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Effect of Deep Cryogenic Treatment on Microstructure and Mechanical Properties of Fe50mn30co10cr10 High Entropy Alloy Fabricated by Laser Metal Deposition

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SSRN 2024年

作者： Liu, Guocheng Dang, Tianqi Hu, Ning Sun, Ming Li, Jianjiang Wei, Wenting Hua, Lin Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China School of Automotive Engineering Wuhan University of Technology Wuhan430070 China State Key Laboratory of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology Wuhan430074 China Hubei Longzhong Laboratory Xiangyang441000 China The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology Wuhan430081 China

As a typical additive manufacturing technology, laser melting deposition (LMD) has been widely used to process high entropy alloy (HEA). However, deposited products usually have poor mechanical properties. In this study, deep cryogenic treatment (DCT) is proposed to enhance the mechanical performance of the laser melting deposited Fe50Mn30Co10Cr10 high entropy alloy. When the specimen underwent 48 hours of immersion during DCT processing, the tensile strength, hardness and strength-plasticity product of the DCTed HEA were 901 MPa, 286HV and 33.3 GPa%, respectively. Compared with as-deposited state, the HCP Ε phase content, average grain size and tensile strength of the DCT 48h samples increased by 2.2 times, 58.0% and 30.8%, respectively. Furthermore, the friction coefficient and wear rate of the DCT Fe50Mn30Co10Cr10 reduced by 25.6% and 30.3%, respectively. More HCP Ε phases generated inside and at the boundaries of FCC γ grains because of the transformation-induced plasticity (TRIP) effect for the Fe50Mn30Co10Cr10 alloy triggered by the DCT processing. Dynamic recrystallization helped to refine FCC γ grain structures in the HEA due to high temperature gradient soaking in liquid nitrogen. The results showed that the excellent mechanical performances could be attributed to the synergistic effects of fine-grain strengthening and second-phase particle dispersion strengthening. Moreover, the DCT processing played an important role in overcoming the strength-ductility trade-off for the additively manufactured Fe50Mn30Co10Cr10 high entropy alloy. © 2024, The Authors. All rights reserved.

关键词： High-entropy alloys

Dynamic Recrystallization Behaviors and Cracking Mechanism for the Hot Deformation of New-Generation High Nitrogen Bearing Steel

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SSRN 2024年

作者： Qian, Dongsheng Sun, Mengli Wang, Feng Xie, Lechun Hua, Lin School of Materials Science and Engineering Wuhan University of Technology Wuhan430070 China Hubei key Laboratory of Advanced Technology for Automotive Components Wuhan430070 China Hubei Engineering Research Center for Green Precision Material Forming Wuhan430070 China

The hot forming as the necessary process of bearings will genetically affect the final performance. However, the dynamic recrystallization (DRX) behaviors and the crack formation mechanism under hot deformation remain unclear. In this work, the hot deformation behaviors of the X30CrMoN15-1 from 900 ℃ to 1200 ℃ have been investigated. The microstructure observation indicates that the fully DRX occurs at the conditions of high temperature and high strain rate (1000 ℃-1200 ℃, 1 s-1-5s-1). There are two main mechanisms of crack formation. Under lower temperatures (900 ℃-1000 ℃), the significant stress concentration produced by M2(C, N) should be responsible for crack propagation along the DRXed grain boundaries. As the temperature increases to 1100 ℃, the cracks are likely to initiate between the interface of DRXed grain and deformed grains, which is mainly attributed to the uncoordinated deformation and huge pinning of dislocations by Lomer-Cottrell (L-C) locks. Based on detailed findings of microstructure and cracks, a new hot processing map has been established. It reveals that the optimal processing domains are located at 1000℃ - 1100 ℃ with strain rate of 0.3 s-1 -5 s-1 and 1020 ℃ - 1200 ℃ with strain rate of 1.5 s-1 -5 s-1. © 2024, The Authors. All rights reserved.

关键词： Strain rate

Analysis of the Thermal Behavior of a Lithium Cell Undergoing Thermal Runaway

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Fluid Dynamics & Materials Processing 2021年第5期17卷 887-898页

作者： Qifei Du Zhigang Fang National Demonstration Center for Experimental Engineering Training Education Tiangong UniversityTianjin300387China School of Automotive Engineering Wuhan University of TechnologyWuhanChina Hubei Key Laboratory of Advanced Technology of Automotive Components Wuhan University of TechnologyWuhanChina

This study examines the thermal runaway of a lithium ion battery caused by poor heat dissipation *** heat transfer process is analyzed on the basis of standard theoretical *** mist additives are considered as a tool to suppress the thermal runaway *** ensuing behaviour of the battery in terms of surface temperature and heat generation is analyzed for different charge and discharge *** is found that when the remaining charge is 100%,the heat generation rate of the battery is the lowest,and the surface temperature with a 2C charge rate is higher than that obtained for a 0.5C charge *** experimental results show that when the additive concentration is 20%NaCl,its ability to inhibit the thermal runaway is the strongest.

关键词： Lithium ion battery thermal runaway discharge rate heat generating rate water mist

Research on Anode Pressure Control and Dynamic Performance of Automotive Fuel Cell System

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SSRN 2023年

作者： Wei, Heng Du, Changqing Li, Xingyi Shi, Chenxu Zhang, Jiaming Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China Hubei Research Center for New Energy & Intelligent Connected Vehicle Wuhan University of Technology Wuhan430070 China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Foshan528200 China

The anode pressure supply meeting the system power demand can not only improve the performance output of proton-exchange membrane fuel cell (PEMFC), but also effectively prevent the degradation of proton-exchange membrane (PEM) caused by the fluctuation of anode and cathode pressure. In this article, a practicable feedforward-based proportional-integrative (FFPI) anode pressure control strategy is designed and successfully applied to a 100 kW-class automotive PEMFC system, where the current and anode purging are considered as interferences to apply feedforward compensation. The fuel cell system test bench exhibits good dynamic performance in load change experiments, the cell voltage consistency, power generation efficiency and hydrogen utilization of the system remain at a high level. To further suppress interference and reduce overshoot, oscillation and pressure response hysteresis, a control-oriented model of this 100 kW PEMFC system is constructed, and a novel second-order fuzzy active disturbance rejection controller (SOFADRC) is designed. Simulation results suggest that the proposed SOFADRC is superior than the FFPI controller and the second-order ADRC (SOADRC). The maximum absolute error (MAE), average absolute error (AAE), and root-mean-square error (RMSE) of SOFADRC all reach the minimum values respectively under the step-load and China light-duty vehicle test cycle (CLTC) load conditions, which are 6.51 kPa, 0.09 kPa, 0.42 kPa and 8.95 kPa, 0.62 kPa, 1.35 kPa respectively, showing the outstanding control effect. © 2023, The Authors. All rights reserved.

关键词： Fuzzy logic

Lumped Model for Evaluating Dynamic Filtration and Pressure Drop Behaviours in Diesel Particulate Filters

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SSRN 2024年

作者： Cai, Zhizhou Yan, Fuwu Shao, Yuankai Liao, Jianxiong Wu, Yan Zheng, Shijie Li, Yu xuan Hu, Jie Wang, Zhihong Li, Zhenguo Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of Technology Wuhan430070 China Hubei Research Center for New Energy & Intelligent Connected Vehicle Wuhan University of Technology Wuhan430070 China National Engineering Laboratory for Mobile Source Emission Control Technology China Automotive Technology & Research Center Tianjin300300 China

Particulate matter (PM) emitted from diesel vehicles poses significant risks to global climate, environment, and human health. Diesel particulate filters (DPF) are currently the only effective aftertreatment device for PM emissions reduction and it is important to reflect the DPF filtration and pressure drop performance by numerical method. This study established and validated a lumped model based on the spherical packed beds theory and Darcy’s law. The PM effective density was firstly used to obtain the PM loading rate for model input. The model described the dynamic PM filtration process in DPF, predicting real-time characteristics such as wall porosity, soot load, and pressure drop with improved accuracy. The effects of channel characteristics, monolithic size, and exhaust conditions on filtration and pressure drop performance were then investigated. The results showed that an increase in cell density, wall thickness, DPF length and diameter is beneficial for increasing filtration efficiency, while DPF inlet temperature and exhaust mass flow rate have adverse effect. Wall thickness, DPF diameter and exhaust flow rate have especially significant impact on total pressure drop. The results contributes to a better understanding of the PM filtration process and provide a theoretical basis for the DPF structural optimization. © 2024, The Authors. All rights reserved.

关键词： Pressure drop

10-Hz Repetitive Transcranial Magnetic Stimulation over the Frontal Eye Field Modulates Feature-Based Attention

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10-Hz Repetitive Transcranial Magnetic Stimulation over the ...

Intelligent Supercomputing and BioPharma (ISBP), International Conference on

作者： Ningna Li Fuwu Yan Lirong Yan Yibo Wu Biao Xiang Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan China Tumxuk Xinguang Jingwei UAV Technology Co. Ltd Tumxuk Xinjiang China

The frontal eye field (FEF) is an important brain area related to visual feature-based attention (FBA). In this study, we applied 10-Hz repetitive transcranial magnetic stimulation (rTMS) to the right FEF (rFEF), designed an improved version of attention network test (ANT) with two attributes (direction and color), to explore the relationship between rFEF and the attentional network (including alerting, orienting and executive control network) and between rFEF and visual FBA. 24 healthy subjects completed the improved ANT after stimulation. The sham stimulation experiment was set as the control group. The experimental results show that the stimuli applied to rFEF can not significantly affect the attention subnetwork. However, rFEF, as a part of the frontoparietal network, affects the relevant connections of the frontoparietal network after a short local stimulation, thereby significantly reducing the reaction time of the subjects. In addition, rFEF is closely related to attribute selection in visual FBA tasks, which has been confirmed.

关键词： Visualization Brain Transcranial magnetic stimulation Color Task analysis

Positioning accuracy optimization of DSO-SLAM and its use for the localization of unmanned vehicle

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Positioning accuracy optimization of DSO-SLAM and its use fo...

2021 International Conference on Computer Communication and Artificial Intelligence, CCAI 2021

作者： Wang, Xudong Wang, Xinyu Gao, Chao Wu, Jing Wuhan University of Technology Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan430070 China Wuhan Digital Engineering Institute Wuhan430074 China

ISBN: (纸本)9781728194011

In present work, Direct Sparse Odometry (DSO) of visual SLAM is selected as an auxiliary scheme for unmanned vehicles to solve the problem of poor positioning accuracy or inability to locate caused by multipath refraction. By extracting pixels and feature points jointly in the frontend, it can be ensured that the DSO maintained robustness in weak texture regions, while not omitting the feature corners with repeatability. To improve the positioning accuracy of DSO, the pose-graph optimization and loop closure detection with bag-of-words (BoW) are adopted. The optimized DSO has been compared with the original model in the dataset and verified by experiment in the campus scene. The results show that, the optimized algorithm can accurately detect loop closing, reduce the absolute trajectory error (ATE) of DSO by 61.26%, and greatly improve the positioning accuracy without sacrificing real-time and robustness. It verifies the validity of the DSO with loop closure detection, and provides a new method for the core positioning algorithm of driverless vehicles. © 2021 IEEE.

关键词： Unmanned vehicles

The Gas Production Characteristics and Catastrophic Hazards Evaluation of Thermal Runaway For LiNi0.5Co0.2Mn0.3O2 Lithium-Ion Batteries Under Different Socs

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SSRN 2023年

作者： Qi, Chuang Liu, Zhenyan Lin, Chunjing Liu, Dinghong Li, Zhaoyang Yi, Aibin Key Laboratory of Advanced Manufacturing Technology for Automobile Parts Ministry of Education Chongqing University of Technology Chongqing400054 China Guangxi Key Laboratory of Automobile Components and Vehicle Technology Guangxi University of Science and Technology China CATARC（Changzhou）Automotive Engineering Research Institute Co. Ltd China Co. Ltd China

Lithium-ion batteries (LIB) are widely used as electrochemical energy storage systems in electric vehicles due to their high energy density and long cycle life. However, fire accidents present a trend of frequent occurrence caused by thermal runaway (TR) of LIBs, so it is especially important to evaluate the catastrophic hazards of these LIBs. This study conducted the adiabatic TR test coupled gas production test, Gas Chromatography-Mass Spectrometry test, and explosion limit test on a commercial LIB with Ni0.5Co0.2Mn0.3 as the cathode material at different states of charges (SOCs). The results show that the TR temperature and the maximum temperature at low SOC are lower compared to that at a high SOC. The probability of LIBs TR at less than 50% SOC is small also causing less harm. For the gas production characteristics, the lower the SOC of the battery, the lower the gas production volume. The peak and steady-state gas production increase with the increase of SOC. For the mixed gas generated during thermal runaway, the content of CO2 shows a trend of decreasing with the increasing of battery SOC, while that of H2 and CO increases with the increasing of SOC. For the explosion limit of the mixed gas, the lower explosion limit and upper explosion limit decreases and increases with the increasing of SOC, respectively. Finally, by using the analytic hierarchy process method, the safety level of LIBs at different SOCs is evaluated with seven parameters obtained from the experimental results, which we believe enlightening for establishing a comprehensive quantitative evaluation method for battery safety in practical engineering applications. © 2023, The Authors. All rights reserved.

关键词： Lithium-ion batteries

Accelerated Solid-Liquid Interdiffusion Bonding of Cu Joint Using a Cu10ni Alloy Mesh Reinforced Sac305 Composite Solder

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SSRN 2023年

作者： Liu, Jiajun Xiao, Yong Li, Dan Liu, Bowen Yan, Fei Zhang, Jian School of Materials Science and Engineering Wuhan University of Technology Wuhan430070 China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China

Highly reliable packaging interlayer materials are essential for utilizing the benefits of wide band-gap power devices. In this study, a two-dimensional mesh structure of Cu-10Ni (wt.%) alloy skeleton-reinforced SAC305 (Sn-3.0Ag-0.5Cu, wt.%) solder was employed to create solid-liquid interdiffusion (SLID) bonding connections on a Cu substrate at 250 °C and 0.03 MPa auxiliary pressure. The microstructural evolution and the mechanical property strengthening mechanisms of bonded joints with different composite solders were investigated. Due to the addition of Cu-10Ni alloy skeleton, the Cu-Ni atoms diffused into the Sn melt and acted as heterogeneous nucleation sites, contributing to the rapid nucleation and growth of (Cu,Ni)6Sn5 grains. The incorporation of Ni inhibited the merging and coarsening of intermetallic compound (IMC) grains, and the joint was composed of fine-grained (Cu,Ni)6Sn5 phase and interspersed Cu10Ni skeleton. Shear strength of the joint at soldering time 210 s reached 47.75 MPa, marking a 104.58% enhancement compared to the pristine SAC305 solder joint. The influence of grain refinement on the mechanical properties of the joint was discussed based on the Hall–Petch relationship. The grain boundary strengthening effect synergized with the toughening effect of the alloy skeleton, ultimately achieving highly reliable joints. © 2023, The Authors. All rights reserved.

关键词： Nucleation