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Effect of extrusion ratios on hardness,microstructure,and crystal texture anisotropy in pure niobium tubes subjected to hydrostatic extrusion

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Transactions of Nonferrous Metals Society of China 2021年第6期31卷 1689-1699页

作者： Jongbeom LEE Haguk JEONG Sangyong PArK Advanced Materials and Process R&D Department Korea Institute of Industrial TechnologyIncheon City21999Korea Department of Advanced Materials Science and Engineering Inha UniversityIncheon City22212Korea

Nb tubes were fabricated through hydrostatic extrusion at extrusion ratios of 3.1 and 6.1 at ambient temperature,and then their microstructure,texture,and Vickers hardness were investigated based on electron back-scattered diffraction(EBSd)*** fraction of low-angle boundaries(LABs)largely decreased with a sharp decrease in mean grain sizes after hydrostatic extrusion and was not proportional to extrusion ratios,assuming that mixed-asymmetrical junctions forming LABs dissociate at high extrusion ratios from the external stress(>981 MPa)with thermal activation by the generated *** correlation between grain size and Vickers hardness followed the Hall−Petch relationship despite the texture gradient of theá111ñcyclic fiber textural microstructure at low extrusion ratios and theá100ñtrue fiber textural microstructure at high extrusion *** increase in hydrostatic pressure on the Nb tubes contributed to texture evolution in terms of extrusion ratios due to the difference between{110}<111>and{112}<111>components based on EBSd data.

关键词： niobium tube hydrostatic extrusion microstructure characterization mechanical properties texture evolution

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Evolution of surface quality in micromilling Ti-6A1-4V alloy with increasing machined length

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Procedia CIrP 2024年 123卷 221-226页

作者： Maria Clara Coimbra Gonçalves rob Alsters david Curtis rachid M’Saoubi Hassan Ghadbeigi University of Sheffield Mechanical Engineering Department Mappin Street Sheffield UK R&D Materials and Technology Development Seco Tools AB Zandterweg 14 5973 RC Lottum Netherlands Advanced Manufacturing Research Centre University of Sheffield Rotherham S60 5TZ UK R&D Materials and Technology Development Seco Tools AB 737 82 Fagersta Sweden Division of Production and Materials Engineering Lund University Ole Römers väg 1 221 00 Lund Sweden

Micromilling is a subtractive manufacturing process that presents challenges due to scale effects and rapid tool wear. To understand the evolution of surface quality when increasing the machined length during the micromilling process, this study assessed the surface roughness, topography, and defects of slots micromilled on Ti-6A1-4V. For the experiments, 1 mm diameter flat end mills were employed, and the cutting parameters were varied using a full factorial design. Subsequently, the surface texture field parameter S a was assessed every 20 mm, up until the machining length of 260 mm. The analysed results led to the conclusion that, for the adopted set of parameters and the machining length of up to 260 mm, surface roughness was not significantly correlated to the machined length in the micromilling process of Ti-6A1-4V, as the Pearson coefficient, obtained from the correlation analysis, was -0.052. However, the surface roughness was mainly influenced by feed rate (Pearson coefficient of 0.82), with higher feed rates leading to roug surfaces (up to S a = 0.4 µm) duhere to the tool load increase that causes wider feed marks on the surface. regarding the feed marks, they were affected by the tool rotational frequency due to system vibration. Additionally, surface defects of adhered material, smearing, tearing and side flow were observed. For lower feeds, material adhesion was the main type of defect observed, while higher feed rates favoured the side flow phenomenon.

关键词： micromilling surface quality tool wear

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Effect of Welding Speed on Microstructural Evolution and Strengthening Mechanism of Friction-Stir Welded 7075 Aluminum

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SSrN 2024年

作者： Kim, Jong-Hun Choi, Hyo-Nam Lee, Kwang-Jin Shin, Jae-Hyuck Seo, Nam-Hyuk Jung, Jae-Gil Lee, Seok-Jae Lee, Seung-Joon Gyeonggi-do Siheung-si15073 Korea Republic of Carbon & Light Materials Application R&D Group Korea Institute of Industrial Technology Jeollabuk-do Jeonju-Si54666 Korea Republic of Advanced Materials R&D Department Korea Automotive Technology Institute Chungcheongnam-do Cheonan-Si31214 Korea Republic of Division of Advanced Materials Engineering Jeonbuk National University Jeollabuk-do Jeonju-Si54896 Korea Republic of

In present study, we aim to analyze the microstructural characteristics and strengthening mechanism of AA7075-T6 alloy after the friction-stir welding speeds from 150 to 350 mm min-1. The continuous dynamic recrystallization underwent actively with faster speed, leading to equiaxial and fine grains of 350 specimen, as evidenced by misorientation distribution, grain orientation spread, and aspect ratio. regarding the textural evolution, the 150 specimen retained the deformation texture (e.g., Brass), while the 350 specimen showed the development of recrystallization texture (e.g., Goss). The 250 specimen revealed superior weldability for strength of over ~80% owing to both grain refinement and accumulated dislocations despite the dissolution of precipitates (e.g., GP II zone and ηˊ). © 2024, The Authors. All rights reserved.

关键词： Textures

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Aeroacoustic simulation of broadband sound generated from a cross-flow fan using immersed boundary-lattice Boltzmann method 16

Aeroacoustic simulation of broadband sound generated from a ...

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16th Asian International Conference on Fluid Machinery, AICFM 2021

作者： Kusano, K. Furukawa, M. Sakoda, K. Fukui, T. Department of Mechanical Engineering Kyushu University 744 Motooka Nishi-ku Fukuoka819-0395 Japan Advanced Technology R&d Center Mitsubishi Electric Corp. Japan8-1-1 Tsukaguchihonmachi Amagasaki661-8661 Japan

In this study, we investigated the capability of the immersed boundary-lattice Boltzmann method (IB-LBM) in simulating the broadband sound generated from a cross-flow fan. The present method is based on the lattice Boltzmann equation with the d3Q27 particle velocity model, and the cascaded collision operator was used to stably simulate high-reynolds-number flows. Furthermore, the direct-forcing approach was used to consider rotating blades in the regular lattice. To capture turbulence eddies in the rotor, we used a high-resolution grid that contained approximately 340 million nodes. The simulation successfully captured the fundamental flow features of the cross-flow fan such as the eccentric vortex, and the simulation results were consistent with the experimental results in terms of the time-averaged velocity distribution at the outlet of the fan. In addition, by resolving turbulent eddies in the impeller, the simulation successfully predicted the broadband sound spectrum in the frequency range of 2 kHz or less. © Published under licence by IOP Publishing Ltd.

关键词： Fans

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In Situ Fabrication of Spherical Oxide dispersion Strengthened Ti Powder Through Gas Atomization

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SSrN 2023年

作者： Im, Hyeon-Tae Kim, Woo Jin Kim, Nam-Seok Kim, dae Ha Park, Chang-Soo Park, Kwangsuk Kim, Young do Park, Hyung-Ki Functional Materials and Components R&D Group Korea Institute of Industrial Technology Gangneung25440 Korea Republic of Division of Materials Science and Engineering Hanyang University Seoul04763 Korea Republic of Department of Materials Science and Engineering Hongik University Seoul121-791 Korea Republic of Industrial Materials Processing R&D Department Korea Institute of Industrial Technology Incheon21999 Korea Republic of KONASOL R&D Center KONASOL Dangjin31806 Korea Republic of

Oxide dispersion strengthened (OdS) alloys exhibit excellent mechanical properties due to fine oxide dispersion, but they have great limitations due to utilizing powder fabrication via mechanical alloying. Therefore, this study examined the alloy composition and process that can fabricate OdS titanium (Ti) powder in situ through a gas atomization method. The composition and content of the oxide, which can dissolve in molten Ti during melting and precipitate inside powders during cooling in the gas atomization, were derived through thermodynamic calculations. The OdS Ti alloy composition of Ti + 1 wt% yttria (Y2O3) was derived, and the alloy was prepared as a powder through an electrode induction melting gas atomization (EIGA) method. First, rod-shaped ingots were prepared through vacuum arc remelting (VAr), and Y2O3 was coarsely precipitated along the grain boundaries due to the slow cooling rate. Then, the OdS Ti powder was fabricated by EIGA using the rod ingot and spherical powders could be continuously fabricated. The cross-section microstructure of the powder was observed, and the Y2O3 particles with several tens of nm were uniformly distributed inside the powder. These thermodynamic calculations and experiments confirmed that OdS Ti powder could be fabricated in situ using the gas atomization method. © 2023, The Authors. All rights reserved.

关键词： Powders

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design of Multi-Layered Gradient Catalysts for Efficient Proton Exchange Membrane Fuel Cells

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SSrN 2023年

作者： Shin, Jeehoon Son, Mingyu Kim, Sun-I Song, Shin Ae Lee, duck Hyun Green Materials and Processes R&D Group Korea Institute of Industrial Technology Ulsan44413 Korea Republic of Digital Transformation R&D Department Korea Institute of Industrial Technology Ansan15588 Korea Republic of School of Advanced Materials and Electrical Engineering Andong National University Andong36729 Korea Republic of

Efficient catalyst layers (CLs) in proton exchange membrane fuel cells (PEMFCs) should possess a highly active surface for electrochemical reaction and an ideal platform for simultaneous mass transfer. Efforts have been devoted to lower the widely used Pt and Nafion loading due to their high cost. However, the increase in gas transport resistance and decrease in transfer ability of protons and electrons result in a degraded fuel cell performance. Therefore, CL design with optimal efficiency is important for high performance and stability of PEMFCs. In this study, we design gradient multi-layered CLs in which the loadings of Pt-C catalyst and Nafion ionomer are set differently for each layer to increase efficiency. For ideal cell performance, the ionomer loading should be higher near the membrane layer and Pt-C loading should be higher near the gas diffusion layer. In addition, we confirm that if the loading difference between layers in the gradient CL becomes excessively large, performance can degrade due to the non-uniform Pt active surface. Thus, we design a 5-layer CL and find that designing more layers to reduce the difference in loading between layers results in higher electrochemical surface area (ECSA) and improved performance. © 2023, The Authors. All rights reserved.

关键词： Catalysts

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robust bonding at 175°C of pressureless Ag nanoparticle sinter joint on Ni/Au finished Cu substrates in air

Robust bonding at 175°C of pressureless Ag nanoparticle sin...

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International Conference on Electronics Packaging (ICEP)

作者： Seoah Kim Min-Su Kim Sungwook Mhin dongjin Kim Advance Joining and Additive Manufacturing R&D Department Korea Institute of Industrial Technology Incheon Republic of Korea Department of Advanced Materials Engineering Graduate School Kyonggi University Suwon Korea

Ag sinter joining which has exceptional characteristics is promising as a die-attach material for wide band-gap (WBG) power devices in electric vehicles (EVs). So far, many Ag sinter joining technologies in the range of 250 °C to 300 °C have been developed, but the industry still requires lower die-attach temperatures and more accessible processing methods. We have been pursuing technology that minimizes die-attach temperature and pressure to minimize the warpage of the power module structure. In this work, a pressureless Ag sintering was carried out in air at 175 °C without any pressure, and the bonding strength achieved approximately 37 MPa. The robust bonding mechanism of the Ag sinter joining was investigated using EBSd and Xrd analysis on the microscale. This study can provide a solution for the possibility of the diebonding process at 175 °C and effective heat dissipation design of the power module.

关键词： Heating systems Industries Temperature distribution X-ray scattering Photonic band gap Multichip modules Sintering

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Energetic and Smart design of Battery Management Scheme to Improve the Lifetime of Electric Vehicles

Energetic and Smart Design of Battery Management Scheme to I...

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2023 International Conference on Sustainable Communication Networks and Application, ICSCNA 2023

作者： Varatharaju, V.M. Chidambaranathan, C.M. Karthik, Mamidala Vijay Sathi, G. Pandi, V. Samuthira Shobana, d. University of Technology and Applied Science Electrical Section Engineering Department Ibra Oman Vel Tech Rangarajan Dr. Sagunthala R&d Institute of Science and Technology Department of Computer Science and Engineering Tamil Nadu India Cmr Engineering College Department of Electrical & Electronics Engineering Telangana Hyderabad India Prince Shri Venkateshwara Padmavathy Engineering College Department of Mechanical Engineering Tamil Nadu Chennai India Chennai Institute of Technology Centre for Advanced Wireless Integrated Technology Tamil Nadu Chennai India Rajalakshmi Engineering College Department of Electrical and Electronics Engineering Tamil Nadu Chennai India

ISBN: (纸本)9798350313987

In order to maximize efficiency, electric vehicles use Battery Management Systems (BMS) to manage their rechargeable batteries. The battery's safety and dependability are ensured by the battery management system, and the battery's age is extended without being damaged. Various monitoring methods are used to keep track of the battery pack's charging capacity, voltage-levels, current-ratings and ecological pressure ratio. A variety of analogue and digital sensors are employed with microcontrollers for this purpose. Several powerful batteries have been developed as a result of the tremendous advances in the field of batteries over the past ten years. High-power batteries with suitable battery management systems are essential for the safe and reliable operation of Electric Vehicles (EVs). This paper will address the power sources utilized by electric automobiles and the primary problems of battery control systems, as well as compare both the lithium ion battery as well as the metal based nickel-hydride batteries in regards to growing older along with the impact caused by climate through the use of the State-of-Charge (SOC) and closed device electricity. This study's goal is to compare and contrast different intelligence techniques along with the control methods used in electric vehicle battery management platforms. The study assesses the characteristics, structure, configuration, accuracy, benefits, and downsides of intelligent algorithms for estimating the condition of a battery. Focusing on parts, characteristics, aims, outcomes, advantages, and restrictions, this research analyses the various controllers used for warming, cooling, balancing, and protecting batteries. © 2023 IEEE.

关键词： Battery Management Systems BMS Electric Vehicles EVs SOC State-of-Charge

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Cloud-Enabled Predictive Vehicle Health Monitoring and Maintenance with LSTM Networks for Time-Series Analysis 1

Cloud-Enabled Predictive Vehicle Health Monitoring and Maint...

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1st International Conference on Innovations in Communications, Electrical and Computer Engineering, ICICEC 2024

作者： Vinya, Viyyapu Lokeshwari Manivannan, K.K. Manivannan, S.K. Sathiyamoorthy, C. Jagadeeswaran, M. Meenakshi, B. SRM Institute of Science and Technology Department of Computing Technologies School of Computing Kattankulathur Tamil Nadu Chennai India Easwari Engineering College Department of Electrical and Electronics Engineering Tamil Nadu Chennai India Vit Bhopal University Department of Physics School of Advanced Sciences and Languages Madhya Pradesh Bhopal India J.J College of Engineering and Technology Department of Information Technology Tamil Nadu Tiruchirappalli India Vel Tech Rangarajan Dr. Sagunthala R&d Institute of Science and Technology Department of Computer Science and Engineering Tamil Nadu Chennai India Saveetha University Saveetha Institute of Medical and Technical Sciences Department of Computer Science and Engineering Saveetha School of Engineering Tamil Nadu Chennai India

ISBN: (纸本)9798350376517

Maximizing operational efficiency and customer satisfaction in the automobile sector depends on maintaining vehicle health and avoiding maintenance downtime. Vehicle Internet of Things (IoT) devices capture massive volumes of sensor data, enabling predictive maintenance. This research offers cloud-based predictive vehicle health monitoring and maintenance systems using Long Short-Term Memory (LSTM) networks for time-series analysis. System architecture uses IoT sensors in automobiles to gather real-time data on engine temperature, oil pressure, and vibration. This data is stored, analyzed, and predicted on clouds. To assess time-series sensor data and forecast failures or maintenance requirements, LSTM networks, a form of recurrent neural network, are used. The proposed system uses data preprocessing to manage missing values and outliers, feature extraction to find significant sensor data patterns, and LSTM-based predictive modeling to predict vehicle health conditions. technology may predict future faults by continually monitoring and evaluating the vehicle's state, allowing proactive maintenance to avoid expensive breakdowns and downtime. The cloud-based architecture is scalable and flexible, providing smooth connection with fleet management systems and remote vehicle health monitoring across scattered sites. The suggested method optimizes maintenance schedules and resource allocation using predictive insights from real-time sensor data to improve operational efficiency and save costs. It may improve predictive vehicle health monitoring and maintenance in the automobile sector, improving dependability, safety, and cost. © 2024 IEEE.

关键词： Customer satisfaction

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Efficiency Analysis of delta Winding Connected BLdC Motor According to Occurrence of Circulating Current

Efficiency Analysis of Delta Winding Connected BLDC Motor Ac...

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IEEE Conference on Electromagnetic Field Computation

作者： Ho-Young Lee Kyoung-Soo Cha Seung-Young Yoon Chang-Hoon Seok Soon-O Kwon Myung-Seop Lim Advanced Mechatronics R&D Group Korea Institute of Industrial Technology Daegu Korea School of Electronic and Electrical Engineering Kyungpook National University Daegu Korea Department of Automotive Engineering Hanyang University Seoul Korea

ISBN: (数字)9798350348958

ISBN: (纸本)9798350348965

This paper studied the effect of circulating current generated in a surface-mounted synchronous motor (SPMSM) with delta winding on efficiency. In a delta-connected motor, when the 3nth component occurs in the phase basck electromotive force (BEMF), a circulating current that flows only inside the circuit occurs. This current causes additional joule losses and degenerate motor performance. In this paper, the 3nth component of the phase BEMF was reduced by chaging the shape of the permanent magnet of SPMSM, and the performance of the motor was compared. For this purpose, a six step dirve was used, and the loss was separated into copper loss and iron loss according to the torque and speed of the motor. At this time, copper loss was divided into loss due to the fundamental wave and the 3nth component of the phase current. Finally, an efficiency map according to torque and speed was presented, and the diifference in efficiency between the basic and improved models was analyzed. The performace of the prototype was verified by a dynamometer load test.

关键词： Torque Shape Windings Prototypes Motors Synchronous motors Permanent magnets

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