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Influencing mechanism of pre-existing nanoscale Al5Fe2 phase on Mg-Fe interface in friction stir spot welded Al-free ZK60-q235 joint

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Journal of Materials Science & Technology 2020年第7期42卷 220-228页

作者： R.Z.Xu q.yang D.R.Ni B.L.Xiao C.Z.Liu Z.Y.Ma Institute of Metal Research Chinese Academy of SciencesShenyang110016China College of Material Science and Engineering Shenyang Aerospace UniversityShenyang110136China Department of Materials Science and Engineering University of Illinois at Urbana-Champaign1304 W Green StUrbanaIL61801United States Fredrick Seitz Materials Research Laboratory University of Illinois at Urbana-Champaign104 S Goodwin AveUrbanaIL61801United States

Al-free ZK60 magnesium (Mg) alloy sheet was selected as substrate material of Mg-steel pinless friction stir spot welding (FSSW), avoiding the effect of the Al element in the substrate on the alloying reaction of Mg-iron (Fe) interface. The sound FSSW joint of ZK60 Mg alloy and q235 steel with a hot-dipped aluminum (Al)-containing zinc (Zn) coating was successfully realized. The detailed microstructural examinations proved that Al5Fe2 phase at the Mg-Fe interface came from the pre-existing Al5Fe2 phase in the coating and acted as the transition layer for promoting the metallurgical bonding of Mg and Fe. The interfaces with well-matched lattice sites among Fe, Al5Fe2 and Mg were formed during FSSW. A low energy interface with good match of lattice sites ((002)Al5Fe2//(110)Fe, [110]Al5Fe2//[113]Fe) between Al5Fe2 and Fe was identified. For the interface between Al5Fe2 and Mg, an orientation relationship of (622)Al5Fe2//(3112)Mgand[158]Al5Fe2//[2423]Mg was observed. The tensile-shear load of the ZK60-steel joint could reach 4.6 kN. Moreover, the joint fracture occurred at the interface between the Al5Fe2 layer and the Mg alloy substrate, suggesting the brittle fracture characteristic.

关键词： Dissimilar welding Friction stir spot welding Magnesium alloys Steels Zinc coating

Improving ionic conductivity of polymer-based solid electrolytes for lithium metal batteries

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Chinese Journal of Chemical Engineering 2022年第3期35卷 202-215页

作者： q.yang A.Wang J.Luo W.Tang Key Laboratory for Green Chemical Technology of Ministry of Education State Key Laboratory of Chemical EngineeringSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Shanghai Key Lab of Advanced High-Temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Because of its superior safety and excellent processability,solid polymer electrolytes(SPEs)have attracted widespread *** lithium based batteries,SPEs have great prospects in replacing leaky and flammable liquid ***,the low ionic conductivity of SPEs cannot meet the requirements of high energy density systems,which is also an important obstacle to its practical *** this respect,escalating charge carriers(***^(+))and Li^(+)transport paths are two major aspects of improving the ionic conductivity of *** article reviews recent advances from the two perspectives,and the underlying mechanism of these proposed strategies is discussed,including increasing the Li^(+)number and optimizing the Li^(+)transport paths through increasing the types and shortening the distance of Li^(+)transport *** is hoped that this article can enlighten profound thinking and open up new ways to improve the ionic conductivity of SPEs.

关键词： Solid polymer electrolyte Ion conductivity Charge carriers Transport paths Lithium battery

Deep learning approach to genome of two-dimensional materials with flat electronic bands

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npj Computational Materials 2023年第1期9卷 1316-1324页

作者： A.Bhattacharya I.Timokhin R.Chatterjee q.yang A.Mishchenko Department of Physics and Astronomy University of ManchesterManchesterUK Department of Mechanical Engineering Indian Institute of Technology DelhiNew DelhiIndia Department of Physics Indian Institute of Technology DelhiNew DelhiIndia

Electron-electron correlations play central role in condensed matter physics,governing phenomena from superconductivity to magnetism and numerous technological ***-dimensional(2D)materials with flat electronic bands provide natural playground to explore interaction-driven physics,thanks to their highly localized *** search for 2D flat band materials has attracted intensive efforts,especially now with open science databases encompassing thousands of materials with computed electronic *** we automate the otherwise daunting task of materials search and classification by combining supervised and unsupervised machine learning *** this end,convolutional neural network was employed to identify 2D flat band materials,which were then subjected to symmetry-based analysis using a bilayer unsupervised learning *** hybrid approach of exploring materials databases allowed us to construct a genome of 2D materials hosting flat bands and to reveal material classes outside the known flat band paradigms.

关键词： Deep electronic approach

Pinless Friction Stir Spot Welding of Mg-3Al-1Zn Alloy with Zn Interlayer

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Journal of Materials Science & Technology 2016年第1期32卷 76-88页

作者： R.Z.Xu D.R.Ni q.yang C.Z.Liu Z.Y.Ma College of Materials Science and Engineering Shenyang Aerospace University Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

With the addition of a thin Zn interlayer, 2.4 mm thick Mg-3AI-1Zn alloy sheets were friction stir spot welded （FSSW） using a pinless tool with fiat, convex and concave shoulder shapes. The results showed that an alloying reaction took place between the Mg substrate and Zn interlayer during FSSW, forming a discontinuous intermetallics layer composed of dispersive （α-Mg ＋ MgZn） eutectic structure under- neath the shoulder and a Mg-Zn intermetallics bonding zone at the outside of the joints. This alloying reaction increased the bonded area and eliminated the hook defects, thereby producing sound FSSWjoints with a shallow keyhole without hook defects. The increase of plunge depth was beneficial to the Mg-Zn diffusion, thereby increasing the tensile-shear load of the joints. However, excessive plunge depths re- sulted in a decrease of the effective sheet thickness, reducing the strength of the joints. At a small plunge depth, the convex and concave shoulders were more beneficial to the interface reaction than the fiat shoul- der. The maximum joint load of 6.6 kN was achieved by using the concave shoulder at a plunge depth of 1.0 mm. A post-welding heat treatment promoted the dissolution of the discontinuous reaction layer in the joints; however, it led to the occurrence of void defects, influencing the bonding strength.

关键词： Friction stir spot welding Magnesium alloys Zn interlayer Hook defects

Enhancing strength and ductility of AlSi10Mg fabricated by selective laser melting by TiB_(2)nanoparticles

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Journal of Materials Science & Technology 2022年第14期109卷 254-266页

作者： Y.K.Xiao H.Chen Z.Y.Bian T.T.Sun H.Ding q.yang Y.Wu q.Lian Z.Chen H.W.Wang State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China School of Materials Science&Engineering Shanghai Jiao Tong UniversityShanghai 200240China

In the metallic components fabricated by the emerging selective laser melting(SLM)technology,most strategies used for strengthening the materials sacrifice the ductility,leading to the so-called strengthductility *** the present study,we report that the strength and ductility of materials can be enhanced simultaneously by introducing nanoparticles,which can break the trade-off of the metallic *** the case of in-situ nano-TiB_(2)decorated AlSi10Mg composites,the introduced nanoparticles lead to columnar-to-equiaxed transition,grain refinement and texture *** increasing content of nanoparticles,the strength increases ***,the ductility first increases and then *** results show that the ductility is controlled by the competition between the crack-induced catastrophic fracture and ductile fracture associated with dislocation *** first increase of ductility is mainly attributed to the suppression of crack-induced catastrophic fracture when TiB_(2)nanoparticles *** the further increase of TiB_(2)nanoparticles,the subsequent decrease of ductility is mainly controlled by dislocation ***,the materials will exhibit the optimum strength and ductility combination in a certain range of TiB_(2)*** study clarifies the physical mechanism controlling ductility for nano-TiB_(2)decorated Al Si10Mg composites,which provides the insights for the design of structural materials.

关键词： Selective laser melting Aluminium matrix composites Ductility Mechanical behavior Dislocations Cracks

Knock in p53 sequences with and without intron 4 to determine its function in gene expression control

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Chinese Medical Journal 1999年第11期112卷 22-22页

作者： q.yang Z-q.Wang M.Hollstein German Cancer Research Center Division Toxicology and Cancer Risk Factors D-69120 Heidelberg Germany International Agency for Research on Cancer Unit of Gene-Environment Interactions F-69372 Lyon France

Multistage interband cascade photovoltaic devices with a bandgap of 0.23 eV operating above room temperature

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Chinese Science Bulletin 2014年第10期59卷 950-955页

作者： Hao Ye Hossein Lotfi Lu Li Robert T.Hinkey Rui q.yang Lin Lei Joel C.Keay Matthew B.Johnson Tetsuya D.Mishima Michael B.Santos School of Electrical and Computer Engineering University of Oklahoma Norman OK USA Homer L. Dodge Department of Physics and Astronomy University of Oklahoma Norman OK USA

Interband cascade(IC)photovoltaic(PV)device structures,consisting of multiple discrete InAs/GaSb superlattice absorbers sandwiched between electron and hole barriers,were grown by molecular beam *** of the molecular beam epitaxy growth and material characterization of the structures are *** discrete absorber architecture enables certain advantages,such as high open-circuit voltage,high collection efficiency,high operating temperature,and smooth integration of cascade stages with different *** two-and three-stage ICPV devices presented in this article operate at room temperature with substantial open-circuit voltages at a cutoff wavelength of 5.3 lm(corresponding to a bandgap of 0.23 eV),the longest ever reported for room temperature PV *** device characteristics indicate a high level of current matching and demonstrate the advantages of the interband cascade approach in thermophotovoltaic cell design.

关键词： InAs GaSb superlattice Thermophotovoltaic Interband cascade devices

Oxygen vacancies in ferroelectric perovskites and their regulation from first-principles study

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Oxygen vacancies in ferroelectric perovskites and their regu...

MHD Instabilities and Their Effects on Plasma Confinement in Large Helical Device Plasmas with Intense Neutral Beam Injection

第十三届全国物理力学学术会议

作者： q.yang J.X.Cao Y.C.Zhou Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education Xiangtan University

Oxygen vacancy(VO)is one of the common and mobile defects,which is believed to play an important role in the electrical properties of ferroelectric *** present work,the physical properties of VO were studied with a prototypical ferroelectric perovskite oxide Pt Ti O3(PTO)using density functional theory(DFT)***,we studied the effects of potential regulation means,such as epitaxial strain,on the structural and electronic properties of *** was found to result in a tail-to-tail domain configuration and pinning the domain wall *** results show that VO in ferroelectric epitaxial thin films can be systematically tuned from a strong domain-pinning centre to a non-pinning centre by applying a compressive misfit *** formation and migration energies of VO can be enhanced by compressive *** suggests that proper strain may solve the VO-induced ferroelectric failure.

关键词： Ferroelectric perovskites Oxygen vacancies Domain-pinning centre Leakage current First-principles study

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Plasma Science and Technology 2004年第3期6卷 2269-2274页

作者： K.Toi S.Ohdachi S.Yamamoto S.Sakakibara K.Y.Watanabe N.Nakajima X.Ding J.Li S.Morita K.Narihara K.Tanaka T.Tokuzawa H.Yamada q.yang National Institute for Fusion Science Toki 509-5292 Japan Dep. Energy Eng. Sci. Nagoya Univ. Nagoya 464-8603 Japan Southestern Institute of Physics Chengdu China Institute of Plasma Physics Chinese Academy of Science China

MHD stability of the Large Helical Device (LHD) plasmas produced with intenseneutral beam injection is experimentally studied. When the steep pressure gradient near the edge isproduced through L-H transition or linear density ramp experiment, interchange-like MHD modes whoserational surface is located very close to the last closed flux surface are strongly excited in acertain discharge condition and affect the plasma transport appreciably. In NBI-heated plasmasproduced at low toroidal field, various Alfven eigenmodes are often excited. Bursting toroidalAlfven egenmodes excited by the presence of energetic ions induce appreciable amount of energeticion loss, but also trigger the formation of internal and edge transport barriers.

关键词： interchange instabilities L-H transition alfven eigenmodes