bluuebunny/crossref_metadata_2025 huggingface dataset:
The Optimization Research of Geo-Environmental Monitoring Image Fusion Based on Framelet
Authors: Li Xiang , He Yue Shun , Zhan Xuan
Published: June 2010

As various types of geo-environmental monitoring image instrument are sprouting up, there are more and more materials based on infrared, visible light, dim light, remote sensing image, using various types of image data to improve detection accuracy and efficiency of the environment has become a focus for environmental technical personnels. From the perspective of information fusion, as well as comparing framelet and the traditional wavelet features, the environmental image fusion algorithm based on framelet transform is proposed, by choosing suitable integration rules in different directions, the amount of information is further improved. The experiments show that this algorithm has better effects for small target detection with infrared and visible light images.
Boiling Heat Transfer on Small Diameter Tube Bundle
Authors: Adom Ebenezer , Kew Peter , Cornwell Keith
Published: June 2010

An experimental study has been carried out using a tube bank representing a section of a tube bundle. The bank comprised 3 columns each of 10 stainless steel electrically heated tubes of 3mm outside diameter with pitch to diameter ratio of 1.5 in an in-line arrangement. Flow rate through the test section was controlled. Each tube in the central column was instrumented to permit determination of the tube temperature and heat flux, hence permitting calculation of the heat transfer coefficient. These tests were carried out using distilled water at nominal atmospheric pressure over a range of heat fluxes between 6 - 21 kW/m2. Results of the heat transfer tests are presented and compared with correlations used for conventionally sized bundles. Correlations developed for large tube bundle overestimate the experimental results.
Durability of Aluminum Alloy/Rubber Joints in Corrosive Environment
Authors: Mori Masatoshi , The Nguyen Loc , Itoh Goroh , Itoh Nobuhide , Shimada Yasuhiro
Published: June 2010

In automobiles, a suspension bush, a set of aluminum parts connected to each other via rubber, is mounted into the suspension members to link the body to the wheels, and realizes hard and soft mounts contributing both to the stabilization during high speed driving and to absorbing the shock from the road. However, decohesion of the aluminum part from the rubber occurs occasionally, arising from the interface corrosion of aluminum, which deteriorates the performance of the vehicle directly. In this study, effects of alloy composition and processing route on this kind of corrosion will be investigated. Also, development of a new corrosion test that shortens the time for the test will be attempted.
Structure of Porous Copper Fabricated by Unidirectional Solidification under Pressurized Hydrogen
Authors: Du Hao , Qi Jian Zhong , Wu J.X. , Du S.Q. , Xiong Tian Ying
Published: June 2010

Porous copper with elongated cylindrical pores were fabricated by a unidirectional solidification method in a mixture of hydrogen and argon with high pressures. The porous copper with longitudinal pores and radial pores were compared on structure. The effect of both hydrogen pressure and argon pressure on structure of the porous copper including pore size, pore density, and porosity was investigated. The reason for the effect is explained.
Nitriding of a Nb-Microalloyed Thin Strip Cast Steel at 525°C
Authors: Xie Kelvin Y. , Zhu Chen , Cairney Julie M. , Ringer Simon P. , Killmore Chris R. , Barbaro Frank J. , Williams James G.
Published: June 2010

This study investigates the effect of N diffusion on a Nb-microalloyed steel made by twin roll casting at 525o C in a KNO3 salt bath. Nitriding up to 4 h increases the yield strength of the steel by ~50% with only a small drop in ductility, while 6 hours of nitriding causes brittle fracture. The improved mechanical performance after 4 hours of nitriding is thought to be a combined effect of solid solution strengthening of N diffusion and dispersion strengthening from extremely fine Nb-rich precipitates. Coarse features along grain boundaries consistently observed in steel nitrided for 6 hours are considered to be responsible for brittle fracture in samples nitrided for longer.
Devitrification Studies of Mg60Cu29Gd11 Bulk Metallic Glas
Authors: East Daniel R. , Reid Mark H. , Gibson Mark A. , Dippenaar Rian J. , O'Donnell Robert G.
Published: June 2010

The application of moderate cooling rates to metal alloys of certain composition can generate metals that exhibit an amorphous microstructure on a bulk scale. This phenomenon is related to the avoidance of the nucleation of the competing crystalline phases associated with the alloy during solidification. This work describes the devitrification behaviour of the bulk glass forming Mg60Cu29Gd11 system through the use of a number of analytical techniques including DSC, laser confocal microscopy, SEM and XRD. Attention is drawn to the correlation between the more common analytical techniques and the observation of phase transformations on the surface of the metal, evident using a laser scanning confocal microscope fitted with a heating stage.
Low Temperature Synthesis of Silicon Nanocrystals Fabricated by PECVD and their Optical Property
Authors: Jang D.H. , Gu Gil Ho , Park Chan Gyung
Published: June 2010

Bulk silicon is the material for microelectronics fabrication such as memory device. However, its optical properties are poor due to its indirect band gap. Since the photoluminescence from porous silicon at room temperature was first reported by Canham, silicon nanostructures have attracted considerable interest due to their potential applications in optoelectronic devices such as Si-based LEDs, solar cell. In the present study, the nanocrystalline silicons were synthesized by non-thermal plasma from gas phase. And Nitrogen plasma was applied to reduce the nonraidative recombination center which related to the emission efficiency. To confirm the effect of nitrogen plasma, the compositional, electrical and optical analysis of silicon nanocryatals layer were also investigated.
An Investigation on Precipitation Behaviour of Cu-Rich Phase in Super304H Heat-Resistant Steel by Three Dimensional Atom Probe
Authors: Chi Cheng Yu , Dong Jian Xin , Liu Wen Qing , Xie Xi Shan
Published: June 2010

Super304H, a Cu-containing 18Cr-9Ni-3CuNbN heat-resisting steel is wildly used as an superheater/reheater tube material for ultra-super-critical (USC) power plants all over the world. It is recognized that the Cu-rich phase is an important strengthening phase for Super304H. However, the detail precipitation behaviour and its strengthening effect are still not very clear. Investigated material was taken from routine production and was aged at 650°C for different times. The precipitation of Cu-rich phase in Super304H was studied by three dimensional atom probe (3DAP) and TEM. Experimental results show that Cu-rich clusters have been formed at very early stage of 650°C aging. The Cu-rich particle images have been clearly caught just after 650°C aging for 5h. The Cu atoms gradually concentrate to Cu-rich particles and the other elements (such as Cr, Ni etc) diffuse away from Cu-rich particles to γ-matrix with the increasing of aging time. The Cu-rich particle size and its density have been determined as a function of aging time. Cu-rich particles still keep nano-size and distribute homogenously in grains even after long time (1,000h) aging, which is one of the most important reasons for keeping good strength of Super304H heat-resistant steel at high temperatures.
Combined Field and Thermionic Emission Process in ZnO Nanostructure Cold Emission Cathode
Authors: Zhang Qi , Qi Jun Jie , Zhang Yue , Liao Qin Liang , Li Xin
Published: June 2010

With recent research, the author intends to outline the framework of the field emission of ZnO nanostructures. However, many groups’ reports ignored the thermionic emission process in the low electric field. A recently published field emission cathode parameter extraction method [X. He et al., J. Appl. Phys. 102, 056107(2007)] provided unambiguous and reliable cathode. The method utilized Richardson-Laue-Dushman law in low electric field and Fowler-Norheim equation in high electric field to solve a one-dimensional model including both thermionic and field emission. The model gave a much better agreement with the experimental data of ZnO cathode under the applied field and acquired a revised surface field enhancement factors and work function of ZnO cathode in the electron emission process.
Texture Change of Severe Plastically Deformed Al Alloy Sheets
Authors: Kim In Soo , Nam Su Kwon , Akramov Saidmurod
Published: June 2010

Aluminum alloy sheets have lower formability (r-value) than low carbon steel sheets in fully annealed condition. Because the texture of fully annealed aluminum alloy sheet is mainly consists of cube component {001}<100>, which shows low formability. Asymmetric rolling, one of the severe plastic deformations, gives rise to shear deformation texture through the Al sheet thickness. In this paper, the changes of texture components after the severe deformation and subsequent heat treatment in Al sheet were observed. The change of the formability after the severe plastic deformation and subsequent heat-treated Al sheets have been analyzed with the change of texture of Al alloy sheets.
Cyclic Softening of Cu-Ni-Si Alloy Single Crystals under Low-Cycle Fatigue
Authors: Fujii Toshiyuki , Kamio Hiroshi , Sugisawa Yoshifumi , Onaka Susumu , Kato Masaharu
Published: June 2010

Cu-2.2wt%Ni-0.5wt%Si alloy single crystals were grown by the Bridgman method and aged at 723 K for 10 h to form Ni2Si precipitates. Fully reversed tension-compression fatigue tests were conducted on the aged single crystals with a single slip orientation under constant plastic-strain amplitudes at room temperature. Cyclic softening occurred at plastic-strain amplitudes between 2.5x10-4 and 2.5x10-2. Using the maximum stress amplitude in each cyclic hardening/softening curve, a pseudo cyclic stress-strain curve (CSSC) was obtained. The CSSC was found to exhibit a plateau region with a stress level of about 167 MPa. Transmission electron microscopic observation revealed the formation of persistent slip bands (PSBs) in the plateau regime. It was found that the Ni2Si precipitate particles were intensively sheared by glide dislocations within the PSBs and were eventually re-dissolved into the Cu matrix. The macroscopic cyclic softening can be attributed to the local softening induced by the re-dissolution of the Ni2Si particles in the PSBs.
Evidence of Lath Martensite in High-C Japanese Sword Produced from Tamahagane Steel by Tatara Process
Authors: Das Ananda Kumar , Ohba Takuya , Morito Shigekazu , Yaso Muneo
Published: June 2010

Field Emission Scanning Electron Microscopy with Electron Back-Scattering Diffraction (SEM-EBSD) and Optical microscopy were used to point out the microstructural features of a Japanese sword prepared from tamahagane steel using traditional method. A lath martensite structure, which is usually characterized by packet and block in a prior austenite grain, existed both on the surface and the cross-section of the sword. SEM-EBSD study revealed that the development of prior austenite grain and packet were not much distinctive but the blocks within the packets were fairly observed. It was found that the packet size increased with the prior austenite grain size but the increment was small. Vickers micro-hardness measurement revealed that the sharp end was comparatively harder than other sections of the sword. EPMA study showed that the average carbon content of the sword was around 1 mass% along with a variety of non-metallic inclusions. Formation of lath martensite structure in such high carbon steel is remarkable but comparable to 0.6 mass% carbon ordinary steel. It was realized that the traditional method of preparation using tamahagane as well as the higher content of carbon provided the extraordinary features to the Japanese sword different from the ordinary steel.
Formation of Primary Intermetallic Compounds in Sn-Ag-Cu Alloys
Authors: Takamatsu Yoshiko , Esaka Hisao , Shinozuka Kei
Published: June 2010

Sn-Ag-Cu alloys are considered one of the most favorable lead-free solder systems. In slowly-cooled eutectic Sn-Ag-Cu alloys, sometimes large primary Ag3Sn or Cu6Sn5 intermetallic compounds (IMCs) form. These IMCs may affect the mechanical properties of solders. However, explanations for the formation of these IMCs are still not clear. This study deals with interrupted tests in order to clarify the nucleation of IMCs in the liquid phase. In this study, Sn-4.41Ag-0.63Cu and Sn-3.30Ag-1.47Cu alloys were prepared. According to the thermodynamic calculation, Pandat, the equilibrium solidification paths are described as follows: Sn-4.41Ag-0.63Cu :L → primary Ag3Sn → binary eutectic (Ag3Sn +Sn) → ternary eutectic; Sn-3.30Ag-1.47Cu :L → primary Cu6Sn5 → binary eutectic (Cu6Sn5 + Sn)→ ternary eutectic. The actual solidification process was different from the estimation from the equilibrium phase diagram. In the case of Sn-4.41Ag-0.63Cu, only Ag3Sn grew as a primary phase in the liquid, while in the case of Sn-3.30Ag-1.47Cu, not only primary Cu6Sn5 but also pseudo-primary Ag3Sn grew in the liquid. Ag3Sn may nucleate easily in the liquid phase, but Cu6Sn5 would not nucleate in the liquid.
Electromagnetic Continuous Casting Process for Near Net Shape Aluminum Alloy Billet
Authors: Kim Jong Ho , Kim Myoung Gyun , Park Joon Pyo , Lee Gyu Chang , Kim Ju Bum
Published: June 2010

A new method and apparatus for the fabrication of high-quality, near net shaped aluminum alloy billets is developed by the combination of continuous casting and electromagnetic casting/stirring technique. Traditional machine for continuous casting process involves round, square and rectangular billets; therefore it requires additional multistep forging process to fabricate final products of complicated shape. A new process for the fabrication of near net shaped aluminum billets offers some advantages: the process of extrusion and forging is simplified and the cost of plastic working can be greatly reduced. In order to reduce the peculiar problems such as surface crack and internal defect due to inhomogeneous heat transfer of solidified billets, electromagnetic casting and stirring technique were adopted. The effect of electromagnetic field was compared by observing the microstructure of billets. Grain refinement of aluminum billet was clearly observed by applying electromagnetic field to continuous casting process.
Numerical Simulation of Grain Selection Behavior of Single Crystal Ni3Al Based Superalloy Casting
Authors: Pan Dong , Xu Qing Yan , Liu Bai Cheng
Published: June 2010

Ni3Al based superalloy has recently been used for the single crystal gas turbine blade. The grain selection behavior in grain selector directly determines the casting’s final microstructure and properties. A mathematical model based on the modified CA-FD method was developed for the three-dimensional simulation of directional solidification process of Ni3Al based single crystal superalloy castings. The microstructure evolution was simulated with the modified Cellular Automaton method. The grain selection process in the grain selector and final microstructure of casting were simulated. The results indicate that the stray grain is easy to nucleate at the middle part of the pigtail because of the discontinuous mushy zones formation. This agrees with previous published experimental results. Based on simulated results, a newly designed grain selector with optimized geometry was proposed to avoid stray grains.
A Monte Carlo Simulation of Melting in Prototype Crystal
Authors: Sato Kazufumi , Takizawa Satoshi , Mohri Tetsuo
Published: June 2010

We investigate the melting transition of the solids interacting through a simple pairwise potential using conventional and Wang-Landau Monte Carlo simulation. In the simulations, the atomic displacement is discretized for describing the atomic vibration and each atom is confined within its Voronoi polyhedron. The melting point can be uniquely determined by Wang-Landau approach while the temperature hysteresis inevitably appears in the conventional method. The obtained results show typical feature of first-order transition which is the discontinuous change in the internal energy. We discuss the relation between the limit of superheated state and intrinsic instability of the system through the comparison with two results.
Three-Dimensional Modeling and Simulation of Dendrite Morphology of Cast Mg Alloys
Authors: Huo Liang , Han Zhi Qiang , Liu Bai Cheng
Published: June 2010

A three-dimensional (3-D) cellular automaton (CA) model for simulating the dendrite morphology of cast Mg alloys has been developed. In the model a technique based on two sets of mesh is utilized to perform the simulation to reproduce the texture of Mg dendrites. The CA calculation is performed using a set of mesh that is defined by the hexagonal close-packed (HCP) crystal lattice, and other computations are carried out by using a cubic mesh. The two sets of mesh are coupled by using interpolation method. The kinetics of the solid-liquid interface is obtained directly by the difference between local equilibrium composition and local actual composition given by the solute transport equation. The model was used to simulate 3-D columnar growth of sixteen grains and 3-D equiaxed growth of a single dendrite of AZ91D alloy. Permanent mold castings of AZ91D alloy were produced and sampled for optical metallographic examinations, and the simulated results were compared with the metallographic results.
Finite Element Analysis of Multi-Pass Equal Channel Angular Extrusion/Pressing Process
Authors: Krishnaiah A. , Kumaran K. , Uday Chakkingal
Published: June 2010

Equal channel angular extrusion (ECAE) is a severe plastic deformation (SPD) method for obtaining bulk nanostructured materials. The ECAE die consists of two equal channels that intersect at an angle, usually between 90° and 135°. In the present study, the plastic deformation behavior of the Cu during the ECAE process with 120° die through multiple passes was investigated. Finite element modelling was included in order to analyze the deformation behavior as the material passes through the die. In order to perform the FEM simulations the properties of the commercial purity Cu have been selected.
Molecular Dynamics Based Observations of Grain Boundaries and Lattice Defects Functions in Fine Grained Metal
Authors: Kameda Toshihiro , Zhang Bao Rong
Published: June 2010

In order to study the characteristics of fine grained polycrystalline metals, it is important to recognize the function of grain boundaries (GB), crystal defects such as dislocation and/or nanoscale voids, since the fraction of GB increases as grain sizes decreases, the deformation process of these metals could be different from those in larger size grains. In this study, we first evaluate the hypothesis that GB behaves as dislocation source and sink during the deformation of fine grained metal, then compare the behavior between GB and a tiny defect from the view point of dislocation source and sink phenomena. Since continuous dislocation supplies could be considered as the key issue to improve the toughness of fine grained metals, this concept could be helpful to design next generation polycrystalline metals.
The Effect of Cobalt Addition on Structural and Magnetic Properties of Electrodeposited Iron-Platinum Nanocrystalline Thin Films
Authors: Teh Seoh Hian , Yaacob Iskandar Idris
Published: June 2010

Iron-Platinum (Fe-Pt) and Cobalt-Iron-Platinum (Co-Fe-Pt) nanocrystalline thin films were deposited on brass substrates using a single bath electrodeposition system. The effects of addition of various concentrations of cobalt towards the composition, crystallographic structure, microstructure and magnetic properties of the Fe-Pt alloy films were investigated. Ammonium tartrate and ammonia solution were used as complex forming additives to stabilize the Fe2+ and Co2+ ions and to enhance co-deposition with platinum complexes. The as-synthesized thin films were characterized by energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and alternating gradient magnetometry (AGM). EDS results showed that cobalt was preferentially deposited compared to iron during Co-Fe-Pt film electrodeposition. SEM results showed that the microstructure of the films consisted of spherical granules. XRD showed formation of disordered face-centered cubic (fcc) Fe-Pt phase and all peaks were shifted to slightly higher diffraction angles with increasing cobalt content. The average crystallite size calculated from XRD peak broadening varied from 2.33nm to 6.54nm. The saturation magnetization and coercivity increased with increasing cobalt content.
Preparation and Characterization on Cellulose Nanofiber Film
Authors: Zhang Li Yuan , Tsuzuki Takuya , Wang Xun Gai
Published: June 2010

In this study, cellulose nanofibers were obtained from wood pulp using a chemo-mechanical method and thin films were made of these cellulose nanofibers. The morphology of the films was studied by scanning electron microscopy (SEM). SEM image analysis revealed that the films were composed of cellulose nanofibers with an average diameter of around 32 nm. Other properties were also characterized, including the degree of crystallinity by X-ray diffraction, chemical bonding by infrared attenuated total reflectance analysis, and thermal properties by differential scanning calorimetry. The foldable, strong, and optically translucent cellulose nanofiber films thus obtained have many potential applications as micro/nano electronic devices, biosensors and filtration media, etc.
Enhancement of Photocatalytic Reaction of Titanium Dioxide Film by Surface Texturing
Authors: Shimizu Jun , Zhou Li Bo , Takamori Kaoru , Ojima Hirotaka , Yamamoto Takeyuki , Huang Han
Published: June 2010

This study aims to study the influence of surface topography on the photocatalytic reaction of TiO2 film surfaces. In this work, a textured TiO2 film surface was fabricated by anodic oxidizing a titanium plate with micro grooves, and its wettabilty was evaluated. Micro grooves were machined on a 3-axis NC control precision machine tool using a single point diamond cutter with a tip radius of several hundred nanometers. Anodic oxidation experiments were conducted by using the self-developed equipment with diluted acetic acid as the electrolyte. It was found that the wettability of the TiO2 film surface textured by microcutting was superior to that textured by polishing under the irradiation environment of ultraviolet rays. The wettability of photocatalytic film surfaces could be improved by increasing the surface area.
Growth and Characterization of Ge1-xSnx Layers for High Mobility Tensile-Strained Ge Channels of CMOS Devices
Authors: Nakatsuka Osamu , Shimura Yosuke , Takeuchi Shotaro , Tsutsui Noramasa , Zaima Shigeaki
Published: June 2010

We have investigated the growth and characteristics of heteroepitaxial Ge1-xSnx layers on various substrates. The low temperature growth and the large misfit strain between Ge1-xSnx and Si leads to the high density of defects such as vacancy in Ge1-xSnx layers. They effectively enhance the propagation of misfit dislocations and the strain relaxation with suppressing the precipitation of Sn atoms from Ge1-xSnx layers. We succeeded in growing strain-relaxed Ge1-xSnx layers with a Sn content over 9% by controlling the dislocation structure on Si substrates. We also characterized the Hall mobility of Ge1-xSnx layers and found that the incorporation of Sn into Ge effectively reduced the concentration of holes related with vacancy defects, and improved on the hole mobility.
Development of a Processing Window for the Transformation Hardening of Nickel-Aluminium-Bronze
Authors: Cottam Ryan Edwin , Brandt Milan
Published: June 2010

Nickel-Aluminium-Bronzes (NAB) are typically used in marine applications because of their good combination of corrosion resistance and strength. Even though these alloys exhibit good properties they do suffer from wear, corrosion, dealloying, cavitation corrosion-erosion or corrosion fatigue during service. Therefore methods of increasing the resistance of this class of alloy to surface sensitive damage mechanisms are desirable. Transformation hardening through laser processing offers the potential to increase the resistance of these alloys surface sensitive mechanisms of damage and increase their life. A processing window has been developed through the use of an analytical heat transfer model to determine laser processing parameters that are close to the critical temperature for surface melting. The absorption of the laser by NAB has been determined and the processing window calculated taking into account the velocity of the laser, laser spot size and type as well as laser power.
Investigation on Oxidation Resistance of NiCoCrAlY Coating Irradiated by High Current Pulsed Electron Beam
Authors: Mei Xian Xiu , Wang Cun Xia , Qu Wei , Qin Ying , Dong Chuang , Wang You Nian
Published: June 2010

In this paper, the NiCoCrAlY bond-coats was deposited onto the DZ4 nickel-based superalloy substrate by using low-pressure Plasma Spraying (LPPS) process, and then the coats were irradiated by high-current pulsed electron beam (HCPEB). Phase structures and microstructure of the HCPEB-treated NiCoCrAlY coating were analyzed by SEM, XRD and EDAX. The present results showed that the coating surface was remelted after HCPEB treatments, became smooth, had crater eruption, and the coating hadn’t produced distinct residual stresses. The results of the isothermal oxidations experiment performed in 900°C static air revealed that the oxidation resistance of the coating was enhanced obviously after HCPEB-treated and the oxides were mainly Aluminum-oxides, but without HCPEB-treated, the oxides of coating also had Nickel-oxides.
Hot Corrosion Behavior of a Novel Enamel-Based Thermal Barrier Coating
Authors: Shen Ming Li , Zhu Sheng Long , Xin Li , Wang Fu Hui
Published: June 2010

A novel thermal barrier coating comprised two layers: sputtered bond coat and enamel-zirconia composite top layer. The hot corrosion tests were carried out at 900 °C for 100 h. The salt used in the tests was 25wt% NaCl + 75wt% Na2SO4. Mass loss and spalltion of oxide scales of uncoated K444 specimens was obvious. For the coated specimens, no oxide scale spallation and no weight loss were observed. The TGO formed on the coated specimens was thin layer of mixture oxides of Al, Ti and Cr, while thick multi-layered oxide scales formed on the uncoated specimens. Besides, deep internal oxidation zone was observed on the uncoated specimens. The coatings after hot corrosion tests contained t-ZrO2 and NaAlSi3O8, while the oxide scales formed on the uncoated K444 were TiO2, Cr2O3, NiCr2O4 and Na2Cr2Ti6O16.
Impact Indentation Properties and Interfacial Strength of Ceramic Coatings
Authors: Bao Yi Wang , Li Kun Ming , Wan De Tian , Cao Xue Qiang
Published: June 2010

Spherical impact indentation tests with different impact angles (90°, 60°, 45°, and 30°) were carried out to understand the impact resistance and interfacial adhesion of zirconia (ZrO2) ceramic coating on steel and aluminum substrates, respectively. A linear rail with an adjustable impact angle was used to guide the slipping impact head to impact the specimen. It is found that the peak impact force for surface damage decreases but the contact indentation becomes longer with decreasing impact angle. Under almost the same peak impact force, the smaller the impact angle, the higher the impulse. The experimental results indicate that the ZrO2 coating on steel substrate has higher impact resistance than that on the aluminum substrate. The cross bonded test results show that ZrO2 coating on both steel and aluminum substrates exhibit excellent interfacial tensile and shear strength.
Analysis of Advanced Strip Shape during Cold Rolling of Thin Strip
Authors: Jiang Zheng Yi , Du Xiao Zhong , Du Yan Bing , Wei Dong Bin , He Xiao Feng
Published: June 2010

The demand of thin gauge strip with good quality such as the strip shape and surface finish is significantly increasing. In this study, finite element model of the strip shape during cold rolling of thin strip in asymmetrical rolling was developed, and the finite element simulation of the thin strip shape has been carried out in LS-DYNA. The effects of reduction and speed ratio on the strip shape and profile and the strip edge drop have been obtained. The developed finite element model has been verified with the experimental data. The obtained results are applicable to the control of the rolled thin strip shape in rolling practice.
Australian Defence Applications of Advanced Smart Materials Research
Authors: Scala Christine M. , Ibrahim Matthew E. , Wilson Alan R. , Edwards Darren P. , Truong V. Tan
Published: June 2010

This paper overviews some recent S&T innovations in smart materials and structures at the Australian Defence Science and Technology Organisation (DSTO) under a Corporate Enabling Research Program (CERP) on Signatures, Materials and Energy. The CERP program includes development and transitioning of technology across the maritime, air and land domains, with the major focus of the smart materials program component being to increase the safety, availability and maintainability of Defence assets. Three specific examples are provided of the smart materials and structures program, ranging across the spectrum of technology readiness from new concept phase to technology transitioning, viz.: (i) Advances in smart sensing for prognostics-based platform management; (ii) Fabrication of nanostructured and ultrafine grained materials through top-down severe plastic deformation processing of bulk materials; (iii) Innovative application of carbon nanotubes/conducting polymers as artificial muscles for low-power propulsion and control of small autonomous underwater systems. In each case, the DSTO effort is underpinned by strong university or industry linkages to deliver challenging interdisciplinary S&T.
Shape Memory Effect in Fe-Pd Magnetic Shape Memory Alloy Thin Films
Authors: Han Jun Hyun , Ahn Tae , Kim Hyun , Jee Kwang Koo
Published: June 2010

The shape memory effect (SME) and magnetic shape memory effect (MSME) Fe-Pd thin film are using the film curvature method. The corresponding residual stress change due to theSME and MSME in Fe-Pd film is measuredduring thermal cycling and magnetic field changing. AFe-Pd thin film with a lateral composition gradient is deposited onto micromachined x7 cantilever beam arraysubstrate,such that each of the cantilever beams is coated with a film of different composition.There is abrupt stress change in only .1 at % Pd as the temperature of the film is cycled, and the corresponding stress change was measured as 0.16 GPa. The film with .4 at % Pd showsthe abrupt stress change at 0.7 Tesla, which means that the composition has the MSME.
Synthesis and Characterization of Mesoporous Carbon with MoO3 Loading via Ultrasonic Assembly
Authors: Long Xi , Chen Wen , Chen Shao Jiang , Zhao Chun Xia
Published: June 2010

Mesoporous carbon with MoO3 loading (MoO3/CMK-3) was obtained via ultrasonic assembly with CMK-3 as the host material and MoO3 as the guest material which was yield from MoO3ּpH2O2ּqH2O sol precursor. The microstructures of such MoO3/CMK-3 composites were characterized by X-ray diffraction (XRD), nitrogen adsorption and desorption, X-ray photoelectron spectra (XPS), Fourier-transform infrared (FTIR) and transmission electron microscopy (TEM). The results show that the method of ultrasonic assembly was efficient to highly disperse MoO3 nanoparticales into the channels of mesoporous carbon.
Dynamic Atomic Mechanisms of Plasticity of Ni Nanowires and Nano Crystalline Ultra-Thin Films
Authors: Han Xiao Dong , Wang Li Hua , Liu Pan , Yue Yong Hai , Yang Ming Jie , Sun Jia Lin , Zhang Ze
Published: June 2010

Using our recently developed in situ transmission electron microscopy techniques, we revealed that the FCC structured Ni nanowires with diameter of about 30 nm possess ultra-large strain plasticity. Dynamic complex dislocation activities mediated the large strain bent-plasticity and they were monitored at atomic scale in real time. The bent-induced strain gradient allows studying the strain effects on dislocation mediated plasticity. We also explored the deformation techniques to more general cases, the nano thin films. An example of tensile Pt ultra-thin film is presented.
Precipitation Behavior in AL6XN Austenitic Stainless Steel
Authors: Meng Li Jun , Xing Hui , Sun Jian
Published: June 2010

The precipitation behavior in the AL6XN austenitic stainless steel after creep deformation at temperatures 500~750 °C up to 3600 hours has been studied by electron microscope. The results showed that precipitates were hardly observed for the steel crept at 500~550 °C, and that the precipitates of carbides were mainly found at grain boundaries in samples crept at 600 °C. When the creep temperature was increased to 650~750 °C, a high density precipitates was found both at grain boundaries and within grains. The electron diffraction pattern and energy-dispersive X-ray spectroscopy analyses confirmed that these precipitates are  and Laves phases.
Using Chemiluminescence to Study the Photodegradation of Materials
Authors: Millington Keith R. , Jones Michael J. , Zakaria Siti Farhana , Maurdev George
Published: June 2010

Chemiluminescence (CL) is a straightforward method for studying the free radical degradation of organic and biological materials. A simple modification to a commercial thermal CL instrument and an effective experimental protocol allows the study of photoinduced chemiluminescence (PICL) emission. PICL originates from the reactions of macroperoxy radical intermediates formed during the autoxidation chain reaction. We have applied the PICL technique to study the photooxidation of polymer films and coatings, fibrous webs such as textile fabrics or paper, and powdered samples. Oxygen permeability appears to be a key factor affecting the intensity of PICL emission from polymer films.
Surface Damage in Riveted Aircraft Aluminium Lap Joints, in the Presence of Lubricants
Authors: Jaya Aditya , Tiong Ung Hing , Clark Graham
Published: June 2010

This paper discusses experiments investigating the effect of lubrication on surface damage in riveted lap joints which experience fatigue loading in aircraft structure. As part of a larger investigation into the effect of lubricants (specifically Corrosion Inhibiting Compounds, CICs) on fatigue performance, the fracture surfaces were examined to determine the crack initiation sites, and the failure modes involved. Scanning Electron Microscopy was also utilized to assess the nature of the fracture surfaces. The results showed that under the loading used, all the specimens which had not been treated with the CICs, and some treated specimens, failed by tensile failure of the sheet. Some treated specimens failed by rivet shearing. The results suggested that the presence of lubrication at the contacting surface might have reduced frictional load transfer, contributing to the change in failure mode. For specimens that failed in the sheet material, fatigue cracking and micro-void coalescence were the fracture modes, with the potential influence of fretting as a fatigue source.
Synthesis, Characterization and Analytical Modelling of Mechanical Behavior of a Conducting Polymer Actuator
Authors: Kaynak Akif , Yang Chun Hui , Kouzani Abbas
Published: June 2010

Electrochemical synthesis of a tri-layer polypyrrole based actuator optimized for performance was reported. The 0.05 M pyrrole and 0.05 M tetrabutylammonium hexaflurophosphate in propylene carbonate (PC) yielded the optimum performance and stability. The force produced ranged from 0.2 to 0.4mN. Cyclic deflection tests on PC based actuators for 3 hours indicated that the displacement decreased by 60%. PC based actuator had a longer operating time, exceeding 3 hours, compared to acetonitrile based actuators. A triple-layer model of the polymer actuator was developed based on the classic bending beam theory by considering strain
electrode material. A tri-layer actuator was fabricated [4, 6], by initially sputter coating a PVDF film with approximately 100nm of gold layer, resulting in a conductive film with a surface resistance of 8-10Ω. The PVDF film was about ~145µm thick had an approximate pore size of 45μm. A solution containing 0.05M distilled pyrrole monomer, 0.05M (TBAPF6) and 1% (w/w) distilled water in PC (propylene carbonate) solution was purged with nitrogen for 15 minutes. The continuity between PPy and PVDF. Results predicted by the model were in good agreement with the experimental data.
Influence of Mechanical Loading on Failure of Aircraft Protective Coatings
Authors: Tiong Ung Hing , Crawford Bruce R. , Clark Graham
Published: June 2010

The degradation and failure of protective coatings (paints and sealants) is a key element influencing the service life of aircraft. Such degradation is influenced by the response of coatings to environmental factors such as high temperatures and exposure to ultraviolet radiation, as well as chemical factors. However, the effect of loading and load history on coating durability has received little attention, despite clearly being a factor in determining failure sites (such as joints) and the rate of degradation. This paper describes the key characteristics of coatings at aircraft joints, and the nature of the strains experienced by coatings in locations influenced by in-service loads. It is first step in assessing the complex strain history at joint strain concentration locations as part of developing a prognostic capability for the service life of aircraft coatings. The configuration of coating layers at different joints is important and this research has considered a simplification of a butt strap joint from a RAAF military aircraft and a generic lap joint; predictions of critical movements/displacements have been made using finite element analysis; the predictions will be tested later as part of an experimental program associated with a full-scale fatigue test.
The Microstructure and Mechanical Properties of Ni-Based Superalloy after Service Exposure in Gas Turbine
Authors: Yoo Keun Bong , Lee Han Sang
Published: June 2010

Many investigations about superalloys and coatings have been done in the laboratory, but evaluating the degradation condition of hot section components during service is still important not only for repair and reuse but also for outage prevention. Time dependent degradation for second stage blades of gas turbine was investigated. The degradation analysis for used blades was divided into microstructure changes by position of the blade and mechanical tests of high temperature tensile test. In the microstructure analysis, the rafting and coarsening of γ', MC decomposition and TCP phase formation occurred and progressed with increasing service time, and especially the leading and trailing edge of top layer should be a check points for used blade. High temperature tensile results of 25,000 and 52,000 hrs used blades were also compared with serviced time and position in each blade.
Wear Resistance and Microstructural Study of Diamond Coated WC Tools
Authors: Boland Jim N. , Li Xing Sheng , Rassool Roger P. , MacRae Colin M. , Wilson N.C. , Elbracht S. , Luzin Vladimir , Imperia Paolo , Sobott B.
Published: June 2010

Diamond composite materials are classified as superhard and exhibit exceptional abrasive resistance. Cemented tungsten carbide tools with a thick coating of diamond composite material (PCD) are finding increased usage in materials cutting operations in manufacturing, mining, minerals, gas and petroleum exploration and civil construction industries. Two major advantages derived from these coated tools are: (a) increased wear resistance and hence increased life-span of these tools and (b) their proven ability to handle “difficult-to-machine” materials as well as high-strength, extremely abrasive materials such as quartz-rich rocks, granites and basalts. In this research, the variability of the wear resistance of PCD coated tungsten carbide is correlated with microstructural variations. A detailed study of the microstructure and distribution of phases was performed using SEM, cathodoluminescence (CL) imaging, direct x-ray imaging, Raman spectroscopy as well as residual stress measurements using neutron diffraction.
Effects of Aging Parameters on the Mechanical Properties in Corson Alloy System with High Contents of Ni and Si
Authors: Hagino Genjiro , Eguchi Hayao , Takayama Yoshimasa , Kato Hajime
Published: June 2010

The influences of solution treatments, prior cold drawings and aging treatments on mechanical properties in Corson alloy with high contents more than 8.0 mass% of Ni and Si have been investigated. As a result of the optimization of conditions, the maximum hardness and tensile strength reached 306HV and 968MPa, respectively. Effects of temperatures of solution treatment and aging on the mechanical properties were analyzed based on solid solute concentrations in matrix phase, which were estimated by using the linear analysis and calculated from the electrical conductivity. The solute concentrations were also measured directly by SEM-EDS. Consequently, the precipitation hardening of the alloys was governed mainly by the solute concentrations of Ni and Si in matrix phase in solution treatment. The hardness depended on not only the solute concentrations but also the excess of Ni and Si in the alloys.
Residual Strength of a Helicopter Composite Structure Subjected to Small Arms Fire
Authors: Callinan Richard J. , Wang John , White C.
Published: June 2010

Carbon fibre composites are being used in the structure of new generation helicopters in order to reduce weight. Helicopters such as armed reconnaissance vehicles, are potentially vulnerable to small arms fire. As a result a series of ballistic tests were carried out on laminate test specimens using 7.62mm and 12.7mm small arms fire. These specimens are representative of typical helicopter composite structure. These ballistic tests were followed by ultrasonic ‘A’ scans, hammer tap and thermography techniques to determine the extent of delamination damage.
Fabrication of Carbon Nano-Fiber / Aluminum Composites by Low-Pressure Infiltration Method
Authors: Sasaki Gen , Hara Yoshimasa , Xu Zhe Feng , Sugio Kenjiro , Fukushima Hiroshi , Choi Yong Bum , Matsugi Kazuhiro
Published: June 2010

In this study, the fabrication of carbon containing aluminum composites was attempted by using low-pressure infiltration method. At first, porous preform containing vapor grown nano-fiber (VGCF) and pure aluminum powder was fabricated by spark plasma sintering (SPS) method. Porosity in preform was controlled by changing the applied pressure during plasma sintering. Consequently, the porous preform with 40-50vol％ in porosity was obtained, which has enough compression strength for low-pressure infiltration (<1MPa). Then, the molten pure aluminum infiltrated to porous preform with 0.4MPa in applied pressure at 1023K, and consequently we can obtain the composite with 62-86% in density. The electrical and thermal conductivity of composites was affected by the porosity, strongly.
Microstructure and Interface Of Mg3Zn6Y Quasicrystal Particulate Reinforced Mg-8Gd-3Y Alloy
Authors: Wu Shi Ping , Kang Hui Jun , Guo Jing Jie
Published: June 2010

Mg3Zn6Y quasicrystal particulate reinforced Mg-8Gd-3Y alloy was fabricated by adding the Mg3Zn6Y quasicrystal particles into the Mg-8Gd-3Y matrix alloy melt. The effect of volume fraction of quasicrystal particles on the microstructure of quasicrystal particulate reinforced Mg-8Gd-Y alloy was studied using XRD, SEM, TEM and HRTEM. It was found that Mg3Zn6Y quasicrystal particles were melted partly and only 1/3 of them were added into the matrix alloy. The quasicrystal particles distributed in the grain and grain boundary. At the same time, the intermetallic phase composition and the morphology in Mg-8Gd-3Y matrix alloy were changed. The interface between quasicrystal particles and α-Mg was smooth and clear, they combined closely each other and there is no obvious interface chemical reaction when the direction of electron beam was parallel to the 2-fold and 3-fold axes of icosahedral quasicrystal phase particles.
Synthesis and Characterization of the Layered Hybrids (CnH2n+1NH3)2MCl4 (M=Co,Cu,Zn and n=2,4,6,8,10,12)
Authors: Guo Li Ling , Wu Xian , Liu Han Xing
Published: June 2010

A series of hybrids (CnH2n+1NH3)2MCl4 with quantum-well energy-band structure were synthesized by chemical reaction in HCl solutions, in which M(Co,Ni,Cu,Zn) and n(2,4,6,8,10,12) varied to adjust the quantum-well depth and the barrier width, respectively. The X-ray diffraction patterns and scanning electron microscopy images of the products demonstrate that they crystallize well with the typical layered structures. However, the analogues of Ni can not be successfully synthesized in the same way. Concerning the energy-band structure, the colors of the products reveal that the quantum-well depth is more important than the barrier width for controlling the properties of the hybrids.
Fabrication of Nanocrystalline TiO2 Films by Aerosol Deposition Method for Dye-Sensitized Solar Cells
Authors: Cheng Da Long , Lin Chia Yi , Liu Chih Sheng , Kao Kuo Sheng , Wang Chih Ming
Published: June 2010

This work present a low resistance dye-sensitized solar cell (DSSC) based on metal substrates. Different kinds of metal meshes are used to fabricate nanocrystalline TiO2 electrode and counter-electrode. The nanoporous TiO2 thin films were fabricated via an aerosol deposition method. The TiO2 colloid was produced by dissolving P25 powder in deionized (DI) water and atomized using an ultrasonic nebulizer. The flexible electrodes can be sintered under 450–550 °C and exhibit high-temperature sinterability. The tuning of TiO2 film thickness coated on metal mesh towards optimization of solar energy conversion efficiency had been investigated. Experimental results show that the excellent electric conductivities improve the fill factor and conversion efficiency for the large-size DSSCs due to the reduced internal resistance of the cell. These flexible metal substrates are a promising approach especially from the viewpoint of large-scale, cost effective industrial manufacturing of solar cells.
Thermodynamic Characterization on Hydrogen Absorption and Desorption Reactions of Lithium – Silicon Alloy
Authors: Doi Koichi , Hino Satoshi , Miyaoka Hiroki , Ichikawa Takayuki , Kojima Yoshitsugu
Published: June 2010

Lithium hydride LiH is one of the attractive hydrogen storage materials, because it stores 12.7 mass% of H2. However, H2 desorption reaction occurs over 600 °C due to the large enthalpy change of H2 desorption Ho = 181 kJ/mol H2. The purpose of this work is to control the enthalpy change of LiH to much lower value by a mechanical alloying with Si, where the Li-Si alloy is thermodynamically more stable than Li. The alloy was synthesized from Li granule and Si powder by a mechanical alloying method. The H2 absorption and desorption properties were characterized by High-Pressure Differential Scanning Calorimetry and Thermogravimetry - Differential Thermal Analysis - Mass Spectroscopy, and X-ray diffraction measurement. Pressure - Composition - Isotherm measurements were performed at 400, 450, and 500 °C to estimate the enthalpy change. From the results, it was confirmed that reversible H2 ab/desorption reactions of the Li-Si alloy were expressed as 7LiH + 3Si ↔ (3/7)Li12Si7 + (13/7)LiH + (18/7)H2 ↔ Li7Si3 + (7/2)H2 (theoretically 5.0 mass% H2) at 400 °C. From van’t Hoff plot obtained by the results of PCI measurements, the enthalpy change of the former reaction was estimated to be Ho = 103 kJ/mol H2, which is lower than that of LiH.