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Modeling the tensile behaviour of Al-7075 composites prepared with xB4C under a high flow water cooling rate

Modeling the tensile behaviour of Al-7075 composites prepare...

2024 International Conference on science, engineering and Business for Driving Sustainable Development Goals, SEB4SDG 2024

作者： Adediran, Adeolu Adesoji Adewale Akinwande, Abayomi Afolalu, Sunday A. Ikumapayi, Omolayo M. Bello, Kazeem Aderemi Landmark University Department of Mechanical Engineering Kwara State Omu-Aran Nigeria University of Johannesburg Department of Mechanical Engineering Science South Africa Federal University of Technology Department of Metallurgical and Materials Engineering Ondo State Akure Nigeria Afe Babalola University Department of Mechanical Engineering Ado-Ekiti Nigeria Federal University Department of Mechanical Engineering Oye Ekiti Nigeria

ISBN: (纸本)9798350358155

The choice of stir casting has attracted interest among researchers in the development of boron carbide-Al 7075 composites. Most literatures focus on stir casting parameters like stirring temperature, speed, and time with few or no studies on cooling rate which is the last and very essential stage of the process. In this investigation, boron carbide (B4C) was introduced in Al-7075 at constant stirring parameters with varying water cooling rates. The two variables used are A and B for boron carbide dosage (5, 10, 15 wt. %) and water flow rate at room temperature (100, 300, and 500 cm3/s), respectively. The result showed that dosages of 5 to 10 are dispersed within the matrix resulting in enhanced strength while 15 wt. % resulted in particle clustering, thereby leading to depreciation of strength. Meanwhile, increasing the water cooling rate brought about grain refinement which led to improved tensile properties. However, at 500 cm3/s it resulted in the storage of residual stress, which was detrimental to the strength values. At 5 - 15 wt. % and 100 - 500 cm3/s, it amounted to a consecutive decrease in elongation. The statistical analysis showed that the experimental variables significantly affected the tensile properties. From the regression models developed, there were good representations of the data and are statistically fit in predicting the responses. The Optimum condition stipulated was 11.7414 wt. % B4C and 329.7 cm3/s. © 2024 IEEE.

关键词： Grain refinement

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Applicability of Transition metals as grain refiners in Cu shape memory alloy: potentials and trends

Applicability of Transition metals as grain refiners in Cu s...

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2024 International Conference on science, engineering and Business for Driving Sustainable Development Goals, SEB4SDG 2024

作者： Adediran, Adeolu A. Babalola, Faith Edoziuno, Francis O. Ajisegiri, Emanuel Landmark University Mechanical Engineering Kwara State Omu-Aran Nigeria University of Johannesburg Mechanical Engineering Science South Africa Landmark University Faith Mechanical Engineering Babalola Nigeria Nnamdi Azikiwe University Metallurgical and Materials Engineering Department Awka Nigeria

ISBN: (纸本)9798350358155

Shape memory alloys and in this context, copper-based shape memory alloys are gaining fast recognition in recent times. Great research is being done on the properties, applicability, production methods, and their limitations. This paper discusses shape memory alloys in general and focuses more on the effect of transitional elements such as scandium, indium, cerium, and others on the mechanical properties of Cu-based SMAs. It was found that when combined in micro quantities transitional metals are great refiners of these alloys which in turn affect the mechanical properties. © 2024 IEEE.

关键词： Scandium alloys

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Investigation of mechanical properties, viscoelastic properties and free vibration analysis of natural fibre reinforced composite materials

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Interactions 2024年第1期245卷 1-21页

作者： SathishKumar, G. Prashanth, K.S. Khatoon, Umme Thahira Selvarani, A. Geetha Sridhar, R. Sivabalan, S. Chakravarthy, P. R. Kalyana V.Vijayan Baskar, S. School of Engineering Vels Institute of Science Technology & Advanced Studies Chennai600117 India Department of Physics New Horizon College of Engineering Bengaluru India Department of Metallurgical and Materials Engineering National Institute of Technology Warangal Hanamkonda India Department of Civil Engineering Vel Tech Rangarajan Dr. Sagunthala R & ampD Institute of Science and Technology Avadi India Department of Mechanical Engineering K.Ramakrishnan College of Technology Tamil Nadu Tiruchirappalli India

This study aims to assess the mechanical properties and damping characteristics of polyester composites reinforced with flax and kenaf fibers, incorporating 5 wt.% each of rice husk and wood dust. The research will employ mechanical testing, dynamic mechanical analysis across various temperatures and frequencies, and Scanning Electron Microscopy (SEM). Experiments will measure tensile strength, flexural strength, impact strength, hardness, natural frequency, and damping coefficient (tan δ). SEM imaging will examine the fractured surfaces of tensile samples. Composites will be fabricated using a manual layup technique, combining mat fiber with 5 wt.% each of rice husk and wood dust. Initial findings suggest that fiber incorporation decreases damping curves (tan δ), while the addition of rice husk and wood dust positively correlates with the composite's natural frequency and damping factor. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.

关键词： Tensile strength

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Strengthening and deformation mechanism of high-strength CrMnFeCoNi high entropy alloy prepared by powder metallurgy

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Journal of materials science & Technology 2023年第1期132卷 119-131页

作者： Y.Xing C.J.Li Y.K.Mu Y.D.Jia K.K.Song J.Tan G.Wang Z.Q.Zhang J.H.Yi J.Eckert Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China Laboratory for Microstructures Institute of MaterialsShanghai UniversityShanghai 200444China School of Mechanical Electrical&Information EngineeringShandong UniversityWeihai 264209China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Erich Schmid Institute of Materials Science Austrian Academy of SciencesJahnstraße 12Leoben A-8700Austria Department of Materials Science Chair of Materials PhysicsMontanuniversität LeobenJahnstraße 12Leoben A-8700Austria Adjunct with National University of Science and Technology«MISiS» Leninsky Prosp.4Moscow 119049Russia

Multiphase CrMnFeCoNi high-entropy alloys(HEAs)were prepared by a powder metallurgy process com-bining mechanical alloying(MA)and vacuum hot-pressing sintering(HPS).The single-phase face-centered cubic(FCC)HEA powder prepared by MA was sintered into a bulk HEA specimen containing FCC phase matrix along with precipitated M 23 C 6 phase and nanoscaleσphase *** the sintering temper-ature was 1223 K,the ultimate strength reaches 1300±11.6 MPa,and the elongation exceeds 4%±0.6%.Microstructural characterization reveals that the formation of nanoscale particles and deformation twins play critical roles in improving the strain hardening(SH)*** the MA time promoted the formation of the precipitated phase and enhanced the SH ability by increasing the number of precip-itated *** SH capacity increases significantly with increasing sintering temperature,which is attributed to a significant enhancement in the twinning capacity due to grain growth and the reduced number ofσphase *** systematic studies,the planar glide of dislocations was found to be the main mode of deformation,while deformation twinning appeared as an auxiliary deformation mode when the twinning stress was *** the formation of precipitates leads to grain bound-ary and precipitation strengthening effects,crack initiation is more prominent owing to increased grain boundary brittleness around the precipitated M 23 C 6 *** prominence of crack initiation is a contra-diction that must be reconciled with regard to precipitation *** work serves as a useful reference for the preparation of high-strength HEA parts by powder metallurgy.

关键词： High entropy alloy Powder processing Grain reﬁnement Precipitation strengthening Deformation twinning

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Metastable hybridized structure transformation in amorphous carbon films during friction-A study combining experiments and MD simulation

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Friction 2023年第9期11卷 1708-1723页

作者： Yefei ZHOU Zhihao CHEN Tao ZHANG Silong ZHANG Xiaolei XING Qingxiang YANG Dongyang LI School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science&Technology Yanshan UniversityQinhuangdao 066004China Chemical and Materials Engineering Department University of AlbertaEdmonton T6G 2H5Canada

Amorphous carbon films have attracted substantial interest due to their exceptional mechanical and tribological *** studies revealed that the amorphous carbon films exhibited lower coefficient of friction(COF)because of the transformation in bond structure from sp^(3)-C to sp^(2)-C during friction ***,the mechanism for such a transformation during friction is not well *** study is conducted to get an insight into the metastable transformation in amorphous carbon film during friction by means of experiments and molecular dynamics(MD)*** wear tests showed that wear of the film changed from an abrasive wear mode to a mixture of abrasion and adhesive wear,resulting in a decrease in growth rate of the wear rate after the running-in *** is worth noting that the sp^(3)-C atoms were increased during the running-in stage when the films contained lower sp^(3)/sp^(2) ***,the formed sp^(3)-C atoms could only be short-lived and gradually transformed to sp^(2)-C atoms with the graphitization generated on the wearing surface of the *** radial distribution function and translational order parameter indicated that the films'high sp^(3)/sp^(2) ratio led to an increased sp^(2)-C proportion on the wear scar after friction,which caused an increased structural ordering.

关键词： amorphous carbon film metastable transformation structural order molecular dynamics(MD)simulation tribological performance

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Fabrication and Evaluation of the High-Temperature Bending Strength for Mo2NiB2-Ni Cermets

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Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 2024年第11期71卷 551-555页

作者： Takahashi, Eri Morimoto, Akiko Hayashi, Ayumi Shiraki, Naoto Nishimura, Toshiyuki Maruyama, Satofumi Department of Mechanical Engineering Faculty of Science and Engineering Tokyo City University 1-28-1 Tamazutsumi Setagaya-ku Tokyo158-8557 Japan National Institute for Materials Science 1-2-1 Sengen Tsukuba305-0047 Japan

Mo2NiB2-Ni cermets, a type of boride-based cermet, exhibit attractive mechanical properties such as high hardness and good wear resistance. However, the mechanical properties of these cermets have predominantly been evaluated at room temperature. In this study, three-point bending tests were conducted at high temperatures to investigate the mechanical properties and fractography of Mo2NiB2-Ni cermets. A ternary Mo2NiB2-Ni cermet was prepared using a calcination process to synthesize Mo2NiB2 before sintering. The calcination process resulted in finer and more uniform Mo2NiB2 particles, enhancing the microstructure. Consequently, hardness and transverse rupture strength (TRS) were improved. Three-point bending strengths were measured for samples measuring 4.0 × 3.0 × 24 mm at temperatures up to 800°C in an argon environment, using silicon carbide jigs with a 16 mm span. The results indicated that TRS remained approximately constant at about 1.6 GPa up to 500°C but decreased sharply above 600°C, reaching about 0.12 GPa at 800°C. This decrease was attributed to the softening of the nickel binder phase, which adversely affected the TRS. ©2024 Japan Society of Powder and Powder Metallurgy.

关键词： Sintering

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Graphene Oxide-Based Nanofluid for Heat Transfer Applications 10

Graphene Oxide-Based Nanofluid for Heat Transfer Application...

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10th International Multidisciplinary engineering Research Conference on Moratuwa engineering Research, MERCon 2024

作者： Arachchi, M.D.P. Sandaru, D.M.C. Rajapaksha, S.M. Abeygunewardane, A.A.G.A. Sitinamaluwa, H.S. University of Moratuwa Department of Materials Science and Engineering Moratuwa Sri Lanka University of Sri Jayawardenepura Department of Materials and Mechanical Technology Nugegoda Sri Lanka

ISBN: (纸本)9798331529048

This research investigates the performance of Graphene Oxide-Deionized Water (GO-DI water) nanofluid, and partially reduced Graphene Oxide-Deionized water (prGO-DI water) nanofluid for enhanced heat transfer efficiency. GO and prGO were derived from Sri Lankan graphite via the modified hummers method followed by thermal reduction in a tube furnace. The effect of particle loading was analyzed on the viscosity, thermal conductivity (TC) and stability of nanofluid. The results show that the nanofluids beyond mass loading of 0.5 wt% of GO/prGO show poor stability. prGO was found to be more effective in enhancing the TC of the nanofluid, due to enhanced TC of the prGO particles. TC enhancement of nanofluids up to 30% was achieved, with the highest increment shown by the nanofluid with 0.75 wt % prGO. Furthermore, the thermal transport characteristics of the nanofluids were computationally modelled using finite element analysis. The average convection heat transfer coefficient (CHC) of 0.5 wt % prGO-based nanofluid showed a 52% increment, highlighting the effectiveness of prGO-based nanofluids. Importantly, the nanofluids with particle concentrations below 0.5 wt % show performance enhancement ratio (PER) values suitable for practical applications. The outcome of this research shows the potential of GO-based nanofluids as state-of-the-art heat transfer fluid to be used in the coolant industry. © 2024 IEEE.

关键词： Nanofluidics

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Confinement and synergy effects of supported-confined bimetal catalysts with superior stability and catalytic activity

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Journal of Energy Chemistry 2024年第12期99卷 93-99页

作者： Yujun Sheng Farah Hazmatulhaq Abdullah Al Mahmud Mostafa S.Sayed Iftikhar Hussain Stefano Leoni Wail Al Zoubi Young Gun Ko Integrated Materials Chemistry Laboratory School of Materials Science and EngineeringYeungnam UniversityGyeongsan 38541Republic of Korea School of Chemical Engineering Yeungnam UniversityGyeongsanGyeongbuk 38541Republic of Korea Analysis and Evaluation Department Egyptian Petroleum Research InstituteNasr CityCairo 11727Egypt Department of Mechanical Engineering City University of Hong KongHong Kong 999077China Cardiff University School of ChemistryCardiff CF103ATUnited Kingdom

Bimetallic nanocrystals have attracted considerable attention because of their complicated systems,which are far superior to those of their individual constituents.A TiO_(2)-confined PtMnP bimetallic catalyst(PtMnP@TiO_(2)) was prepared using an ultrasonic-assisted coincident strategy,which demonstrated exceptional catalytic activity in the universal hydrogen evolution reaction (HER).Owing to the bimetallic synergistic effect and TiO_(2) confinement,PtMnP@TiO_(x)showed ultrasmall metal nanoparticles (NPs),a higher active Pt^(0) content,adequate activation at the porous surface,and abundant acid *** were performed to visualize the strain properties of Mn and Pt during the bending process and demonstrate the high activity of *** Pt-Mn bimetallic catalysts were enriched with Pt NPs,convoyed by electron transfer from Mn to ***,PtMnP@TiO_(2) showed robust evolution reaction activities (an overpotential of 220 mV at a current density of 10 mA cm^(-2) and a Tafel slope of 186 mV dec^(-1))and the ability to contrast stated catalysts without *** protocol revealed that the geometrical and electronic effects of Pt and P surrounding the Mn species in PtMnP@TiO_(2) were crucial for increasing the catalytic activity (99%) and durability (over 20 cycles),which were far superior to those of other reported catalysts.

关键词： Synergy Bimetal Catalyst Stability Activity

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Confinement induced three-dimensional trajectories of microswimmers in rectangular channels

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Physical Review Fluids 2024年第8期9卷 083302-083302页

作者： Byjesh N. Radhakrishnan Ahana Purushothaman Ranabir Dey Sumesh P. Thampi Department of Chemical Engineering Department of Physics and Materials Science Department of Chemical Engineering College of Engineering Department of Mechanical and Aerospace Engineering

We study the trajectories of a model microorganism inside three-dimensional channels with square and rectangular cross sections. Using (1) numerical simulations based on the lattice-Boltzmann method and (2) analytical expressions using far-field hydrodynamic approximations and the method of images we systematically investigate the role of the strength and finite-size of the squirmer, confinement dimensions, and initial conditions in determining the three-dimensional trajectories of microswimmers. Our results indicate that the hydrodynamic interactions with the confining walls of the channel significantly affect the swimming speed and trajectory of the model microswimmer. Specifically, pullers always display sliding motion inside the channel: weak pullers slide through the channel center line, while strong pullers slide through a path close to any of the walls. Pushers generally follow helical motion in a square channel. Unlike pullers and pushers, the trajectories of neutral swimmers are not easy to generalize and are sensitive to the initial conditions. Despite this diversity in the trajectories, the far-field expressions capture the essential features of channel-confined swimmers. Finally, we propose a method based on the principle of superposition to understand the origin of the three-dimensional trajectories of channel confined swimmers. Such construction allows us to predict and justify the origin of apparently complex three-dimensional trajectories generated by different types of swimmers in channels with square and rectangular cross sections.

关键词： Complex fluids Living matter & active matter Self-propelled particles

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Ultralow charge-discharge voltage gap of 0.05 V in sunlight-responsive neutral aqueous Zn-air battery

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Carbon Energy 2024年第9期6卷 172-183页

作者： Zhimin Niu Yan Gao Tianhui Wu Fei Zhang Ran Zhao Zijia Chen Yiming Yuan Tifeng Jiao Jianmin Gu Li Lu Desong Wang State Key Laboratory of Metastable Materials Science and Technology(MMST) Hebei Key Laboratory of Applied ChemistryYanshan UniversityQinhuangdaoChina Department of Mechanical Engineering National University of SingaporeSingaporeSingapore School of Sciences Hebei University of Science and TechnologyShijiazhuangChina

Rechargeable neutral aqueous zinc-air batteries(ZABs)are a promising type of energy storage device with longer operating life and less corrosiveness compared with conventional alkaline ***,the neutral ZABs normally possess poor oxygen evolution reactions(OERs)and oxygen reduction reactions performance,resulting in a large charge–discharge voltage gap and low round-trip ***,we demonstrate a sunlight-assisted strategy for achieving an ultralow voltage gap of 0.05 V in neutral ZABs by using the FeOOH-decorated BiVO4(Fe-BiVO_(4))as an oxygen *** sunlight,the electrons move from the valence band(VB)of Fe-BiVO_(4) to the conduction band producing holes in VB to promote the OER process and hence reduce the ***,the photopotential generated by the Fe-BiVO_(4) compensates a part of the charging potential of neutral ***,the energy loss of the battery could be compensated via solar energy,leading to a record-low gap of 0.05 V between the charge and discharge voltage with a high round-trip efficiency of 94%.This work offers a simple but efficient pathway for solar-energy utilization in storage devices,further guiding the design of high energy efficiency of neutral aqueous ZABs.

关键词： neutral ZABs oxygen catalytic reactions photocatalysis round-trip efficiency solar energy

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