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Development of barium@alginate adsorbents for sulfate removal in lithium refining

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Frontiers of Chemical Science and Engineering 2021年第1期15卷 198-207页

作者： Lisa Xu Kaifei chen George q.chen Sandra E.Kentish Gang(Kevin)Li Department of Chemical Engineering The University of MelbourneParkvilleVIC 3010Australia

The demand for lithium has been steadily growing in recent years due to the boom of electric *** purity lithium is commonly used in the manufacture of battery grade lithium *** residuals originating from acid leaching of lithium ores must be limited to below 20 mg·L^(−1) during *** are methods to remove sulfate such as membrane processing and chemical precipitation using barium ***,membrane separation is unable to achieve the required purity while chemical precipitation often causes secondary contamination with barium and requires extra filtration processes that lead to increased processing *** this study,we developed a polymeric matrix entrapped with barium ions as a novel adsorbent to selectively adsorb sulfate in aqueous *** adsorbent was prepared by dropwise injection method where alginate droplets were crosslinked with barium to form hydrogel *** a typical scenario,the microcapsules had a diameter of 3 mm and contained 5 wt-%*** microcapsules could successfully reduce sulfate concentration in a solution from 100 to 16 mg·L^(−1),exceeding the removal ***,the microcapsules were mechanically unstable in the presence of an excess amount of ***,calcium ions were added as a secondary crosslinking agent to improve the integrity of the *** two-step Ca/Ba@alginate microcapsules showed an exceptional adsorption performance,reducing the sulfate concentration to as low as 0.02 mg·L^(−1).Since the sulfate selective microcapsules can be easily removed from the aqueous system and do not result in secondary barium contamination,these Ca/Ba@alginate adsorbents will find applications in ultra-refining of lithium in industry.

关键词： barium@alginate microcapsules dropwise injection sulfate removal lithium

EVALUATION OF THE PROBABILITY DISTRIBUTION OF PITTING CORROSION FATIGUE LIFE IN AIRCRAFT MATERIALS

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Acta Mechanica Sinica 2003年第3期19卷 247-252页

作者：王清远 N.KAWAGOISHI q.chen R.M.PIDAPARTI Dept.of Civil Eng.and Mechanics Sichuan UniversityChengdu 610065China

Corrosion and fatigue properties of aircraft materials are known to have a considerable scatter due to the random nature of materials,loading,and environmental conditions.A probabilistic approach for predicting the pitting corrosion fatigue life has been investigated which captures the effect of the interaction of the cyclic load and corrosive environment and all stages of the corrosion fatigue process (*** pit nucleation and growth,pit-crack transition,short- and long-crack propagation).The probabilistic model investigated considers the uncertainties in the initial pit size,corrosion pitting current,and material properties due to the scatter found in the experimental *** Carlo simulations were performed to define the failure probability *** cumulative distribution functions of fatigue life agreed reasonably well with the existing experimental data.

关键词： pitting corrosion fatigue probabilistic modeling fatigue life prediction

Analysis of Convolution quadrature Applied to the Time-Domain Electric Field Integral Equation

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Communications in Computational Physics 2012年第2期11卷 383-399页

作者： q.chen P.Monk X.Wang D.Weile Department ofMathematical Sciences University of DelawareNewarkDE 19716USA Department of Electrical and Computer Engineering University ofDelawareNewarkDE 19716USA

We show how to apply convolution quadrature(Cq)to approximate the time domain electric field integral equation(EFIE)for electromagnetic *** a suitable choice of Cq,we prove that the method is unconditionally stable and has the optimal order of ***,the resulting semi discrete EFIE is dispersive and dissipative,and we analyze this ***,we present numerical results supporting and extending our convergence analysis.

关键词： Electromagnetism scattering time-domain integral equation EFIE convolution quadrature multistep method

Adiabatic shear instability in a titanium alloy:Extreme deformation-induced phase transformation,nanotwinning,and grain refinement

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Journal of Materials Science & Technology 2023年第19期150卷 104-113页

作者： X.R.Guan q.chen S.J.qu G.J.Cao H.Wang A.H.Feng D.L.chen School of Materials Science and Engineering Tongji UniversityShanghai 201804China Southwest Technology and Engineering Research Institute Chongqing 400039China Shanghai Key Laboratory of D&A for Metal-Functional Materials School of Materials Science&EngineeringTongji UniversityShanghai 201804China Key Laboratory for Light-weight Materials Nanjing Tech UniversityNanjing 210009China Interdisciplinary Center for Additive Manufacturing School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 2000093China Department of Mechanical and Industrial Engineering Toronto Metropolitan University(formerly Ryerson University)TorontoON M5B 2K3Canada

Increasingly harsh service conditions place higher requirements for the high strain-rate performance of titanium *** shear band(ASB),a phenomenon prone to dynamic loading,is often accom-panied by catastrophic ***,it is unclear how the internal nanostructures are related to shear *** we report detailed microstructural evolution in the ASB of a titanium alloy via in-depth focused ion beam(FIB),transmission Kikuchi diffraction(TKD),and high-resolution transmission electron microscope(HRTEM)analyses,with the deformation instability phenomenon discussed from the energy *** ASB interior undergoes multifaceted changes,namely deformation-induced beta-to-alpha transformation and deformation-induced martensitic transformation to form substantially refined and heterogeneous ***,two types of extremely fine twins are identified to occur within both nano-sized martensite and alpha *** critical plastic work representing the onset of adiabatic shear instability and dynamic equilibrium is observed to be constant for a specific structure in the same deformation *** energy analysis could be extended to other materials subjected to high strain-rate dynamic deformation.

关键词： Adiabatic shear instability Deformation-induced phase transformation Deformation-induced nanotwinning Dynamic recovery Energy analysis

Novel transcatheter aortic heart valves exhibiting excellent hemodynamic performance and low-fouling property

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Journal of Materials Science & Technology 2019年第1期35卷 207-215页

作者： F.Guo K.Jiao Y.Bai J.Guo q.chen R.Yang X.Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China School of Textile and Material Engineering Dalian Polytechnic University Lumenous Peiertech

Transcatheter aortic heart valves(TAHVs) have been widely used for aortic valve replacements, with less trauma and lower clinical risk compared with traditional surgical heart valve replacements. In the present study, composites of poly(ethylene glycol) diacrylate(PEGDA) hydrogels and anisotropic highshrinkage polyethylene terephthalate/polyamide6(PET-PA6) fabric(PEGDA/PET-PA6) were fabricated as artificial heart valve leaflets. Dynamic mechanical analyses(DMA) indicated that PEGDA/PET-PA6 composites possessed anisotropic mechanical properties(i.e., storage moduli ~23.30 ± 1.36 MPa parallel to the aligned fabric fibers and ~9.68 ± 0.90 MPa perpendicular to the aligned fibers at 1 Hz) that were comparable to aortic valve leaflets. The PEGDA/PET-PA6 composites with smooth surfaces were highly hydrophilic(contact angle ~41.6°± 3.8°) and had low-fouling properties without platelet adhesion,suggesting a low risk of thrombogenicity when they interacted with blood. Furthermore, transcatheter aortic heart valves were fabricated using nitinol self-expanding frames and PEGDA/PET-PA6 composites as artificial leaflets, which presented excellent hemodynamic performance with a large orifice area(1.75cm2) and low regurgitation(3.41%), thus meeting the requirements of ISO 5840-3 standard. Therefore,PEGDA/PET-PA6 composites had suitable mechanical properties, good biocompatibility, and low-fouling properties, indicating that they might be used for TAHVs in the future.

关键词： Transcatheter aortic heart valve Textile fabric Poly(ethylene glycol)diacrylate Anti-fouling

On the mechanism of Si-promoted destabilization of TiC_(x)particles in Al alloys

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Journal of Materials Science & Technology 2023年第34期165卷 17-26页

作者： H.Dong Y.C.Guo Y.Z.chen F.Xia q.q.Guo q.chen G.L.Li J.Y.Zhao Y.Zhong J.P.Li School of Materials and Chemical Engineering Xi’an Technological UniversityXi’an 710021China State Key Lab.of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China School of Science Xi’an University of Science and TechnologyXi’an 710054China

TiC_(x)is an excellent composite strengthening particle and grain refiner for Al ***,the stability of TiC_(x)is poor when solute Si exists in Al alloy melts,which significantly depresses its strengthening and grain refining *** this work,the destabilization mechanisms of the TiC_(x)particles in Al-Si alloy melt with a composition of Al-7Si-7.5TiC were explored via experiments,first-principles calculations and thermodynamic *** experimental results show that Si atoms diffuse into TiC_(x)and Ti atoms are released into the Al melt to form a Ti-rich transition zone during the insulation of TiC_(x)in Al-Si melt,and the TiAlySiz and Al_(4)C_(3)phases are solidified in the Ti-rich zone and at Ti-rich zone/TiC_(x)interface,*** first principles calculations show that the low formation energy of C vacancies facilitates the rapid diffusion of Si atoms in TiC_(x),while the doping of Si atoms reduces the energy barrier of diffusion of Ti atoms in TiC_(x)and promotes the formation of Ti-rich *** thermodynamic calculations show that the wide crystallization temperature range of the destabilized product TiAlySiz phase is the key to continuous decomposition of TiC_(x)*** addition,the driving force of the main destabilization reaction of TiC_(x)in the Al-Si alloys is about 44 times higher than that in the Al alloys without Si *** indicates that the presence of solute Si remarkably promotes the subsequent decomposition process of TiC_(x)in the Al-Si alloy melts.

关键词： Al-Si alloy TiC_(x)particles Destabilization First principles calculations Thermodynamics

INFLUENCE OF HEAT TREATMENT ON OXIDATION PROPERTIES OF C/C COMPOSITES FABRICATED BY HIGH PRESSURE IMPREGNATION CARBONIZATION

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 426-430页

作者： q.chen H.J.Li A.J.Li H.M.Han K.Z.Li School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 ChinaSchool of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 ChinaSchool of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 ChinaSchool of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 ChinaSchool of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 China

Felt base carbon/carbon composites fabricated by super-high pressure impregnation carbonization process (SPIC) were heat treated at high temperature 2773K. The oxidation properties of felt base carbon/carbon composites were investigated at different temperatures (773-1173K), and the microstructures of carbon/carbon composites were studied by SEM and X-ray diffraction. The experimental results showed that the inter-laminar distance of (002) plane (d002) deceased while the microcrystalline stack height (Lc) increased. The oxidation rate of felt base carbon/carbon composites was invari-able at certain temperatures. The oxidation mechanism of carbon/carbon composites changed remarkably at the oxidation temperature 973K. At the initial oxidation stage of carbon/carbon composites, carbon matrix was oxidized much more rapidly than carbon felt.

关键词： carbon/carbon composites high pressure impregnation carbonization high temperature heat treatment oxidation mi-crostructure

Unexpected creep behavior in a rejuvenated metallic glass

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Journal of Materials Science & Technology 2023年第32期163卷 140-149页

作者： J.P.Wu Y.Lin F.H.Duan q.chen H.T.Wang N.Li J.L.Wen J.Pan L.Liu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Material Processing and Die&Mould Technology and School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Laboratory of Nanomaterials&Nanomechanics Department of Mechanical EngineeringCity University of Hong KongHong KongChina Wuhan National High Magnetic Field Center Huazhong University of Science and TechnologyWuhan 430074China Shenzhen Polytechnic Shenzhen 518055China

Rejuvenation,bringing metallic glasses(MGs)to the younger and higher energy states,provides an alternative avenue to explore the interplay between the property and microstructures of *** this study,the creep behavior of the Zr_(69.5)Cu_(12)Ni_(11)Al_(7.5)MGs was experimentally examined by controlling the energy state in terms of structural rejuvenation and thermal *** is found that compared to the as-cast counterpart,the annealed MG at a lower energy state exhibits a higher hardness,a smaller displacement,and a lower creep rate due to the decreased free volume and the inhibited activation of the shear transformation ***,the rejuvenated MG at a high energy state displays lower hardness and increased free volume content,yet it demonstrates superior creep resistance compared to its as-cast counterpart,which deviates from conventional *** unexpected phenomenon occurs as the initial high-content free volume annihilates during creep,and strain hardening takes precedence over strain softening as the prevailing process during creep deformation,leading to a superior creep performance in extremely rejuvenated MGs.

关键词： Metallic glass Energy state Rejuvenation Creep Strain-hardening

Improving high-temperature mechanical properties of cast CrFeCoNi high-entropy alloy by highly thermostable in-situ precipitated carbides

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Journal of Materials Science & Technology 2021年第13期72卷 29-38页

作者： X.W.Liu N.Gao J.Zheng Y.Wu Y.Y.Zhao q.chen W.Zhou S.Z.Pu W.M.Jiang Z.T.Fan State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621999China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China School of Materials Engineering Purdue UniversityWest LafayetteIN 47907USA Southwest Technology and Engineering Research Institute Chongqing 400039China Center for Electron Microscopy Wuhan UniversityWuhan 430072China

The Cr Fe Co Ni high-entropy alloy(HEA)exhibits excellent mechanical properties at lower temperatures due to its low stacking-fault energy,however,its medium-and high-temperature strengths are still *** consideration of the potential diversified applications,more strengthening approaches except for the previously proposed L12 phase hardening deserve further exploration due to its rapid coarsening tendency at high ***,we achieved significant high-temperature strengthening of the cast Cr Fe Co Ni HEA by in-situ precipitation of highly thermostable *** with 0.5 at.%and 1 at.%niobium and carbon were prepared by simple casting processes,*** cast,solute solution and aging.A highly thermostable microstructure was formed,which comprises very coarse grains accompanied with extensive thermostable carbide precipitates embedded,including submicrometer coherent Nb C particles in grain interiors and intergranular coherent M_(23)C_(6)*** high thermostability of microstructure,which is beneficial for the high-temperature loading,is ascribed to the synergy of lacking growth driving force and Zenner pinning effect by the *** properties tested at 673,873 and1073 K show that the yield strength and ultimate tensile strength are significantly increased by Nb/C doping,along with the elongation escalation at higher *** strengthening is mainly due to the precipitation hardening of carbide particles.

关键词： High-entropy alloy Carbides Precipitation High-temperature property Strengthening