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A review of the origin of equiaxed grains during solidification under mechanical stirring,vibration,electromagnetic,electric-current,and ultrasonic treatments

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Journal of Materials Science & Technology 2023年第13期144卷 243-265页

作者： Nagasivamuni Balasubramani Jeffrey Venezuela David StJohn Gui Wang Matthew Dargusch Centre for Advanced Materials processing and Manufacturing(AMPAM) School of Mechanical and Mining EngineeringUniversity of QueenslandSt.LuciaQLD 4072Australia

Refinement of grains and intermetallic phases in the as-solidified alloy structure offers uniform struc-tural properties,eliminates or minimizes common solidification defects,including segregation and hot cracking,and improves thermomechanical processing of wrought *** processing by an external field is an efficient process for achieving refinement of the solidification structure of Al and Mg alloys without altering the alloy composition.A wide range of melt processing methods and solidification stud-ies(conventional,directional,and in-situ approaches)have been reported in the literature that explore the mechanism of *** the dominant grain refinement mechanism has been a focus of most investigations because significant variations exist according to the casting conditions and the type of applied external *** origin of fine grains occurs through either one or a combination of heterogenous nucleation,fragmentation of dendrites and grains formed and then separated from the surface of the melt and mould wall under vibration or *** first part of this review describes the prominent external field techniques and the mechanisms proposed for the origin of fine *** second part critically compares the current understanding of these grain refinement mechanisms to de-termine differences and commonalities to identify the factors that promote the formation of equiaxed zones occupying a large volume fraction of the casting.

关键词： Grain refinement Solidification melt processing Equiaxed grains Intermetallic refinement

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Biocomposites Based on Thermoplastic Starch and Granite Sand Quarry Waste

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Journal of Renewable Materials 2019年第4期7卷 393-402页

作者： María G.Passaretti Mario D.Ninago Cecilia I.Paulo Horacio A.Petit Edgardo F.Irassarc Daniel A.Vega Marcelo A.Villar Olivia V.López Planta Piloto de Ingeniería Química PLAPIQUI(UNS-CONICET)Camino"La Carrindanga"Km 7Bahía Blanca8000Buenos AiresArgentina Departamento de Ingeniería Química Universidad Nacional del Sur(UNS)Bahía Blanca8000Buenos AiresArgentina Facultad de Ciencias Aplicadas a la Industria(FCAI) Universidad Nacional de Cuyo(UNCuyo)Bernardo de Irigoyen 375San Rafael5600MendozaArgentina Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET) Godoy Cruz 2290Ciudad Autónoma de Buenos AiresC1425FQBBuenos AiresArgentina Facultad de Ingeniería Universidad Nacional del Centro de la Provincia de Buenos Aires(UNCPBA).Centro de Investigaciones en Física e IngenieríaCIFICEN(UNCPBA-CICPBA-CONICET)7400OlavarríaArgentina Instituto de Física del Sur IFISUR(UNS-CONICET)Bahía Blanca8000Argentina

Granite stone is a by-product of the rock crushing *** industrial waste in powder form that causes health problems and environmental *** particles fraction can be used as a partial replacement of sand in concrete *** this work,an alternative exploitation of this waste fraction is *** sand(GS)with particles mean size of ~1μm was employed as thermoplastic starch(TPS)filler at different *** were obtained by melt-mixing and thermo-compression,achieving translucent and easy to handle films.A good GS dispersion within the matrix was evidenced by *** presence induced a shift of starch’s melting point to higher values and a better thermal *** UV absorption capacity was increased ~90% by GS *** increment in TPS Young’s modulus and maximum tensile stress of 5 and 3 times,respectively was observed by adding 5%w/w GS.

关键词： Thermoplastic starch granite sand melt processing final properties

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Synthesis and Properties of melt Processed Poly(thiourea-azo-sulfone)/Carbon Nanotubes Nanocomposites

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Chinese Journal of Polymer Science 2014年第1期32卷 64-72页

作者： Ayesha Kausar Nanosciences and Catalysis Division National Centre for Physics Quaid-i-Azam University Campus

An aromatic azo-polymer, poly（thiourea-azo-sulfone）（PTAS）, has been prepared using 4-（4- aminophenylsulfonyl）benzenamine and diazonium salt solution of 2,6odiaminopyridine. PTAS was easily processable using polar solvents and had high molar mass 63 × 103 ***1-1 according to GPC. Mechanically and thermally stable and electrically conducting polymer/CNTs nano-composites were obtained via melt processing technique. Fine distribution of CNTs in a polymer matrix performed an essential role in the preparation of polymer/CNTs nano-composites based on interfacial interaction between CNTs and polymer matrix. Scanning electron micrographs showed good dispersion of filler and adhesion of matrix on the surface of nanotubes. Accordingly, increasing the amount of CNTs from 0.1 wt% to 5 wt% increased the electrical conductivity from 2.99 ***-1 to 3.56 ***-1. Mechanical strength of functional nanotubes-based hybrids was enhanced from 43.22 MPa to 65.02 MPa compared with that of hybrids with non-functional filler in matrix 37.21 MPa. A rapport between nanotube loading and thermal stability of the materials was also observed. 10% gravimetric loss temperature was increased from 528 ~C to 578 ~C, while glass transition was improved from 241 ℃ to 271 ℃. Adding up of small quantity of functional CNTs strongly affected the tensile, electrical and thermal properties of materials. Improvement of the physical properties of CNT-reinforced polymer nano-composites was ascribed to the melt processing technique.

关键词： Poly(thiourea-azo-sulfone) melt processing Tensile strength Thermal stability Electrical conductivity.

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melt-and air-processed selenium thin-film solar cells

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Science China Chemistry 2022年第11期65卷 2197-2204页

作者： Wenbo Lu Zongbao Li Mingjie Feng Hui-Juan Yan Bin Yan Liyan Hu Xing Zhang Shunchang Liu Jin-Song Hu Ding-Jiang Xue Beijing National Laboratory for Molecular Sciences(BNLMS) CAS Key Laboratory of Molecular Nanostructure and NanotechnologyInstitute of ChemistryChinese Academy of SciencesBeijing100190China School of Material and Chemical Engineering Tongren UniversityTongren 554300China National Engineering Research Center for Advanced Polymer processing Technology Zhengzhou UniversityZhengzhou 450002China University of Chinese Academy of Sciences Beijing 100049China

Elemental selenium(Se), as the world’s first but long-neglected photovoltaic material, has regained great interest recently in tandem solar cells as top cells due to its wide bandgap(~1.8 eV), simple, non-toxic and earth-abundant composition, and intrinsic environmental stability. In particular, Se possesses the lowest melting point of 217 °C among the photovoltaic absorbers reported so far, endowing Se with a unique advantage of film fabrication by blade coating the Se melt on substrate. However, the poor wettability of Se melt on widely-used photovoltaic functional layers such as TiO_(2) limits its melt processing. Here we introduce a wettability-modification strategy that decreases the contact angle of Se melt on substrate and improves the wettability by appropriately enhancing the heating temperature of molten Se while avoiding Se volatilization. We further reveal the mechanism of the inherent air stability of Se that originates from the high activation energy of oxygen chemisorption on Se(3.21 eV). This enables the realization of compact Se films through melt-based blade coating in ambient air. The resulting Se solar cells exhibit an efficiency of 3.5%. Unencapsulated devices show no efficiency loss after 1,000 h of storage under ambient conditions.

关键词： selenium thin film photovoltaic melt processing

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In-line Plasma-induced Graft-copolymerization of Pentaerythritol Triacrylate onto Polypropylene

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Chinese Journal of Polymer Science 2018年第8期36卷 979-983页

作者： Gui-Qiu Ma Guan-Kai Sun Zhe Ma Jing-Qing Li Jing Sheng Department of Polymer Material Science and Engineering Institute of Advanced Polymer MaterialsSchool of Material Science and EngineeringTianjin Key Laboratory of Composite and Functional MaterialsTianjin University

Pentaerythritol triacrylate （PETA） was successfully grafted onto the plasma-treated isotactic polypropylene （iPP） via the in situ melt processing. The X-ray photoelectron spectroscopy （XPS） results showed that the hydroxyl and carbonyl groups, and peroxides could be generated via plasma treatment. The content of free radical in plasma-treated iPP （PiPP） was measured by 2,2-diphenyl-1- picrylhydrazyl （DPPH）. It was found that the resulting peroxides induced the grafting copolymerization of PETA onto iPP, and the grafted PETA promoted the formation of β-crystal in PiPP, which was evidenced by Fourier transform infrared spectroscopy （FTIR）, differential scanning calorimetry （DSC） and wide-angle X-ray diffraction （WAXD） measurements, respectively.

关键词： Plasma treatment melt processing Graft copolymerization Pentaerythritol triacrylate

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Fabrication and Properties of (Y,Gd)BCO Superconductors

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Journal of Rare Earths 2004年第6期22卷 867-870页

作者：焦玉磊肖玲任洪涛郑明辉 Superconducting Materials Researeh Center General Research Institute for Non-Ferrous Metals Beijing 100088China

The microstructures and superconducting properties of melt textured(Y_(1-x)Gd_x)BCO bulk samples were studied. It was found that the peritectic decomposition temperature(T_m)of(Y_(1-x)Gd_x)BCO samples increases with increasing x. Large single domain growth in air is readily obtained in all the composites. The results of X-ray distribution maps of x=0.4 composite indicate that the RE123 matrix is homogeneous and Y and Gd elements in the RE site forms a perfect solid solution. The onset T_c values exceeding 91 K with relatively broad transitions are obtained for almost all the samples. Magnetization measurements show no marked indication for the formation of a peak effect in the J_c-B curves, and the highest J_c measured is 3.08×10~4 A·cm^(-2) for x=0.4 sample at 77 K and self-field. The results clearly indicate that Y dominates the superconducting properties of x=0.2 and (0.4) composites.

关键词： Y,Gd)BCO superconductor melt processing peritectic decomposition temperature rare earths

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Miscibility of Poly(hydroxybutyrate)/Poly(vinyl alcohol)melt Blends Plasticized With Glycerol

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Journal of Renewable Materials 2019年第4期7卷 325-333页

作者： Deliane da Silva Cabral Antonio JoséFelix Carvalho Department of Materials Engineering São Carlos School of EngineeringUniversity of São PauloAv.João Dagnone110013563-120São Carlos-SP-Brazil

Poly(hydroxybutyrate)/poly(vinyl alcohol)(PHB/PVA)blends plasticized with glycerol were prepared by melt blending of PHB and glycerol plasticized *** PHB/PVA-glycerol compositions were 90:10,75:25 and 50:50 w/w,being the concentration of glycerol in the PVA mixture of 10 wt%.The blends were characterized by infrared spectroscopy,dynamic-mechanical thermal analysis,and scanning electron microscope of the fragile fractured *** results showed one single phase blend,indicating miscibility corroborated by the presence of a single glass transition *** blending method proved to be an efficient way to tune PHB properties keeping its biodegradable nature since both PVA and glycerol are fully biodegradable materials.

关键词： Blend miscibility melt processing poly(hydroxybutyrate) poly(vinyl alcohol)

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单畴熔融织构YBCO/Ag样品的生长工艺研究

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低温物理学报 2003年第S1期25卷 87-91页

作者：焦玉磊肖玲任洪涛郑明辉陈云霞北京有色金属研究总院北京有色金属研究总院北京100088

本文研究了用冷籽晶技术制备掺Ag单畴熔融织构YBCO超导块材的工艺 .通过引入有效的隔离层避免了籽晶的熔化 .使用纯Y1 .8粉作为隔离层的材料 ,并探索出同时施加两个隔离层的方法 .对施加隔离层后大块单畴YBCO/Ag样品生长窗口的研究发现 ... 详细信息

本文研究了用冷籽晶技术制备掺Ag单畴熔融织构YBCO超导块材的工艺 .通过引入有效的隔离层避免了籽晶的熔化 .使用纯Y1 .8粉作为隔离层的材料 ,并探索出同时施加两个隔离层的方法 .对施加隔离层后大块单畴YBCO/Ag样品生长窗口的研究发现 ,加入隔离层后使慢降温上限温度升高 ,970℃到 955℃是Y1 2 3/Ag系单畴生长的主要窗口 .制备的直径2 6mm单畴超导块材的磁浮性能已达到 1 2N/cm2 (77K ,0 .5T) .认为如果进一步提高熔化温度或延长保温时间将有助于抑制自发成核 .

关键词： melt processing YBCO Ag addition Y-{1.8} separating layer

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