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International Journal of Minerals,Metallurgy and Materials 2014年第10期21卷 1037-1043页

作者： A.Mosleh M.Ehteshamzadeh R.Taherzadeh Mousavian department of Materials Science and Engineering Shahid Bahonar University of Kerman department of Metallurgy Zanjan Branch Islamic Azad University

In this study, a powder mixture with an Al/TiO2 molar ratio of 10/3 was used to form an r-Al2Ti intermetallic matrix composite （IMC） reinforced with α-Al2O3 ceramic by a novel milling technique, called discontinuous mechanical milling （DMM） instead of milling and ignition of the produced thermite. The results of energy dispersive X-ray spectroscopy （EDX） and X-ray diffraction （XRD） of samples with varying milling time indicate that this fabrication process requires considerable mechanical energy. It is shown that Al2Ti-α-Al2O3 IMC with small grain size was produced by DMM after 15 h of ball milling. Peaks for γ-TLA1 as well as Al2Ti and Al2O3 are observed in XRD patterns after DMM followed by heat treatment. The microhardness of the DMM-treated composite produced after heat treatment was higher than Hv 700.

关键词： composite materials intermetallics alumina titanium aluminide ball milling thermite reaction process

Electrochemical Study of Diffusion Bonded Joints between Micro-duplex Stainless Steel and Ti6A14V Alloy

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Journal of Materials Science & Technology 2014年第2期30卷 163-171页

作者： Shaily M.Bhola Sukumar Kundu Rahul Bhola Brajendra Mishra Subrata Chatterjee department of Metallurgical and Materials Engineering Colorado School of Mines department of Metallurgy and Materials Engineering Bengal Engineering and Science University

In the present study, corrosion behavior of diffusion bonded joints formed between micro-duplex stainless steel （MDSS） and Ti6AI4V alloy （TiA）（at 900 ~C for 60 min under 4 MPa uniaxial pressure in vacuum） was investigated in 1 mol/L HCI and 1 mol/L NaOH solutions using various electrochemical measurements such as open circuit potential （OCP）, electrochemical impedance spectroscopy （EIS） and potentiodynamic polarization （PD）. For comparison, corrosion behavior of base metals （MDSS and TiA） was also evaluated. Bonded joint was characterized by light optical microscopy and scanning electron microscopy using backscattered electron mode. The layer wise σ phase and λ ＋ FeTi phase mixture has been observed at the bond interface and the bond tensile strength and shear strength were - 556.4 MPa and -420.2 MPa, respectively.

关键词： Diffusion bonding Micro-duplex stainless steel titanium ahoy Corrosion EIS

Entropy analysis of unsteady magneto-nanofluid flow past accelerating stretching sheet with convective boundary condition

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Applied Mathematics and Mechanics(English Edition) 2015年第12期36卷 1593-1610页

作者： S.DAS S.CHAKRABORTY R.N.JANA O.D.MAKINDE department of Mathematics University of Gour Banga department of Applied Mathematics Vidyasagar University Faculty of Military Science Stellenbosch University

The unsteady laminar magnetohydrodynamics （MHD） boundary layer flow and heat transfer of nanofluids over an accelerating convectively heated stretching sheet are numerically studied in the presence of a transverse magnetic field with heat source/sink The unsteady governing equations are solved by a shooting method with the Runge-Kutta- Fehlberg scheme. Three different types of water based nanofluids, containing copper, aluminium oxide, and titanium dioxide, are taken into consideration. The effects of the pertinent parameters on the fluid velocity, the temperature, the entropy generation num- ber, the Bejan number, the shear stress, and the heat transfer rate at the sheet surface are graphically and quantitatively discussed in detail. A comparison of the entropy generation due to the heat transfer and the fluid friction is made with the help of the Bejan number. It is observed that the presence of the metallic nanoparticles creates more entropy in the nanofluid flow than in the regular fluid flow.

关键词： unsteady MHD flow nanofluid heat source/sink entropy generation Bejan number

Magnesium nanocomposites:An overview on time-dependent plastic(creep) deformation

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Defence Technology（防务技术） 2019年第2期15卷 123-131页

作者： M.Haghshenas M.Gupta department of Mechanical Engineering University of North Dakota department of Mechanical Engineering National University of Singapore

Magnesium(Mg) nanocomposites are created when nano-size particles are embedded into the Mg(or Mg alloy) matrix. The Mg nanocomposites, cited as high-strength energy-saving materials of future, are a group of emerging materials with excellent combination of strength and ductility and superior specific strength property(strength-to-weight ratio). Having said this, Mg nanocomposites are considered as promising replacement for other structural alloys(i.e. aluminum and titanium) wherever low density and high strength are required, i.e. transportation, aerospace, defense, etc. To be able to apply this group of materials for real components, different failure mechanisms at ambient and elevated temperatures under static and dynamic loading condition must be well documented. Compared with other metals and alloys,rate-dependent plastic deformation(creep), at ambient and elevated temperatures, of these novel materials is not yet well studied which seems a tangible lack of knowledge. This is required since the materials in service are often exposed to medium and elevated temperatures and/or static loads for long duration of time and this encourages creep failure on them. To this end, the information and the controlling mechanisms on time/temperature-dependent response of the material need to be developed to be able to predict the response of the Mg nanocomposites where the materials are under creep conditions. This paper aims at providing an overview on(i) creep-resistant Mg alloys(as matrix) and their chemical compositions, and(ii) responses of the Mg nanocomposites at different creep conditions(time and temperature). The controlling mechanisms contributing to the strength and ductility of the Mg nanocomposites due to the presence of the nanoparticles have been reviewed briefly in the present article. In this paper both traditional(uniaxial) and depth-sensing indentation creep of Mg nanocomposites are reviewed. Also, some fundamental questions and possible explanations have be

关键词： Mg nanocomposite Creep Strength Reinforcement Nanoparticles

Magnesium alloys as extremely promising alternatives for temporary orthopedic implants-A review

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Journal of Magnesium and Alloys 2023年第8期11卷 2688-2718页

作者： C.A.Niranjan T.Raghavendra Madhuri P.Rao C.Siddaraju M.Gupta Vikram Kumar S.Jain R.Aishwarya department of Industrial Engineering and Management Ramaiah Institute of TechnologyBengaluru-54India department of Mechanical Engineering National Institute of EngineeringMysuru-08India department of Chemistry B.M.S.College of EngineeringBengaluru-19India department of Mechanical Engineering Ramaiah Institute of TechnologyBengaluru-54India department of Mechanical Engineering NUS Singapore-75Singapore department of Metallurgical and Materials Engineering Indian Institute of TechnologyMadras-36India

Mg alloys are emerging as potential and very promising alternatives for replacing permanent metallic implant materials such as steels and titanium in applications where the implants need to be removed following healing through revision *** of Mg alloys for implant application is seen as a game changer and Mg alloys are almost perfect materials for the future in both engineering and biomedical *** review therefore focuses on highlighting significance of Mg alloys in biomedical field and risks of using permanent metallic implants particularly when the implants are no longer required after the injury is *** this review,importance of orthopedic implants in present scenario,serious concern related to accidents that are causing permanent disabilities,demand in orthopedic implant market worldwide,potential applications of Mg based materials and their compatibility in biological environment is presented and *** addition,degradation rate,major reactions associated with Mg based materials and effect of alloying elements on implant performance are also discussed based on in-vivo *** advances in development of Mg alloys through various techniques and their performance in in-vitro conditions are also *** ways to eliminate the limitations of Mg alloys include alloying,melt purification,surface alterations,surface modifications,chemical treatment,secondary processing *** *** and opportunities for Mg alloys to become ideal implant material is also addressed.

关键词： Accidents Fractures Burden of fracture Magnesium Ultimate alternative Degradation rate Alloying Melt purification Coating

Effects of TiO_2 nanoparticles on the aquatic plant Spirodela polyrrhiza: Evaluation of growth parameters, pigment contents and antioxidant enzyme activities

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Journal of Environmental Sciences 2018年第2期30卷 130-138页

作者： Ali Movafeghi Alireza Khataee Mahboubeh Abedi Roshanak Tarrahi Mohammadreza Dadpour Fatemeh Vafaei department of Plant Biology Faculty of Natural Sciences University of Tabriz Research Laboratory of Advanced Water and Wastewater Treatment Processes Department of Applied Chemistry Faculty of ChemistryUniversity of Tabriz department of Materials Science and Nanotechnology Near East University department of Horticultural Science Faculty of Agriculture University of Tabriz

Plants are essential components of all ecosystems and play a critical role in environmental fate of nanoparticles. However, the toxicological impacts of nanoparticles on plants are not well documented. titanium dioxide nanoparticles（TiO2-NPs） are produced worldwide in large quantities for a wide range of purposes. In the present study, the uptake of TiO2-NPs by the aquatic plant Spirodela polyrrhiza and the consequent effects on the plant were ***, structural and morphological characteristics of the used TiO2-NPs were determined using XRD, SEM, TEM and BET techniques. As a result, an anatase structure with the average crystalline size of 8 nm was confirmed for the synthesized TiO2-NPs. Subsequently, entrance of TiO2-NPSto plant roots was verified by fluorescence microscopic images. Activity of a number of antioxidant enzymes, as well as, changes in growth parameters and photosynthetic pigment contents as physiological indices were assessed to investigate the effects of TiO2-NPs on S. polyrrhiza. The increasing concentration of TiO2-NPs led to the significant decrease in all of the growth parameters and changes in antioxidant enzyme activities. The activity of superoxide dismutase enhanced significantly by the increasing concentration of TiO2-NPs. Enhancement of superoxide dismutase activity could be explained as promoting antioxidant system to scavenging the reactive oxygen species. In contrast, the activity of peroxidase was notably decreased in the treated plants. Reduced peroxidase activity could be attributed to either direct effect of these particles on the molecular structure of the enzyme or plant defense system damage due to reactive oxygen species.

关键词： TiO2 nanoparticles Spirodela polyrrhiza Growth parameters Antioxidant enzymes Pigment contents

Multilayer ceramic coating for impeding corrosion of sintered NdFeB magnets

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Journal of Rare Earths 2009年第6期27卷 1003-1007页

作者： A.Ali A.Ahmad K.M.Deen department of Metallurgical & Materials Engineering University of Engineering & Technology department of Metallurgy and Materials Engineering CEET University of the Punjab

Sintered NdFeB magnets have complex microstructure that makes them susceptible to corrosion in active *** current paper evaluated the anticorrosion characteristics of multilayer titanium nitride ceramic coating applied through cathodic arc physical vapour deposition(CAPVD) for protection of sintered NdFeB permanent *** performance of ceramic coating was compared to the electrodeposited nickel coating having a copper *** impedance spectroscopy(EIS) and cyclic polar...

关键词： sintered NdFeB magnets multilayer ceramic coating permeable defects rare earths

Preparation and tribological properties of lanthanum-doped TiO_2 nanoparticles in rapeseed oil

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Journal of Rare Earths 2013年第6期31卷 589-594页

作者：谷科城陈波水陈勇 department of Oil Application & Management Engineering Logistical Engineering University department of Barracks Management & Environmental Engineering Logistical Engineering University

Oleic acid （denoted as OA） surface-capped lanthanum-doped titanium dioxide composite nanoparticles, abbreviated as OA/La-TiO2, were prepared via sol-gel method in association with surface modification by oleic acid. The microstructure of as-prepared OA/La-TiO2 was characterized by means of X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectrometry, and their thermal stability was evaluated by thermogravimetry and differential scanning calorimetry. Moreover, the tribological properties of OA/La-TiO2 as lubricant additives in rapeseed oil were evaluated with a four-ball friction and wear tester. The morphology as well as elemental composition and chemical characteristics of worn steel surfaces was investigated by scanning electron microscopy, energy dispersive X-ray spectrometry and X-ray photoelectron spectroscopy. Results showed that as-prepared OA/La-TiO2 particles were of spherical shape and had an average diameter of 20 nm. In the meantime, OA/La-TiO2 particles doped with 1.5% （molar ratio; the same hereafter） and 2.5% of lanthanum could markedly improve the anti-wear and friction-reducing capacities of rapeseed oil. This is attributed to the formation of a complex boundary lubrication film mainly composed of the oxides of iron, titanium and lanthanum as well as the formation of an adsorption film of oleic acid on steel sliding surfaces.

关键词： titanium dioxide lanthanum nanoparticle preparation rapeseed oil lubricant additive tribological properties rare earths

Analysis of some critical aspects in hot machining of Ti-5553 superalloy: Experimental and FE analysis

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Defence Technology（防务技术） 2019年第3期15卷 344-352页

作者： Asit Kumar Parida Kalipada Maity Mechanical Engineering department Indian Institute of Technology Delhi India National Institute of Technology Rourkela Mechanical Engineering Department India

In this study, a newly developed titanium superalloy, i.e., the Ti-5553 alloy has used for hot machining. This material replaced Ti-grade-5 alloy in the application of aerospace, automobile, and biomedical sector. However, similar to Ti-grade-5 alloy, the Ti-5553 alloy has a low thermal conductivity which makes it difficult-to-cut material categories hence, high tool wear, cutting force and bad surface finish. Hot machining of Ti-5553 has been studied at different machining condition (room and hot) using Deform-2D finite element analysis. The result from the simulation test was compared with the experimental value and reduction of cutting and thrust forces was observed. The experiment was carried out with the same input parameters as simulation, and good coherence between them observed. Additionally, cutting zone temperature, effective stress, etc. for both room and elevated the temperature are also discussed.

关键词： Ti-5553 Hot machining Cutting force Flank wear Finite element analysis

Scalable production of mesoporous titanium nanoparticles through sequential flash nanocomplexation

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Chinese Chemical Letters 2024年第4期35卷 303-309页

作者： Feng Cui Fangman Chen Xiaochun Xie Chenyang Guo Kai Xiao Ziping Wu Yinglu Chen Junna Lu Feixia Ruanb Chuanxu Cheng Chao Yang Dan Shao School of Biomedical Sciences and Engineering South China University of TechnologyGuangzhou International CampusGuangzhou 511442China Institutes for Life Sciences School of MedicineSouth China University of TechnologyGuangzhou 510006China School of Biology and Biological Engineering South China University of TechnologyGuangzhou 510006China department of Orthopedics Academy of Orthopedics-Guangdong ProvinceOrthopedic Hospital of Guangdong ProvinceGuangdong Provincial Key Laboratory of Bone and Joint Degenerative DiseasesThe Third Affiliated Hospital of Southern Medical UniversityGuangzhou 510665China National Engineering Research Center for Tissue Restoration and Reconstruction South China University of TechnologyGuangzhou 510006China

Mesoporous titanium nanoparticles(MTNs) have emerged as an important porous semiconductor owning to their large surface area and unique electronic/optical properties. However, the fundamental research for rational manufacturing MTNs in a highly scalable manner remains a challenge. In this study, we report a two-step flash nanocomplexation(FNC) approach to large-scalable generate MTNs through the sequential combination of two multi-inlet vortex mixers. By optimizing the concentrated titanium precursor,polyethylene glycol(PEG)-functionalized silane amount and p H, we have been able to produce MTNs with small particle size(31.5 nm), larger surface area(416.9 m^(2)/g) and pore volume(0.59 cm^(3)/g). Different from the traditional MTNs bulk, FNC-produced MTNs exhibited well-controlled manner and exceptional photocatalytic and antibacterial properties. Importantly, the optimized MTNs outperformed commercial P25 not only in protecting ultraviolet A(UVA)-exposed skin, but also in treating P. aeruginosa-infected wound. We believe that the high controllability and scalability of sequential flash nanocomplexation method offers great opportunities in enhancing the performance of mesoporous titanium nanoparticles.

关键词： Mesoporous titanium nanoparticles Flash nanocomplexation Photocatalytic Antibacterial Sequential