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refinement mechanism of cerium addition on solidification structure and sigma phase of super austenitic stainless steel S32654

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Journal of Materials Science & Technology 2022年第7期102卷 105-114页

作者： Shucai Zhang Jiangtao Yu Huabing Li Zhouhua Jiang Yifeng Geng Hao Feng Binbin Zhang Hongchun Zhu School of Metallurgy Northeastern UniversityShenyang 110819China School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051China

The influence of Ce addition on the solidification structure and σphase of super austenitic stainless steel S32654 was systematically investigated via microstructural characterization and thermodynamic calcula- tion. The results indicate that a small addition of Ce could modify MgO and MnS into Ce-bearing inclu- sions Ce_(2)O_(3)and Ce_(2)O_(2)S. Ce addition led to noticeable refinement of both the dendrite structure and σphase. The refinement mechanism could be attributed to the combined actions of effective Ce-bearing inclusions and solute Ce. Effective Ce-bearing inclusions could serve as heterogeneous nucleation cores of austenite as well as σphase, which provided a favorable prerequisite for their refinement. Solute Ce significantly enhanced the undercooling degree of the system, further promoting dendrite structure re- finement. Meanwhile, solute Ce improved the eutectic precipitation conditions of σphase and further promoted its nucleation, while the dendrite refinement limited its growth space. Finally, more fine and dispersed σphase particles formed in S32654 with Ce addition. The refinement of dendrite structure and σ phase will reduce the temperature and time required for high-temperature homogenization, which is beneficial to the hot working of this steel.

关键词： Super austenitic stainless steel Cerium Solidification structure Sigma phase refinement

Plethysmograph training:A refinement for collection of respiration data in mice

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动物模型与实验医学(英文) 2023年第4期6卷 369-374页

作者： Jorid B.Sørli Karin S.Hougaard Niels Hadrup Chemical Work Environment The National Research Centre for the Working EnvironmentCopenhagenDenmark Department of Public Health University of CopenhagenCopenhagenDenmark Research Group for Risk-Benefit National Food InstituteTechnical University of DenmarkLyngbyDenmark

Inhaled chemicals can harm the airways.Different effects can result in distinct changes in respiratory patterns;the type of change indicates where and how the respiratory system is affected.Furthermore,changes in respiratory patterns may be detected at much lower substance concentrations than those that cause more serious effects,such as histopathological changes.Changes in respiratory patterns can be studied experimentally by monitoring the breathing of mice placed in plethysmographs and exposing head-out to the test substance.The method is well established;however,it is not known if training mice in being restrained in the plethysmograph could increase the quality of data collection.Here we report the results of training mice to be restrained in plethysmographs for 5 consecutive days,with respect to body weight,respiratory parameters,and time spent in the plethysmograph,before they are removed because of unstable breathing patterns.The mice tolerated the procedure better(measured by time in the plethysmograph)on the second day of training than the first day.Training did not change the breathing parameters between days.Breathing parameters stabilized within 5 min after the mice were placed in the plethysmographs on all days.There was an average of 3%weight loss between the first and last days of the training,indicating that the training procedure placed some strain on the animals.Training reduces the number of mice attempting to escape from the plethysmograph.

关键词： Alarie assay refinement sensory irritation

Flow fields control for bubble refinement induced by electromagnetic fields

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Journal of Iron and Steel Research(International) 2022年第4期29卷 575-587页

作者： Lian-yu Wang Ze-yi Liu Ming He Xiao-ming Liu Masamichi Sano Li-jia Zhao Qiang Wang Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

Large bubbles seriously reduce the efficiencies of the interactions between the bubbles and the molten steel,such as energy transfer,momentum transfer,mass transfer and chemical reaction.To reduce the size of the bubbles and increase the gas–liquid interface area,a novel non-intrusive method of bubble refinement was proposed,which only depends on the molten steel flow field controlled by the rotating electromagnetic field.The flow fields of the molten steel for bubble refinement were analyzed,and the corresponding bubble refinement was investigated.It was found that the molten steel formed obvious rotating turbulent flow for bubble refinement under the unidirectional rotating electromagnetic field.However,the large vortex in the center of the molten pool caused by the rotating flow made the bubbles aggregate and coalesce again,resulting in formation of larger bubbles and gas cavity.To suppress the central vortex formation and enhance the bubble refinement,the forward-reverse rotating electromagnetic field for bubble refinement was proposed.The irregular and chaotic flow occurred repeatedly because of alternating forward and reverse rotating in a short period,so that the turbulent kinetic energy and turbulent dissipation of the flow field always remained at a high level which favors bubble refinement.As a result,the bubble diameter can decrease by more than 50%compared to that without electromagnetic field.Furthermore,it is important that this non-intrusive kind of bubble refinement method completely avoids the introduction of non-metallic inclusions caused by intrusive configuration.

关键词： Bubble refinement Electromagnetic field Flow field Forward-reverse rotating Bubble Sauter

SFR-Net:sample-aware and feature refinement network for cross-domain micro-expression recognition

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光电子快报:英文版 2023年第7期19卷 437-442页

作者： LIU Jing JI Xinyu WANG Mengmeng School of Electrical and Information Engineering Tianjin UniversityTianjin 300072China Key Laboratory of Artificial Intelligence Ministry of EducationShanghai 200240China

Over the past several decades,micro-expression recognition(MER) has become a growing concern for scientific community.As the filming conditions vary from database to database,previous single-domain MER methods generally exhibit severe performance drop when applied to another database.To deal with this pressing problem,in this paper,a sample-aware and feature refinement network(SFR-Net) is proposed,which combines domain adaptation with deep metric learning to extract intrinsic features of micro-expressions for accurate recognition.With the help of decoders,siamese networks increasingly refine shared features relevant to emotions while exclusive features irrelevant to emotions are gradually obtained by private networks.In order to achieve promising performance,we further design sample-aware loss to constrain the feature distribution in the high-dimensional feature space.Experimental results show the proposed algorithm can effectively mitigate the diversity among different micro-expression databases,and achieve better generalization performance compared with state-of-the-art methods.

关键词： database Net refinement

3DPF-FBN: video inpainting by jointly 3D-patch filling and neural network refinement

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Science China(Information Sciences) 2022年第7期65卷 251-252页

作者： Yan HUANG Chuanchuan YANG Zhangyuan CHEN State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronics Peking University

Dear editor, Video inpainting is a new technology of recovering the lost motion vectors or image blocks during the video sequence transmission. It aims to speculate the correct value of missing voxels from a given video to achieve the automatic inpainting and make the inpainted video frames present a natural visual effect. However, video inpainting remains challenging owing to the difficulties coming from computational complexity, complex scenarios and the high requirement on spatial and temporal consistency.

关键词： video inpainting patch-based searching optical flow neural network refinement

refinement and migrating behaviors in Al-Si hypereutectic alloys solidified under electromagnetic vibration

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Acta Metallurgica Sinica(English Letters) 2011年第4期24卷 301-308页

作者： Jianbo YU Zhongming REN Kan9 DENG Shanghai Enhanced Laboratory of Ferro-Metallurgy Shanghai University Shanghai 200072 China

The effects of electromagnetic vibration （EMV） on the refinement and migration of primary silicons in the A1-18 wt pct Si alloy were investigated systematically. It was found that EMV could effectively refine primary silicons. The equivalent diameter of primary silicon first decreases slowly with the current increasing from 1 A to 3 A, but then drops rapidly between 3 A and 10 A, next gradually decreases with increasing current intensity. When the EMV intensity was low, the primary silicons were agglomerated and expelled to the top of a sample, the segregation of silicon grains gradually decreased and the agglomerating phenomena disappeared with the increase of EMV intensity, and the star-like coarse primary silicons turned refined flake or square morphology. The refinement and migration of primary silicons depended on the Lorentz force, gravity and the effective viscous force.

关键词： High magnetic field Electromagnetic vibration HypereutecticAl-Si alloys Primary silicon refinement Migrating

refinement of packet size in low carbon bainitic steel by special thermo-mechanical control process

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Journal of University of Science and Technology Beijing 2004年第3期11卷 221-224页

作者： Chengjia Shang Xuemin Wang Shanwu Yang Xinlai He Materials Science and Engineering School, University of Science and Technology Beijing, Beijing 100083, China Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The packet size of bainitic steel can be refined by a specialrelaxation-precipitation-control phase transformation (RFC) technology. When processed by RPCprocess, the low carbon bainitic steel composes of two kinds of main intermediate transformationphases. One is ultra-fine lath-like bainitic ferrite and the lath is less than 1μm in width andabout 6 μm in length; the alignment of laths forms a refined packet, and the size of packets isabout 5-7 μm in length and about 3-4μm in width. The other is acicular structure. The morphologyand distribution of these acicular structures are influenced by relaxation process, the thin andshort acicular structures cut the prior austenite grain and refine the bainitic packet size. For theoptimum relaxation time, the packet size can be refined to the finest. The mechanical propertiesare influenced by relaxation time and the 800 MPa grade low carbon bainitic steel with excellenttoughness can be obtained by RPC process.

关键词： packet size refinement bainitic steel RPC process

refinement of austenite grain using uniform experiment design for AISI H13

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Journal of Central South University of Technology 2002年第4期9卷 240-245页

作者：张斌柳建韬张鸿冰阮雪榆 Department of Plasticity Forming Engineering Shanghai Jiaotong University Department of Materials Engineering Institute of Shanghai Technology

The uniform experiment design is an effective way of optimizing technology scheme for refining the grain size during multistage deformation. In this paper, it is adopted to evaluate the effect of each technology parameter on final grain size of AISI H13 hot work tool steel during multistage deformation. It has been verified that the technology scheme for refining the final grain size can be determined rapidly and efficiently with the aid of the uniform design. The results show that the deformation parameters and the intermission time after deformation of the first stage affect the final grain size remarkably. For AISI H13 hot work tool steel, the final grain size can be refined notably when deformation parameters for the first stage are set as follows: a deformation temperature range of 1?025 1?085 ℃; a true strain of above 0.26 and the interpass time between the first and the second stage of deformation less than 10 s.

关键词： grain refinement deformation parameter dynamic recrystallization uniform design experiment

An improved process for grain refinement of large 2219 Al alloy rings and its influence on mechanical properties

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Journal of Materials Science & Technology 2019年第1期35卷 55-63页

作者： Hailin He Youping Yi Shiquan Huang Yuxun Zhang Research Institute of Light Alloy Central South University State Key Laboratory of High Performance Complex Manufacturing School of Mechanical and Electrical Engineering Central South University

The large 2219 Al alloy rings used to connect propellant tank components of a satellite launch vehicle to each other are conventionally manufactured by radial-axial ring rolling at 460°C with 50% deformation,but often suffer from coarse elongated grain and low ductility. An improved process(hot ring rolling at460°C with 30% deformation, then air cooling to 240°C, followed by ring rolling at 240°C with 20% deformation) was tested for ring manufacturing. The corresponding microstructure evolution and mechanical properties of the produced rings were studied. The results show that the improved process can successfully be applied to manufacture the large 2219 Al alloy rings without formation of macroscopic defects,resulting in a product with fine and uniform grains after heat treatment. The fracture mechanism of both rings was mainly intergranular fracture. With the resulting grain size refinement due to the improved process, more homogeneous slip occured and the crack propagation path became more tortuous during the tensile testing process. Thus, the elongation in all three orthogonal directions was greatly improved,and the axial elongation increased from 3.5% to 10.0%.

关键词： 2219 Al alloys Large rings Ring rolling Grain refinement Mechanical properties