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Journal of Materials science & technology 2021年第16期75卷 27-38页

作者： Xinkai Ma Zhuo Chen Dongling Zhong SNLuo Lei Xiao Wenjie Lu Shanglin Zhang Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710072China National Key Laboratory of Reactor System Design Technology Nuclear Power Institute of ChinaChengdu 610041China

Microstructural evolution and deformation mechanism of a metastableβalloy(Ti-10 V-2 Fe-3 Al)processed by rotationally accelerated shot peening(RASP)were systematically investigated with optical microscopy,X-ray diffraction,electron backscatter diffraction and transmission electron *** gradient hierarchical microstructures(gradients inα″martensite andβphase,and hierarchical twins range from the nanoscale to microscale)can be fabricated by RASP via changing the shot peening *** hardening behavior and tensile mechanical properties of gradient hierarchical microstructure were systematically *** deformation twinning systems of{112}α″and{130}<310>α″in the kinkedα″martensite were revealed during the tensile *** was found that stress-induced martensitic transformation,twinnedα″martensite and the related dynamic grain refinement contribute to hardness and work hardening *** improvement of strength and ductility of the metastableα″titanium alloy can be achieved by introducing a gradient hierarchical microstructure.

关键词： Titanium alloys Gradient hierarchical microstructure α″martensite Rotationally accelerated shot peening Mechanical behavior

Characterization of the Oxide Film and Deuterium Permeation Behavior of Cocrmnfeni High Entropy Alloy Oxidized at 550 °C for 24 Hours

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SSRN 2023年

作者： Yin, Chunyu Li, Wenxuan Qiu, Xi Luo, Bin Huang, Hongtao Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Sino-French Institute of Nuclear Energy and Technology Sun Yat-Sen University Zhuhai519082 China

High entropy alloys have become potential candidate materials for high temperature nuclear reactor due to its high strength, high hardness, excellent corrosion resistance and radiation resistance, therefore the compatibility of hydrogen isotopes with HEAs becomes a key issue that has attracted a lot of attentions. The deuterium permeation behavior of the CoCrMnFeNi high entropy alloy after oxidation at 550 °C for 24 h was investigated by gas-phase deuterium permeation testing, SEM, X-ray diffraction methods in this paper. The results show that a dense oxide film with a thickness of about 1μm was formed on the surface of the sample after oxidation. The outer layer of the oxide film is rich in Mn2O3 and the inner layer is rich in Cr2O3. The deuterium permeability of the CoCrMnFeNi sample after oxidation was reduced by an order of magnitude and was 1/7-1/17 times as high as that for the unoxidized one. © 2023, The Authors. All rights reserved.

关键词： Entropy

Effect of Fission Defects on Tensile Strength of U3si2 Σ5(210) Grain Boundary from First-Principles Calculations

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SSRN 2023年

作者： Zhao, Jiajun Sun, Dan Xi, Liu Chen, Ping Zhao, Jijun Wang, Yuanyuan Key Laboratory of Materials Modification by Laser Ion and Electron Beams Ministry of Education Dalian University of Technology Liaoning Dalian China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu China

U3Si2 is regarded as a promising accident tolerant fuel (ATF) to replace the commercial fuel UO2;however, U3Si2 grain boundary (GB) embrittlement caused by irradiation-induced defect segregation remains to be clarified. In this work, U3Si2 Σ5(210) symmetrically tilt GB is taken as representative to elucidate the individual effect of xenon (Xe) and vacancy on the tensile strength and failure of GB using first-principles calculations. Compared with the predicted segregation energies of defects at the most energetically favourable positions of GB, Si vacancy (VSi) has much stronger preference to segregate to GB than that of Xe substitution on Si sublattice (XeSi). Moreover, the strengthening/embrittlement potency of GB with single vacancy/Xe is evaluated using the first-principles-based uniaxial tensile test. Although both VSi and XeSi yield a weakening effect on the strength of U3Si2 Σ5(210) GB, such defective GBs exhibit significantly stronger interface strengths compared to the corresponding defects segregated to UO2 Σ3(111) GB. The underlying mechanism of strength change of U3Si2 GB is discussed in terms of charge analysis. Our results can provide fundamental understanding on the mechanical behavior of irradiated GB from an atomic perspective. © 2023, The Authors. All rights reserved.

关键词： Grain boundaries

Thermally-Induced Fracture in the Oxide Scale of T91 Ferritic/Martensitic Steel after Exposure to Oxygen-Saturated Liquid Lead-Bismuth Eutectic

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SSRN 2024年

作者： Liu, Yunpeng Du, Juan Zhou, Zhikun Tian, Chenwen Liu, Zhenyu Zhang, Ying Shi, Kaikai Chen, Ziguang Department of Engineering Mechanics School of Aerospace Engineering Huazhong University of Science and Technology Wuhan430074 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment 1037 Luoyu Road Wuhan430074 China

Ensuring the continuity and stability of the oxide scale to separate T91 steel from lead-bismuth eutectic (LBE) is an effective method for limiting corrosion in the lead-based fast reactor system. In this study, we specifically investigate the impact of cooling thermal stress on the stability and damage of the oxide scales of T91 steel when exposed to oxygen-saturated liquid lead-bismuth eutectic at high temperatures. We revisit a corrosion test conducted on T91 steels exposed to stagnant oxygen-saturated LBE at 500 °C. Experimental results indicate that oxide damage exists without any external force, including interface cracks and through-scale cracks perpendicular to the interface. We develope a three-layer peridynamic model of T91-(Fe,Cr)3O4-Fe3O4 to simulate the deformation and failure of oxides under a cooling process from high temperature to room temperature. The simulation results show that a temperature drop of about 200 °C from 500 °C can cause through-oxide cracks in the oxide scale, and subsequent cooling can lead to the propagation of interfacial cracks. Additional modifications are introduced in the model to account for the porosity of the oxide scale. Parametric investigations illustrate the effects of oxide scale thickness and porosity on the resulting crack patterns. © 2024, The Authors. All rights reserved.

关键词： Oxygen

MDDA: A Multi-scene Recognition Model with Multi-dimensional Domain Adaptation 4

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MDDA: A Multi-scene Recognition Model with Multi-dimensional...

4th IEEE International Conference on Electronics technology, ICET 2021

作者： Wan, Naijia Zhang, Changhua Chen, Qian Li, Hao Liu, Xiaobo Wei, Xuedong University of Electronic Science and Technology of China School of Information and Software Engineering Chengdu China University of Electronic Science and Technology of China School of Mechanical and Electrical Engineering Chengdu China Science and Technology on Reactor System Design Technology Laboratory Chengdu China

ISBN: (纸本)9781728176734

Optical Character Recognition is widely used in scenarios from license plate recognition, chip detection to text translation. However, in some special scenarios, there are very few data for training or the target datasets are not marked. This paper mainly aims to establish a multi-scene text recognition model that can achieve accurate results even when the target test dataset is not marked. The model reduces the distance between domains at the feature level by using an adversarial loss and flipping the gradient. For the adversarial loss, each letter has a different domain discriminator to align the features at the character level. We also align the source domain features and target domain features in the background. Experimental results show that our model achieves good performance when the training dataset and test dataset have domain shift, and suggest possible scenarios for potential applications. © 2021 IEEE.

关键词： Optical character recognition

Hard-magnetic liquid metal droplets with excellent magnetic field dependent mobility and elasticity

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Journal of Materials science & technology 2021年第33期92卷 60-68页

作者： Xiaokang He Mingyang Ni Jianpeng Wu Shouhu Xuan Xinglong Gong CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsCAS Center for Excellence in Complex System MechanicsUniversity of Science and Technology of ChinaHefei 230027China

Magnetic liquid metal droplets(MLMDs)have been proven to be very important in many fields such as flexible electronics and soft ***,soft magnetic particles such as nickel(Ni)and iron(Fe)are mixed or suspended into the liquid metal to obtain soft MLMDs(S-LMDs),which can be easily manipulated under the magnetic field due to the favorable deformability and *** addition,hard magnetic particles such as neodymium iron boron(Nd Fe B)with a high residual magnetization can also be dispersed into the liquid metal and the hard MLMDs(H-LMDs)become more compact due to the interaction between internal particles induced by *** work reports a kind of H-LMDs with high surface tension,high flexibility and mechanical robustness,whose electrical conductivity and strength are better than the *** the magnetic field,the H-LMDs have a faster response time(0.58 s)and a larger actuating velocity(4.45 cm/s)than the ***,the H-LMDs show excellent magnetic controllability,good elasticity and favorable mobility,as demonstrated by magnetically actuated locomotion,bounce tests and rolling angle ***,the droplets can be further applied in wheeldriven motors and micro-valve switches,which demonstrates their high application potential in robotic manipulation and microfluidic devices.

关键词： Magnetic liquid metal droplets NdFeB particles Magnetic controllability Micro-valve

High-Precision Point Cloud Data Acquisition for Robot Based on Multiple Constraints 16th

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High-Precision Point Cloud Data Acquisition for Robot Based ...

16th International Conference on Intelligent Robotics and Applications, ICIRA 2023

作者： Li, Bingbing Zhang, Teng Sun, Hao Deng, Runpeng Peng, Fangyu Yan, Rong Tang, Xiaowei The National NC System Engineering Research Center School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan430074 China The Wuhan Digital Design and Manufacturing Innovation Center Co. Ltd. Wuhan430074 China The State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan430074 China

ISBN: (纸本)9789819964796

The foundation of high-precision 3D reconstruction is the acquisition of high-precision point clouds. Through multi-view point cloud scanning and alignment, the point cloud of parts can be obtained. The great flexibility of the robot enables it to carry out scanning operations that require multi-view. However, the robots are limited in position error, and the accuracy of the camera varies depending on the range of vision. In addition, the point cloud density is influenced by the curvature of the workpiece, which seriously limits the accuracy of point cloud acquisition and registration. To solve these problems, a method of high-precision point cloud data acquisition for robots based on multiple constraints is proposed. The precision of the measuring system is increased by imposing constraints. So the high-performance field of vision of the camera and the high-performance motion space of the robot are obtained. The effect of workpiece curvature on point cloud scanning is thought to require increased camera viewpoints. After obtaining the camera viewpoints, the moving route planning of the robot is implemented using the ant colony voting method. In this paper, a curved blade experiment was carried out to prove the advantages of our method. It is not necessary for the point cloud overlap rate or the parts with many features. The accuracy of scanned point clouds is 0.249 mm, which is less than the results of using intelligent algorithms and marked points. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.

关键词： Cameras

An Adaptive Peridynamics with Correspondence Material Model for Coupled Creep-Plastic Fracture Problems

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SSRN 2024年

作者： Zhang, Hanbo Li, Chengxuan Liu, Zhenhai Ye, Hongfei Li, Hui Zheng, Yonggang State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial Equipment Department of Engineering Mechanics School of Mechanics and Aerospace Engineering Dalian University of Technology Dalian116024 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610200 China

This paper introduces an adaptive peridynamics with a correspondence material model (A-PD-CMM) to effectively simulate the coupled creep-plastic behavior and the creep crack propagation in metal materials. In this method, to describe the coupled creep-plastic deformation with considering the creep damage, the multiaxial coupled constitutive model that integrates the Wen-Tu creep damage model and the J2 plastic model is developed. Moreover, a damage associate criterion is incorporated into the peridynamics framework to effectively capture the influence of damage on the force state. To detail the rapid damage evolution during the tertiary creep stage, a time-adaptive solving strategy is proposed. Additionally, the constitutive integration algorithm of the multiaxial coupled model is efficiently realized by decoupling it into two parts, that is, an implicit computation of creep-plasticity and an explicit evolution of creep damage. The efficacy and engineering applicability of the proposed A-PD-CMM are validated through several representative numerical examples, showcasing its potential in addressing complex material behavior. © 2024, The Authors. All rights reserved.

关键词： Crack propagation

Coupled Axisymmetric Peridynamics with Stabilized Correspondence Material Model for Ablation and Fracture Problems

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SSRN 2024年

作者： Zhang, Hanbo Liu, Zhenhai Li, Chengxuan Ye, Hongfei Zhang, Hongwu Li, Hui Zheng, Yonggang State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial Equipment Department of Engineering Mechanics School of Mechanics and Aerospace Engineering Dalian University of Technology Dalian116024 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610200 China

A coupled axisymmetric peridynamics with a stabilized correspondence material model (CA-PD-SCMM) is proposed in this work to effectively simulate the ablation and ductile fracture behaviors of metals under high temperatures. To quantify the damage resulting from compression and shearing deformations, a strain energy density decomposition method is incorporated into the ductile damage model. Furthermore, a novel axisymmetric stabilization method based on peridynamics linearization theory is introduced to mitigate numerical oscillations arising from zero-energy modes in both thermal and mechanical scenarios. To capture the varying geometries and update the boundary conditions during ablation, a moving boundary model is developed based on temperature-associated criteria. To validate the capacity of the proposed CA-PD-SCMM, several representative numerical experiments are conducted. These examples not only affirm its ability to stabilize numerical oscillations in coupled axisymmetric thermoplastic problems but also demonstrate its capability for accurately simulating ablation and predicting crack propagation. © 2024, The Authors. All rights reserved.

关键词： Ductile fracture

Characteristic Parameters Analysis of Bond-Wire Failure for Multi-Chips Parallel IGBT Modules

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Characteristic Parameters Analysis of Bond-Wire Failure for ...

IEEE/IAS Industrial and Commercial Power system Asia (I&CPS Asia)

作者： Yuan Min Zhen Xing Xueni Ding Hui Li Ran Yao Wei Lai Cheng Yang Wenxing Han Yannan Yuan Key Laboratory of Nuclear Reactor System Design Technology ChengDu China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China Chongqing University Chongqing China

Multi-chips parallel IGBT module is widely used in new energy power grid connection, flexible AC and DC transmission, electric vehicles and charging devices, rail transit electric traction and other fields, and the reliability of their operation is very important. Therefore, how to select the characteristic parameters that can characterize the aging state of multi-chips parallel IGBT device is particularly important for system active operation and maintenance and reliability improvement. This paper takes the widely used multi-chips parallel IGBT module as the research object. According to the failure mode of bond wire lift-off, the degradation law of electrothermal and magnetic characteristic parameters in the aging failure process of the multi-chips parallel IGBT module was studied, and finally the magnetic flux density was selected as the aging state monitoring parameter of the multi-chips parallel IGBT module.

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