to evaluate the hydraulic performance of a regulator, the pressure loss and the stabilization performance of the regulator installed in the fire water monitor were introduced. The effects of structures on a regulator were investigated by the structural model made in UG and the flow simulation conducted in ANSYS. The hydraulic performance of a star-shaped regulator was analyzed with different structure parameters, such as the blade number, axial length and rounded-corner. The effects of structure parameters on the regulator were revealed, based on which the hydraulic performance of the improved regulator with different blade numbers was analyzed. The results show that the improved regulator with two cross-sections in dislocation and six even-distributed blades has the better hydraulic performance. The preliminary experimental results show that the improved regulator can improve the jet range of a fire water monitor. © 2018 IET Conference Publications. All rights reserved.

关键词： Flow simulation

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High temperature stress–strain curves of MnS and their applications in finite element simulation

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Transactions of Nonferrous Metals Society of China 2018年第10期28卷 2082-2093页

作者： Miao JIN Lin-lin YU Xin-gang LIU Bao-feng GUO Key Laboratory of Advanced Forging&Stamping Technology and Science Ministry of EducationYanshan UniversityQinhuangdao 066004China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China

A novel method for testing stress–strain curves of non-metallic materials was *** high temperature stress-strain curves of MnS were preliminarily obtained and corrected to account for the influence of *** the finite element method,the influence of deformation parameters on the deformation evolution of MnS inclusions was investigated based on the experimental reference *** corresponding physical experiment was designed for comparative *** results indicate that the experimental high-temperature deformation data of MnS are highly *** the process of matrix deformation,the shapes of MnS inclusions change from spherical to ellipsoidal and even to *** are some differences in the morphological deformation of MnS inclusions located at different *** the increase in the initial size of MnS inclusions,the risk of failing the inclusion-flaw inspection increases and the forging quality further deteriorates.

关键词： inclusion MnS stress-strain curve finite element method morphology

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Deep drawing of cup shell by powder cavity flexible forming technology

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Journal of Central South University 2017年第4期24卷 766-772页

作者： XUE Ya-hong CHEN Ke FAN Cun-jie LUO Jun-ting Education Ministry Key Laboratory of Advanced Forging and Stamping Technology and Science Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China

A forming method named powder cavity flexible forming was proposed. It is a forming technology which uses powder medium instead of rigid punch or die to form sheet metals. Cup shells were successfully obtained by this technology. The theoretical calculation equation of forming load was obtained through mechanical analysis and the stress state in cup shells was analyzed by finite element simulation. The results show that powder cavity flexible forming technology can improve the forming limit of sheet metal. Compared with rigid die forming process, the thickness reduction in the punch fillet area significantly decreases and the drawing ratio increases from 1.8 to 2.2. The thinning compressive stress in the bottom of cup shell emerges, which makes the bottom of the cup shell in three-dimensional stress state and the stress in punch fillet region decrease due to powder reaction force, which can effectively inhibit the sever thinning of the sheet and prevent the generation of fracture defects.

关键词： cup shell powder cavity flexible forming drawing finite element simulation

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Correction to: Tuning dual three-dimensional porous copper/graphite composite to achieve diversified utilization of copper current collector for lithium storage

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Rare Metals 2021年第2期44卷 1409-1409页

作者： Ma, Xia Zhang, Zhi-Jia Wang, Jia-Min Sun, Shi-Hao Zhang, Shao-Fei Yuan, Shen Qiao, Zhi-Jun Yu, Zhen-Yang Kang, Jian-Li Li, Wei-Jie State Key Laboratory of Separation Membrane and Membrane Processes Tianjin Municipal Key Laboratory of Advanced Fibers and Energy Storage School of Materials Science and Engineering School of Mechanical Engineering Tiangong University Tianjin China School of Materials Science and Engineering Tianjin University Tianjin China School of Materials Science and Engineering Hebei Key Laboratory of Material Near-Net Forming Technology Hebei University of Science & Technology Shijiazhuang China Institute for Superconducting and Electronic Materials University of Wollongong Wollongong Australia

A correction to this paper has been published: https://***/10.1007/s12598-021-01749-6

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