bluuebunny/crossref_metadata_2025 huggingface dataset:
The Research on the Generated Mechanism about the End Concavity of Shaft in the Closed Type of Cross Wedge Rolling
Authors: Ma Ji Dong , Shu Chang , Sun Bao Shou , Chao Cheng , Cheng Chao
Published: March 2015

To further improve the material utilization in cross wedge rolling, the paper simulated the forming of closed cross wedge rolling through DEFORM-3D, a rigid-plastic finite element analysis software, and analyzed the distribution and changing rule on the fields of strain and displacement in the parts rolling. Then the paper clarified the generated mechanism about the end concavity of shaft in the closed type of cross wedge rolling, which has great theoretical significance and engineering applied value in controlling and decreasing the end concavity in closed type cross wedge rolling and improving the parts’ end quality.
Velocity Control with SGARC 440 Alloy in the Roll Forming Process
Authors: Zhang Ya , Kim D.H. , Jung Dong Won
Published: March 2015

Cold roll-forming of metal sections is a significant field in advancing forming of strip metal, and the forming processes are influenced by many factors. The scientific design of passes is worked out by combining theoretical analysis with finite element analysis, in accordance with the principles of cold roll-forming; thus the desired high-quality bending sections are achieved through a combination of theory and practice. This study mainly addresses the velocity of the rolls for sheets that have angle sides, and the spring-back of SGARC 440 alloy sheets in the roll forming process, where we use DEFORM to simulate the sheet.
Effect of Different Methods on Properties of SMA490BW Steel Welded Joints
Authors: Wu Xiang Yang , Qi Wei Chuang , Liu Yong Jun , Han Yong Bin , Xia Chun Hui
Published: March 2015

Because of its advantages of high strength, good toughness and strong corrosion resistance capability, SMA490BW was access to a wide range of applications in bogie frame of high-speed train. Manual welding, single-wire automatic welding and double-wires automatic welding were used to weld plate butt joints of SMA490BW steel. The mechanical properties testing and microstructure observation were carried out. Results showed that the strength of welded joint and impact toughness could meet the design requirements with the above methods. Double-wires welding owned an outstanding advantages of saving energy and welding productivity in such the above methods which laid the foundation for application of double wires welding in bogie frame of high-speed train.
Microstructure and Mechanical Properties of Electron Beam Welded 5A90 Al-Li Alloy
Authors: Lin Bo , Chen Long , Cheng Dong Hai
Published: March 2015

The microstructure and fracture of electron beam welded 5A90 Al-Li alloy joints were investigated by metallographic microscope and scanning electronic microscope. The results show that the focus of electron beam was on the surface of workpiece when the electron beam focusing current was 1570mA, and the joint formed best. The joints microstructure analysis demonstrated that the weldment mainly consists of fine equiaxed grains which growing coarser with the electron beam current increasing. The tensile strength up to 304.4MPa under the optimal welding parameters (Ua=90KV, If=1570mA, v=25mm/s, Ib=16mA). There were a lager number of dimples on the fracture surface,and the joints obviously present the characteristic of transgranular fracture.
Numerical Simulation of Distribution Characteristics of Electromagnetic Field for Round Billet with Mold Electromagnetic Stirring
Authors: Li Xing , Jiang Zhou Hua
Published: March 2015

A three-dimensional mathematical model of mold electromagnetic stirring (M-EMS) for round billet was established. Based on Maxwell’s equations, the distribution of electromagnetic field was solved by ANSYS software. Different process parameters’ influence on magnetic flux density and electromagnetic force (EMF) was studied. The results show that the magnetic flux density reaches the maximum at the stirrer center in the axis direction and increases with the increasing distance from the circle center on the cross section of the stirrer center. The tangential EMF is symmetric about the circle center and reaches the maximum at the edge of round billet. Both the magnetic flux density and the tangential EMF increase with the increasing current intensity. With the increasing current frequency, the magnetic flux density decreases, while the tangential EMF increases in the applied range of current frequency for M-EMS.
The Effect of Punch Radius on the Deformation of Ultra-High Strength Steel in Bending
Authors: Arola Anna Maija , Kesti Vili , Ruoppa Raimo
Published: March 2015

Bendability is an important material property for ultra-high strength steel. The bendability of a certain material is expressed as the minimum bending radius Rmin of the inner surface of the bend and expressed in multiples of the sheet thickness. Bendability is limited by either cracking on the surface or the edges of the bend or by surface waviness that usually precedes cracking on the outer surface. Surface waviness is a form of strain localization in bending and the intensity of the phenomenon is dependent on e.g. the punch radius, the lower tool width and the sheet thickness. In this study the bendability of a 960MPa grade steel was investigated using optical strain measurements of three-point bending tests to determine the strain level and the bending angle when localization starts with different punch radii. The unbent samples were marked with a grid using laser marking and the deformation was measured with the GOM ARGUS strain analysis system after bending. The quality of the bend was also evaluated visually. In addition, tensile tests were performed and evaluated with the GOM ARAMIS deformation analysis system to investigate the local mechanical properties of the studied steel. The results of strain measurements and visual evaluation were then compared. It was found that beyond a certain angle the maximum strain across the bend did not significantly change with further increases in the bending angle when the punch radius was at least three times the sheet thickness. But with smaller punch radii the maximum strain increased almost linearly with increasing bending angle until fracture appeared. With the smaller punch radii deformation localizes and surface waviness begins to form in smaller bending angles because the deformation is concentrated in a narrow zone.
Experimental and Numerical Determination of the Required Initial Sheet Width in Die Bending
Authors: Traub Tilman , Groche Peter
Published: March 2015

So far, determining the necessary precut dimensions of metal sheets prior to bending has been an unsolved question. During the last decades numerous calculation methods have been suggested. However, comparing these different methods indicates that different calculation methods suggest diverging precut dimensions. Especially in roll-forming, where multiple bend operations occur within the same bend part, these differences between several calculation methods can add up to some millimetres. The accuracy of presently available methods can hardly be compared. Thus an optimized method is needed. One possibility to determine the initial sheet width is identifying the position of the unlengthened layer in the bend zone. This study compares the position of the unlengthened layer determined in experiments and numerical simulations for different bend geometries and materials. The results indicate that even state of the art measuring technique is not accurate enough to determine the position of the unlengthened layer properly. Due to high measurement uncertainties, numerical simulations are required to assess the influence of geometry or material parameters on the position of the unlengthened layer. However, combining numerical and experimental results shows that the geometry of the bend part influences the position of the unlengthened layer and thus the required precut dimension. In contrast, a significant influence of material strength on the position of the unlegthened layer was not found.
On the Identification of a Loading Scheme in Large Radius Air Bending
Authors: Vorkov Vitalii , Aerens Richard , Vandepitte Dirk , Duflou Joost R.
Published: March 2015

Large radius air bending has a different loading diagram than conventional bending, which affects the material behavior during the bending process. In order to establish a correct loading diagram, the position of the contact points between the plate and the punch is determinant. The position of the contact points is depending on the evolution of the bending process and the influence of the material is unknown. In this work, the determination of the position of the contact points in large radius air bending has been studied by means of both an experimental campaign and finite element analysis. Experiments were performed on a press-brake with a capacity of 50 metric tons. High-strength steel Weldox 1300 and aluminum alloy AlMg3, and punches of radii 30, 35 and 40 mm have been used. During the bending process, the punch movement has been monitored and the bending angle has been measured by means of images recorded by a camera system. Based on the obtained results, the relation between the bending angle and the position of the contact points is discussed.
Tribological Behaviour of Lubricants in Hot Stamping of AA6016
Authors: Medea Francesco , Ghiotti Andrea , Bruschi Stefania
Published: March 2015

The increasing demand for fuel-efficient vehicles has led automotive industry to introduce new alloys in car manufacturing, characterized by a high stiffness and strength-to-weight ratio. Due to their mechanical and chemical properties, aluminium alloys appear potential candidates to replace traditional steels for several parts of the car-body-in-white, even if the limited formability at room temperature, the marked springback and the severe tribological behaviour have often represented important drawbacks in traditional properties. Recently, the use of temperature-assisted processes, such as hot stamping, allows overcoming such limits thanks to substantial increase of the formability and, at the same time, a drastic reduction of springback. However, the choice of proper process parameters, in terms of lubrication at the interfaces between the dies and the blank, and thermal parameters of the dies materials still represent critical points for the feasibility of the process. Recent investigations have proved the limits of assuming constant friction for all the areas of the dies and the steps of the deformations, especially with variable pressures and non-constant temperatures at the interfaces. Such factors, together with the lubricants and the lubricant deposition on the blank, the blank and dies coatings, the surface roughness, the stamping speed are not always considered, despite their considerable influence on the process tribology. In this paper the friction behaviour of commercially available automotive aluminium (AA6016 alloy) is studied. The friction coefficient is measured by means of a new machine for strip draw test at different levels of pressure, temperature, sliding speed and type of lubricant. The results report the investigation of the surface topography of the metal sheets, investigated by Energy-Dispersive X-ray spectroscopy and optical profilometry.
Investigation of Weld Seam Structures of Tailor Welded Blanks for Hot Stamping
Authors: Kolleck Ralf , Vollmer Robert , Both Christian , Breuer Arndt
Published: March 2015

Increasing safety requirements for hot stamped structural car body parts are demanding sufficient mechanical properties of integrated welding seams. Especially conventional tailor welded AlSi-coated 22MnB5 sheets are only fulfilling these requirements when ablated before laser welding and thermo-mechanically treated in a correct way. This paper shows a method that evaluates the hot stamping process of tailor welded blanks by press hardening different sheet thicknesses and thickness combinations in a testing tool. Furthermore, appropriate testing methods for the evaluation of mechanical properties of the welding seam are introduced. The results are ultimately compared with a special developed FEM analysis to predict failure cases in future.
Experimental Verification of a Benchmark Forming Simulation
Authors: Landkammer Philipp , Loderer Andreas , Krebs Eugen , Söhngen Benjamin , Steinmann Paul , Hausotte Tino , Kersting Petra , Biermann Dirk , Willner Kai
Published: March 2015

Forming of near-net-shaped and load-adapted functional components, as it is developed in theTransregionalCollaborative Research Centreon Sheet-Bulk Metal FormingSFB/TR73, causes different problems, which lead to non-optimal manufacturing results. For these high complex processes the prediction of forming effects can only be realized by simulations. A stamping process of pressing eight punches into a circular blank is chosen for the considered investigations. This reference process is designed to reflect the main aspects, which strongly affect the final outcome of forming processes. These are the orthotropic material behaviour, the optimal design of the initial blank and the influences of different contact and friction laws. The aim of this work is to verify the results of finite element computations for the proposed forming process by experiments. Evaluation methods are presented to detect the influence of the anisotropy and also to quantify the optimal blank design, which is determined by inverse form finding. The manufacturing accuracy of the die plate and the corresponding roughness data of the milled surface are analysed, whereas metrological investigations are required. This is accomplished by the help of advanced measurement techniques like a multi-sensor fringe projection system and a white light interferometer. Regarding the geometry of the punches, micromilling of the die plate is also a real challenge, especially due to the hardness of the high-speed steelASP2023(approx. 63 HRC). The surface roughness of the workpiece before and after the forming process is evaluated to gain auxiliary data for enhancing the friction modelling and to characterise the contact behaviour.
Experimental and Simulative Investigations of Tribology in Sheet-Bulk Metal Forming
Authors: Beyer Florian , Blum Heribert , Kumor Dustin , Rademacher Andreas , Willner Kai , Schneider Thomas
Published: March 2015

Friction has a considerable influence in metal forming both in economic and technical terms. This is especially true for sheet-bulk metal forming (SBMF). The contact pressure that occurs here can be low making Coulomb’s friction law advisable, but also very high so that Tresca’s friction law is preferable. By means of an elasto-plastic half-space model rough surfaces have been investigated, which are deformed in such contact states. The elasto-plastic half-space model has been verified and calibrated experimentally. The result is the development of a constitutive friction law, which can reproduce the frictional interactions for both low and high contact pressures. In addition, the law gives conclusion regarding plastic smoothening of rough surfaces. The law is implemented in the framework of the Finite-Element-Method. However, compared to usual friction relations the tribological interplay presented here comes with the disadvantage of rising numerical effort. In order to minimise this drawback, a model adaptive finite-element-simulation is performed additionally. In this approach, contact regions are identified, where a conventional friction law is applicable, where the newly developed constitutive friction law should be used, or where frictional effects are negligible. The corresponding goal-oriented indicators are derived based on the “dual-weighted-residual” (DWR) method taking into account both the model and the discretisation error. This leads to an efficient simulation that applies the necessary friction law in dependence of contact complexity.
Structural and Frictional Performance of Fused Deposition Modelled Acrylonitrile Butadiene Styrene (P430) with a View to Use as Rapid Tooling Material in Sheet Metal Forming
Authors: Leacock Alan G. , Cowan Graham , Cosby Mark , Volk Gregor , McCracken David , Brown Desmond
Published: March 2015

Using additive layer manufacturing techniques, such as Fused Deposition Modelling (FDM), it is possible to produce complex geometry relatively quickly and cheaply. For this reason these processes offer intriguing possibilities for tooling in metal forming processes. A common material utilised in the FDM process is Acrylonitrile Butadiene Styrene (ABS). A series of compression and tensile tests were carried out on FDM ABS test specimens built in a range of orientations. The tensile tests were carried out until fracture and the specimen cross-sections analysed to investigate the cause of failure. In uniaxial tension the vertical build direction was found to be the weakest, failing in a brittle fashion. The FDM material elastic modulus and Poisson’s ratio were found to be isotropic in nature within experimental scatter. The ‘yield’ strength in compression was found to be higher than that observed for equivalent tensile orientations. Following a series of strip pull friction tests using commercially pure titanium as the blank material, it was found that without the utilisation of an interfacial lubricant a favourable frictional performance was achievable on ABS tool surfaces. Due to tool wear however, the frictional performance of these tool pieces deteriorated with increasing sliding distance.
New Approach for Wrinkle Prediction in Deep Drawing Process
Authors: Han Fei , Radonjic Ranko
Published: March 2015

Due to the extensive use of thin sheet metals to reduce weight of car bodies, wrinkling is becoming a more common and one of the most undesirable defects in sheet metal forming processes. Recent experiments at the Institute for Metal Forming Technology (IFU), University of Stuttgart, indicated that the buckling test using modified specimens can enhance accuracy for the predication of wrinkling [1]. In this paper a new method to predict the onset of the wrinkling will be introduced, and results of this test will be compared with real deep drawing parts. The wrinkle heights will be considered an evaluated regarding to results obtained by an optical measurement system.
Formability of AA6060 Tubes in Hot Metal Gas Forming at High Temperatures
Authors: Michieletto Francesco , Ghiotti Andrea , Bruschi Stefania
Published: March 2015

The continuous need of improved performances in automotive in terms of dynamic behaviour, fuel consumption and safety of passengers, have raised the interest for lightweight alloys as well as for the optimization of the design of the structural components of the car chassis. With this twofold aim, many researches are focused in the evaluation of new car designs, materials, and processes to manufacture even more complex components with increased stiffness-to-weight ratio. From that standpoint, the use of shaped hollow parts in the car body in white appears one of the most promising solutions, due to the elevated stiffness of tubular structures and the reduced weight. However, hydroforming processes that have been traditionally used to shape such components have shown several limitations with lightweight alloys, suffering their reduced formability, the temperature limitations of the forming liquids as well as long process time and complex machines. In this paper the recently introduced technology of Hot Metal Gas Forming (HMGF) has been considered, in order to investigate the influence of the process parameters on the formability of AA6060 tubes. The semi-finished tubes were produced through direct hot extrusion, with different temperatures and feed rates process, and tested by HMGF at elevated temperatures. The properties of the final products are investigated through analyses of the microstructure, micro hardness and thickness measurements.
Cranial Reconstruction Using Double Side Incremental Forming
Authors: Lu Bin , Xu Dong Kai , Liu Run Zhe , Ou Heng An , Long Hui , Chen Jun
Published: March 2015

Incremental sheet forming (ISF) is a highly versatile and flexible process for rapid manufacturing of complex sheet metal parts. Comparing to conventional sheet forming processes, ISF is of a clear advantage in manufacturing small batch or customized products such as cranial implant. Although effort on cranial reconstruction by using incremental sheet forming approach has been made in recent years, research has been mostly based on the single point incremental forming (SPIF) strategy and there are still considerable technical challenges for achieving better geometric accuracy, thickness distribution and complex cranial shape. In addition, the use of a backing plate or supporting die reduces the process flexibility and increases the cost. To overcome these limitations, double side incremental sheet forming (DSIF) process is employed for forming Grade 1 pure titanium sheet by using different toolpath strategies. The geometric accuracy and thickness distribution of the final part are evaluated so the optimized tool path strategies are developed. This leads to an assessment of the DSIF based approach for the application in cranial reconstruction.
Friction Adjustment within Dry Deep Drawing by Locally Laser Textured Tool Surfaces
Authors: Häfner Tom , Heberle Johannes , Dobler Michael , Gränitz Michael , Alexeev Ilya , Schmidt Michael
Published: March 2015

In deep drawing processes sustainability can be increased and processing steps can be omitted by abolishing any lubricants. Tailored tools with locally textured surfaces offer a possibility to compensate higher strains caused by the changed tribological system. Ultrashort pulsed laser machining is an advantageous approach to generate surface features. Thus, very hard and brittle materials can be processed inducing negligible heat affected zones so that the surrounding tool material keeps its initial properties. The material-dependent process parameters for efficient picosecond laser structuring are applied. The effects of features with single feature sizes in the range of 100 µm to 500 µm on friction of the tribological pairing are presented. The dependencies of the friction coefficient on the properties of the micro features - the geometry, the shape, the density and the orientation - are investigated by using a ring-on-disc-tribometer. The ring representing the tool is made out of the cold work steel 1.2379. The zinc-coated deep-drawing steel DC04 is used as disc respectively workpiece material. During the ring-on-disc-tests a constant contact pressure of 2.1 MPa and a mean sliding velocity of 100 mm/s are applied. To obtain the significant influences of micro features on friction, screening tests by varying the parameters according to the Shainin method are carried out. Because of the stochastically occurring high wear observed in reference experiments a changed methodology of ring-on-disc-tests is proposed. Applying this method the effects of textured ring surfaces on friction coefficient of steel-zinc-sliding are evaluated and compared to untextured rings. The latter are tested non-lubricated as well as with lubrication. The screening tests show that the feature orientation is the significant parameter influencing the friction. Selecting this parameter together with the feature density the friction coefficient can be adjusted with regard to untextured surfaces.
Embossing of Metal Inserts for Subsequent Assembly Injection Moulding of Media Tight Electronic Systems
Authors: Frey Philipp , Heinle Martina , Leisen Christoph , Drummer Dietmar , Merklein Marion
Published: March 2015

Due to the increasing number of electronics in several industrial sectors, especially in the automotive industry, there is a rising demand for flexible and adaptable electronic systems with high functional density and resilience. An efficient method for producing such parts is the encapsulation of metal inserts, for example lead frames, by means of assembly injection moulding. Often such parts are exposed to water and moist at the place of action. Thus, one major challenge is to provide electronics with enduring media tightness in a severe environment. The research work covered in this paper focuses on embossing surface structures in metal inserts for subsequent assembly injection moulding. The influence of geometrical parameters of the embossed profile on both the material flow and the accuracy of the created structure are investigated. For this purpose experimental as well as numerical results are presented. Furthermore, the performance of embossed inserts in subsequent assembly injection moulding is analysed.
Influence of Surface Chemical Groups and Content of Carbon Nanotubes on Electrical Property of Epoxy Resin Composites
Authors: Lin Shao Feng , Jiang Cai , Zhang Jian Wei , Jiang Da Zhi , Ju Su
Published: March 2015

In this study, electrical properties of multi-walled carbon nanotubes (MWCNTs) reinforced epoxy resin composites were investigated, with respect to the method of dispersion, surfactants, content and chemical groups of CNTs. Experimental results show that chemical functionalization and surfactants improved the dispersion of CNTs in epoxy resin. Electrical conductivity of epoxy increased by two orders of magnitude with 0.5 wt% MWCNTs, while seven orders of magnitude with 2.0 wt% MWCNTs-NH2. The results also indicated that an effective electron transport channels formed in the composites with 0.5 wt% CNTs approximately.
Entanglement of CeO2 Nanorods and Graphene Nanoribbons and their Properties Studies of Nanocomposites
Authors: Zhang Bo , He Xiao Chun , Gao Ming Jun , Ma Xing Fa , Li Guang
Published: March 2015

Nano/Micro-structured CeO2and their nanocomposites have been received considerable attention in basic research and commercial applications, such as, new energy fields, photocatalysts, environmental fields, et al. To extend its visible light response and pave the effective conductive channels for charge transfer and separation in nanoscale is still facing great challenges. To explore these key issues of materials chemistry and physics, CeO2nanorods were prepared with aid of soft templates by wet chemical approach. Graphene nanoribbons were obtained with unzipping method of carbon nanotube (CNTs). Entanglement of CeO2nanorods and graphene nanoribbons oxides was realized based on the supermolecular interactions between surface active groups of CeO2nanorods and graphene nanoribbons oxides and excellent flexibility of graphene nanoribbons. A series of characterizations were examined by SEM (scanning electron microscopy), TEM (transmission electron microscopy), XRD (X-ray diffraction), the Fourier-Transform Infrared (FTIR) spectra, ultraviolet-visible spectroscopy (UV-Vis) and so on. Photocatalytic efficiency was examined by selecting typical organic pollutants. The results indicated that the entanglement of a small amount of graphene nanoribbons on the surface of CeO2nanorods not only expanded the light response of nanocomposite to visible light, but also enhanced the adsorption properties to organic pollutants. Because of excellent charge transfer properties and high mobility of graphene nanoribbons, the nanocomposites of CeO2/graphene nanoribbons are favor for electron-holes pairs generated by visible light, separation, and transfer, which would be important potential applications in photocatalysts, artificial photosynthesis system, nano/micro-devices, et al.
Synthesis of TiO2/RGO Nanocomposites by Hydrothermal Method and their Photocatalytic Activity Research
Authors: Leng Jin Feng , Wang Ying Zi , Teng Xin Ying , Hu De Jiang
Published: March 2015

The TiO2 reduced graphene oxide (TiO2/RGO) nanocomposites were synthetized by hydrothermal method. The microstructure and morphologies of them were characterized by XRD and SEM. The photocatalytic activity was investigated by the methyl orange photogradation under UV illumination. The results showed that GO sheets had wrinkles and folds, and anatase-structured TiO2 covered on graphene surface after hydrothermal reaction. Compared to the TiO2 nanoparticles, the TiO2/RGO nanocomposites display the higher photogradation efficiency. In 90 minutes, the gradation percentage of TiO2/RGO nanocomposites to methyl orange is 80%, higher than TiO2 nanoparticle (40%). This is attributed to the large surface area of TiO2/RGO nanocomposites and their improved separation efficiency of electron-hole pair.
Development of Functional Polymer as Oil-Well Cement Retarder
Authors: Xia Xiu Jian , Guo Jin Tang , Liu Shuo Qiong , Jin Jian Zhou , Yu Yong Jin , Feng Ya Kai
Published: March 2015

In this study, a novel polymer retarder DRH-200LG was synthesized to solve the problems of retarding failure, strong dispersivity under high temperature and adverse impact on the strength development of cement stone. The composition of the polymer was confirmed by IR, and its thermal stability was proved by DSC, TG analysis and thermal treatment at 200 °C. Furthermore, the stability and strength development of cement slurry was evaluated by the comparative consistency method and ultrasonic method, respectively. The results show that DRH-200LG has good high temperature-resistance and retarding performance, presenting favourable influence on the stability and strength development of cement slurry. DRH-200LG shows a good application prospect in the cementation of deep & ultra-deep wells. And it has some guiding significance in the research and innovation of a novel polymer used as oil well cement retarder.
Modified Mechanism and Properties of Water-Soluble Sodium Silicate for Oil and Gas Field
Authors: Zhang Hong Xu , Zhao Yu Jie , Zhuang Jia , Qin Hai Yang , Zhang Han Ling
Published: March 2015

With an analysis on the structure of water-soluble sodium silicate and its polymerization, it was found that the poor stability of silicate drilling fluids lies in the relevance between the inherent nature and the pH value of sodium silicate. The modification of water-soluble sodium silicate in this paper was to improve its stability and keep the inhibitive property simultaneously. The a-olefin sulfonate (AOS) was employed as the modifer agent acted on the water-soluble sodium silicate monomer and oligomers. Furthermore, the modification mechanism was discussed through FTIR, Laser particle size, Zeta potential and SEM. A stable sodium silicate drilling fluids with better inhibitive property was obtained by the comparison of modified sodium silicate and unmodified ones.
Thermodynamic Study of Ag-Au-Gd, Tb Ternary Systems
Authors: Li Jia Lian , Wang Shu Liang , Zhou Lu Jiang , Wang Xiao Hong , Lin Yuan Hua , Liu Xing Jun
Published: March 2015

The addition of the rare earth elements into the Ag-based filler alloy, which is typical and important, can control and eliminate the negative effect of impurity elements, and furthermore, it improves the spreading property of the Ag-based filler alloy. Phase diagram provides an important direction for materials design of the Ag-based filler alloy. Thus it is necessary to investigate the phase diagrams and construct the thermodynamic database. On the basis of this background, thermodynamic assessments of the Au-Gd, Tb binary systems were carried out by using the CALPHAD (Calculation of Phase Diagrams) method based on the experimental data including thermodynamic properties and phase equilibrium. The Gibbs free energies of the solution phases were described by sub-regular solution models with the Redlich-Kister equation, while all of the intermetallic compounds were described by sub-lattice models. A consistent set of thermodynamic parameters was derived from describing the Gibbs free energies of each solution phase and intermetallic compound. The calculated phase diagram achieved consistency with the available experiments. Then combined with the assessed relevant binary systems, the Ag-Au-Gd, Tb ternary systems have been predicted. The thermodynamic database of these ternary systems has been developed to present the significant information for the design of Ag-based filler alloys.
Microstructure and Properties of X100 High Strength Pipeline Steel
Authors: Tian Yu Xiao , Wang Bin , Li Jun Liang , Chen Bo Li , Feng Quan
Published: March 2015

In order to study the effect of welding process on the microstructure and properties of weld joint of X100 pipeline steel, GMAW was used to prepare the weld joint with low-carbon high manganese-molybdenum-nickel flux cored welding wire. SEM and XRD were used to analyze the microstructure and phase morphology of HAZ and weld metal. Hydraulic tensile testing machine and impact test machine were used to test the mechanical properties. The experimental results showed that the weld metal and HAZ were composed of bainite, ferrite and M/A, the microstructure was fine and uniform with columnar crystal morphology, and HAZ was quite coarse. Hardness of weld metal was 248HV, which is higher than that of base metal, however, HAZ was softening. The tensile strength of weld joint was 832Mpa, which is about 96% of the base metal. The impact absorbed energy at-20°C of the base metal and weld metal were 291J and 121J respectively, exhibiting excellent strength and toughness.
Effects of Synthesis Temperature and Holding Time on the Electrochemical Properties of LiNi1/3Co1/3Mn1/3O2 Cathode Material Using Rheological Phase Method
Authors: Peng Hui , Zhu Ze Hua , Huang Peng Xiao , Li Xing
Published: March 2015

In this paper, LiNi1/3Co1/3Mn1/3O2 was prepared via a facile rheological phase reaction method. The effect of synthesis temperature and holding time on its electrochemical performance has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV) tests and galvanostatic charge–discharge tests. The results suggest that the synthesis temperature and holding time greatly affect the electrochemical performance of the LiNi1/3Co1/3Mn1/3O2 and the optimized synthesis condition for the synthesis of LiNi1/3Co1/3Mn1/3O2 via rheological phase reaction method is 900 °C for 8 h. The obtained sample possesses a highly ordered layered structure and low cation mixing. It delivers an initial discharge capacity of 198 mAh g-1 at 0.2 C and 140 mAh g-1 at 1.0 C between 2.5 and 4.6 V, respectively.
In Situ Synthesis of Graphitized-Carbon Coated Li4Ti5O12/C Anode for High-Rate Lithium Ion Batteries
Authors: Huang Peng Xiao , Tang Shui Hua , Peng Hui , Li Xing
Published: March 2015

Graphitized-Carbon coated Li4Ti5O12/C (Li4Ti5O12/GC) composites were prepared from Li2CO3, TiO2 and aromatic resorcinol via a facile rheological phase method. The microstructure and morphology of the samples were determined by XRD and SEM. The electrochemical performances of the samples were characterized by galvanostatic charge-discharge test and electrochemical impedance spectroscopy (EIS). The results reveal that the coating of graphitized carbon could effectively enhance the charge/transfer kinetics of the Li4Ti5O12 electrode. The Li4Ti5O12/GC could deliver a discharge specific capacity of 166 mAh/g at 0.2 C, 148 mAh/g at 1.0 C, 142 mAh/g at 3.0 C, 138 mAh/g at 5.0 C and 127 mAh/g at 10.0 C, respectively, and it still could remain at 132 mAh/g after cycled at 5.0 C for 100 cycles. The excellent rate capability of the Li4Ti5O12/C makes it a promising anode material for high rate lithium ion batteries.
Removal of Nickel (II) Ion from Wastewater by Modified Maifanite
Authors: Zhou Wen Xin , Guan Deng Gao , Sun Yao , Sun Chuan Min , Xu Guan Li , Chen Ting , Yu Zhi Sheng , Xu You , Yan Han
Published: March 2015

The nickel ions in industrial wastewater derive from electroplating and chemical plating industry. Heavy metal ions can result in water pollution, and do harm to people’s health. Maifanite is a kind of nontoxic and harmless silicate rock mineral materials which have a certain biological activity. Maifanite porthole effect and surface effect can apply to removal of heavy metal ions from wastewater, for example, nickel ion, etc. However, natural Maifanite porous structure could be jammed by humus and sediment gradually; in order to play better adsorption performance of Ni (II) and other heavy metal ions in water, we need to adopt necessary modification treatment processes. H2SO4 was used to modify Maifanite, which prepared a high efficient adsorbent. At the same time, the removal effect of Ni (II) in water at different acid concentration, dosage, temperature, time and etc. was studied. The results showed that the Maifanite obtain better adsorption of 90% when the acid concentration was 2.5 mol/L, dosage of 50 mL, contact time and temperature of Ni (II) were 0.5 h and 30°C respectively. The above treatment has certain effect and meaning to reduce harm extent of industrial wastewater on environment and human health.
Preparation and Electrical Conductivity of Polythiophene/Microcrystal Muscovite Layered Composites
Authors: Ling Ying , Long Jian Ping
Published: March 2015

Polythiophene(PTP)/microcrystal muscovite conductive composites were prepared by the method of intercalating polymerization via Fe3+-H2O2 catalytic oxidation system in water. The morphology, structures, electrical conductivity and thermal stability of composites have been studied preliminary. The influence of the different synthesis conditions (temperature, monomer ratio, reaction time) on the conductivity of composite materials was explored. The results of the FTIR and XRD confirmed that thiophene (TP) inserted into the layers of microcrystal muscovite to polymerize and formed intercalation compounds. TG analysis indicated the improved thermostability of composite materials. The PTP/microcrystal muscovite composite made from 2g/ml solution of microcrystal muscovite/TP with reacting for 12h and 15°C showed the highest conductivity 3.56 ×10-5s/cm-1.
Effects of Sr2+ Doping on the Luminescent Properties of CaTiO3: Pr3+
Authors: Yan Guo Yin , Qiu Ke Hui , Chen Si Zhu , Zhao Ce
Published: March 2015

The perovskites red phosphors activated by Pr3+were prepared via the combustion method, using citric acid as a fuel and complex agent. The samples were characterized by X-ray powder diffraction and fluorescence spectrophotometry respectively. The effects of calcination temperature and doping Sr2+ion concentration on the phase compositions and luminescence properties were investigated. The CaTiO3: Pr3+can be obtained with high purity and good crystallinity by the combustion method at different calcination temperatures (750 oC, 850 oC, 900 oC, 950 oC and 1000 oC) for 1 h. The sample obtained at 900 oC exhibits the maximum emission intensity. The crystal structure of the obtained Ca1-xSrxTiO3: Pr3+(x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6) changes from perovskite to calcium strontium titanate when x ≥ 0.3. The sample exhibits the maximum red emitting when x = 0.4.
Study of Structural and Optical Properties of Cu2ZnSnS4 and Cu2ZnGeS4 Thin Films Synthesized by Sulfurization of Stacked Metallic Layers
Authors: Huang Ling , Deng Hong Mei , He Jun , Chen Lei Lei , Yang Ping Xiong , Chu Jun Hao
Published: March 2015

Cu2ZnSnS4and Cu2ZnGeS4thin films made from the earth abundant and non-toxic materials are quaternary semiconducting compounds which have received increasing interest for solar cells applications. Cu2ZnSnS4and Cu2ZnGeS4thin films have been synthesized by sulfurization of radio frequency magnetron sputtered precursors. The structural and optical properties of the thin films have been investigated and discussed. The result of X-ray diffraction demonstrates that the Cu2ZnSnS4and Cu2ZnGeS4thin films have kesterite (KS; space groupI) crystal structure. An obvious blue shift is observed in the Raman spectra as smaller Ge replaces Sn. It is due to the fact that the radius of Ge cation is smaller than that of Sn cation , which results in the shrink of the lattice. Further transmission spectra demonstrate that the values of band gap for CZTS and CZGS thin films are 1.54 eV and 1.98 eV, respectively.
Accounting Model of CO2 and its Application in Integrated Iron and Steel Enterprises
Authors: Huang Zhi Jia , Jiang Xue Hang , Sun Huan Huan
Published: March 2015

Integrated iron and steel enterprises is taken as the research object. Under the guidance of GHG Protocol standards for carbon emissions, the carbon dioxide accounting models on the process as a whole boundary are established, in which, the carbon emissions inventory is divided into three levels and the input data consists of CO2emission coefficient and activity factor level data. The process model is the accounting model that the carbon emission is obtained through the balance of carbon input and carbon output outside the process boundary under the condition of considering the enterprise circulation. This article also researched one integrated iron and steel enterprise as a case. The results show that the model can quantify the emissions of different processes, provide basic value for the enterprise reduction, Identify major carbon source, identify the influence on carbon emissions by the changes of fuel structure, the structure of the process parameters and outsourcing by-product internal circulation. Therefore the model results can be used in the carbon emissions of enterprise internal assessment and decision-making.
Effects of Nutrition on Mild Steel Corrosion by Sulfate Reducing Bacteria under Aerobic Environment
Authors: Duan Dong Xia , Lin Cun Guo , Liu Guang Zhou , Yao Ping
Published: March 2015

Sulfate reducing bacteria (SRB) are traditionally considered as anaerobic organism. In this paper, the potential of sulfate reducing bacteria to cause mild steel corrosion under aerobic situation was investigated. Natural biopolymer agar and sulfate reducing bacteria cells were used to produce artificial biofilm. Micro-sensors were used to investigate the microenvironment in artificial biofilm. Environmental scanning electron microscopy and energy dispersive spectroscopy were used to study mild steel corrosion covered by artificial biofilm. The results indicated that SRB could grow and reduce sulfate both in suspension and in biofilm. The hydrogen sulfide produced by SRB and mild steel corrosion were influenced by the nutrients in the environment. The concentration of H2S in SRB biofilm exposed to culture medium was as twenty times as that exposed to marine water. The main corrosion product of mild steel in culture medium was iron sulfide, whereas the main product of mild steel in marine water was iron oxide.
Preparation of NiO Microspheres by Hydrothermal Method and its Electrochemical Capacitive Properties
Authors: Li Qian Qian , Fan Run Hua , Yan Ke Lan , Sun Kai , Wang Xu Ai , Chen Min , Xie Pei Tao
Published: March 2015

The precursor Ni (OH)2was synthesized by a simple hydrothermal method with hexamethylenetetramine ((CH2)6N4) as precipitant and template, and then NiO was gained after calcination. The phase and morphology of the synthesized product were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), and the electrochemical capacitive characterization was performed using cyclic voltammetry (CV), chronopotentiometry and electrochemical impedance spectroscopy (EIS) in a 6mol/L KOH aqueous solution electrolyte. The result shows that spherical NiO without impurity was synthesized, the average diameter of the spheres is 5 um and these spheres were constructed by the interactive arrangement of many nanoflakes in three dimensions. This kind of NiO shows the typical electrochemical characteristics of pseudo capacitance with high specific capacity and excellent rate capability. The specific capacity can reach 515F/g at the current density of 1A/g
Preparation of LSMO/PLZT Composite Film by Sol-Gel Technique and its Ferroelectric and Ferromagnetic Properties
Authors: Duan Zong Fan , Wei Juan Ning , Cui Ying , Zhao Gao Yang
Published: March 2015

La0.67Sr0.33MnO3 (LSMO)/Pb0.92La0.08Zr0.65Ti0.35O3 (PLZT) composite film was fabricated on a (001) LaAlO3 (LAO) single crystal substrate by a sol-gel technique. The results from X-ray diffraction (XRD) indicated that LSMO and PLZT could grow successively on LAO substrate with (001) preferred orientation. The ferroelectric and ferromagnetic properties of LAO/LSMO/PLZT composite film were also investigated. The results showed that the remnant polarization Pr, and coercive field Ec of the composite film at room temperature were 36.38 μC/cm2 and 512.43 kV/cm respectively. Moreover, the composite film exhibited significant ferromagnetic hysteresis loops and soft magnetic behavior at temperatures lower than 250 K.
Enhancement of Oxygen Vacancies Induced Photovoltaic Effects in Bi0.9La0.1FeO3 Thin Films
Authors: Gao Rong Li , Fu Chun Lin , Cai Wei , Chen Gang , Deng Xiao Ling , Yang Huai Wen , Sun Ji Rong , Shen Bao Gen
Published: March 2015

The photovoltaic effect in Ag/Bi0.9La0.1FeO3/La0.7Sr0.3MnO3heterostructures was investigated and the short circuit photocurrent was found to be strongly dependent on the polarization orientation and oxygen vacancies (VOs) distribution. The photocurrent direction was switched accompanying polarization switching. Besides, according to manipulate theVOsaccumulated at either the Ag/Bi0.9La0.1FeO3or the Bi0.9La0.1FeO3/La0.7Sr0.3MnO3interface by electric pulses, obvious enhancement of photovoltaic effects was obtained. These results can be explained well using the concepts of drift current and diffusion current controlled by the combination of oxygen vacancies and polarization. This work provides deep insights into the nature of photovoltaic effects in ferroelectric films, and will facilitate the advanced design devices combining spintronic, electronic, and optical functionalities.
Synchronous Characterization of Self-Bias Magnetoelectric Composite Materials
Authors: Shi Zhan , Deng Shu Wen , Li Xiao Fei , Yang Shui Yuan , Lu Yong , Wang Cui Ping , Liu Xing Jun
Published: March 2015

To investigate the mechanism of self-bias magnetoelectric effect in magnetoelectric composite materials, a synchronous characterization technique was developed to characterize the magnetoelectric effect, the magnetostrictive effect, and the magnetic hysteresis loop by one-time test. The results of a magnetoelectric composite consisting of hybrid ferromagnetic phases showed that the obvious magnetoelectric hysteresis behavior was found with significant self-bias magnetoelectric effect. In addition, after demagnetizing, the residual magnetic polarization became zero and the magnetoelectric effect disappeared at the same time. Since the ferromagnetic phases were separated from each other, the mechanism of self-bias magnetoelectric effect mainly resulted from static magnetic coupling instead of build-in magnetic field. It was concluded that the synchronous characterizing technique was quite helpful when analyzing the mechanism of magnetoelectric behavior.
Ultrahigh Purity Copper Alloy Target Used Innanoscale ULSI Interconnects
Authors: Zeng Hao , Lv Chao , Gao Yan , Dong Ting Yi , Wang Yong Hui , Wang Xing Quan
Published: March 2015

Current ULSI circuits have features with dimensions in the nanoscale region. As the critical dimension shrinks, Cu BEOL systems face reliability impacts. Alloying has been proved to be a promising technique to retard grain boundary electro-migration (EM). In this paper, dilute Cu Alloys such as Cu-Al, Cu-Mn for dual-damascene interconnect applications have been investigated. The alloy chosen principle for nanoscale interconnects has been discussed. The ultrahigh purity copper alloy target properties including purity, alloy composition, grain size and sputtering performance were investigated, to lay the foundation for the application of the large-size ultrahigh purity copper alloy target used for 300mm wafer fabrication. The relationships between deposited film behaviors and sputtering target properties in some applications were also discussed. In order to acquire high quality thin film, the properties of sputtering target such as alloy composition homogeneity, grain size and uniformity et al. have to be well controlled by proper fabrication techniques.