bluuebunny/crossref_metadata_2025 huggingface dataset:
Deformation Behavior and Formability of Sheet Metal Laminate Consisting of Perforated Core Sheet and Thin Skin Sheets
Authors: Hino Ryutaro , Nakamura Masato , Ishida Yo , Yoshida Fusahito
Published: March 2013

This study presents a new type of sheet metal laminate for lightweight products, and investigates its plastic behavior and formability. The sheet metal laminate consists of three layers, i.e. two thin skin sheets and a perforated core sheet with round holes, which are bonded together by diffusion bonding. Pure copper sheets are used for both of the core and the skins. Plastic deformations of the laminate and its component layers under uniaxial and biaxial tension are examined experimentally and analytically. Results of uniaxial stress-strain responses and yield loci (contours of plastic work) show that the perforated core sheet exhibits anisotropic behavior induced by the hole array but the laminated sheet becomes rather isotropic. Forming limit diagrams of the laminate and its component layers are also obtained by performing stretch forming test. Forming limit of the perforated core sheet is markedly lower than that of the monolithic sheet, and that of the thin skin is in between. It is found that forming limit of the laminate is comparable to that of the thin skin.
Development of Cup Inner Surface Smoothing Process by Ironing
Authors: Tanaka Atsushi , Wang Zhi Gang , Hibi Nobuyuki
Published: March 2013

Ironing process is a normal method to improve the surface quality and thickness precision of a drawn cup. Multi-stage processes that combined drawing and ironing, have been developed to obtain the cups with a each surface quality. However, the ironing process is generally used to outside of the drawn cup, and the trial to improve the inside surface property is not carried out very much. The purpose of this study is to clarify the effect of ironing process on the improvement of the surface quality of multi-stage drawn cup. The effects of the ironing reduction, lubricants and punch shape on the improvement of the inner surface properties are investigated by using a series of experiment. It is found that the inner ironing process is effective to improve the inner surface properties of a drawn cup.
Effect of the Constitutive Laws on the Accuracy of Sheet Metal Simulation
Authors: Banabic Dorel
Published: March 2013

During the last three decades, numerical simulation has gradually extended its applicability in the field of sheet metal forming. Constitutive modeling is one of the domains closely related to the development of numerical simulation tools. The paper is devoted to a comprehensive testing of the advanced materials models as implemented in the finite-element code. The test proves the capability of the advanced materials models response of DC04 steel sheet to describe the effects of the plastic anisotropy of the sheet metals subjected to industrial forming processes.
Hot Working and Processing Maps of TiCp Reinforced Aluminum Alloy Matrix Composite
Authors: Kim Su Hyeon , Lee Jung Moo , Cho Young Hee , Kim Yeong Hwa , Kim Hwa Jung
Published: March 2013

Hot working behavior of an aluminum alloy matrix composite reinforced with TiC particulates was investigated by a high temperature compression test. Power dissipation maps were constructed using a dynamic material model and the deformation mechanism was investigated by means of an EBSD analysis. The interrelationship between the microstructure evolution and the efficiency of power dissipation was derived and the roles of TiC particles and other constituent phases in determining processing maps were further discussed.
The Effect of Interatomic Potentials on the Onset of Plasticity in the Molecular Dynamics (MD) Simulation of Nanometric Machining
Authors: Oluwajobi Akinjide , Chen Xun
Published: March 2013

The effect of interatomic potentials on the onset of plastic deformation in the nanometric machining of a crystalline diamond tool on a crystalline copper workpiece, was investigated by using the MD simulation. Three potential pairs were used for the copper-copper (workpiece) and the copper-carbon (tool-workpiece interface) atomic interactions. For case 1, the Morse potential was used for both the copper-copper and the copper-carbon interactions; for case 2, the Embedded Atom Method (EAM) potential was used for the copper-copper interactions and the Morse potential was used for the copper-carbon interactions; and for case 3, the EAM potential was used for the copper-copper interactions and the Lennard-Jones (LJ) potential was used for the copper-carbon interactions. The diamond tool was modelled as a deformable body and the Tersoff potential was applied for the carbon-carbon interactions. From the simulation results, pile-up volume and the force ratio appear to indicate the onset of plasticity during the machining. The pile-up volume shows that ploughing starts from 0.25nm, 0.20 and 0.30nm depth of cut for case 1, case 2 and case 3 respectively and the formation of chips starts to occur from the depth of cut of 1.5nm for case 3. The force ratio also indicate the onset of ploughing at different depths of cut from 0.10nm-0.3nm.
Analytical Solution for Elastic and Elastoplastic Bending of a Curved Beam Composed of Inhomogeneous Materials
Authors: Nie Guo Jun , Zhong Zheng
Published: March 2013

We present an analytical solution for elastic and elastoplastic bending problem of a curved beam composed of inhomogeneous materials. Suppose the material is isotropic, ideally elastoplastic and it obeys Tresca’s yield criterion and the corresponding associated flow rule. And the elastic modulus and yield limit of the material vary radially according to general power functions. The expressions of stresses and displacements of a curved beam in both purely elastic stress state and partially plastic stress state are derived. The influence of material inhomogeneity on the elastoplastic behavior of a curved beam is demonstrated in numerical examples. Analytical solutions presented here can serve as benchmark results for evaluating numerical solutions.
Analysis of Elastic-Viscoplastic Behavior of Honeycomb Sandwich Panels Based on a Homogenization Theory for Free Edge Analysis
Authors: Koda Takayuki , Matsuda Tetsuya
Published: March 2013

In this study, the elastic-viscoplastic properties of aluminum honeycomb sandwich panels are investigated using a homogenization theory for free edge analysis. For this, the mathematical homogenization theory is reconstructed for elastic-viscoplastic analysis of honeycomb sandwich panels by introducing a traction free boundary condition. Moreover, the domain of analysis is reduced to a quarter using point-symmetry of internal structures of honeycomb sandwich panels. The present method is then applied to the analysis of macroscopic elastic-viscoplastic behavior and microscopic stress distribution of an aluminum honeycomb sandwich panel subjected to in-plane uniaxial compression. It is shown that the stress concentration arises at face/core interfaces, especially at intersections of core walls.
A Study on the Collapse Characteristics of CFRP Circular Member According to Collision Energy Conditions
Authors: Choi Ju Ho , Yang In Young , Hwang Woo Chae
Published: March 2013

Vehicle structure must be lightweight in order to improve fuel-efficiency and reducing exhaust fumes. The most important goals in designing automobile are safety and environment-friendliness. There are lots of studies on the crushing absorption energy of a structural members in automobile. The crashworthy behavior of circular composite material tubes subjected to axial compression under same conditions is reported in this paper. Energy absorption of CFRP circular member is affected by lamination conditions. Test was executed in order to compare the results to the energy absorption and collapse shape.
Effects of Thicknesses of Sheet and Adhesive Layer on Plastic-Bending of Adhesively Bonded Sheet Metals
Authors: Takiguchi Michihiro , Yoshida Tetsuya , Funaki Mitsuo , Yoshida Fusahito
Published: March 2013

In this paper, the effects of the thicknesses of sheet and adhesive layer on plastic forming of adhesively bonded sheet metals were investigated by experiments and the corresponding numerical simulation. The main conclusions obtained are as follows: (1) When the thickness of the adherends increases, the gull-wing bend of the bent sheet and the transverse shear deformation in the adhesive layer become larger, which in some cases the delamination occurs in the adhesive layer. (2) The gull-wing bend of the bent sheet becomes larger with increasing adhesive layer thickness, but conversely the shear strain in the adhesive layer becomes smaller.
Elasto-Plastic Property of High Strength Steel at Warm Temperature and its Springback
Authors: Saito Naoko , Fukahori Mitsugi , Hisano Daisuke , Ichikawa Yuya , Hamasaki Hiroshi , Yoshida Fusahito
Published: March 2013

Stress-strain responses of a high strength steel sheet of 980MPa grade under uniaxial tension and its springback in V- and U-bending were investigated at elevated temperatures ranging from 573-973K. The flow stress decreased drastically with the increase of temperature, from which it was expected that springback is reduced by warm forming. In V-bending test, however, the temperature effect on springback was not so clear, while in U-bending springback decreased with temperature rise. It was found that such difference in temperature dependent springback behavior between V- and U-bending was caused by stress relaxation which took place during unloading process.
Homogenized Elastic-Viscoplastic Behavior of Thick Perforated Plates with Pore Pressure
Authors: Ikenoya Kazutaka , Takano Noriko , Ohno Nobutada , Kasahara Naoto
Published: March 2013

The homogenized elastic-viscoplastic behavior of thick perforated plates with pore pressure is investigated for macro-material modeling. To this end, the homogenized behavior is analyzed using a FE homogenization method of periodic solids. It is assumed that the base metal of perforated plates exhibits the elastic-viscoplastic behavior based on Hooke’s law and Norton’s power-law. The resulting homogenized behavior is simulated using an elastic-viscoplastic macro-material model developed for pore-pressurized anisotropic open-porous bodies. It is shown that the macro-material model suitably represents the macro-anisotropy and macro-volumetric compressibility that are revealed by the FE homogenization analysis in the presence and absence of pore pressure.
A Comparison of EFGM and FEM for Nonlinear Solid Mechanics Problems
Authors: Kumar Rajesh , Singh Indra Vir , Mishra B.K. , Cardoso R. , Yoon J.W.
Published: March 2013

In this paper, element free Galerkin method (EFGM) has been applied to solve nonlinear solid mechanics problems using updated Lagrangian approach. The nonlinear equations have been solved using Newton Raphson method. An associative J2 flow rule and isotropic hardening has been used for the modelling of elasto-plastic material behaviour. Elastic predictor and plastic corrector algorithm has been used for the integration of incremental stress-strain relation. Few test problems involving large deformations have been simulated and the results obtained by EFGM have been compared with those obtained by FEM.
The Response of Circular Plates to Repeated Uniform Blast Loads
Authors: Yuen Steeve Chung Kim , Nurick Gerald , Ranwaha Nzudzanyo , Henchie Travis
Published: March 2013

This paper presents an experimental investigation into the response of circular Domex-700 MC steel plates to repeated uniform blast loads. The experiments are carried out on a ballistic pendulum for a 3mm thick test plate to witness up to five similar uniform blast loads. As expected, a trend of increasing permanent mid-point deflection is observed for an increase in charge mass and number of blast loads. In general, the results showed that the incremental increase in mid-point deflection decreases while the Vickers hardness of the plate increases with increasing number of blast loads.
An Investigation on the Nose Mass Abrasion of Projectile
Authors: Qian Fei , Wu Hai Jun , Huang Feng Lei , Wang Yi Nan
Published: March 2013

Based on the dynamic spherical cavity expansion theory of concrete and the analysis of experimental data, a mass abrasion model of projectile considering the hardness of aggregates, the relative strength of target and projectile and the initial impact velocity is constructed in this paper. The initial impact velocity is the most important factor of mass abrasion. The hardness of aggregates and the strength of projectile are also the significant factor of mass abrasion. But relatively speaking, the sensitivity of strength of projectile to mass abrasion is higher, which indicates that the effect of projectile material on mass abrasion is more dramatic than the hardness of aggregates.
Analysis for the Impact of an Engine Hood to a Radiator Support Frame in a Car Body Structure
Authors: Hung Ting Fang , Chang Chia Che , Chen Fuh Kuo
Published: March 2013

The dynamic behavior of a radiator support frame impacted by a free-falling engine hood was studied with the use of the 3-D finite element simulations. The engine room including an engine hood, a radiator support frame, and a hood ledge was modeled first. Taking computing efficiency and accuracy into account, approaches for selecting element size, cleaning up complicated features of CAD files were then studied. In order to make the simulations more efficient, the contact spot weld model was adopted. To further reduce the computing time, a theoretical model was also proposed in the present study to calculate the instantaneous angular velocity of the engine hood at the incipient impact to the radiator support frame. The engine hood free-falling tests were also conducted to validate the finite element simulations. The consistency between the experimental data and the simulation results confirms the validity of the finite element model constructed in the present study.
Analytical Modelling of a Clamped Sandwich Beam under Impact Loading
Authors: Liu Y. , Jiang W.Z. , Lu G.X.
Published: March 2013

This paper examines a projectile impact on a fully clamped sandwich beams with foam core. By modeling the sandwich beam into two perfect rigid-plastic beams connected by perfect rigid-plastic springs, different coupling mechanism for the responses of the two beams are constructed so that a complete solution considering small deformation is derived.
Blast Resistance of Clamped Cylindrical Sandwich Shells with Metallic Foam Cores
Authors: Jing Lin , Wang Zhi Hua , Zhao Long Mao , Shim V.P.W.
Published: March 2013

The deformation/failure modes and dynamic response of fully clamped cylindrical sandwich shells with aluminum foam cores subjected to air blast loading were investigated experimentally. A four-cable ballistic pendulum system was employed to measure the impulse imparted to the blast-loaded specimen. The deformation/failure modes of specimens were classified and analyzed, the effects of face-sheet thickness, core relative density, specimen curvature and mass of charge on the structural response of metallic sandwich shells were examined. Experimental results indicate that both the deformation/failure modes and the dynamic response of the sandwich shells are sensitive to the structural configurations and blast impulse. The experimental results are useful for validating theoretical predictions, as well as in engineering applications of cellular metal sandwich structures.
Experimental Study of Sandwich Panels Subjected to Foam Projectile Impact
Authors: Yahaya Mohd Azman , Ruan Dong , Lu Guo Xing
Published: March 2013

Similar blast loading characteristics can be obtained using impact of aluminium foam projectiles, which enables blast tests to be mimicked in a laboratory scale and in a safer environment. The purpose of this study is to determine the back-face deflection history of aluminium sandwich panels experimentally by aids of a laser displacement meter when panels are subjected to the impact of metal foam projectiles. This information was usually determined using finite element analysis (FEA) due to the difficulty in the experiment. The projectiles are cylindrical ALPORAS aluminium foam with diameter of 37 mm, length of 50 mm and nominal relative density of 10%. The sandwich panels consist of two 1 mm aluminium face-sheets and an aluminium honeycomb as the core. There are five different core configurations with a brand name of HEXCEL. The projectiles are fired towards the centre of the sandwich panels at different velocities using a gas gun. During the tests, a laser optical displacement measuring device is used to record the history of the back-face deflection experimentally. The deflection of the back-face is found to reach the maximum before coming to rest at a smaller value. The final back-face deflections of the sandwich panels show exponential relationship with the projectile impulse. The final deflections are compared with the deflection of monolithic plates with equal mass. The sandwich panels deflect less than the monolithic plate with an equal mass up to a critical value but continue to increase significantly afterwards. Care should be taken when using sandwich panels as protective structures against foam projectiles as beyond this point, the monolithic plates outperform the sandwich panels in absorbing the impact load.
Numerical Studies on the Blast-Resistant Capacity of Stiffened Multiple-Arch Panel
Authors: Chen Wen Su , Hao Hong
Published: March 2013

Blast-resistant structures are traditionally designed and fabricated with solid materials of heavy weight to resist blast loadings. This not only increases the material and construction costs, but also undermines the operational performance of protective structures. To overcome these problems, new designs with either new structural forms or new materials are demanded against blast loads. A multi-arch double-layered unstiffened panel has been proposed as a new structural form in the previous study[1]. Its performance has been numerically demonstrated better than other forms of double-layered panels in resisting blast loads. In this study, to further improve the effectiveness of the multi-arch double-layered panel in resisting blast loads, responses of a five-arch double-layered panel with rectangular stiffeners to blast loads are investigated by using finite element code Ls-Dyna. Peak displacement, internal energy absorption, boundary reaction forces and plastic strain are extracted and used as response parameters to demonstrate the effectiveness of stiffened panel on the blast resistance capacities. The numerical results show that the stiffened panel outperforms the unstiffened panel of the same weight on the blast-resistant capacity. The stiffened multi-arch double-layered panel has great potential applications in the blast-resistant panel design.
Possible Schemes to Reduce Nose Blunting of High-Speed Projectile into Concrete
Authors: He Li Ling , Chen Xiao Wei
Published: March 2013

High-speed projectile usually has significantly nose blunting which may decrease performance of projectile. Since the peeling of molten surface layer is the primary cause of mass loss of projectile, the projectile made of refractory material may reduce nose blunting. Two possible schemes to distribute refractory material in projectile are suggested in the present manuscript, i.e. layering refractory material outside the projectile nose surface and using material with gradient melting heat to make projectile nose. Based on one numerical model previously constructed by our team, both schemes are able to reduce nose blunting and enhance performance of projectile.
Preliminary Study of Sandwich Panel with Rotational Friction Hinge Device against Blast Loadings
Authors: Chen Wen Su , Hao Hong
Published: March 2013

Blast-resistant structures, such as blast door panel, are designed and fabricated in a solid way to resist blast loads. This not only increases the material and construction costs, but also undermines the operational performance of the protective structures. To overcome these problems, many researchers try to use high-strength materials and different structural forms in structural design to resist the blast and impact loads. This study introduces a new configuration of sandwich door panel equipped with rotational friction hinge device with spring (RFHDS) to resist blast loading. The RFHDS can help the panel equipped with RFHDS to recover, at least partially its original configuration after blast loading and maintain its operational and blast-resistance capability after a blast event. The energy absorption and blast loading resistance capacities of this proposed sandwich panel are numerically investigated by using finite element code Ls-Dyna. It is found that the proposed sandwich door panel with RFHDS can improve the blast-resistant capacity significantly. This new configuration of sandwich door panel can be employed to mitigate blast loading effects in structural panel design.
Resistance of Metal Sandwich Plates with Polymer Foam-Filled Core to Localized Impulse
Authors: Qin Qing Hua , Zhang Jian Xun , Wang T. , Wang Zheng Jin , Wang Tie Jun
Published: March 2013

This work examines the resistance of metal sandwich plates with corrugated core subjected to impulsive loading over central patch, in which effects of the low-density polymeric foam filling the interstices of the corrugated core on dynamic response of sandwich plate are studied to ascertain the enhancement of sandwich plate under impulsive loading. The face sheets and corrugated core are made of the same metal materials. The resistance of the metal sandwich plates with foam-filled cores is compared to that of the metal sandwich plates with unfilled core with the same weight. The results of comparison show that the foam-filled core does not make the overall deflection decrease compared with empty core, but it can make the sandwich plate achieve multifunctional advantages. The membrane method is employed to predict large deflection response of metal sandwich plates with foam-filled and unfilled cores under impulsive loading over a central patch. The theoretical predictions agree well with FE results of sandwich plates with foam-filled and empty cores.
Analysis on EFP Penetrating against Water-Partitioned Armor
Authors: Ju Yuan Yuan , Zhang Qing Ming , Yang Li , Gong Zi Zheng
Published: March 2013

Based on the experiments and numerical simulation of EFP penetrating against the water-partitioned armor, the velocity attenuation law of EFP in water is obtained by dimensional analysis. The relationship between the pressure of the water shock wave and the deflection of the latter target is established, which is validated by the experimental results. The influence of the water shock wave on the motion of EFP is also analyzed. The results in this paper provide remarkable benchmark in designing and optimizing the liner, as well as increasing the damage efficiency of the torpedo warhead.
3D SPH Modeling of Heterogeneous Materials Failure under Dynamic Loads
Authors: Ma Guo Wei , Yi Xia Wei , Wang Xue Jun
Published: March 2013

A mesh-free smoothed particle hydrodynamics (SPH) method is developed to simulate the failure of heterogeneous materials under different strain rates on 3D compression specimens. An elasto-plastic damage model is adopted to describe the pressure-sensitive strength behavior of the heterogeneous materials. Numerical simulations are performed for the constructed 3D artificial granite specimens. Results demonstrate that the proposed 3D modeling method can better resemble the rock microstructure and heterogeneity and it can be further used in other applications.
Experimental Study on Shear Strength Characteristics and Stress-Strain Relationship of Loess
Authors: Han Bo , Liao Hong Jian , Li Hang Zhou , Xiao Zheng Hua
Published: March 2013

This paper mainly concerns the non-linear strength characteristics of the loess. A series of consolidated undrained triaxial tests(CU test) and consolidated drained triaxial tests (CD test) of normal consolidation and over consolidation loess specimens are carried out by using the normal triaxial apparatus of strain control. The stress-strain relationship curves and strength characteristics of loess are investigated and analyzed. The results show that the stress-strain relationship obtained by CU tests appears strain softening, while the stress-strain relationship for CD tests appears strain hardening. Different failure modes have different stress-strain relationships. Furthermore, the results also show that the peak strength, residual strength and residual strength ratio change with the different confining pressure. Based on the triaxial shear tests of normal consolidated loess, the influences of over-consolidated loess on the stress-strain relationships and strength characteristic are discussed. Several conclusions obtained in this paper can be referenced for the loess experimental study.
Cellular Rod with Varying Cross-Section under Impact
Authors: Shen Chang Jian , Lu Guo Xing , Yu Tong Xi
Published: March 2013

The aim of this paper is to investigate the effect of the gradient on the cross-section on the dynamic behavior of the graded cellular rods under impact loading. A graded cellular rod, whose cross-section varies along the axial direction, is supposed to impinged by a rigid mass G with initial velocity . The shock theory proposed by Reid and Peng [1] is employed to establish the analytical model. Similar to the previous work [2], the analytical results show that only one shock front appears when the gradient is positive while two shock fronts exist in the rod with negative gradient. Closed form solution is found for the single shock (SS) mode, while finite difference method is employed to obtain solutions for the double shock (DS) mode.
Factors Affecting the Fracture Strength of Freestanding Diamond Films
Authors: Song J.H. , Lu F.X. , Hei L.F. , Li C.M. , Tang W.Z. , Chen G.C.
Published: March 2013

As an emerging brand new type of engineering material for a variety of important high technology applications, the deep understanding of the mechanical behavior of freestanding diamond films has become an emergent task of vital importance. Unfortunately the mechanical behavior of this brand new material is not fully understood. Effects that affect the fracture strength are still not very clear except that the fracture strength of freestanding diamond films is only depended on the grain size (film thickness), and is insensitive to the microscopic defects, and the strength is considerably higher when the nucleation side is in tension than that when the growth side is in tension. However, this is not the full story. Based on the experimental date accumulated in USTB (University of Science and Technology Beijing) for high power dc arcjet diamond films, other factors that may affect the fracture strength of freestanding diamond films are discussed in detail. Effects of the quality of the diamond films, impurities (nitrogen, hydrogen, non-diamond carbon etc.), film morphology and texture, on fracture strength are discussed. Effects of the deposition parameters are explained. Advantages for small amount of nitrogen addition, and for the use of higher substrate temperatures in the increase in fracture strength are demonstrated, which have already been applied in the mass production of tool grade freestanding diamond films. It is hoped that the present paper will be helpful for those who wish to understand and use this brand new type of engineering material
Preparation and Properties of Dy Doped La and Sc Solution of BiFeO3 Film
Authors: Qi Xi Wei , Zhang Xiao Yan , Wang Xuan , Sun Hai Bin , Qi Jian Quan
Published: March 2013

A series of Dy doped La and Sc solution of BiFeO3 thin films have been prepared by using spin-coating process on conductive indium tin oxide (ITO)/glass substrates, which a simple sol-gel possess is applied and annealed at 500°C. With the increase of content of Dy, the strongest peak (110) of La and Sc solution BiFeO3 film tends to further broaden. There is no second phase existence within the present Dy doping level. Cross section scanning electron microscope (SEM) pictures revealed that the thickness of BiFeO3 film was about 370 nm. For Dy doping level is 0.05, the maximum double remanent polarization 2Pr of as-prepared BiFeO3 thin film is15.44 μC/cm2. Image of atomic force microscopy indicated that the root-mean-square surface roughness value of as-prepared BiFeO3 thin film is 2.11 nm. The dielectric constant of as-prepared films tends to firstly increase and then decrease with the increase of Dy content
Dielectric and Ferroelectric Properties of Er2O3-Doped Bi4Ti3O12 Thin Films
Authors: Liu X.B. , Mei X.A. , Huang C.Q. , Liu J.
Published: March 2013

Er2O3-doped bismuth titanate (Bi4-xErxTi3O12, BET) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. Er-doping into BIT caused a large shift of the Curie temperature ( TC ) from 675°C to lower temperature and a improvement in dielectric property. The experimental results indicated that Er doping into BIT also result in a remarkable improvement in ferroelectric property. The Pr and the Ec values of the BET film with x=0.75 were 21 μC/cm2 and 80 kV/cm, respectively.
Preparation of NASICON Disk by Tape Casting and its CO2 Sensing Properties
Authors: Li Jian Guo , Liang Xi Shuang , Yin Cheng Guo , Liu Feng Min , Lu Ge Yu
Published: March 2013

In this work, NASICON-type disks with the formula, Na3Zr2Si2PO12 were prepared by non-aqueous tape casting method. The effect of the dispersant on the slurry viscosity was investigated, triethanolamine was found to be an effective dispersant for NASICON slurry. The correlation between the overall conductivity and the sintering conditions (temperature and time) for the NASICON disk was also studied. Green tapes were calcined at 900°C, 1000°C, 1100°C for 6h and 12h, respectively. Results revealed that the overall conductivity increased with the increasing of the sintering temperature and decreased with the increasing of the sintering time. The segregation of resistive monoclinic ZrO2 phase was examined to have a negative effect on the overall conductivity. The CO2 sensor using NASICON disk and Li2CO3-BaCO3 complex thick film was fabricated and evaluated, the sensitivity was about 82.9 mV/decade at 450°C.
Preparation and Properties of ZnO/ZAO Double-Layers Thin Films on the Substrate of Glass
Authors: Liu Gui Shan , Wang Ming Jun , Hu Zhi Qiang , Jiang Yan Yan , Shen Xiao Yue
Published: March 2013

Aluminium zinc oxide(ZAO) thin films were deposited on soda-Lime-Silica glass substrate by middle frequency power magnetron sputtering. Then zinc oxide(ZnO) thin films were deposited above ZAO thin films by electrochemical deposition method at different time. ZAO thin films and ZnO/ZAO double-Layers thin films were characterized by X-Ray diffraction(XRD) and scanning electron microscope(SEM). A four-Point probe was used to determine the resistivity of the films. The optical transmittance of ZAO films and ZnO/ZAO films was measured by UV-Visible spectrum. The results represent that the transmittance of ZAO/ZnO thin films decreases gradually with deposition time increasing. When the deposition time is 5 minutes, the maximum transmittance of ZnO/ZAO films reaches to 85% at wave length from 400nm to 600nm, and the thickness and resistivity of thin film are 610nm and 2.04×10-3Ω•cm, respectively. However, the thickness and resistivity are highest when the deposition time is 20 minutes, which reaches to 808nm and 1.2×10-2Ω•cm. Meanwhile, the lattice constants a and c of ZAO/ZnO thin films demonstrate an expansion with deposition time increasing. In essence, good-Quality double-Layers thin films of ZnO/ZAO play an important role in CIGS solar cells.
Electrochemical Performance of V2O5 Nano-Porous Aerogel Film
Authors: Zhang Li Feng , Wu Guang Ming , Gao Guo Hua , Yang Hui Yu
Published: March 2013

Nano-porous V2O5 aerogel films were prepared by dip-coating vanadium oxide sol onto ITO substrate, using V2O5 powder, Benz alcohol, Isopropanol as precursor materials. The nano pores were characterized by scaning electron microscope (SEM). The electrochemical properties were investigated by chronopotenyiometry(CP) and cyclic voltammograms(CV). Results showed that this porous V2O5 aerogel film exhibited good cycling stability with initial discharge capacity of 143mAh/g and 128 mAh/g after 18 cycles, staying 89.5 % of the initial discharge capacity, at a charge/discharge current density of 200 mA/g.
Preparation and Characterization of Cube-Textured Ni-5 at.% W Substrates for Coated Conductors
Authors: Chen Xing Pin , Zhang Jing Peng , Chen Xue , Ji Yong Bin
Published: March 2013

The goal of present study was to manufacture and characterize the Ni-5 at.% W alloy substrates for coated conductor applications with a strong cube texture. Cube-textured Ni-5 at.% W alloy substrates were fabricated by heavy cold rolling (98%) and a high temperature annealing (1200°C). From the EBSD and XRD analysis of the fully recrystallized tapes, the cube texture component in the tape was found to reach a proportion as high as 99.5% within a tolerance angle of less than 9o, while the FWHM (full width at half maximum) values of the out-of-plane and in-plane textures are about 5.8o and 6.9o, respectively. Moreover, the grain size distribution is homogeneous, and there is a large amount of low angle grain boundaries (95.6%). This process is very suitable for preparation of substrates for coated conductors.
Fabrication and Properties of Al-Cr Coatings on the Inner Wall of Steel Pipe by Mechanical Alloying Method
Authors: Tian Zhong Qing , Zhang Guo Xing , Huang Wei Jiu , Zhu Yu Kai
Published: March 2013

Surface coatings; Mechanical alloying; Microstructure; Tribological properties Abstract. The mechanical alloying method process has been innovatively used to prepare Al-Cr coating on the inner wall of steel pipe. The coating thickness was measured from all samples using optical and Scanning Electron Microscope was used to observe the surface microstructure of Al-Cr coating. Microhardness was analyzed by Digital Microhardness Tester. A wear test was performed by high speed reciprocating friction testing machine. The results show that the coating thickness is 20μm and 26μm at the rotating speed of 200 rpm and 300 rpm, respectively. The surface morphology is significantly influenced by the the rotating speed. When the rotating speed was 200 rpm, a heterogeneous coating surface consisting of flattened particles produced by cold welding with less interparticle contact is formed. When the rotating speed was 300 rpm, the coating became denser and a smooth, highly consolidated and dense coating is formed. The hardness of the Al–Cr coating prepared at 200 and 300 rpm are about 250 Hv and 270 Hv. The friction coefficient of the Al–Cr coating prepared at 200 rpm are about 0.37, 0.39 and 0.24 at the frequencies of 3, 4 and 5 Hz. The friction coefficient of the Al-Cr coating prepared at 300 rpm are about 0.3, 0.18 and 0.28 at the frequencies of 3, 4 and 5 Hz.
Crack Formation and Distribution of SiC Coating Prepared by CVD on Carbon/Carbon Composites
Authors: Zhu Jun Liang , Shi Xiao Hong , Li He Jun , He Zi Bo
Published: March 2013

In order to further study the cracks initiation and distribution mechanism of SiC coating, then optimize the coating structure and composition on surface of C/C composites, CVD method is used to deposit SiC coating on C/C composites and pyrolytic carbon. Through the analysis on the reasons of cracks initiation via SEM, the influence of different kinds of substrates and the toughening of SiC whisker on the cracks initiation and distribution are researched. The results show that the cracks easily form in the area near the defects and sample edge, and the cracks also mainly distribute in the direction which are perpendicular to the first fiber layer. Compared with pyrolytic carbon matrix, cracks on C/C composites matrix are width and numerous, and SiC whisker toughening coating can significantly reduce the number of cracks.
The Preparation and Characterization of Copper Silicon Alloy Films
Authors: Feng Xiu Li , Li Bi Jin
Published: March 2013

In this paper, the fabrication,physical and electrochemical properties of copper silicon alloy film were systematically studied and the optimized preparation conditions were obtained.When KrF excimer laser (λ=248 nm) repetition rate is 10Hz, laser energy is 260mJ,vacuum is 10-5Pa, target and substrate revolution per minute of target is 10, substrate temperature is 300°C and deposition time is 1.0h, as-deposited film from Si target and Cu substrate is obtained by pulsed laser deposition.The XRD pattern showed that as-deposited film is cubic stucture of Cu9Si, SEM images showed that as-deposited film has regular surface, particle size is about 300nm and particle size distribution is in narrow range.And the same time the electrochemical properties of as-deposited film showed good cycleability.
Preparation and Salt Spray Corrosion Resistance of Ni/BN and NiCrAl/BN Coatings
Authors: Zhang Feng , Huang Chuan Bing , Liu Wei , Zhou Kui , Zhang Wen Ting , Du Ling Zhong , Zhang Wei Gang
Published: March 2013

Ni/BN and NiCrAl/BN abradable sealing coatings used in turbo engines were prepared by plasma spray technology. The phases and the microstructures of the coatings were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM). Corrosion behaviors of these coatings were investigated with open-circuit potential (OCP) and salt spray corrosion test. The results showed that the NiCrAl/BN possess better corrosion resistance as compared with Ni/BN.
Microstructure and Properties of CrN Multilayer Coatings
Authors: Guo Ting , Wang Chen , Yang Bing
Published: March 2013

The CrN and Cr/CrN multilayer coatings with different modulation ratios were deposited onto stainless steel and cemented carbide substrates by arc ion plating technology. The phase composition, surface and cross-sectional morphology were analyzed by using X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscope (SEM). The micro Vickers was used to test the hardness. The results indicated that the coatings were mainly composed of Cr, CrN and Cr2N phase. No columnar grain growth was observed in Cr/CrN multilayer coatings, and the crystalline orientation of the Cr/CrN multilayer was different from CrN film. There exists an optimal modulation ratio of 10:10 to the coating deposition, under which the surface was compact and smooth with a relatively lower roughness. The coatings hardness increased with decreasing modulation ratio and the hardness of CrN+Cr2N was lower than that of single CrN phase.
Preparation and Properties of Asymmetric Porous Aluminium-Oxide Ceramic Hollow Fibre Membranes
Authors: Mu Hai Bo , Hao Gui Zeng , Li Xiao Wei , Meng Bo
Published: March 2013

Asymmetric porous aluminium-oxide ceramic hollow fibre membranes have been prepared by the phase inversion / sintering technique. The effect of non-solvent such as ethanol, isopropanol and ethylene glycol monomethylether(2-methoxyethanol) on the geometry and performance of hollow fibres was investigated. Morphologies of Al2O3 ceramic hollow fibre membranes were characterized using a scanning electron microscope (SEM). The effective porosity and the mechanical strength were determined by Archimedes method, and three point method, respectively. The prepared Al2O3 hollow fibre membranes show the asymmetric structure with a finger-like layer and a sponge-like layer. The effective porosity of the prepared hollow fibre membranes exceeds 47%, and the bending strength of the hollow membranes exceeds 63 MPa. The Al2O3 hollow fibre membranes with moderate permeation characteristics for gas and pure water are prepared by the introduction of nonsolvent in membrane casting solution. The separation factors of H2 to N2 or CO2 of the hollow fibers with nonsolvent are over 2.0.
Effects of Al2O3 Nanoparticles on Microstructure and Performance of Ceramic Coatings by Micro-Arc Oxidation
Authors: Yin Yu Jun , Li Shu Hua , Shen Da Wei , Zu Yuan Yuan , Qu Chang Zheng
Published: March 2013

A dense ceramic oxide coating approximately 45 µm thick was prepared on a Ly12 aluminum alloy by micro-arc oxidation in an alkali-phosphate electrolytic solution. Coating thickness and surface roughness (Ra) were measured after the coating had been synthesized. The effects of Al2O3 Nanoparticles in electrolyte on phase composition, microstructure and microhardness of the micro-arc oxidation ceramic coatings on Ly12 aluminum alloy were investigated by means of XRD, SEM and hardness experimentation. The results show that the ceramic coatings become more dense and its microhardness increased by adding Al2O3 Nanoparticles in electrolyte. In addition, the roughness of the micro-arc oxidation ceramic coatings is obviously improved by addition of Al2O3 Nanoparticles.
Influence of Single Layer-Thickness on Residual Thermal Stresses in Sm2Zr2O7/YSZ Thermal Barrier Coatings
Authors: Hu Ren Xi , Chen Xiao Ge , Li Gang
Published: March 2013

In this paper, influence of single-layer thickness on residual stresses in Sm2Zr2O7/YSZ thermal barrier coating was analyzed by finite element method. Results show that the radial stress remains stable in x range 0-12mm, and it decreases abruptly at edge of the sample. The distribution of axial stress resembles that of radial stress, the shear stress increase abruptly at edge of sample. In three typical residual stresses, radial stress has the highest value, axial stress and shear stress can be ignored. The best thickness combination of Sm2Zr2O7/YSZ TBCs should be 0.1mm-NiCoCrAlY layer, 0.05-0.1mm -TGO, 0.1mm-YSZ and 0.9mm-Sm2Zr2O7
Influence of Hydrogen Dilution on Microstructure of μc-Si: H Films
Authors: Chen Lan Li , Yu Jia Hui , Wang Sheng Zhao , Shi Ming Ji
Published: March 2013

The influence of hydrogen dilution (D) on glass/stainless steel-based intrinsic amorphous/microcrystalline silicon thin film prepared was investigated by PECVD technology. The crystallization ratio and grain size of the silicon thin film at different hydrogen dilution is studied. The results reveal that the crystallization ratio and grain size of silicon thin film changed along with D. The crystallization ratio and grain size of the silicon thin film become larger when D is higher. However, the deposition rate is slow when the D value is too high. On this work, optimal μc-Si:H can be obtained at D of about 98% in the suitable experimental conditions.
Environmental Oxidative Degradation and Biodegradation of Eco-Benign Plastics
Authors: Tang Xin De , Zhou Jing Lun , Lu Hai Rong , Han Nian Feng
Published: March 2013

Polyethylene (PE) has found widespread use as a packaging material. Plastics waste disposal, as one of the serious environmental issues, has caused much criticism. The environmental oxidative- and bio- dual degradable linear low-density polyethylene (LLDPE) samples containing Eco-Benign Plastics (EBP) pro-oxidant additives were submitted to an investigation aimed at evaluating their preliminary oxidative degradation in natural environment or accelerated oven aging and their ultimate biodegradation in solid incubation substrate or soil composting conditions. Original and test samples submitted to abiotic oxidation including photo degradation and thermal degradation were characterized by means of FT-IR and GPC. Biodegradation test simulating soil burial and composting conditions reveals that the biodegradation degree exceeded 30%. The degradation process is accompanied by a dramatic change in the structural characteristics of the test samples. It is clear that LLDPE-EBP formulations are effective in promoting the oxidation and subsequent biodegradation of polyethylene in natural and soil environment.
Ultrasonication Induced Synthesis of Zn/ZnO Core-Shell Structures
Authors: Ma Qing Lan , Xiong Rui , Huang Yuan Ming
Published: March 2013

Metal-semiconductor Zn/ZnO core-shell structures are fabricated by a simple ultrasonic process of raw Zn particles in water. The crystal structure, morphologies and fluorescence of the Zn/ZnO core-shell particles are characterized with X-ray diffraction (XRD), scanning electronic microscopy (SEM) and fluorescence spectrophotometer. The XRD pattern confirms that the shells of the Zn/ZnO core-shell particles are composed of Wurtzite ZnO crystals. The SEM study clearly exhibits the formation of ZnO on the surface of Zn spheres. The room-temperature fluorescence spectra have been observed a strong ultraviolet (UV)-visible emission at 381 nm and a yellow-green deep-level emission at about 534 nm. It is noted that the very broad green emission at 510 nm appears in the ZnO crystals with increasing the content of ZnO shell on the surface of Zn spheres. Furthermore, a possible formed mechanism of ZnO shells on the Zn core is discussed.
Two-Dimensional Silicon Nitride Photonic Crystal Band Gap Characteristics
Authors: Chen Shou Xiang , Yang Xiu Lun , Meng Xiang Feng , Wang Yu Rong , Wang Lin Hui , Dong Guo Yan
Published: March 2013

Plane-wave expansion method was employed to analyze the photonic band gap in two-dimensional silicon nitride photonic crystal. The effects of filling ratio and lattice structure type on the photonic band gap were studied. The results showed that two-dimensional dielectric cylinder type silicon nitride photonic crystal only has TE mode band gap, while, the air column type photonic crystal has complete band gap for TE and TM modes simultaneously. The distribution of band gap can be influenced by the filling ratio of dielectric materials and the lattice type. It is shown that the triangular lattice structure is much easier to form band gap than square lattice structure.
Dielectric Properties of Li2MgTiO4 Ceramic System at Microwave Frequency
Authors: Yao Guo Guang , Ma Hong , Tian Xiu Lao
Published: March 2013

The rock-salt structure Li2MgTiO4 ceramics were prepared by reaction sintering method and its microwave dielectric properties were investigated. The crystal structure and microstructure were analyzed using X-ray diffraction and scanning electron microscopy techniques. XRD showed that main phase Li2MgTiO4 combined with minor second phase Mg2TiO4 were formed after 1250-1350 oC sintering. The microwave dielectric properties of Li2MgTiO4 ceramics exhibited a significant depend on the density and to some extent on the morphology of the grains. Li2MgTiO4 sintered at 1325 oC/5h exhibits microwave dielectric properties of εr=13.2, Q×f=44 711 GHz (at 9.9 GHz ) and τf=-31ppm/oC.
Morphology and Luminescence of ZnS Quantum Dots Encapsulated in UV-Curable Sealant
Authors: Ma Qing Lan , Xiong Rui , Huang Yuan Ming
Published: March 2013

Zinc sulfide (ZnS) quantum dots (QDs) were encapsulated in ultraviolet (UV)-curable sealant upon the UV irradiation of the 365 nm. The QDs-sealant films were characterized with scanning electron microscopy (SEM), UV-visible spectroscopy and photoluminescence (PL) spectroscopy. Based on SEM analysis, the QDs encapsulated in UV-cured sealant clearly exhibited the formation of different size aggregates with a strong chemical bondage between the QDs and sealant. Optical absorption spectra showed strong red-shift for the QDs encapsulated in the UV sealant due to the aggregates of the QD nanoparticles. Room-temperature PL spectra have demonstrated that the pure QDs showed green emission at 517 nm while QDs-sealant film gave off cyan-blue PL with a strong and broad peak at 485 nm. Our results have demonstrated that the PL efficiency of QDs encapsulated in UV sealant matrix is higher than that of the QDs or UV sealant due to passivation of surfaces.