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Progress in Natural Science:Materials International 2022年第1期32卷 79-86页

作者： ch.Suresh Vidyasagar D.b.Karunakar Department of Architecture and Planning Indian Institute of Technology Roorkee Mechanical and Industrial Engineering Department Indian Institute of Technology Roorkee

This study reports the influence of sintering mechanism and reinforcement materials on the formation of ultra-fine and nanograins in Al-Tib-Y nanohybrid composites. The mechanical properties of the composites and their corresponding micro and nanostructures are correlated. The experimental and characterization results revealed that despite the addition of Tib, the hard and brittle AlTi phase formation in the composites was suppressed and hence, their ductility was retained. It was found that yttrium content of 0.3 wt% was the optimum amount which created advantageous spark plasma sintering conditions, and the addition of 0.3 wt% promoted the formation of bi-modal size grains（ultra-fine and nano） along with micro grains, Ω and other nano precipitates, resulting in a significant enhancement in the composite properties. The formation of ultra-fine and nanograins may be attributed to the combined effect of melting and rapid solidification at necking zones due to joule’s heating and thermomechanical fatigue. Among all the sintered composites, the highest hardness（137 HV）, ultimate tensile strength（UTS）(496 MPa), yield strength（YS）(438 MPa) with 15.7% elongation were obtained in the sintered sample reinforced with 1.0 wt% Tiband 0.3 wt% yttrium.

关键词： Hybrid composites Ultra-fine grains Nano grains Spark plasma sintering Nano precipitates Microstructure

High mechanical strengths and ductility of stainless steel 304L fabricated using selective laser melting

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journal of Materials Science & Technology 2019年第2期35卷 388-394页

作者： Q.b.nguyen Z.Zhu F.L.ng b.W.chua S.M.L.Nai j.Wei Singapore Institute of Manufacturing Technology Institute of Research and Development Duy Tan University

Achieving not only high mechanical strengths but also high ductility is recently established using an additive manufacturing technique called selective laser melting. In the present study, stainless steel 304 L fully dense samples were successfully printed using the 3 D systems – ProX 300 printing machine. The ductility and tensile yield strength were almost two and three times higher compared to those of ASTM cast's alloy. Honey comb like nano-cellular structure with different orientation was observed in the fine grains(~4μm) due to fast cooling rate. In addition, the formation of martensite phase in random grains is also a contributor to the strengths. Furthermore, negative residual stresses in the build and horizontal directions were detected and assisted further increase in the tensile strength. Fractography revealed the ductile feature of plastic deformation and the crack openings at unmelted particles or pores.

关键词： Additive manufacturing Stainless steel Powder Selective laser melting

Microstructure and mechanical behavior of laser aided additive manufactured low carbon interstitial Fe_(49.5)Mn_(30)Co_(10)Cr_(10)C_(0.5)multicomponent alloy

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journal of Materials Science & Technology 2021年第18期77卷 38-46页

作者： Y.chew Z.G.Zhu F.Weng S.b.Gao F.L.ng b.Y Lee G.j.bi Singapore Institute of Manufacturing Technology 73 Nanyang Drive637662Singapore School of Mechanical Aerospace Engineering Nanyang Technological University50 N any ang Avenue639798Singapore

Laser aided additive manufacturing(LAAM)was used to fabricate bulk Fe_(49.5)Mn_(30)Co_(10)Cr_(10)C_(0.5)interstitial multicomponent alloy using pre-alloyed *** room temperature yield strength(σ_y),ultimate tensile strength(σ_(UTS))and elongation(ε_(UTS))were 645 MPa,917 MPa and 27.0%*** asbuilt sample consisted of equiaxed and dendritic cellular structures formed by elemental *** cellular structures together with oxide particle inclusions were deemed to strengthen the *** other contributing components include dislocation strengthening,friction stress and grain boundary *** highε_(UTS)was attributed to dislocation motion and activation of both twinning and transformation-induced plasticity(TWIP and TRIP).Tensile tests performed at-40℃and-130℃demonstrated superior tensile strength of 1041 MPa and 1267 MPa ***,almost no twinning was observed in the fractured sample tested at-40℃and-130℃.Instead,higher fraction of strain-induced hexagonal close-packed(HCP)εphase transformation of 21.2%were observed for fractured sample tested at-40℃,compared with 6.3%in fractured room temperature sample.

关键词： Multicomponent alloys Laser aided additive manufacturing Additive manufacturing Microstructure Mechanical property

(E)-1-[4-(2-hydroxy-5-methoxybenzylideneamino)-phenyl]ethanone and (E)-1-[4-(2-hydroxy-4-methoxybenzylideneamino) phenyl]ethanone:X-ray and DFT-calculated structures

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chinese journal of Structural chemistry 2011年第1期30卷 111-119页

作者： SAHN Onur bYKGngR Orhan ALbAYRAK igdem ODAbASOGLU Mustafa Department of Physics Faculty of Arts and SciencesOndokuz Mayls University Department of Science Education Sinop University chemistry Programme Pamukkale University 20159 Denizli

The isomeric structures of（E）-1-[4-（2-hydroxy-5-methoxybenzylideneamino）-phenyl] ethanone（I） and（E）-1-[4-（2-hydroxy-4-methoxybenzylideneamino） phenyl]ethanone（Ⅱ） ,both C16H15NO3,have been determined using X-ray diffraction techniques and characterized by IR,and their molecular structures have also been optimized at the b3LYP/6-31G（d,p） level using density functional theory（DFT） . The energetic behaviors of the title compounds in solvent media have been examined using b3LYP method with the 6-31G（d,p） basis set by applying the polarizable continuum model（PCM） . The total energies of the title compounds decrease with the increasing polarity of the solvent. In addition,DFT calculations of the title compounds＇ molecular electrostatic potentials（MEP） were performed at the b3LYP/6-31G（d,p） level of theory. X-ray study shows that the title compounds both have strong intramolecular O-H…N hydrogen bonds. The molecules of Ⅰ are linked into a one-dimensional framework structure by C-H…π interactions,while in Ⅱ,intermolecular π···π interactions result in the formation of infinite chains running along the [010].

关键词： crystal structure Schiff base DFT molecular electrostatic potential

Assessment of the kinetic–frictional model for dense granular flow

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Particuology 2008年第1期6卷 50-58页

作者： boon Ho ng Mojtaba Ghadiri Institute of Particle Science&Engineering University of LeedsLeeds LS2 9JTUK

This paper aims to quantitatively assess the application of kinetic-frictional model to simulate the motion of dry granular materials in dense condition, in particular, the annular shearing in Couette configuration. The weight of frictional stress was varied to study the contribution of the frictional stress in dense granular flows. The results show that the pure kinetic-theory-based computational fluid dynamics （CFD） model （without frictional stress） over-predicts the dominant solids motion of dense granular flow while adding frictional stress [Schaeffer, D. G. （1987）. Instability in the evolution equations describing incompressible granular flow. journal of Differential Equations, 66（1）, 19-50] with the solids pressure of [Lun, C. NTK., Savage, S. b., jeffrey, D. j., ＆ chepurniy, N. （1984）. Kinetic theories for granular flow： Inelastic particles in Couette flow and slightly inelastic particles in a general flow field. journal of Fluid Mechanics, 140, 223-256] in the CFD model improves the simulation to better conform available experimental results. The results also suggest that frictional stress transmission plays an important role in dense granular flow and should not be neglected in granular flow simulations. Compatible simulation results to the experimental data are seen by increasing the weight of frictional stress to a factor of 1.25-1.5. These improved simulation results suggest the current constitutive relations （kinetic-frictional model） need to be improved in order to better reflect the real dense granular flow.

关键词： Gas-solids flow CFD Constitutive relations Couette flow Kinetic theory Kinetic-frictional model

‘Whole-molecule Disorder’ Refinement of 4-(4-Hydroxybenzylideneiminio)phenol Hemichloride Hemihydroxide

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chinese journal of Structural chemistry 2011年第9期30卷 1283-1285页

作者： ng Seik Weng Department of chemistry University of Malaya

The two independent cations of the salt, [HO-C6H4-ch=NH-C6H4-OH]·1/2OH·1/2Cl, are both disordered about an axis connecting the two oxygen atoms at the para-positions of the aromatic rings, the disorder being in a 83：17 ratio in one cation and 91：9 in the other. The hydroxide and chloride anions are ordered. The treatment of the nearly ‘whole-molecule disorder’ by employing a small number of restraints is described. Crystal data： C13H12.5Cl0.5NO2.5, triclinic, P , a = 9.1731（4）, b = 9.2048（4）, c = 15.9144（7） , α = 104.822（1）, β = 90.077（1）, γ = 118.641（1）o and V = 1127.86（9） 3 at –173 K.

关键词： whole-molecule disorder

‘Whole-molecule Disorder’ Refinement of 4-Tricyanovinyl-N,N-diethylaniline

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chinese journal of Structural chemistry 2011年第9期30卷 1286-1288页

作者： ng Seik Weng Department of chemistry University of Malaya chemistry Department Faculty of Science King Abdulaziz University

The molecule of 4-tricyanovinyl-N,N-diethylaniline is disordered about an axis that is close to the axis passing through the 1,4-carbon atoms. The disorder is a 1：1 type of disorder that involves only part of the molecule as the diethylamino substitutent and the three nitrogen atoms of the tricyanovinyl substituent are ordered. The treatment of the nearly ‘whole-molecule disorder’ by employing a small number of restraints is described. Crystal data： C15H14N4, triclinic, P , a = 7.1996（5）, b = 7.7232（5）, c = 12.4171（8） , α = 99.350（1）, β = 94.647（1）, γ = 103.312（1）o and V = 657.90（8） 3 at –173 K.

关键词： whole-molecule disorder

4-Amino-3-(p-chlorophenyl)-5-(p-methoxybenzyl)-4H-1,2,4-triazole:X-ray and DFT-calculated Structures

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chinese journal of Structural chemistry 2011年第5期30卷 731-737页

作者： SAHIN Onur KANTAR Cihan bEKIRCAN Olcay SASMAZ Selami büYüKGüngR Orhan Department of Physics Faculty of Arts and SciencesOndokuz Mayls University Department of chemistry Rize University Karadeniz Teknik University

The title compound, 4-amino-3-（p-chlorophenyl）-5-（p-methoxybenzyl）-4H-1,2,4- triazole I , C16H15ClN4O）, has been determined using X-ray diffraction techniques and the molecular structure has also been optimized at the b3LYP/6-31 G（d, p） level using density functional theory （DFT）. The triazole ring exhibits dihedral angles of 41.61（15）o and 80.73（11）o with the phenyl rings. The molecules are linked principally by N–H…N hydrogen bonds involving the amino NH2 group and a triazole N atom, forming C（5） chains which are further linked to give a two-dimensional network of molecules. The N–H…N hydrogen bonding is supported by C–H…N hydrogen bond and C–H…π interaction. Intermolecular N–H…N and C–H…N hydrogen bonds produce R22（9）, R44（10） and R44（20） rings.

关键词： crystal structure chlorophenyl triazole hydrogen bonds

Small Molecule Organic Nanostructures—Fabrication and Properties

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journal of Materials Science & Technology 2008年第4期24卷 563-568页

作者： A.b.Djurii A.M.C.ng Kai-Yin chEUng Man-Kin FUng Wai-Kin chAN Department of Physics University of Hong KongPokfulam RoadHong KongHong Kong SARChina Department of chemistry University of Hong KongPokfulam RoadHong KongHong Kong SARChina

Organic materials are of great interest for the development of low cost electronic and optoelectronic devices. Although majority of research on organic materials is concerned with synthesis of novel compounds and organic thin films, organic nanostructures are attracting increasing interest in recent years. We briefly review different growth methods of organic nanostructures, which can be roughly divided into vapor deposition methods and self-assembly techniques in solution. Then we highlight some interesting properties of organic nanostructures, as well as possible applications, includinf field emission, electronic and optoelectronic devices.

关键词： Organic nanostructures Self-assembly Vapor deposition

Synthesis and Crystal Structure of Trans-bis(acesulfamato-O)tetraaquazinc(Ⅱ)

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chinese journal of Structural chemistry 2010年第7期29卷 1047-1050页

作者： SAHIN Onur ICbUDAK Hasan b(U|¨)Y(U|¨)KG(U|¨)ng(O|¨)R Orhan Department of Physics Faculty of Arts and SciencesOndokuz Mayis UniversitySamsunTurkey Department of chemistry Faculty of Arts and SciencesOndokuz Mayis UniversitySamsunTurkey

The title compound, trans-bis（acesulfamato-O）tetraaquazinc（Ⅱ）（I, C8H16N2O12S2Zn）, crystallizes in the triclinic system, space group P1 with a = 5.1638（5）, b = 8.5338（9）, c = 9.9583（9）A, α = 74.325（8）, β = 81.112（7）, γ = 75.800（8）°, V= 407.77（7） A3, Z = 1, F（000） = 236, Rint = 0.085, T= 296 K, the final R = 0.029 and wR = 0.078 for 1832 observed reflections with I〉 2σ（0. The ZnⅡcentre resides on a centre of symmetry and has a distorted octahedral geometry. The basal plane is defined by two carbonyl O atoms of two monodentate trans-oriented acesulfamato ligands and two trans-aqua ligands. The axial positions in the octahedron are occupied by two trans-aqua ligands. Intermolecular O-H…O hydrogen bonds produce R22（8） and R22（16） rings, which lead to two- dimensional polymeric chains.

关键词： crystal structure zinc(Ⅱ) octahedral complex hydrogen bonds