bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure and Wear Behaviour of Laser Induced In-Situ Formation of TiBx and TiC Titanium Composite Coatings
Authors: Liang Jing , Ren Cui Xia , Liu Chang Sheng , Chen Sui Yuan
Published: June 2010

Two kinds of mixed powders:Ti-6Al-4V/B/C and Ti-6Al-4V/B4C which are pre-pasted on Ti-6Al-4V substrates separately were scanned by a 500W pulsed YAG laser to induce in situ formation of titanium composite coatings contained TiBx and TiC ceramic reinforced phases. The influences of laser processing parameters including Pulse Frequency (PF), Pulse Width (PW), Laser Power (P) and Scanning Speed (V) together with the powder proportions on the microstructure and properties of the coatings were investigated. Microstructure, phase components and micro-hardness of the coating were analyzed by OM, SEM, TEM, XRD and micro-hardness tester respectively. The optimized processing parameters of a single path laser scanned specimen in this case are as follows: PF: 15Hz, PW: 3ms, for the Ti-6Al-4V/B4C specimens the laser line energy ~12.5J/mm, for the Ti-6Al-4V/B/C specimens the laser line energy ~11J/mm. TiB and TiC ceramic were formed evenly reinforced in the matrix of Ti-6Al-4V with the morphology of needle, tiny dendrites and disperse spherical particles. The maximum micro-hardness of single-path layers is up to 750 Hv, which is over twice of that of the substrate (367Hv).The wear weight loss decreased nearly 3 times that of the substrate.
Aluminizing of TiAl-Based Alloy Using Thermal Spray Coating
Authors: Sasaki Tomohiro , Yagi Takahiro , Watanabe Takehiko
Published: June 2010

Aluminizing the surface of a TiAl-based alloy (49.1 at% Al) was carried out by thermally spraying a pure aluminum coating and subsequent diffusion treatment at 1100°C. The influence of the diffusion time for the formation of Ti-Al intermetallic phases in the coating layers and the oxidation resistance of the aluminized TiAl-based alloys were investigated. The layer formed on the outermost surface was comprised of the Al-rich intermetallic T2iAl5 and contained pores. On the other hand, an intermediate layer consisting of TiAl2 and TiAl was formed between the outermost layer and the substrate. The thickness of the outermost layer decreased as the diffusion time increased, while the thickness of the intermediate layer increased. In addition, the coating/substrate interface changed from a wavy to a linear form with the growth of the intermediate layer. The aluminized coating showed good oxidation resistance at 900°C for all diffusion times.
Electrochromic Properties of Nano-Columnar Nickel Oxide
Authors: Wang Chih Ming , Kao Kuo Sheng , Cheng Da Long , Cheng Chien Chuan , Hsieh Po Tsung , Lin Shih Yuan , Shih Tai Yu , Wen Chih Yu
Published: June 2010

Electrochromic properties of transition metal oxides had much attention in recent years. The electrochromic thin films can be assembly as electrochromic devices (ECDs) and then used for applications in devices such as mirrors, panels and smart windows. A kind of complementary ECD is popular in resent years. Therefore, a specific investigation on nickel oxide (NiO) electrochromic properties is completed in this study. The crystalline structure of the NiO films was analyzed using XRD (PANalytical X’Pert PRO) with Cu-Kα radiation. The atmosphere of oxygen concentration increasing has changed the NiO films crystalline from (200) to (111). The thicknesses and surface microstructures of the NiO films were investigated using a scanning electron microscope (SEM, Philips/FEI XL40 FEG). It is observed that films are relatively smooth deposited without oxygen. The characterization of the electrochromic properties was carried out in a two-electrode cell with an electrochemical analyzer (CHI 611B). The NiOx changes the transmittance of NiO films in the wavelength range of 300-1500 nm and the color of the film changes from transparent to brown. The nano-crack exhibits in the NiO film did enhance the electrochromic properties.
The Effects of Heat Treatment on the Bonding Strength of Surface-Activated Bonding (SAB)-Treated Copper-Nickel Fine Clad Metals
Authors: Kim Kyung Hoon , Lim Sung Chul , Kwon Hyouk Chon
Published: June 2010

Surface activated bonding (SAB) is a novel method for the precise joining of dissimilar materials. It is based on the concept that two atomically clean solid surfaces can develop a strong adhesive force between them when they are brought into contact at high vacuum condition without high deformation at a 40~90%. With this SAB process, the effects of heat treatment on the bonding strength of surface-activated bonding (SAB)-treated copper-nickel fine clad metals were investigated. An increase in the SAB rolling load of the copper-nickel fine clad metals increased the peel strength after heat treatment, indicating that increases in the SAB rolling load decreased the interface voids formed by initial micro-range surface roughness between the clad materials in the SAB cladding process. Unlike conventional cold rolling, outstanding interface diffusion between the clad materials was not observed after heat treatment. In addition, the peel strength increase of the clad metals compare with initial peel strength increased with SAB rolling load (<1% reduction ratio at a roll load of 5000 kgf ) up to 3.99 N/mm after heat treatment.
Corrosion and Oxidation Protection of Ti6Al4V Alloy by an Inorganic Metal Modified Silicate Composite Coating
Authors: Wang Cheng , Zhu Sheng Long , Wang Fu Hui
Published: June 2010

An inorganic metal modified silicate composite coating was developed to protect the corrosion and oxidation of Ti6Al4V alloy at 650°C. The properties of the coatings were investigated by oxidation and corrosion experiments, and the microstructure of the coatings was studied by SEM. The isothermal oxidation results indicated that the Ti6Al4V alloy suffered serious oxidation after exposed for 100h at 650°C and the mass of the alloy gained almost lineally, while the coated alloy had almost no mass gain and the coatings keep intact after oxidation. The salt spray test for 20h and oxidation at 650°C for 2h was carried out to investigate the corrosion and oxidation properties of the coatings. The results indicated that the alloy experienced serious corrosion after experiment for 20 cycles, while the coated alloy did not corrode after the experiments. The thermal shock experiments indicated that the coatings could withstand 50 times thermal shock when kept for 5min at 700°C and then immediately put into 3.5%NaCl solution at room temperature.
Recent Product Developments with Ultra-Thin Cast Strip Products Produced by the CASTRIP® Process
Authors: Killmore Chris R. , Edelman Daniel G. , Carpenter Kristin R. , Kaul Harold R. , Williams James G. , Campbell Peter C. , Blejde Walter N.
Published: June 2010

Recent product development has focussed on developing a range of higher strength structural grades, covering the strip thickness range 0.9-1.5 mm, utilising Nb microalloying. A wide range of Nb levels have been successfully strip cast by the CASTRIP® process. Niobium was found to retard austenite grain refinement and substantially enhanced hardenability, which produced significant microstructural hardening and higher strength hot band. Niobium was retained in solid solution enabling further significant strengthening to be achieved from an age hardening heat treatment. Strength levels ranging from 400 MPa to in excess of 550 MPa, in combination with high ductility, were achieved in the age hardened and hot dip galvanised condition, utilising the annealing furnaces of a conventional hot dip galvanising line. The effect of microalloying content and processing conditions on the microstructure and final mechanical properties of Nb microalloyed UCS products produced by the CASTRIP process are described.
Effect of LiNbO3 on Piezoelectric Properties of K0.5Na0.5NbO3 Ceramics
Authors: Cao Ming He , Li Zhuo , Li Fan , Hao Hua , Liu Han Xing
Published: June 2010

Lead-free (1-x)K0.5Na0.5NbO3–xLiNbO3 piezoelectric ceramics have been prepared by a conventional solid state process. The phase structure and the electrical properties of the ceramics were studied. A polymorphic phase transition (PPT) between the orthorhombic and tetragonal phases was identified in the composition range of 0.08<x<0.10. The ceramics near the PPT show better piezoelectric properties. At a level of 10mol% LiNbO3, the sample sintered at 1100oC for 1h exhibits optimal piezoelectric properties.
Design of a New Biocompatible Ti-Based Shape Memory Alloy and Its Superelastic Deformation Behaviour
Authors: Xiong Jian Yu , Li Yun Cang , Hodgson Peter , Wen Cui E
Published: June 2010

Titanium-nickel (Ti-Ni) shape memory alloys have been widely used for biomedical applications in recent years. However, it is reported that Ni is allergic and possibly carcinogenic for the human body. Therefore, it is desirable to develop new Ni-free Ti-based shape memory alloys for biomedical applications. In the present study, a new Ti-18Nb-5Mo-5Sn (wt.%) alloy, containing only biocompatible alloying elements, was designed with the aid of molecular orbital method and produced by vacuum arc melting. Both β and α″ martensitic phases were found to coexist in the alloy after ice-water quenching, indicating the martensitic transformation. The phase transformation temperatures of the Ti-18Nb-5Mo-5Sn alloy were Ms = 7.3 °C, Mf = −31.0 °C, As = 9.9 °C, and Af = 54.8 °C. Superelasticity was observed in the alloy at a temperature higher than the Af temperature. A totally recovered strain of 3.5 % was achieved for the newly designed Ti-based shape memory alloy with a pre-strain of 4 %.
Computational Modelling of Deformation of NiTi Plates with Circular Holes
Authors: S. Shariat Bashir , Liu Yinong , Rio Gerard
Published: June 2010

This study presents a numerical model for deformation behaviour of near-equiatomic NiTi holey plates using finite element method. Near-equiatomic NiTi alloy deforms via stress-induced AM martensitic transformation, which exhibits a typical hystoelastic mechanical behaviour. In this model, the transformation stress is decomposed into two components: the hyperelastic stress, which describes the main reversible aspect of the deformation process, and the hysteretic stress, which describes the irreversible aspect of the process. It is found that with increasing the level of porosity of the holey plate, the nominal stress for the AM transformation decreases and the strain increases. In addition, the stress-strain slope over the stress plateau also increases with increasing the porosity. While the porosity level has a strong effect on global stress-strain behaviour of the holey plate, regularity of the arrangement of the holes is found to have negligible effect.
Compression Behavior and Texture Development of Polymer Matrix Composites Based on NiMnGa Ferromagnetic Shape Memory Alloy Particles
Authors: Okuno Motoki , Inamura Tomonari , Kanetaka Hiroyasu , Hosoda Hideki
Published: June 2010

Deformation behavior and texture development of NiMnGa ferromagnetic shape memory alloy (FSMA) particles embedded polymer composites were investigated by compression tests and X-ray diffraction pole-figure analysis (XRD-PF). Both the NiMnGa/silicone and NiMnGa/epoxy composites exhibited a characteristic three-stage deformation which is often seen in shape memory alloys due to martensite variant reorientation. XRD-PF revealed that (004) texture was developed in the compressed NiMnGa/silicone due to the retention of martensite variant reorientation. On the other hand, significant texture change was not recognized in the compressed NiMnGa/epoxy. Rearranged martensite variants was kept after unloading in silicone matrix having low Young's modulus, but reverse reorientation occurred in epoxy matrix with high Young's modulus. The rearrangement behavior of martensite variants is strongly affected by elastic properties of matrix.
Phase Constitution and Mechanical Properties of Ti-(Cr, Mn)-Sn Biomedical Alloys
Authors: Kusano Yasuhiro , Inamura Tomonari , Kanetaka Hiroyasu , Miyazaki Shuichi , Hosoda Hideki
Published: June 2010

In order to produce new β (bcc) Ti alloys for medical applications, effects of Mn substitution for Cr on phase constitution and mechanical properties of Ti-Cr-Sn alloys were investigated. All the Ti-7mol%(Cr, Mn)-3mol%Sn alloys investigated by XRD analysis were identified as β (bcc) alloys, and athermal ω phase was also detected in Ti-7mol%Mn-3mol%Sn . The lattice parameter of β was slightly decreased by Mn substitution. Besides, the Mn substitution for Cr raised the hardness and the strength while reduced the ductility of the Ti-Cr-Sn alloys. The hardening by Mn substitution must be due to ω precipitation. The hardening is discussed from the viewpoint of electron atom ratio (e/a) in comparison with Ti-Cr binary alloys in the literature.
Biomedical Titanium Alloy with Ultralow Elastic Modulus and High Strength
Authors: Hao Yu Lin , Yang Rui
Published: June 2010

Ti2448 (Ti-24Nb-4Zr-8Sn wt.%) is a metastable  type titanium alloy developed recently for biomedical applications. The alloy possesses good biomechanical compatibility with human bone, in terms of high strength and an elastic modulus approaching that of the hard tissue of human body, as well as biochemical compatibility since it contains only nontoxic alloying elements. Bone plates manufactured from the Ti2448 alloy has undergone clinical trials and an application for product permission has been submitted to FDA of China. We review briefly the methodology of alloy design and peculiar properties including pronounced nonlinear elasticity and localized plastic deformation. Variations of mechanical properties with processing scheme will be presented. The positive effects of improved elastic matching between implant and bone on healing fractured bone are demonstrated by new bone formation at intramedullary nails implanted in New Zealand white rabbits and bone plates implanted in Beagle dogs.
Cold Rolling and Annealing Microstructures and Textures of Low Carbon Steels
Authors: Almojil Marwan , Bate Pete S.
Published: June 2010

The development of crystallographic textures of IF and HSLA steels after 20, 50, 70 and 90% cold rolling reductions and subsequent recrystallisation have been investigated using Electron Backscattered Diffraction (EBSD). The HSLA steel was initially processed to give a volume fraction of about 0.2 of fine pearlite colonies, which acted as mechanically hard particles. Both cold rolling and recrystallisation textures are shown to be largely dependent on the rolling reduction for both steels. With increasing rolling reduction, the texture shows gradual intensification of α and γ fibre components. Although PSN was the dominant nucleation site in the HSLA steel during annealing, the α and γ fibres also exist in the recrystallisation textures, but with lower density.
Effect of Temperature and Strain Rate on Microstructure of Dynamically Recrystallized Ni45Co5 Mn36.7In13.3 Alloy
Authors: Wang Gang , Zhao Wen Ru , Liu Yan Dong , Wang Chun Yan , Wang Yan Dong , Zuo Liang
Published: June 2010

In recent years, there has been an increasing interest in magnetic shape memory alloys (MSMAs) due to their unique ability to produce very large output strains and rapid response frequency. NiMnCoIn is a new-type MSMAs in which a reversible magnetic-field-induced phase transformation is observed. The microstructural evolution in the process of dynamic recrystallization in polycrystalline Ni45Co5Mn36.7In13.3 was studied in the present paper. The experimental results showed that the high deformation temperature and slow strain rate were necessary to achieve perfect dynamic-recrystallizing microstructure in Ni45Co5Mn36.7In13.3 alloy. Precipitates with two sizes were observed. The content of Co in precipitates was higher than that in the matrix alloy, while the content of In was lower than that in the matrix alloy.
Investigation of Biomimetic Apatite Growth on DLC-ZrO2 Thin Films Prepared by MOCVD
Authors: Admin Sadequl , Randeniya Lakshman , Bendavid Avi , Martin Phil , Preston Edward
Published: June 2010

Thin films of diamond-like carbon (DLC) containing zirconium dioxide (DLC-ZrO2) have been deposited onto conducting (100) silicon wafer substrates using a pulsed direct-current metal–organic plasma activated chemical vapour deposition (MOPACVD) technique. DLC-ZrO2 thin films were immersed in simulated body fluid (SBF) at 37° C. The formation of apatite as a function of time was determined using a number of characterization techniques including XPS, FTIR, XRD, SEM and EDX. The XPS results confirmed the presence of calcium and phosphorus on the DLC-ZrO2 film surfaces after immersion in SBF. FTIR and XRD results confirmed that biomimetic apatite was formed on DLC-ZrO2 as an amorphous film. Ball-like particles composed of Ca and P were observed on the film surface. EDX results also confirmed that Ca and P were deposited on the film surface.
Creating Biomaterials Inspired by the Microstructure of Cuttlebone
Authors: Cadman Joseph , Chen Yu Hang , Zhou Shi Wei , Li Qing
Published: June 2010

The microstructure of cuttlebone is investigated using Scanning Electron Microscopy (SEM). A graded aspect ratio of the base cells between layers is evident in some samples. A method for designing graded biomaterials mimicking this cuttlebone microstructure is developed. Simplified 3D biomaterial samples are created using CAD software. These biomaterials are fabricated using a stereolithographic apparatus (SLA). The homogenisation technique is used to evaluate the mechanical properties of the original cuttlebone sample and the fabricated biomaterial sample. Good agreement is found between the Young’s moduli of corresponding layers. However, it is inconclusive whether the Young’s moduli have a proportional relationship to the aspect ratio of the base cell at this stage of the study.
Study on New Model of Tension Process in Continuous Rolling
Authors: Zheng Shen Bai , Ma Jin Hong , Li Zeng Feng
Published: June 2010

It is proved that a tension peak occurred in the beginning of tension process between two stands by the continuous rolling test. Based on the speed difference, motor rigidity and coefficient of forward and backward slip, the steady equation of the kinematical mechanics is built. The simulation results of the tension formula accorded with the experimental data. The calculation of shock peak provides an important reference for the technology of continuous rolling.
A Study of a Retention of Antimicrobial Activity by Plasma Polymerized Terpinen-4-ol Thin Films
Authors: Bazaka Kateryna , Jacob Mohan V. , Ivanova Elena P.
Published: June 2010

Terpinen-4-ol is the main constituent of Melaleuca alternifolia essential oil known for its biocidal and anti-inflammatory properties. The possibility of fabricating polymer thin films from terpinen-4-ol using radio frequency (RF) plasma polymerisation for the prevention of the growth of Pseudomonas aeruginosa was investigated, and the properties of the resultant films compared against their biologically active precursor. Films fabricated at 10 W prevented bacterial attachment and EPS secretion, whilst polyterpenol films deposited at 25 W demonstrated no biocidal activity against the pathogen.
Simultaneous Incorporation of 5-Fluorouracil and Leucovorin into Chitosan Nanoparticle as Drug Carrier and Its Characterization
Authors: Li Pu Wang , Wang Yi Chao , Peng Zheng , Kong Ling Xue
Published: June 2010

A combined drug loaded system containing two most common anti-cancer drugs 5-fluorouracil (5-FU) and leucovorin (LV) was designed and prepared by ion crosslinking technology. The resulted nanoparticles are spherical in shape, and the particle size becomes larger when drug combination are loaded. Efficient drug encapsulation efficiency (EE) and drug loading (LC) are obtained due to the strong interaction between drugs and polymer. The combined drugs are distributed in the particles in amorpholous state which are demonstrated by the XRD results.
X-Ray Phase-Contrast Tomography for Quantitative Characterisation of Self-Healing Polymers
Authors: Mayo Sheridan , Stevenson Andrew , Wilkins Stephen , Gao Da Chao , Mookhoek Steven , Meure Sam , Hughes Tony , Mardel James
Published: June 2010

X-ray phase-contrast imaging and tomography add an additional dimension to conventional x-ray methods by exploiting the x-ray refraction effects in addition to x-ray absorption in forming an image. This greatly enhances the visibility of edges, voids and boundaries within a sample. It also makes it possible to characterise weakly x-ray absorbing samples which would produce little or no contrast in conventional x-ray imaging. Here we described the application of a laboratory-based x-ray phase-contrast microscope to x-ray micro-tomography of a self-healing polymer system and the quantitative analysis of the resulting three dimensional (3D) datasets to better understand the healing and ageing processes.
Nucleation of Bainite on Allotriomorphic Ferrite/Austenite Interface in a Low Carbon Steel
Authors: Guo Hui , Bai Yin , Yang Shan Wu , He Xin Lai
Published: June 2010

. A low carbon steel is austenitized and isothermally held at 680°C to form allotriomorphic ferrite and followed by a holding at lower temperature to form bainite. The morphology of allotriomorphic ferrite/bainite interfaces is studied using optical microscope. Three kinds of combination are observed: Type I: interface on one side is clear while on the other side, unclear; Type II: unclear on both sides; Type III: clear on both sides. Clear interface indicates a large difference in the orientation between the bainite and the ferrite, and unclear interface, a very small difference. The statistical counting shows that the ratio of Type I is about 80-82%, and that of Type II, 7-8%, and Type III, 9-11%. It is observed that this ratio does not change with the austenite grain size and bainite forming temperature. And the clear and unclear side of allotriomorphic ferrite may have different influence on the nucleation rate of bainite at allotriomorhic ferrite/prior austenite interface.
Coarsening Process of Decomposed Phases in Cu-Ni-Cr Alloys
Authors: Hernandez-Santiago Felipe , Victoria-Hernández V.M. , Saucedo-Muñoz M.L.
Published: June 2010

A study of the coarsening process of the decomposed phases was carried out in the Cu-34wt.%Ni-4wt.%Cr and Cu-45wt.%Ni-10wt.%Cr alloys using transmission electron microscopy. As aging progressed, the morphology of the coherent decomposed Ni-rich phase changed from cuboids to platelets aligned in the <100> Cu-rich matrix directions. Prolonged aging caused the loss of coherency between the decomposed phases and the morphology of the Ni-rich phase changed to ellipsoidal. The variation of mean radius of the coherent decomposed phases with aging time followed the modified LSW theory for thermally activated growth in ternary alloy systems. The coarsening rate was faster in the symmetrical Cu-45wt.%Ni-10wt.%Cr alloy due to its higher volume fraction of precipitates. The activation energy for thermally activated growth was determined to be about 182 and 102 kJ mol-1 in the Cu-34wt.%Ni-4wt.%Cr and Cu-45wt.%Ni-10wt.%Cr alloys, respectively. The size distributions of precipitates in the Cu-Ni-Cr alloys were broader and more symmetric than that predicted by the modified LSW theory for ternary alloys.
Three Dimensional Microstructure Characterization of an Al-Zn-Mg Alloy Foam Using Synchrotron X-Ray Microtomography
Authors: Zhang Qiang , Toda Hiroyuki , Kobayashi Masakazu , Suzuki Yoshio , Uesugi Kentaro
Published: June 2010

Synchrotron X-ray microtomography (SPring-8, Japan) has been used for the microstructure characterization in a closed cell Al-Zn-Mg alloy foam. Some sophisticated microstructure features, such as micropores and intermetallic particles inside the cell wall, were visualized and quantified three dimensionally(3D) by the high-resolution phase contrast imaging technique. By microtomographies tuned to energies above and below the Zn K-absorption edge, the 3D quantitation of Zn distribution was obtained using subtraction imaging technique. It has been clarified that the Zn distribution was inhomogeneous in the cell wall of the foam. And the agglomeration of Zn-bearing particles was confirmed to induce the brittle fracture of cell wall. The distributions of Ti and Ca in the foam were also visualized by subtraction method. The current tomographic techniques provide novel solutions for the 3D microstructure analysis in the highly inhomogeneous foam materials.
TEM and STEM Study of the Au Nano-Particles Supported on Cerium Oxides
Authors: Akita Tomoki , Tanaka Shingo , Tanaka Koji , Kohyama Masanori
Published: June 2010

The structures of Au particles on CeO2 surfaces were observed by an analytical transmission electron microscopy (TEM) equipped with annular dark field scanning transmission electron microscopy (HAADF-STEM) systems. The Au/CeO2 model catalysts were prepared by using the poly-crystalline CeO2 substrates. The Au particles of 2-5 nm in diameter were deposited on the substrates. The preferential orientation relationship of (111)[1-10]Au//(111)[1-10]CeO2 was frequently observed in profile-view HRTEM images on CeO2 (111) surface. High resolution HAADF-STEM images were also obtained for Au-CeO2 interfaces. The position of atomic columns of Au and Ce at Au-CeO2 interface is directly investigated from HAADF-STEM images. The structure of the interfaces between Au particles and CeO2 (111), (100), (110) surfaces were discussed.
Microstructure for Printed Multilayer LTCC Tape of Different Paste Rheology
Authors: Shapee Sabrina Mohd , Alias Rosidah , Azmi Ibrahim , Ambak Zulkifli , Yusoff Mohd Zulfadli Mohamed , Saad Muhammad Redzuan
Published: June 2010

Screen printing is the most common method of transferring silver thick film paste to a low temperature co-fired ceramic tape. Silver paste with varying rheology will have a varying print quality. The effect of silver paste rheology on the microstructure is investigated. Although there are many parameters to be considered, this parameter is a critical parameter which will control the line width and roughness on the substrate. To study the effect of paste rheology, a test pattern design was printed on the Heraeus CT2000 LTCC tape using silver paste. Then the LTCC tape was stacked and laminated at pressure of 28 MPa and temperature of 65 oC for 10 minutes. The laminated sample then was fired up to 850 oC. The fired silver conductor printed on the LTCC tape then was analyzed. Prints were evaluated by scanning electron microscopy. It was found that silver paste with high viscosity produce a good microstructure.
Defect Observation of Embedded Components of a Low Temperature Co-Fired Ceramic
Authors: Alias Rosidah , Shapee Sabrina Mohd , Yusoff Mohd Zulfadli Mohamed , Azmi Ibrahim , Ambak Zulkifli , Saad Muhammad Redzuan
Published: June 2010

This paper reports observations of defects in laminated eight layers of a glass-ceramic composite system fabricated by a standard low temperature co-fired ceramic (LTCC) technology. The layers were laminated at 3000 psi and 70 °C for 10 minutes and were fired at 850 °C for 15 minutes. Material characterizations of the green compact and fired substrate were carried out on density, surface roughness and microstructure. The crack and warpage of the substrate were related to the microstructure and densification process of the system. It was found that the presence of these defects could be due to a mismatch of the sintering kinetics of the glass-ceramic composite system and silver conductor materials which lead to the development of stresses which act on both materials. The detailed microscopic observation of the internal and surface defects is explained.
Numerical Simulation of Double Specimens in Split Hopkinson Pressure Bar Testing
Authors: Kariem Muhammad Agus , Beynon John H. , Ruan Dong
Published: June 2010

The split Hopkinson pressure bar (SHPB) is the most commonly used technique to characterize the dynamic behaviour of materials at very high strain rates. However, a classic single specimen test only generates a single stress-strain curve at the average strain rate of the test. This paper proposes three arrangements on the use of double specimens in SHPB compression testing. All waves propagating along the bars have been used to analyse the dynamic behaviour of the specimens. To simulate the test and predict its dynamic performance, an axisymmetric finite element analysis using LS-DYNA was conducted for the experiment using 13 mm bar diameter. The validity of the simulations was checked with experimental data from normal SHPB testing. Based on the simulations, the modified techniques are achievable and at least two stress-strain curves of materials can be extracted without violating the requirement of a valid SHPB test.
Tool Failure Criteria while Drilling Titanium Alloys
Authors: Palanisamy Suresh , Cong Luo , Verijenko Viktor , McDonald Stuart D. , Owen Robert , Dargusch Matthew S.
Published: June 2010

This paper presents a feasible machining test to measure, compare and predict the machinability of different titanium alloys. A drilling test was developed and investigated on the two most common grades of titanium, commercial purity and Ti6Al4V. The experiments and analysis revealed that tool wear followed a characteristic pattern for all machining conditions investigated. When machining Ti6Al4V, tool life was shorter and cutting forces higher compared with commercial purity Ti. Paradoxically, despite the more difficult machining, Ti6Al4V samples had better surface integrity than commercial purity samples. A procedure was developed that could be incorporated into a real-time process monitoring device to warn of imminent tool failure.
Effects of Strain Rate on Mechanical Properties and Microstructure of V-5Cr-5Ti Alloy
Authors: Hu Wen Jun , Huang Xi Cheng , Zhang Fang Ju , Mei Jun , Yan Yi Xia , Chen Yong Mei
Published: June 2010

In this work the static and dynamic tensile properties of vanadium alloy V-5Cr-5Ti were investigated at strain rates ranged from 3.3x10-5/s to 1.2x102/s. The material microstructures were analyzed using optical microscope, SEM, TEM, XRD and EDS. Results show that the yield strength a increases with strain rate. The brittle-ductile transition strain-rate is about 101/s to102/s. At room temperature the tensile fracture at a low strain rate occurs via mixed modes of microvoid aggregating and transgranular cracking; at high strain rate the fracture occurs via a brittle mode. The analysis by TEM, XRD and EDX shows the existence of lath martensite, and on there exits precipitate phase of Ti(O,C, N) in grain boundaries.
Effect of Thermomechanical Processing Parameters on the Microstructure Development in Low Si TRIP Steel
Authors: Al Harbi Fayez , Pereloma Elena V.
Published: June 2010

The effect of thermomechanical processing (TMP) parameters on the microstructure of the low Si, Al-added Ti-Mo TRIP steel was investigated using Gleeble 3500 thermo-mechanical simulator. The results showed that the formation of a significant volume fraction of polygonal ferrite is essential for the retained austenite presence in the microstructure of the TRIP steel.
High-Speed Fracture Phenomena of Glass Bottle by Underwater Shock Wave
Authors: Sakamoto Hidetoshi , Kawabe Shinjiro , Ohbuchi Yoshifumi , Itoh Shigeru
Published: June 2010

The high-speed fracture phenomena of glass bottles by using underwater shock wave technique for recycling the glass containers were discussed. The proposed technique is an efficient method for the crushing of glass bottles. In this study, the influence of various explosive conditions, that is, the explosive shape, set position, amount, the bottle size and the contents of bottle, on the cullet size, which is the crushed glass fragments, was studied. Furthermore, the behaviors of underwater shock wave were observed by high-framing photograph and the high-speed fracture mechanism was clarified.
Thermo-Physical Properties of Ti-Coated Diamond/Al Composites Prepared by Pressure Infiltration
Authors: Zhang Yang , Wang Xi Tao , Jiang Sen Bao , Wu Jian Hua
Published: June 2010

Thermo-physical properties of diamond reinforced Al composites were investigated. Volume fraction of diamond particles was up to 55%. In order to improve the interfacial bonding between diamond and aluminum, diamond particles were pre-coated with titanium using molten salt method. XRD and SEM observation showed that the Ti coating on diamond consists of carbide layer and metal layer, which mainly depend on temperature and time. The influences of the Ti coating on interfacial characteristic and the thermo-physical properties of the composites were studied. The interfacial characterization and thermal diffusivity measurements indicated that Ti coated diamond was more favorable on interfacial bonding and thermal properties. Ti coating on diamond resulted in an increase of thermal conductivity of the composites, from 200 to 430 W/mK along with a coefficient of thermal expansion of 6.40 × 10-6/K.
Computational Analysis of the Structural Integrity of Self-Healing Composites
Authors: Zhou Feng , Wang Chun H. , Mouritz Adrian P.
Published: June 2010

This paper presents a computational and experimental investigation of the influence of self-healing micro-vessels on the structural properties of laminated composites. Embedded self-healing system is rapidly emerging as an important technology for improving the damage resistance of laminated composites. Introduction of hollow fibres or hollow spheres can, however, potentially weaken the structure and lead to excessive reduction in mechanical performance of composites. In this research, computational simulation is carried out to investigate the effect of embedded microvascular vessels on the mechanical properties of self-healing composite, focusing on the stress concentrations around self-healing vessels and delamination cracking.
Crack Propagation Monitoring of DCB Composite Specimens Using Distributed Optical Fiber Sensor
Authors: Yoon Huk Jin , Song Kwang Yong , Kim Jung Seok , Shin Kwang Bok , Kim Seung Chul
Published: June 2010

In the conventional DCB test, test is usually conducted by observing the crack growth with a microscope, in this paper, new technique is tried to monitor the crack propagation in real time using optical fiber attached in the Kevlar/epoxy specimen. Crack tip position was monitored using strain distribution field data from the optical fiber and compared with the microscope data. BOCDA (Brillouin Optical Correlation Domain Analysis) system was used to measure the strain distribution of the optical fiber and spatial resolution, strain accuracy were about 9mm, ±20με each.
Polymer Based Composite and Hybrid Materials for Wind Power Generation
Authors: Chikhradze N.M. , Marquis Fernand D.S. , Japaridze L.A. , Abashidze G.S. , Okujava L.M.
Published: June 2010

In recent years considerable attention has been dedicated to renewal power sources, such as wind power. This work was carried out in order to develop a small wind turbine of 1-10kW power generation capability. This wind turbine is designed to be energetically more efficient by 30-50% and having a lesser specific cost (by 25-30%). This work focused on the development of composite materials for application on the blades in the wind generator. In this paper we present the results of the research work done on the development of flexible technology for the fabrication matrix-epoxy resin based hybrid composites, reinforced with carbon, basalt and glass fibers. These new composite and hybrid materials were fabricated using epoxy matrixes. These matrices were reinforced with basalt and carbon fibers of different content and strengthened by mullite-like crystals. The basalt fibers for composite reinforcing were prepared from raw materials, with chemical composition: SiO2-15.3%; CaO-10.8%; Na2O-4.2%; MgO-8.8%; Fe2O3-12.1%; MnO-0.7%; TiO2-0.7%. The properties of new composites developed depend on the content and architecture of reinforcing components and are: tensile strength-(0.012-1.590)GPa; compression strength-(0.078-0.656)GPa; modulus of elasticity-(8.4-162.9)GPa; Poisson ratio-(0.015-0.559). The variation of strength and elastic characteristics under tension and compression of the new composites are presented.
Development of High Modulus/High Strength Carbon Fiber Reinforced Nanoparticle Filled Polyimide Based Multiscale Hybrid Composites
Authors: Naito Kimiyoshi , Yang Jenn Ming , Kagawa Yutaka
Published: June 2010

The polyacrylonitrile (PAN)-based and pitch-based carbon fiber-reinforced nanoparticle filled polyimide based multiscale hybrid composites have been fabricated using vacuum assisted resin transfer molding (VaRTM) and autoclave curing. The carbon fibers used in this study were high tensile strength PAN-based (T1000GB) and high modulus pitch-based (K13D) carbon fibers. Fiber orientations of the T1000GB/K13D hybrid composites were set to [0(T1000GB)/0(K13D)]2S (T1000GB and K13D unidirectional layers were alternately and symmetrically laminated). The fiber volume fraction was 50 vol% (T1000GB: 24.9 vol%, K13D: 25.1 vol%). Polyimide used in this study was a commercially available polyimide precursor solution (Skybond 703). Four different types of nanoparticle (25nm-C, 20-30nm-β-SiC, 130nm-β-SiC and 80nm-SiO2) and particle volume fraction was 5.0 vol% used for the inclusion. The tensile properties and fracture behavior of T1000GB/K13D nanoparticle filled and unfilled hybrid composites have been investigated. For 25nm-C, 20-30nm-β-SiC and 80nm-SiO2 nanoparticle filled and unfilled hybrid composites, the tensile stress-strain curves show a complicated shape. By the high modulus pitch-based carbon fiber, the hybrid composites show the high modulus in the initial stage of loading. Subsequently, when the high modulus carbon fiber begin to fail, the high strength fiber would hold the load (strength) and the material continues to endure high load without instantaneous failure.
Mechanical Properties of Metallic Closed Cellular Materials Containing Polymer Fabricated by Polymer Penetration
Authors: Kishimoto Satoshi , Shimizu Toru , Yin Fu Xing , Naito Kimiyoshi , Tanaka Yoshihisa
Published: June 2010

Metallic closed cellular materials containing polymer were fabricated by the penetrating polymer into metal foam. The aluminum and stainless steel foams were selected for the metal foam and epoxy resin and polyurethane resin were selected for the penetrated polymer. The many kinds of mechanical properties of this material were measured. The results of the compressive tests show that these materials have different stress-strain curves among the specimens that containing different materials in the cells. Also, this metallic closed cellular materials containing polymer have higher compressive strength, higher Young’s modules, higher energy absorption and higher internal friction than that of metallic closed cellular material without any polymer.
Constitutive Modeling of TWIP Steel in Uni-Axial Tension
Authors: Kim Jin Kyung , Estrin Yuri , Beladi Hossein , Kim Sung Kyu , Chin Kwang Geun , De Cooman Bruno C.
Published: June 2010

High Mn steels demonstrate an exceptional combination of high strength and ductility due to their high work hardening rate during deformation. The microstructure evolution and work hardening behavior of Fe18Mn0.6C1.5Al TWIP steel in uni-axial tension were examined. The purpose of this study was to determine the contribution of all the relevant deformation mechanism : slip, twinning and dynamic strain aging. Constitutive modeling was carried out based on the Kubin-Estrin model, in which the densities of mobile and forest dislocations are coupled in order to account for the continuous immobilization of mobile dislocations during straining. These coupled dislocation densities were also used for simulating the contribution of dynamic strain aging on the flow stress. The model was modified to include the effect of twinning.
A Research on Interfacial Reaction of Brazing Joint of Alumina Ceramics to Metals
Authors: Ma Xiang Dong , Wang Xin Yang , Li Ji Wen , Wei Shi Zhong
Published: June 2010

Brazing with active filler alloys containing some active elements, which promotes wetting of ceramics surfaces, is one of the most widely methods for joining ceramics to metals. The joints formed by brazing A12O3 to metal by using copper-titanium-nickel (Cu-Ti-Ni) as brazing filler were investigated. The metals/ceramics joints were produced at a vacuum level of 10-2-10-3 Pa at 1273K, using a constant holding time of 10 min. The surfaces were studied both morphologically and structurally using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). In the brazing process, copper and titanium in the braze alloy form a series of reaction products. The formation of Ti3Cu3O and Ti2Ni at the interface is characteristic of these joints. The estimated free energies of formation of the Ti3Cu3O and Ti2Ni are -119kcal/mol and -245.92 kJ ~-263.78kJ/mol at 1200~1288K respectively. The highly negative values for the free energies of formation suggest that these compounds are thermodynamically stable.
Synthesis of Ni3Al/ZrO2 Nanocomposite and Study on Its High Temperature Oxidation in Mixed Gas Environment
Authors: Ismail Roslina , Yaacob Iskandar Idris
Published: June 2010

Intermetallic nanocomposites of nickel aluminide (Ni3Al) alloy and nanosized zirconia (ZrO2) were fabricated using combined powder metallurgy technique and reaction synthesis. Nanosized zirconia as dispersed phase at 2 and 5 weight percent were pre-mixed with nickel, aluminum powders and other alloying elements in a planetary ball mill for 18 hours at 175 rpm to achieve mechanical alloying effect. The mixture was then compacted using a hydraulic press at 400MPa for 15 minutes. Sintering was done under inert condition (flowing Argon gas) in a tube furnace at 850oC with 3 hours holding time. The saturation magnetization (Ms) values of nickel aluminide nanocomposites containing 2wt% ZrO2 (ICZ2) and 5wt% ZrO2 (ICZ5) were 7.94 and 3.65 emu/g respectively. Reduced elastic modulus (Er) for ICZ5 was lower than ICZ2. Isothermal oxidation/sulfidation test in 1%SO2/air gas mixture at 800 and 1000oC were performed using a thermogravimetric analyzer (TGA) for up to 24 hours duration. The isothermal kinetic results for ICZ2 and ICZ5 are parabolic indicating rate limiting step. Reaction rates increased with increasing temperature. At this low concentration of sulfur, the test specimen only exhibited adsorption of sulfur in the vicinity of the surface region and no sulfide phase was observed.
Development of a Robust TRIP800 Concept for GI/GA Automotive Applications
Authors: Lee Your Yeol , Kwak Jae Hyun , Kim Jong Sang , De Cooman Bruno C.
Published: June 2010

A robust TRIP 800MPa tensile strength concept was developed for automotive applications. An optimal TRIP steel composition containing 0.3 mass-% Si and 1.0 mass-% Al was identified. Galvannealing tests revealed that this TRIP steel had an ideal surface structure prior to hot dipping. Galvannealing could be achieved successfully in normal operating conditions. The contribution gives an in depth overview of the development of this new TRIP800 concept, with a special focus on achieving the optimum properties in various CGL line configurations.
Electronic Structure of Bilayer (Fe, Ni) Metallic α-Al2O3(0001) Catalysts Towards CH4 Adsorption and Dissociation
Authors: Wong Kenneth , Zeng Qing Hua , Yu Ai Bing
Published: June 2010

Density functional theory calculations are performed on the monometallic (Fe or Ni) bilayer modified α-Al2O3(0001) surface. Comparison has been made to their structural and electronic behaviors upon CH4 adsorption and dissociation. Local density of states and frontier orbital analysis show that C-H activation proceeds through weak chemical interactions with the metallic 3d electrons. It was found that electron transport within the sp and 3d type orbitals of the catalyst is important for the equilibration of the system. Such electron transport also promotes electron donation to the σ*(C-H) antibonding orbital for C-H bond activation. The calculated adsorption energies showed that the CH+H intermediate is most stable on the Fe/α-Al2O3 catalyst and is suspect to deactivation via carburization. Furthermore, C-H bond activation is most pronounced in cases where the CH4 molecule has one or two H atoms directed towards the catalyst surface.
Friction and Wear Behaviors of Solid Lubricants/Polyimide Composites in Liquid Mediums
Authors: Mu Li Wen , Feng Xin , Shi Yi Jun , Wang Huai Yuan , Lu Xiao Hua
Published: June 2010

The tribological properties of polyimide (PI) composites reinforced with graphite or MoS2 sliding in liquid alkali and water as well as dry friction were investigated using a ring-on-ring tester. The results show that the friction coefficient (μ) and wear rate (W) for both graphite/PI and MoS2/PI composites in different liquid mediums are μdry>μwater >μalkali and Wwater>Wdry >Walkali. Results also indicate that the friction coefficient and wear rate of the PI composites filled with different solid lubricants are μMoS2 >μgraphite and W MoS2 >Wgraphite in different liquid mediums. In addition, the hydrophobic inorganic fillers are fit for the reinforcement of polymer-based composites sliding in liquid mediums. It is also concluded from the authors’ work that the wear rate and friction coefficient of polymer-based (such as PI, PTFE) composites in the alkali lubricated conditions is lowest among all the friction conditions. This may be attributed to the ionic hydration in the alkaline solution.
Effects of Carbon Black and Carbon Nanotube on Mechanical and Thermal Properties of 80NR/20SBR Composites
Authors: Boonmahitthisud Anyaporn , Song Zheng Hua
Published: June 2010

This work aims to investigate the effects of carbon black (CB) and carbon nanotube (CNT) on mechanical properties and thermal behaviors of natural rubber (NR)/styrene butadiene rubber (SBR) blend at NR/SBR weight ratio of 80/20. CB loadings from 3-9 phr and CNT with 0.1-0.4 phr loadings were used as fillers in this study. The composites were prepared by latex compounding method. The specimens were examined for their tensile and dynamic mechanical properties and thermal stability using the universal testing machine, dynamic mechanical analyzer and thermal gravimetric analyzer, respectively. The tensile strength and modulus of the composites were improved as a result of the incorporation of CB and CNT. Dynamic mechanical analysis showed that the CB and CNT filled composites possessed high stiffness and low damping characteristics. Thermal stability of the composites was also proved to be better than the unfilled-rubber blend.
Structural Design for the Development of the Floating Type Photovoltaic Energy Generation System
Authors: Choi Hoon , Joo Hyung Joong , Nam Jeong Hun , Kim Kyoung Soo , Yoon Soon Jong
Published: June 2010

In this paper, we present the structural design for the development of the floating type photovoltaic energy generation system using pultruded FRP members. Pultruded FRP has superior material properties compared with those of conventional structural materials. Especially, pultruded FRP has an excellent corrosion-resistance along with high specific strength and stiffness, which are highly appreciated for the design and fabrication of the floating type photovoltaic energy generation system. In the paper, investigations pertaining to the mechanical and structural behaviors of FRP structural members based on the experiments are discussed. In addition to the experimental investigation, finite element analysis of the floating type photovoltaic energy generation system composed of pultruded FRP structural shapes has been performed. Finally, we have designed and developed the floating type photovoltaic energy generation system using the results of investigations.