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Wear modes in open porosity titanium matrix composites with TiC addition processed by spark plasma sintering

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Transactions of Nonferrous Metals Society of China 2019年第8期29卷 1653-1664页

作者： I. FARíAS L. OLMOS O. j.MéNEZ M. FLORES A. BRAEM j. vleugels Departamento de Ingeniería de Proyectos Universidad de Guadalajara 45100 Zapopan Jalisco México Instituto de Investigaciones en Ciencias de la Tierra - INICIT Universidad Michoacana de San Nicolás de Hidalgo 58060 Morelia Michoacán México KU Leuven Department of Materials Engineering Kasteelpark Arenberg 44 B-3001 Heverlee Belgium

This work focused on the influence of TiC reinforcing particles on the tribological properties of titanium matrix composites(TMCs)with open porosity,processed by spark plasma sintering(SPS).Materials composed of an equimolar mixture of Ti and TiH2 with 0,3,10 and 30 vol.% of TiC were sintered at 850 ℃.Nanoindentation and wear tests were carried out to assess the nanohardness and the wear resistance in a tribometer with a reciprocating sliding ball-on-flat *** showed a nanohardness increment from 5 to 14 GPa with increasing TiC *** coefficient of friction(CoF)showed a minimum of 0.2 for 10% TiC grade,which also showed the lowest wear *** the low TiC content sample,adhesive wear with severe plastic deformation was ***,medium content TiC sample showed a mechanical mixed layer(MML),whereas high TiC content composite showed abrasive as the main wear *** conclusion,the wear mechanisms,CoFs and wear volume changed with TiC content.

关键词： porous titanium spark plasma sintering wear titanium matrix composites

Influence of Phase Constitution on Mechanical Performance of 12Ce-3Y-ZrO_2/2.5 wt pct Al_(2)O_(3) Composites

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j.urnal of Materials Science & Technology 2004年第3期20卷 284-286页

作者： ShuigenHUANG LinLI j.vleugels O.V.D.Biest SchoolofMaterialsScienceandEngineering.ShanghaiUniversity Shanghai200072China DepartmentofMTM KatholiekeUniversiteitLeuvenB-3001HeverleeBelgium

The phase constitution of a composite consisting of 12 at. pct CeO_2-3 at. pct Y_2O_3-ZrO_2/2.5 wt pct Al_2O_3 (3Y12Ce2.5Al)was determined by thermodynamic calculation. It is a combination of 36.9 at. pct cubic phase and 63.1 at. pct tetragonalphase at 1450℃. Green compacts were fabricated by cold isostatic pressing with powder synthesized by coating technique,and pressureless sintered at 1450℃. The fracture toughness and Vickers hardness, evaluated by the micro-indentation method,are 2.02 MPa·m^(1/2) and 11.395 GPa, respectively. The addition of 3 at. pct Y_2O_3 to 12 at. pct CeO_2-ZrO_2 ceramic leads todrastically decrease in toughness compared to composites without yttria stabilizer. No monoclinic phase is detected on thesudece of all the ground samples. The high content of cubic phase and lack of phase transformation can be attributed to thelow toughness based on the thermodynamic prediction.

关键词： Thermodynamics Mechanical properties ZrO_2-CeO_2-Y_2O_3

Study of Thermodynamic Properties of Nonstoichiometric Phase with Compound Energy Model

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j.urnal of Materials Science & Technology 2002年第5期18卷 422-426页

作者： ShuigenHUANG LinLI O.V.D.Biest j.vleugels PeilingWANG Sch. of Mat. Sci. and Eng. Shanghai Univ. Shanghai 200072 China Dept. MTM Katholieke Univ. Leuven B-3001 Heverlee Belgium Shanghai Inst. of Ceramics Chinese Acad. of Sci. Shanghai 200050 China

Using compound energy model (CEM), the thermodynamic properties of and were evaluated. The evaluation was based on the optimization of ZrIO2-CeO2 and ZrO2-CeO1.5 systems, as well as the miscibility gap in CeO1.5-CeO2 system. Except the cubic fluorite structure phase assessed with compound energy model, all the other solution phases were assessed with subsitutional solution model. The model parameters were evaluated through fitting the selected experimental data by means of thermodynamic optimization. A set of parameters with thermodynamics self-consistency was obtained and satisfactorily described the complex relation between y in and the partial pressure of oxygen at different temperatures, also the interdependence among miscellaneous factors such as temperature, oxygen partial pressure, the reduction amount of CeO2 as well as the nonstoichiometry in cubic phase - The calculated results seem to be reasonable when put into the explanation of pressureless sintering of Ce02-stabilized ZrO2 powder compacts at a controlled oxygen partial pressure.

关键词： Zirconia Ceria Nonstoichiometry Thermodynamic

Thermo dynamic Assessment and Microstructure of the ZrO2-CeO2-Al2O3 System

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j.urnal of Materials Science & Technology 2004年第1期20卷 75-78页

作者： ShuigenHUANG LinLI j.vleugels O.V.D.Biest PeilingWANG SchoolofMaterialsScienceandEngineering ShanghaiUniversityShanghai200072China DepartmentofMTM KatholiekeUniversiteitLeuvenB-3001HeverleeBelgium StateKeyLaboratoryofHighPerformanceCeramicsandSuperfineMicrostructure ShangHaiInstituteofCeramicsChineseAcademyofSciencesShanghai200050China

The ZrO2-CeO2-AI2O3 system has been assessed with the CALPHAD (Calculation of Phase Diagrams) technique using the PARROT procedure. The experimental information on the ZrO2-AI2O3, AI2O3-CeO2 systems as well as the isothermal sections of the ternary system at 1673 K and 1873 K is well reproduced. According to the assessed isothermal section at 1723 K, no alumina dissolves into the tetragonal zirconia phase. Specimens with different alumina content are fabricated from commercial 12 mol pct CeO2-stabilized ZrO2 powder (12Ce-ZrO2). The thermodynamic properties are consistent with the observed microstructure, which present a combination of tetragonal phase and alumina grains.

关键词： Ce-TZP A12O3 Thermodynamics

Validity of Amontons's law for run-in short-cut aramid fiber reinforced elastomers:The effect of epoxy coated fibers

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Friction 2020年第3期8卷 613-625页

作者： M.KHAFIDH D.j.SCHIPPER M.A.MASEN N.vleugels W.K.DIERKES j.W.M.NOORDERMEER Faculty of Engineering Technology University of TwenteEnschede 7500AEThe Netherlands Dutch Polymer Institute Eindhoven 5600AXThe Netherlands Department of Mechanical Engineering Universitas Islam IndonesiaYogyakarta 55584Indonesia Department of Mechanical Engineering Imperial College LondonLondon SW72AZUnited Kingdom

Friction between two contacting surfaces is studied *** of the k n o w n friction theories is Amontons,law which states that the friction force is proportional to the normal ***,Amontons7 law has been found to be invalid for *** the present study,the validity of Amontons7 law for short-cut aramid fiber reinforced elastomers is *** types of fillers are used to reinforce the elastomers,namely highly dispersible silica and short-cut aramid ***-cut aramid fibers with two different surface treatments are used,namely non-reactive fibers with standard oily finish(SF-fibers)and fibers treated with an epoxy coating(EF-fibers).A pin-on-disc tribometer is used to investigate the frictional behavior of the composites in sliding contact with a granite counter *** results show that,after the run-in phase,Amontons,law is valid for those composites that are reinforced by short-cut aramid fibers(without reinforcing filler,i.e.,silica)if the contact pressure is below a threshold ***,once the contact pressure exceeds this threshold value,Amontons'law will be *** threshold contact pressure of the composites containing EF-fibers is higher than of the composites containing *** composites that are reinforced by silica and short-cut aramid fibers do not follow Amontons7 law.

关键词： Amontons's law elastomer epoxy coated fiber short-cut aramid fiber

Sintering of WC-Co powder with nanocrystalline WC by spark plasma sintering

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Rare Metals 2006年第3期25卷 246-252页

作者： WANG Xingqing XIE Yingfang GUO Hailiang O.Van der Biest j.vleugels School of Materials Science and Engineering Shanghai University Shanghai 200072 China Materials Engineering Faculty of Engineering Katholikeke Universiteit Leuven Leuven 3000 Belgium

A 92WC-8Co powder mixture with 33 nm WC grains was prepared by strengthening ball milling and was then sintered by spark plasma sintering （SPS） at 1000-1200℃ for 5-18 rain under 10-25 kN, respectively. Movement of the position of low punch shown shrinkage of the sintered body began above 800℃. The shrinkage slowly rose as the temperature rose from 800 to 1000℃ and then quickly rose at above 1000℃ and then gradually rose at above 1150℃. The densities of the samples increased with an increase in sintering temperature, rapidly below 1100℃, and then gradually above 1100℃. WC grains grow gradually with increasing sintering temperature. The powder was sintered to near full density at 1100℃ for 5 rain under 10 kN. The best result of the sample with 275 nm WC grains and no pores was obtained at 1150℃ under 10 kN for 5 rain. The research found the graphite die had a function of carburization, which could compensate the sintered body for the lack of carbon, and had the normal microstructure.

关键词： nanocrystalline cemented carbide spark plasma sintering low temperature sintering strengthening ball milling

Apples to oranges:environmentally derived,dynamic regulation of serotonin neuron subpopulations in adulthood?

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Neural Regeneration Research 2025年第9期20卷 2596-2597页

作者： Christopher j.O’Connell Matthew j.Robson Department of Genetics College of MedicineHarvard UniversityBostonMAUSA j.mes L.Winkle College of Pharmacy Division of Pharmaceutical SciencesUniversity of CincinnatiCincinnatiOHUSA Neuroscience Graduate Program College of MedicineUniversity of CincinnatiCincinnatiOHUSA

Traumatic brain inj.ry(TBI)is a public health problem with an undue economic burden that impacts nearly every age,ethnic,and gender group across the globe(Capizzi et al.,2020).TBIs are often sustained during a dynamic range of exposures to energetic environmental forces and as such outcomes are typically heterogeneous regarding severity and pathology(Capizzi et al.,2020).

关键词： sustained orange dynamic

Alumina/Ce-Tzp Functionally Graded Materials by Electrophoretic Deposition

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材料科学与工程学报 2000年第Z1期20卷 250-254页

作者： C.Zhao, j.vleugels Department of Metallurgy and Materials Engineering K. U. Leuven De Croylaan 2B-3001 Heverlee Belgium

Cylindrical Al2O3/Ce-TZP functionally graded composites were fabricated by electrophoretic deposition and pressureless sintering in air. A continuous change in composition was realized by changing the composition of the suspension during deposition. In order to achieve full densification, a temperature above 1550℃ was necessary. The resultant FGM cylinder with a diameter of 5.6 mm shows the following structure: a central hole with a diameter less than 0.5 mm, a tough Ce-ZrO2 core with a diameter of about 3 mm, a gradient layer of about 1 mm, and a hard Al2O3-rich surface layer. The Ce-ZrO2 core has a Vickers hardness between 10and 11 GPa and an excellent toughness (＞10 MPa√m). In the gradient layer, hardness and toughness vary continuously along the radius. The surface layer has a hardness of 15.5 GPa and a modest toughness of 2.5MPa√m.

关键词： Electrophoretic Deposition surface layer electrophoretic deposition Vickers hardness

Prediction of the Isothermal Sections in the ZrO_(2)- YO_(1.5)-CeO_(2) System

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j.urnal of Materials Science & Technology 2001年第5期17卷 529-534页

作者： LinLI Shuigen HUANG Luoping XU Omer Van Der Biest j.zef vleugels Dept.of Materials Science and Engineering Shanghai UniversityShanghai 200072China Dept.of Materials and Metallurgy Katholieke Universiteit LeuvenB-3001 HeverleeBelgium

The experimental work on the ZrO2-YO1.5-CeO2 system, its limiting quasi-binaries and previous thermodynamic assessments are reviewed and evaluated. Isothermal sections of ZrO2-YO1.5-CeO2 system in the temperature region between 1450 and 1800 C are estimated according to the substitutional model using the Bonnier equation. The CSS + YSS two-phase region of the calculated isothermal section at 1700 degreesC was found to be in good agreement with the experimentally obtained ternary diagram of Longo and Podda. The phase composition in the ZrO2-rich corner however disagreed significantly.

关键词： Soc CALPHAD CeO2 System Prediction of the Isothermal Sections in the ZrO2-YO