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Towards the diffusion source cost reduction for NdFeB grain boundary diffusion process

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Journal of Materials Science & Technology 2020年第1期36卷 50-54页

作者： H.x.Zeng Z.W.Liu J.S.Zhang x.F.Liao H.Y.yu School of Materials Science and Engineering South China University of TechnologyGuangzhou 510640China

Aiming at improving the performance/cost ratio in grain boundary diffusion process(GBDP),the critical RE containing Pr-Al-cu alloy,less expensive RE containing La-Al-cu alloy and non-RE Al-cu alloy were employed as the diffusion *** preliminary results show that the coercivity was successfully enhanced from 1000 kA/m to 1695,1156 and 1125 kA/m by Pr70Al20cu10,La70Al20cu10 and Al75cu25(at.%) alloys diffusion,respectively,due to the formation of(Nd,Pr)-Fe-B,La2 O3 and c-Nd2 O3 phases respectively,after *** is also found that the corrosion resistance can be improved by Al-cu diffusion due to the positive effects of Al and cu elements in grain *** present results demonstrated the various coercivity enhancement mechanisms for the GBDP based on different diffusion sources,and provided feasible solutions for cost reduction of GBDP and NdFeB production by saving RE resource.

关键词： Grain boundary diffusion cost reduction coercivity Microstructure corrosion resistance

Underwater acoustic metamaterials

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National Science Review 2023年第6期10卷 258-280页

作者： Erqian Dong Peizheng cao Jinhu Zhang Sai Zhang Nicholas x.Fang yu Zhang Key Laboratory of Underwater Acoustic communication and Marine Information Technology of the Ministry of Education College of Ocean and Earth Sciences Xiamen University State Key Laboratory of Marine Environmental Science Xiamen University School of Physics and Electronic Engineering Jiangsu University Department of Mechanical Engineering Massachusetts Institute of Technology

Acoustic metamaterials have been widely investigated over the past few decades and have realized acoustic parameters that are not achievable using conventional *** demonstrating that locally resonant acoustic metamaterials are capable of acting as subwavelength unit cells,researchers have evaluated the possibility of breaking the classical limitations of the material mass density and bulk *** with theoretical analysis,additive manufacturing and engineering applications,acoustic metamaterials have demonstrated extraordinary capabilities,including negative refraction,cloaking,beam formation and super-resolution *** to the complexity of impedance boundaries and mode transitions,there are still challenges in freely manipulating acoustic propagation in an underwater *** review summarizes the developments in underwater acoustic metamaterials over the past 20 years,which include underwater acoustic invisibility cloaking,underwater beam formation,underwater metasurfaces and phase engineering,underwater topological acoustics and underwater acoustic metamaterial *** the evolution of underwater metamaterials and the timeline of scientific advances,underwater acoustic metamaterials have demonstrated exciting applications in underwater resource development,target recognition,imaging,noise reduction,navigation and communication.

关键词： underwater acoustic metamaterials invisibility cloaking beam formation topological acoustics metasurfaces absorbers

Mechanical Properties and Defective Effects of 316LN Stainless Steel by First-Principles Simulations

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Journal of Materials Science & Technology 2011年第11期27卷 1029-1033页

作者： x.Q. Li J.J. Zhao J.c. xu x. Liu Key Laboratory of Materials Modification by Laser Ion and Electron Beams Ministry of Education Dalian University of Technology Dalian 116024 China college of Advanced Science and Technology Dalian University of Technology Dalian 116024 China School of chemical Engineering Dalian University of Technology Dalian 116024 China

In current International Thermonuclear Experimental Reactor （ITER） design, the 316LN austenitic stainless steel （316LN SS） is used for first-wall/blanket structures. Thus, it is necessary to study the fundamental mechanical properties and irradiation effect of 316LN SS. A random solid solution model of Fe-cr-Ni-Mn- Mo-Si alloy is used for describing 310LN S$. Using first-principles approaches, the elastic constants and ideal strength of the alloy were calculated. Such alloy exhibits good ductile behavior according to the theoretical values of cauchy pressure and ratio of bulk modulus and shear modulus. Within the 256-atom supercell, inclusion of single vacancy defect further enhances the ductility of the alloy, and the existence of interstitial （Fe, H, He） atoms enhances the Young＇s modulus.

关键词： Stainless steel Mechanical properties Vacancy Interstitial

Electrically conductive Honeycomb Monolith of Nanolaminated Ti_3Alc_2:Preparation and characterization

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Journal of Materials Science & Technology 2015年第1期31卷 125-128页

作者： x.M.Fang x.H.Wang H.Zhang Y.c.Zhou Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences University of chinese Academy of Sciences Science and Technology of Advanced Functional composite Laboratory ARIMPT

Nanolaminated Ti3Alc2honeycomb monolith with parallel and uniform holes has been prepared through a facile extrusion route by using Ti3Alc2powder as the main raw *** fabricated honeycomb monolith has high compressive strength of 133 ± 11 and 59 ± 9 MPa,along and perpendicular to the extrusion direction,*** also has good electrical conductivity,and excellent match of thermal expansion coefficient with the washcoat material of γ-*** combined properties endow the honeycomb monolith a promising candidate as catalysis substrate for cleaning vehicle exhaust.

关键词： Honeycomb ceramic Ti3Alc2 Extrusion catalysis

Recent experimental progress of fractional quantum Hall effect: 5/2 illing state and graphene

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National Science Review 2014年第4期1卷 564-579页

作者： x.Lin R.R.Du x.c.xie International center for Quantum Materials Peking University

The phenomenon of fractional quantum Hall efect(FQHE)was irst experimentally observed 33 years *** involves strong coulomb interactions and correlations among the electrons,which leads to quasiparticles with fractional elementary *** decades later,the ield of FQHE is still active with new discoveries and new technical developments.A signiicant portion of atention in FQHE has been dedicated to illing factor 5/2 state,for its unusual even denominator and possible application in topological quantum ***,FQHE has been observed in high-mobility Ga As heterostructure,but new materials such as graphene also open up a new area for *** review focuses on recent progress of FQHE at 5/2 state and FQHE in graphene.

关键词： fractional quantum Hall efect experimental progress 5/2 state graphene

On the spray drying of uniform functional microparticles

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Particuology 2015年第5期13卷 1-12页

作者： W.Liu x.D.chen c.Selomulya Department of chemical Engineering Monash University18 Alliance LaneClayton 3800VICAustralia Department of Pharmaceutics School of Pharmaceutical SciencesCentral South University School of chemical and Environmental Engineering Soochow UniversitySuzhou Industrial Park

Spray drying is a typical method to produce particles in dry powder forms at industrial scale. Most spray-dried products often show a wide range of particle properties even within the same batch. At Monash University, we utilise a microfluidic spray drying approach to generate uniform microparticles with tightly controlled characteristics and sizes in a scalable, almost waste-flee process. The technique is useful to correlate the effects of formulation and spray drying conditions on the properties of spray-dried particles, and can be used to test new formulations for targeted applications such as encapsulation and release of active ingredients. The synthesis route can be applied to other self-assembling systems, includ- ing mesoporous, crystalline, and hierarchically structured microparticles. As spray drying is commonly used in commercial scales, the understanding of how functional particles are formed in relation to formulations and process conditions could assist in developing a cost effective, energy and material-efficient route to produce powders with better properties and ease of handling for more advanced applications such as selective adsorption and bio-separation.

关键词： Microfluidic spray drying Uniform microparticles Encapsulation controlled release

A Novel Melt Processing for Mg Matrix composites Reinforced by Multiwalled carbon Nanotubes

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Journal of Materials Science & Technology 2016年第12期32卷 1303-1308页

作者： H.L.Shi x.J.Wang c.L.Zhang c.D.Li c.Ding K.Wu x.S.Hu School of Materials Science and Engineering Harbin Institute of Technology

carbon nanotubes（cNTs） reinforced Mg matrix composites were fabricated by a novel melt *** novel processing consisted of two courses：cNTs pre-dispersion and ultrasonic melt *** ball-milling was employed to pre-disperse cNTs on Zinc（Zn） *** cNT entanglements were well dispersed to single cNT or tiny clusters on Zn *** ultrasonic melt processing further dispersed cNTs in the Mg melt,especially tiny cNT ***,a uniform dispersion of cNTs was achieved in the as-cast *** extrusion further improved the distribution of *** increased both the strength and elongation of the matrix ***,the elongation of the matrix alloy was enhanced by 40%.Grain refinement and the pulling-out of cNTs resulted in the evident improvement of ductility for the composites.

关键词： Pre-dispersion carbon nanotubes Magnesium matrix composites Ultrasonic

NEW VIEW ABOUT BAINITIc TRANSFORMATION IN STEEL

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Acta Metallurgica Sinica(English Letters) 1999年第3期12卷 229-234页

作者： Liu, c.c. Liu, Z. chen, G.x. Tsinghua Univ Beijing China

The bainitic transformation was analyzed according to the factors such as morphology, crystallography, mechanical property of bainite and transformation kinetics. It was found that the bainitic transformation is controlled by displacive mechanism and self-tempering of displacive microstructure, i.e. bainite is the product of such procedure during which undercooled austenite first transforms into one certain displacive microstructure by displacive mechanism and then this microstructure experiences self-tempering. With this idea, several questions that can not be illustrated only by displacive transformation mechanism can be explained successfully.

关键词： Bainite Morphology Steel

correlation between test temperature, applied load and wear transition of Mg97Zn1Y2 alloy

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Journal of Magnesium and Alloys 2021年第2期9卷 592-603页

作者： J.An Y.x.Tian c.Q.Feng Key Laboratory of Automobile Materials Ministry of EducationDepartment of Materials Science and EngineeringJilin UniversityChangchun 130025PR China

Dry sliding wear tests were performed on Mg97 Zn1 Y2 alloy at various temperatures of 20,50,100,150 and 200°c using a pin-on-disc wear testing machine in order to reveal mild-severe(M-S)wear transition mechanism during elevated-temperature wear *** was shown that at each test temperature,the wear rate increased with increasing load,and all wear rate-load curves demonstrated two distinct stages *** and severe wear *** predominant wear mechanisms operating in mild and severe wear stages were analyzed,and they were indicated in the mild and severe wear regimes of a wear mechanism transition map,respectively.M-S wear transition mechanism was analyzed by comparison of microstructure transformation and hardness change in subsurfaces of samples tested in mild and severe wear stages,from which M-S wear transition mechanism was confirmed as softening of surface material arising from dynamic recrystallization(DRx)microstructure *** M-S wear transition load was found to have a linear relationship with test temperature,and decreased with rising test temperature.M-S wear transition obeyed a critical surface DRx temperature(SDT)criterion under given conditions,and the transition loads were estimated at various test temperatures by using the criterion.

关键词： Mg-alloys Elevated temperatures Wear rate Wear mechanism Wear transition