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    题名 作者 年代 出处 被引量
1Critical Time and Temper Embrittlement Isotherms显示文摘Temperembritlementinlow-aloysteelsisgeneralydefinedasembritlementwhichappearsafterheatingorslowcoolinginthecriticaltempera-tu...Xu Tingdong 1999Journal of Iron and Steel Research(International)1999,6,1:15
2EFFECT OF P,S AND Si ON THE SOLIDIFICATION,SEGREGATION,MICROSTRUCTURE AND MECHANICAL PROPERTIES IN Fe-Ni BASE SUPERALLOYS显示文摘EFFECTOFP,SANDSiONTHESOLIDIFICATION,SEGREGATION,MICROSTRUCTUREANDMECHANICALPROPERTIESINFe-NiBASESUPERALLOYSZ.Q.Hu;W.R.SunandS...Z.Q. Hu W.R.Sun and S.R. Guo(Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China 1996Acta Metallurgica Sinica(English Letters)1996,9,6:13
3EFFECT OF ALLOYING ELEMENTS ON SENSITIVITY TO ENVIRONMENTAL EMBRITTLEMENT OF L1_2 INTERMETALLICS显示文摘The effect of Zr doping in Ni 3Al and B doping in Co 3Ti intermetallics on the sensitivity to moisture induced environmental embrittlement and on the hydrogen diffusivity was investigated. The results show that both B in Co 3Ti and Zr in Ni 3Al do not reduce the hydrogen diffusivity along the grain boundaries, therefore can not suppress the moisture induced environmental embrittlement. The above mentioned behavior of Zr in Ni 3Al and B in Co 3Ti is attributed to the fact that Zr and B are not segregated on the grain boundaries.X.J.Wan, X.Y.Cheng and Y.X.Chen Materials Research Institute, Shanghai University, Shanghai 200072, China 1999中国有色金属学会会刊:英文版1999,9,S1:9
4Segregation behaviors of Sc and unique primary Al3Sc in Al-Sc alloys prepared by molten salt electrolysis显示文摘This work mainly deals with the segregating behaviors of Sc and the growth of unique primary Al3Sc in AlSc alloys prepared by molten salt electrolysis. The alloys contain 0.23–1.38 wt%Sc where Sc segregation is observed. It is found that a high current density and long electrolysis time are in favor of high Sc content, and so do the high temperature and the addition level of Sc2O3. Sc content at the edge of Al based alloy(average Sc content: 0.75 wt%) can be as high as 1.09 wt%, while it is merely 0.24 wt% at the central area. The cooling rates have a strong impact on the morphology and particle size of primary Al3Sc,but a weak influence on Sc segregation. The cusped cubic and dendritic primary Al3Sc can precipitate in the prepared Al-Sc alloys. In a slightly hypereutectic Al-0.67 wt%Sc alloy, a large and cusped dendrite grows from the edge into the center. The primary and secondary dendritic arms can be as long as 600 and 250 μm, respectively. The Sc segregating behaviors in Al-Sc alloys is due to the mechanism controlled by the limited diffusion rate of Sc in liquid Al. This can involve the establishment of a near spherical discharge interface between liquid Al and the electrolyte. The Sc rich layer near Al-molten salt interface may provide the potential primary nuclei and sufficient Sc atoms for the growth of large dendritic primary Al3Sc.Xuan Liu Jilai Xue Zhichao Guo Cheng Zhang 2019Journal of Materials Science & Technology2019,35,7:8
5Genetic Analysis for Large TiN Inclusions in Wire Rod for Tire Cord Steel of SWRH82A显示文摘The law of element segregation of Ti, N, Mn and S, and the sequence of selective precipitation of TiN and MnS inclusions during solidification of molten steel of SWRH82 A are studied on the basis of thermodynamics. The origin of large TiN inclusions which affect the titanium inclusions point penalty in SWRH82 A wire rod is analyzed based on the research on the distribution characteristics of MnS and large size of TiN inclusions observed on metallographic specimen of SWRH82 A steel wire rod. The solidification segregation ratio of Ti is far more than that of N, and the solidification segregation ratio of S is far more than that of Mn. In the range of cooling rate of the continuous casting production, the cooling rate of solidification has little effect on the segregation ratios of Ti, N, Mn and S. MnS inclusions will precipitate earlier than TiN inclusions during solidification of the molten steel of SWRH82 A. The large TiN inclusion which is wrapped by MnS in the SWRH82 A wire rod may be foreign inclusions and it is not precipitated product during solidification in the molten steel of SWRH82 A.Yue-dong JIANG Zheng-liang XUE Jing ZHANG 2014Journal of Iron and Steel Research(International)2014,21,S1:8
6Study on Interaction between Lanthanum and Phosphor in Purity Steel显示文摘Using SEM and EDS some particles containing La and P were discovered in low oxygen and sulfur purity steel with lanthanum. In these particles low melting point elements such as As and Sb also were detected. According to the result of simulative calculation of segregation, it is shown that La and P enrich so strongly in the process of solidification that their concentrations can satisfy thermodynamic condition to forme LaP compound or meet the requirements to forme eutectic phase in the last stage of solidification. Therefore, the particles are concluded as LaP compound or eutectics, which exist on grain boundary mainly.郭锋 林勤 2006Journal of Rare Earths2006,24,z2:6
7Characterization of surface liquid segregation in SSM-HPDC aluminium alloys 7075,2024,6082 and A201显示文摘The surface liquid segregation(SLS) phenomenon in semi-solid metal-high pressure die casting(SSM-HPDC) plates of 7075,2024,6082 and A201 was investigated by different techniques.Depth profiles were determined by firstly measuring the chemical composition of the surface of the plates using a Thermo Quantris optical emission spectrometer(OES).Material was then removed by a grinding process followed by measurement of the amount of material removed and chemical analysis.Chemical profiles of the main alloying elements were plotted for the cross-section of the plates in the as-cast and T6(after solution treatment) temper conditions.Vickers hardness profiles from the surface to the centre of the plates were determined.Metallographic samples of cross-sections of the castings were prepared and evaluated using a scanning electron microscope.The results show that surface liquid segregation in SSM-HPDC alloys causes significant differences in properties between the surface and the bulk of these castings in both the F and T6 temper conditions.H.MLLER U.A.CURLE E.P.MASUKU 2010中国有色金属学会会刊:英文版2010,20,S3:6
8A study on centrifugal casting of high speed steel roll显示文摘High speed steel (HSS) rolls can replace traditional rolls such as alloyed cast iron rolls and powder metallurgical (PM) hard alloy rolls. The main reasons for the replacement are that the wear resistance of low-cost alloyed cast iron rolls is poor and the cost of high-quality PM hard alloy rolls is very high. By means of centrifugal casting, HSS rolls having excellent wear resistance have been manufactured. The hardness of the HSS roll is 6.5~67 HRC, the range of variation is smaller than 2 HRC and its impact toughness is 15 J/cm2. The wear rate of HSS rolls used in the pre-finishing stands of high-speed hot wire-rod rolling mill reaches 2.5×10-4mm per ton steel. Furthermore, the manufacturing cost of HSS rolls is significantly lower than that of PM hard alloy rolls; it is only 30 percent of that of PM hard alloy rolls.~*H. G. Fu~1, X.H. Zhang~2(1. Department of Mechanical engineering, Tsinghua University, Beijing 100084, P. R. China 2. Roll Made LTD. of Taiyuan Iron and Steel(Group)Company, Taiyuan 030003, Shanxi, P. R. China) 2004China Foundry2004,1,S1:6
9Unique synthesis of graphene-based materials for clean energy and biological sensing applications显示文摘Graphene has unique physical properties,and a variety of proof-of-concept devices based on graphene have been demonstated.A prerequisite for the application of graphene is its production in a controlled manner because the number of graphene layers and the defects in these layers significantly influence transport properties.In this paper,we briefly review our recent work on the controlled synthesis of graphene and graphene-based composites,the development of methods to characterize graphene layers,and the use of graphene in clean energy applications and for rapid DNA sequencing.For example,we have used Auger electron spectroscopy to characterize the number and structure of graphene layers,produced single-layer graphene over a whole Ni film substrate,synthesized well-dispersed reduced graphene oxide that was uniformly grafted with unique gold nanodots,and fabricated graphene nanoscrolls.We have also explored applications of graphene in organic solar cells and direct,ultrafast DNA sequencing.Finally,we address the challenges that graphene still face in its synthesis and clean energy and biological sensing applications.XUMingSheng GAO Yan YANG Xi CHEN HongZheng 2012Chinese Science Bulletin2012,57,23:6
10LRIF1 interacts with HPla to coordinate accurate chromosome segregation during mitosis显示文摘Heterochromatin protein 1α (HP1α)regulates chromatin specification and plasticity during cell fate decision.Different structural determinants account for HP1α Localization and function during cell division cycle.Our earlier study showed that centromeric Localization of HP1α depends on the epigenetic mark H3K9me3 in interphase,while its centromeric location in mitosis relies on uncharacterized PXVXL-containing factors.Here,we identified a PXVXL-containing protein,Ligand-dependent nuclear receptorinteracting factor 1 (LRIF1),which recruits HPla to the centromere of mitotic chromosomes and its interaction with HP1α is essential for accurate chromosome segregation during mitosis.LRIF1 interacts directly with HPla chromoshadow domain via an evolutionariLy conserved PXVXL motif within its C-terminus.Importantly,the LRIF1-HPla interaction is critical for Aurora B activity in the inner centromere.Mutation of PXVXL motif of LRIF1 Leads to defects in HPla centromere targeting and aberrant chromosome segregation.These findings reveal a previously unrecognized direct Link between LRIF1 and HP1α in centromere plasticity control and illustrate the critical role of LRIF1-HP1α interaction in orchestrating accurate cell division.Saima Akram Fengrui Yang Junying Li Gregory Adams Yingying Liu Xiaoxuan Zhuang Lingluo Chu Xu Liu Nerimah Emmett Winston Thompson McKay Mullen Saravana Muthusamy Wenwen Wang Fei Mo Xing Liu 2018Journal of Molecular Cell Biology2018,10,6:5
11Segregation during crystal growth from melt and absorption cross section determination by optical absorption method显示文摘Segregation during crystal growth from melt under two conditions is studied by using crystal mass,which can be measured easily,as an independent variable,and a method to determine the effective segregation coefficient and absorption cross section of optical dopant is given.When the segregated solute disperses into the whole or just a part of melt homogenously,the concentration CS in solid interface will change by different formulas.If the crystal growth interface is conical and segregated solute disperses into melt in total or part,the solute concentration at r=2/3R,where r is the distance from the growth cross section center and R the crystal radius,is independent on the shape of the crystal growth interface,and its variation at r=2/3R can be regarded as the result from crystal growth in flat interface.With CS variation formula in solid and absorption cross section σ for optical dopant,the absorption coefficients along the crystal growth direction can be calculated,and the corresponding experimental value can be obtained through the crystal optical absorption spectra.By minimizing the half sum,whose independent variables are k,ΔW or σ,of the difference square between the calculated and experimental absorp-tion coefficients from one or more absorption peaks along the crystal growth di-rection,k and σ,or k and ΔW,can be determined at the same time through the Levenberg-Marquardt iteration method.Finally,the effective segregation coefficient k,ΔW and absorption cross sections of Nd:GGG were determined,the results fitted by two formula gave more closed effective segregation coefficient,and the value ΔW also indicates that the segregated dopant had nearly dispersed into the whole melt.Experimental results show that the method to determine effective segregation coefficient k,ΔW and absorption cross sections σ is convenient and reliable,and the two segregation formulas can describe the segregation during the crystal growth from melt relatively commendably.ZHANG QingLi YIN ShaoTang SUN DunLu WAN SongMing 2008Science China(Physics,Mechanics & Astronomy)2008,51,5:5
12Investigation on the homogenization treatment and element segregation on the microstructure of a γ/γ′-cobalt-based superalloy显示文摘The aim of the present study was to investigate the effect of element segregation on the microstructure and γ′ phase in a γ/γ′ cobalt-based superalloy. Several samples were prepared from a cast alloy and homogenized at 1300°C for different times, with a maximum of 24 h. A microstructural study of the cast alloy using wavelength-dispersive spectroscopic analysis revealed that elements such as Al, Ti, and Ni segregated mostly within interdendritic regions, whereas W atoms were segregated within dendrite cores. With an increase in homogenization time, segregation decreased and the initial dendritic structure was eliminated. Field-emission scanning electron microscopy micrographs showed that the γ′ phases in the cores and interdendritic regions of the as-cast alloy were 392 and 124 nm, respectively. The size difference of γ′ was found to be due to the different segregation behaviors of constituent elements during solidification. After homogenization, particularly after 16 h, segregation decreased; thus, the size, chemical composition, and hardness of the precipitated γ′ phase was mostly uniform throughout the samples.Saeed Aliakbari Sani Hossein Arabi Shahram Kheirandish Golamreza Ebrahimi 2019International Journal of Minerals,Metallurgy and Materials2019,26,2:5
13Grain boundary segregation and its influences on ionic conduction properties of scandia doped zirconia electrolytes显示文摘Solid oxide fuel cell is a promising energy conversion system which converts chemical energy into electrical energy directly. Electrolyte is the key component and determines the working temperature. In this paper,ceria and scandia co-doped zirconia electrolytes sintered from 1300 to 1550 ℃ were chosen as research objects. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy were performed to characterize the ceramic samples. The effects of grain size and grain boundary element segregation on the electrical conductivity were focused. Electrochemical impedance spectroscopy was used to calculate the bulk, grain boundary and specific grain boundary conductivity. Results show that the bulk and grain boundary ionic conductivity increases with the increasing grain size.However, the specific grain boundary conductivity decreases with the increasing grain size. This is explained by the fact that Sc^(3+) is segregated at the grain boundary, which leads to higher oxygen vacancy concentration when sintered at lower temperature.Qiannan Xue Xiaowei Huang Jianxing Zhang He Zhang Zongyu Feng 2019Journal of Rare Earths2019,37,6:4
14Spouting behaviour of binary mixtures in square-based spouted beds显示文摘From experime nts, the influe nee of the physical characteristics of different bin ary mixtures of solids on the spouting regime of a pyramidal square-based spouted bed reactor is assessed. The applied methodology permits a more precise evaluation of the effects of the tested variables (diameter, density, sphericity) on the response variables (minimum air flows at which spouting begins and at which to maintain spouting con ditions). The associated pressure drops along the bed of particles a nd the height of the formed fountai n are analysed in each case. During the initial stages of fluidisation, binary mixtures containing different density ratios show dead zones. Segregation becomes more evident at large-size and high-density ratios. The lack of sphericity was found to be the main reason leading to blocking, channelling, and start-up problems when system failures occur. Nevertheless, the extent of segregation in all cases decreases with increasing the spouting velocity. In addition, a computational fluid dynamic model based on the discrete element method, previously validated for a single solid bed, is proposed as a tool to predict and evaluate potential segregation phenomena in binary mixtures. This model reproduced with high accuracy the encountered segregation phenomena. Its use may help define the technical limts inherent in the pyramidal spouted bed reactor.Cristina Moliner Filippo Marchelli Massimo Curti Barbara Bosio Giorgio Rovero Elisabetta Arato 2019Particuology2019,17,2:4
15Visualization of flow behavior in ore-segregated packed beds with fine interlayers显示文摘Ore particles,especially fine interlayers,commonly segregate in heap stacking,leading to undesirable flow paths and changeable flow velocity fields of packed beds.Computed tomography(CT),COMSOL Multiphysics,and MATLAB were utilized to quantify pore structures and visualize flow behavior inside packed beds with segregated fine interlayers.The formation of fine interlayers was accompanied with the segregation of particles in packed beds.Fine particles reached the upper position of the packed beds during stacking.CT revealed that the average porosity of fine interlayers(24.21%)was significantly lower than that of the heap packed by coarse ores(37.42%),which directly affected the formation of flow paths.Specifically,the potential flow paths in the internal regions of fine interlayers were undeveloped.Fluid flowed and bypassed the fine interlayers and along the sides of the packed beds.Flow velocity also indicated that the flow paths easily gathered in the pore throat where flow velocity(1.8×10^-5 m/s)suddenly increased.Fluid stagnant regions with a flow velocity lower than 0.2×10^-5 m/s appeared in flow paths with a large diameter.Lei-ming Wang Sheng-hua Yin Ai-xiang Wu 2020International Journal of Minerals,Metallurgy and Materials2020,27,7:4
16Genome-wide dissection of segregation distortion using multiple inter-subspecific crosses in rice显示文摘Mendelian inheritance can ensure equal segregation of alleles from parents to offspring, which provides fundamental basis for genetics and molecular biology. Segregation distortion(SD) leads to preferential transmission of certain alleles from generation to generation. Such violation of Mendelian genetic principle is often accompanied by reproductive isolation and eventually speciation. Although SD is observed in a wide range of species from plants to animals, genome-wide dissection of such biased transmission of gametes is rare. Using nine inter-subspecific rice crosses, a genome-wide screen for SD loci is performed, which reveals 61 single-locus quantitative trait loci and 194 digenic interactions showing distorted transmission ratio, among which 24 new SD loci are identified. Biased transmission of alleles is observed in all nine crosses, suggesting that SD exists extensively in rice populations. 72.13% distorted regions are repeatedly detected in multiple populations, and the most prevalent SD hotspot that observed in eight populations is mapped to chromosome 3. Xian alleles are transmitted at higher frequencies than geng alleles in inter-subspecific crosses, which change the genetic composition of the rice populations. Epistatic interaction contributes significantly to the deviation of Mendelian segregation at the whole-genome level in rice, which is distinct from that in animals. These results provide an extensive archive for investigating the genetic basis of SD in rice, which have significant implications in understanding the reproductive isolation and formation of inter-subspecific barriers during the evolution.Guangwei Li Jiye Jin Yan Zhou Xufeng Bai Donghai Mao Cong Tan Gongwei Wang Yidan Ouyang 2019Science China(Life Sciences)2019,62,4:4
17Formation mechanism of shrinkage and large inclusions of a 70t 12Cr2Mo1 heavy steel ingot显示文摘Shrinkage cavities and large inclusions are serious internal defects of heavy steel ingot and influence the quality of subsequent forgings. In order to remove these two types of defects, a 70 t 12Cr2Mo1 heavy ingot fabricated by vacuum carbon de-oxidation process was sectioned and investigated by means of structure observation and EDS analysis. To further study the forming mechanism of shrinkage and inclusion defects and find possible solutions, simulation on pouring and solidification processes was also carried out using Fluent and ProCAST software, respectively. Results show that the shrinkage defects do not appear in the middle-upper part of the ingot. The critical value of shrinkage cavity criterion is ascertained as 0.013 on the basis of sectioning investigation and simulation results, which can be used in computer simulation to predict and avoid shrinkage defects in production of 12Cr2Mo1 ingots with different weights. However, large inclusions are found at the bottom of the ingot body. The bad thermal conditions of the ingot surface and large amount of entrained slag are the main origin of the large inclusions. The simulation result of the pouring process shows that large inclusions may be eliminated by combined measures of improving the top thermal condition and controlling the height of rudimental molten steel in the ladle to above 300 mm.Liu Hongwei Fu Paixian Kang Xiuhong Ma Xiaoping 2014China Foundry2014,11,1:4
18Microstructure and homogenization process of as-cast GH4169D alloy for novel turbine disk显示文摘To investigate the microstructure, segregation, and suitable homogenization process of as-cast GH4169D alloy, the microstructure, elements segregation, and precipitates of cast GH4169D ingots prepared by vacuum induction melting (VIM) and vacuum arc remelting (VAR) were observed by optical microscopy (OM), scanning electron microscopy, and energy-dispersive X-ray spectroscopy (EDS). According to the residual segregation model and simulation results of DICTRA thermodynamic software, the homogenization temperature and time range were set as 1120–1170°C and 5–20 h, respectively. The experimental results showed that microscopic dendrite and element segregation occurred in the interior of ingots and the main segregation elements were Nb and Ti. In addition, the precipitates were mainly distributed in interdendritic regions and were composed of NbC, Laves,γ′, and δ phases. The homogenization process suggested that the interdendritic detrimental precipitated Laves phase can be eliminated or redissolved after homogenization at 1150°C for 20 h, suggesting it was the most suitable homogenization treatment. Thermal compression test results showed that the GH4169D alloys after homogenization treatment had no cracks and dynamic recrystallization occurred, with recrystallization volume fraction increasing with temperature, indicating a good working plasticity at temperatures from 1050 to 1200°C.Kai Chen Shu-yuan Rui Fa Wang Jian-xin Dong Zhi-hao Yao 2019International Journal of Minerals,Metallurgy and Materials2019,26,7:4
19Numerical Simulation and Experimental Study of F-EMS for Continuously Cast Billet of High Carbon Steel显示文摘A final electromagnetic stirring model was developed for billet continuous casting of high carbon steel using the commercial software ANSYS and CFX, and the numerical model was validated by the magnetic flux density measured under a Teslameter CT-3. The magnetic flux density and fluid flow in the liquid pool at the location of final electromagnetic stirring(F-EMS) were calculated by the present numerical model. Meanwhile, the plant trials were carried out to determine the optimum current intensity and frequency of F-EMS for the continuously cast billet of high carbon steel. The numerical results show that, through increasing the current intensity by 100 A, the corresponding increases of magnetic induction intensity, tangential electromagnetic force and flow velocity at the solid/liquid interface in the strand are 0.025 T, 1933 N/m3 and 6.9 cm/s, respectively. Moreover, the industrial trial results showed that for the continuously cast billet of 60 steel, the optimum current intensity and frequency of F-EMS, which is 8.2 m from the meniscus, are respectively 380 A and 6 Hz. With the optimum F-EMS parameters, the significant improvement of center segregation of billet is achieved, and the center carbon segregation index in billet reaches 1.04.Sen LUO Feng-yun PIAO Dong-bin JIANG Wei-ling WANG Miao-yong ZHU 2014Journal of Iron and Steel Research(International)2014,21,S1:4
20Effect of cross-section shape of rotating chute on particle movement and distribution at the throat of a bell-less top blast furnace显示文摘Rotating chutes are widely used to control the burden distribution and enhance the gas distribution in a blast furnace.The chute cross-section shape has a significant effect on the particle movement and distribution.Therefore,this study developed a three-dimensional model of a blast furnace top with rotating chute using the discrete element method.The effect of different chute shapes on the particle movement and radial burden distribution was then investigated.The results showed that the burden stream height at the chute discharge agrees well with the burden stream thickness at the burden surface.A semicircular chute had the largest main striking point,where the chute discharge joins the burden surface,and trapezoidal and rectangular chutes had successively smaller MSPs.The semicircular chute helped to obtain a uniform radial size distribution.The trapezoidal chute helped form an aggregated burden stream at low rotating speeds,while the rectangular shape chute achieved this at higher rotating speeds and different chute angles.Mingyin Kou Jian Xu Shengli Wu Heng Zhou Kai Gu Shun Yao Bingjie Wen 2019Particuology2019,17,3:3
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