检索结果-内蒙古大学图书馆

Impact of aging temperature on the metallurgical and dry sliding wear behaviour of LM25 / Al2O3 metal matrix composite for potential automotive application

引用

International Journal of Lightweight materials and Manufacture 2023年第3期6卷 416-433页

作者： Ravinath, Harinath Ahammed I, Ijas P, Harigovind Devan S, Achu Senan V R, Aravind Shankar, Karthik V. S, Nandakishor Department of Mechanical Engineering Amrita Vishwa Vidyapeetham Amritapuri India Department of Material Science and Engineering KTH Royal Institute of Technology Stockholm100 44 Sweden

The current study exhibits the influence of aging temperatures on the metallurgical, hardness, and dry-sliding wear behaviour of LM25 (Al-6.6Si-0.2Mg) alloy reinforced with Al2O3 particles. The LM25 alloy reinforced with 10 wt% of alumina particles was fabricated using the liquid metallurgy route followed by solutionizing and aging. The baseline LM25 alloy and its composite were solutionized at 538 °C for 8 h and were aged at 155, 165, and 175 °C for 12 h. Optical, FESEM, EDS, and X-ray diffraction analysis were done on the fabricated alloy and its composite in all conditions. The microstructure revealed the formation of the Mg2Si phase in the baseline alloy and the MgAl2O4 spinel generated at the composite interface of the aluminium matrix. The heat-treated alloy and composites were tested for their hardness on the Vickers microhardness tester. It was concluded that the aging temperature of 155 °C displayed significant enhancement in hardness values for tested samples. The heat-treated alloy and composite samples displayed an increment of 96% and 55% in hardness values relative to LM25. The wear rate and friction coefficient for the fabricated samples were analyzed using the pin-on-disc tribometer under dry sliding conditions. The hardness value increased from the as-cast state to samples aged at 155 °C and then decreased at 165 and 175 °C. Based on the wear study, a 14% and 25% decrease in the wear rate values for heat-treated alloy and composites were noted when sliding velocity was increased from 1 m/s to 3 m/s. However, the coefficient of friction (COF) decreased by 23% and 13% for the specimens in the same conditions. Furthermore, a similar trend was displayed by age-hardened LM25 alloy and the composite when subjected to varying load (5, 10, 15 N) condition. Lastly, the worn-out surface mechanisms were examined using FESEM analysis. Amongst the investigated samples, LM25/10 wt% Al2O3 composite aged at 155 °C revealed the least wear rate when subjected to an e

关键词： Hardness

来源：评论

学校读者我要写书评

暂无评论

Process parameter optimization for directed laser deposition of hot work tool steel Dievar

引用

International Journal of Advanced Manufacturing Technology 2025年第3期138卷 1129-1142页

作者： Belsvik, Marius Aga Hansen, Vidar Department of Mechanical and Structural Engineering and Materials Science University of Stavanger Stavanger4021 Norway Kverneland Group Operations Norway as Klepp4353 Norway

Tool steel utilized in hot work applications are prone to costly and time-consuming maintenance repair due to wear generated on the tool surface from static and dynamic high temperature loading during the production processes. Traditionally, the repair is mainly done by subtractive machining of the tool profile. Implementation of an additive manufacturing technology such as directed laser deposition can greatly reduce maintenance time by targeting specifically the worn areas of the tool surface. In the presented work, a commercially available hybrid additive manufacturing and computer numerical control system is used to deposit a powdered hot work tool steel called Dievar. The central composite design is used in the experimental setup to optimize the most influential input parameters;powder feed rate, traverse speed, and laser power by analyzing single track geometry. The presented process window produced defect free parts without the need for preheating, Applying a powder feed rate of 6.5 g/min, traverse speed of 550 mm/min, and laser power of 1500 W, yielding an average as-built hardness of 610 HV0.5 while retaining the required pre-hardened properties in the heat-affected zone in the substrate, with a minor hardness reduction of 4–5% post-deposition. Additionally, the research revealed that the established boundary conditions for aspect ratio and dilution is not an absolute requirement to achieve a fully dense part without lack of fusion or cracks. Engineers working in the field of additive manufacturing may use the presented method to find optimal process parameters and qualify the implementation of directed laser deposition in their industry, avoiding a unnecessarily large selection of samples for testing and thus saving time and resources. © The Author(s) 2025.

关键词： Hot working

来源：评论

学校读者我要写书评

暂无评论

Hydrogen trapping and diffusion in polycrystalline nickel:The spectrum of grain boundary segregation

引用

Journal of materials science & Technology 2024年第6期173卷 225-236页

作者： Yu Ding Haiyang Yu Meichao Lin Michael Ortiz Senbo Xiao Jianying He Zhiliang Zhang Department of Structural Engineering Norwegian University of Science and Technology(NTNU)Trondheim 7491Norway Division of Applied Mechanics Department of Materials Science and EngineeringUppsala UniversityUppsala 75121Sweden Graduate Aerospace Laboratories California Institute of Technology1200 E.California Blvd.PasadenaCA 91125USA

Hydrogen as an interstitial solute at grain boundaries(GBs)can have a catastrophic impact on the mechanical properties of many *** the global research effort,the underlying hydrogen-GB interactions in polycrystals remain inadequately *** this study,using Voronoi tessellations and atomistic simulations,we elucidate the hydrogen segregation energy spectrum at the GBs of polycrystalline nickel by exploring all the topologically favorable segregation *** distinct peaks in the energy spectrum are identified,corresponding to different structural *** first peak(-0.205 eV)represents the most favorable segregation sites at GB core,while the second and third peaks account for the sites at GB *** incorporating a thermodynamic model,the spectrum enables the determination of the equilibrium hydrogen concentrations at GBs,unveiling a remarkable two to three orders of magnitude increase compared to the bulk hydrogen concentration reported in experimental *** identified structures from the GB spectrum exhibit vastly different behaviors in hydrogen segregation and diffusion,with the low-barrier channels inside GB core contributing to short-circuit diffusion,while the high energy gaps between GB and neighboring lattice serving as on-plane diffusion *** square displacement analysis further confirms the findings,and shows that the calculated GB diffusion coefficient is three orders of magnitude greater than that of *** present study has a significant implication for practical applications since it offers a tool to bridge the gap between atomic-scale interactions and macroscopic behaviors in engineering materials.

关键词： Hydrogen embrittlement Grain boundaries Impurity segregation Polycrystal Atomistic simulations

来源：评论

学校读者我要写书评

暂无评论

A large language model-powered literature review for high-angle annular dark field imaging

引用

Chinese Physics B 2024年第9期33卷 76-81页

作者： Wenhao Yuan Cheng Peng Qian He Department of Material Science and Engineering College of Design and EngineeringNational University of Singapore9 Engineering Drive 1EA#03-09117575Singapore Centre for Hydrogen Innovations National University of SingaporeE81 Engineering Drive 3117580Singapore

High-angle annular dark field(HAADF)imaging in scanning transmission electron microscopy(STEM)has become an indispensable tool in materials science due to its ability to offer sub-°A resolution and provide chemical information through *** study leverages large language models(LLMs)to conduct a comprehensive bibliometric analysis of a large amount of HAADF-related literature(more than 41000 papers).By using LLMs,specifically ChatGPT,we were able to extract detailed information on applications,sample preparation methods,instruments used,and study *** findings highlight the capability of LLMs to provide a new perspective into HAADF imaging,underscoring its increasingly important role in materials ***,the rich information extracted from these publications can be harnessed to develop AI models that enhance the automation and intelligence of electron microscopes.

关键词： large language models high-angle annular dark field imaging deep learning

来源：评论

学校读者我要写书评

暂无评论

Wake Effects on A Hybrid Semi-Submersible Floating Wind Farm with Multiple Hub Heights

引用

China Ocean engineering 2023年第1期37卷 101-114页

作者： XU Xiao-sen GU Jia-yang LING Hong-jie YANG Pu-yi WANG Shuai-shuai XING Yi-han Oleg GAIDAI ZHANG Zhong-yu Marine Equipment and Technology Institute Jiangsu University of Science and TechnologyZhenjiang 212100China Department of Mechanical and Civil Engineering Florida Institute of TechnologyMelbourne 32901United States Department of Marine Technology Norwegian University of Science and TechnologyTrondheim 7491Norway Department of Mechanical and Structural Engineering and Materials Science University of StavangerStavanger 4021Norway College of Engineering Science and Technology Shanghai Ocean EngineeringShanghai 201306China

Wind farms generally consist of a single turbine installed with the same hub height. As the scale of turbines increases,wake interference between turbines becomes increasingly significant, especially for floating wind turbines(FWT).Some researchers find that wind farms with multiple hub heights could increase the annual energy production(AEP),while previous studies also indicate that wake meandering could increase fatigue loading. This study investigates the wake interaction within a hybrid floating wind farm with multiple hub heights. In this study, *** is employed to simulate a hybrid wind farm which consists of four semi-submersible FWTs(5MW and 15MW) with two different hub heights. Three typical wind speeds(below-rated, rated, and over-rated) are considered in this paper to investigate the wake meandering effects on the dynamics of two FWTs. Damage equivalent loads(DEL) of the turbine critical components are computed and analyzed for several arrangements determined by the different spacing of the four turbines. The result shows that the dynamic wake meandering significantly affects downstream turbines’ global loadings and load effects. Differences in DEL show that blade-root flapwise bending moments and mooring fairlead tensions are sensitive to the spacing of the turbines.

关键词： hybrid floating wind farm wake meandering multiple hub heights floating wind turbine FAST.Farm fatigue

来源：评论

学校读者我要写书评

暂无评论

Highly sensitive Fe^(3+)luminescence detection via single-ion adsorption

引用

Chinese Chemical Letters 2024年第1期35卷 431-434页

作者： Yujing Li Xiaojun Zhang Zicheng Wang Lina Zhao Yuxin Li Key Laboratory of Function Inorganic Material Chemistry(MOE) School of Chemistry and Material Scienceand School of Civil EngineeringHeilongjiang UniversityHarbin 150080China Department of Food&Environmental Engineering East University of HeilongjiangHarbin 150066China

To achieve a lower detection limit has always been a goal of analytical ***,we demonstrate the first picomolar level detection capability for Fe3+ion via luminescence detection *** results of structural analysis and theoretical calculation show that Fe3+ions are adsorbed on the central node of Eu-DBM(DBM=dibenzoylmethane)sensor in the form of single ion at ultralow ***,the pathways of photo-induced charge and energy transfer of the obtained Eu-DBM@Fe^(3+)material have been changed,from the initial DBM-to-Eu^(3+)before Fe^(3+)adsorption to the ultimate DBM-to-Fe^(3+)after adsorption process,which quenches the luminescence of Eu3+*** work not only obtains the highly sensitive luminescence detection ability,but also innovatively proposes the single-ion adsorption mechanism,both of which have important scientific and application values for the development of more efficient detection agents in the future.

关键词： Luminescence detection Lanthanide complex High sensitivity Fe^(3+)ion Single-ion adsorption

来源：评论

学校读者我要写书评

暂无评论

Novel integration of PSO-enhanced damage mechanics and finite element method for predicting medium-low-cycle fatigue life in perforated structures

引用

Chinese Journal of Aeronautics 2025年第2期38卷 128-142页

作者： Qianyu XIA Zhixin ZHAN Yue MEI Yanjun ZHANG Weiping HU Qingchun MENG National Key Laboratory of Strength and Structural Integrity School of Aeronautical Science and EngineeringBeihang UniversityBeijing 100191China Department of Engineering Mechanics Dalian University of TechnologyDalian 116023China AVIC The First Aircraft Institute Xi’an 710089China

In this research,we introduce an innovative approach that combines the Continuum Damage Mechanics-Finite Element Method(CDM-FEM)with the Particle Swarm Optimization(PSO)-based technique,to predict the Medium-Low-Cycle Fatigue(MLCF)life of perforated ***,fatigue tests are carried out on three center-perforated structures,aiming to assess their fatigue life under various strengthening *** tests reveal significant variations in fatigue life,accompanied by an examination of crack initiation through the analysis of fatigue fracture ***,an innovative fatigue life prediction methodology is applied to perforated structures,which not only forecasts the initiation of fatigue cracks but also traces the progression of damage within these *** leverages an elastoplastic constitutive model integrated with damage and a damage evolution model under cyclic *** accuracy of this approach is validated by comparison with test results,falling within the three times error ***,we explore the impact of various strengthening techniques,including cross-sectional reinforcement and cold expansion,on the fatigue life and damage evolution of these *** is achieved through an in-depth comparative analysis of both experimental data and computational predictions,which provides valuable insights into the behavior of perforated structures under fatigue conditions in practical applications.

关键词： Continuum damage mechanics Medium-low-cycle fatigue Particle swarm optimization Life prediction Perforated structures

来源：评论

学校读者我要写书评

暂无评论

Precise Fabrication of Tetrametallic Metal-Organic Frameworks and Multivariate Hybrids for Enhanced Photothermal Tandem Catalysis

引用

Chemical Research in Chinese Universities 2024年第6期40卷 1141-1150页

作者： FAN Yiwen WANG Yang WANG Huijuan CHEN Yuzhen LI Zhibo Department of Chemistry College of Chemistry and Chemical EngineeringQingdao University of Science and TechnologyQingdao 266071P.R.China Experimental Center of Engineering and Material Science University of Science and Technology of ChinaHefei 230026P.R.China

Multiple metal sites doped in metal-organic frameworks (MOFs) are essential for their promising application in cascade ***,precision synthesis of tetrametallic MOFs with total coordination and regular shapes is challenging due to the different coordination abilities of four metal ***,a series of tetrametallic MOFs (t-MOFs) with four regular morphologies is successfully constructed by regulating the metal ratio,amount of morphologic modulating reagent or growth *** t-MOFs can be flexibly oxidized to afford porous metal oxides (MxCo_(3)O_(4),M=CuZnNi) under air or reduced to carbon-encapsulated CuCoNi under H_(2)/Ar for different reactions to maximize the value-in-use of *** particular,the t-MOF@MxCo_(3)O_(4) obtained upon the surface oxidation of t-MOF well integrates the Lewis-base sites from MOF core with photothermal oxidation activity from MxCo_(3)O_(4) *** hybrid effectively catalyzes the cascade reaction of styrene oxidation coupling Knoevenagel condensation under visible ***,the by-product,benzaldehyde,is successfully converted to easily separated benzylidene malononitrile to finally obtain pure styrene epoxide (SO).In MxCo_(3)O_(4),Ni species afford good photothermal effect,Cu and Co species provide catalytic activity,and Zn species increase SO *** host-object coordination and the synergy among objects may greatly boost more complex reactions in the future.

关键词： Metal-organic framework Multimetallic site Photothermal catalysis Cascade reaction Host-object coordination

来源：评论

学校读者我要写书评

暂无评论

CsPbI_(2)Br epitaxial shell for efficient PbS quantum dot solar cells

引用

Nano Research 2024年第12期17卷 10302-10308页

作者： Sami Ur Rahman Yong-Hui Song Zhen-Yu Ma Xiao-Lin Tai Bai-Sheng Zhu Yi-Chen Yin Li-Zhe Feng Jing-Ming Hao Guan-Jie Ding Kuang-Hui Song Ya-Lan Hu Tieqiang Li Jixian Xu Hong-Bin Yao Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China Department of Applied Chemistry University of Science and Technology of ChinaHefei 230026China Department of Material Science and Engineering University of Science and Technology of ChinaHefei 230026China

Lead sulfide quantum dots(PbS QDs)are promising candidates for high-performance solar cells due to their tunable bandgaps and low-cost solution ***,low carrier mobility and numerous surface defects restrict the performance of the fabricated solar ***,we report the synthesis of novel PbS-perovskite core-shell QDs to solve the low carrier mobility problem of PbS QDs via a facile hot injection ***_(2)Br shell enabled strain-free epitaxial growth on the surface of PbS QDs because of 98%lattice *** results demonstrate a significant improvement in the photoluminescence and stability of the synthesized PbS-CsPbI_(2)Br QDs upon shell formation,attributed to the effective suppression of surface defects by the epitaxial shell of CsPbI_(2)*** a result,the obtained solar cell based on PbS-CsPbI_(2)Br core-shell QD exhibits a power conversion efficiency(PCE)of 8.43%,two times higher than that of pristine PbS ***,the construction of PbS-CsPbI_(2)Br core-shell structures represent a promising strategy for advancing the performance of PbS QDs-based optoelectronic devices.

关键词： lead chalcogenide perovskites core-shell epitaxial growth solar cell

来源：评论

学校读者我要写书评

暂无评论

Effects of Strain and Strain Rates on Microstructure Evolution Within ASB of TC4

引用

Acta Mechanica Solida Sinica 2024年第6期37卷 958-966页

作者： Qiang Zhou Qilin Xiong Zhaoquan Zeng Department of Mechanics School of Aerospace EngineeringHuazhong University of Science and Technology1037 Luoyu RoadWuhan430074China Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment 1037 Luoyu RoadWuhan430074China

Adiabatic shear band(ASB),a typical failure mechanism in a metal at high strain rates,is hardly controllable or predictable to some *** development of the microstructure plays a crucial role in its *** this paper,the effect of strain rate on the development of microstructure in ASB of titanium alloy TC4 is investigated using hat-shaped specimens with the split-Hopkinson pressure bar *** results show that the fracture strength of TC4 is significantly dependent on the shear strain *** increase in fracture strength from a strain rate of 11,300 s^(−1)to 24,930 s^(−1)is much higher than that from 24,930 s^(−1)to 35,620 s^(−1),which can be attributed to the effect of strain rate on dislocation *** in both as-received and deformed states are investigated using various characterization techniques such as electron backscatter diffraction and X-ray *** region of ASB clearly shows three different microstructural features:random distribution of coarse grains(as received),distribution of elongated grains(transition zone),and distribution of equiaxed nanocrystals(shear-localized zone).The width of ASB increases with the strain *** possible reason for this is that the higher the strain rate,the larger the region where dynamic recrystallization(DRX)occurs due to the accumulation of a large number of *** the middle of ASB,a significant decrease in low-angle grain boundaries(LAGBs)and a large increase in high-angle grain boundaries are *** texture of specimens,especially the{11–20}and{10–10}planes,changes significantly during shear deformation at high strain *** mechanism of continuous dynamic recrystallization can well explain the formation and evolution of DRX within the ASB.

关键词： High strain rates Dynamic recrystallization Adiabatic shear band Microstructure evolution TC4

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：