bluuebunny/crossref_metadata_2025 huggingface dataset:
Damage Monitoring of Composite Materials Using Pulsed Phase Thermography and Thermoelastic Stress Analysis
Authors: Emery T.R. , Dulieu-Barton Janice M.
Published: March 2009

The current paper presents a new combined technique for damage detection, localisation
and establishing damage severity. The technique is based on the use of two infrared detection
approaches: Pulsed Phase Thermography (PPT) and Thermoelastic Stress Analysis (TSA). A
methodology is described that allows the technique to be applied to fibre reinforced composites.
The usefulness of the technique is demonstrated on delaminated glass epoxy laminates. A means of
developing controlled delamination damage in such specimens is developed so that real sub surface
damage is evaluated in the paper.
Effect of Impact-Fatigue on Damage in Adhesive Joints
Authors: Casas-Rodriguez Juan Pablo , Ashcroft Ian A. , Silberschmidt Vadim V.
Published: March 2009

In recent decades the use of structural adhesive joints in the aerospace industry has
increased considerably thanks to their high strength-to-weight ratio, low stress concentration and
capacity to join different adherends. There is increasing interest in damage due to low-velocity
impacts produced in adhesively bonded components and structures by vibrating loads. This type of
loading is known as impact fatigue. The main aim of this paper is to investigate damage evolution
in adhesive joints subjected to impact-fatigue and to compare this with damage evolution in
standard fatigue (i.e. non-impacting, constant amplitude, sinusoidal fatigue).
In this work, adhesively bonded lap joints were subjected to multiple tensile impacts tensile and
it was seen that this type of loading was extremely damaging compared to standard fatigue. A
number of methods of studying damage evolution in bonded joints subjected to fatigue and impact
fatigue loading have been investigated and various parameters have been used to characterise these
processes. Two modifications of the accumulated time-stress model [1-4] are proposed and it is
shown that both models provide a suitable characterization of impact-fatigue in bonded joints.
Wire Cable Failures in Climbing Anchor Chocks
Authors: Vogwell Jeffrey , Minguez Jose Maria
Published: March 2009

Anchor chocks are used in the sport of rock climbing for providing secure attachment
to a rock face. They are used at regular intervals and must be light weight (since many are carried)
and also sufficiently strong to withstand an impact force should a climber fall from a height. In
chock design, steel wire cable is widely used for connecting the nut component, which is wedged
into a rock crevice, to the free end which attaches, via a karabiner link, to the safety rope.
However, the wire cable is vulnerable to failure as it can fray with use at exposed ends -
especially when folded into a loop using tight bends. Also, the ferrule end connections are
considered a potential design weakness.
In a research programme tests have been carried out on new and also some well used anchor
chocks and has revealed very different, and some unpredicted, failure modes – depending on the
state of the wire rope and whether the applied load at failure was static or impact. This paper
presents the results of test failures for a range of chocks and discusses the benefits of using single
lengths of wire cable with suitably swaged end ferrules.
A Study on the Evaluation of Probabilistic Durability Life for RC Structures Deteriorated by Chloride Ion
Authors: Kim Dong Seok , Lee Han Seung , Lee Seong Min , Wang Xiao Yong
Published: March 2009

Chloride attacks concrete structures becoming a primary factor that deteriorates the
durability of concrete structures. For this reason, research has been conducted on chloride ion
penetration and diffusion. This research produced an accurate durability life prediction through
reliability assessments and proposes a prediction method for the chloride ion diffusion coefficient of
a concrete applied assessment program for reliability. As a result, test materials were fabricated
using different admixtures and chloride ion diffusion coefficient was calculated by applying an
RCPT test at each equivalent age. Based on these results, reliability prediction formulas were
indicated through the reliability analysis for a durability life design using a Montecarlo method. In
addition, propriety was verified through comparisons and analysis using the proposed formula with
the investigated data for chloride ion diffusion.
Fire Damage and Residual Strengths of Recycled Aggregate Concrete
Authors: Xiao Jian Zhuang , Zhang Chuan Zeng
Published: March 2009

In this paper, recycled aggregate concrete subjected to severe fire or high temperature
loading condition is investigated. Special attention of the study is devoted to analyze the fire-induced
damage and the residual strengths of recycled aggregate concrete. For this purpose, 160 cube
specimens are heated under a single thermal cycle of 20oC (ambient temperature), 200oC, 300oC,
400oC, 500oC, 600o, 700oC and 800oC, respectively. Different replacement percentages of the
recycled coarse aggregates (RCA) with 0, 30%, 50%, 70% and 100% are considered. Damage and
failure patterns of the recycled aggregate concrete specimens are analyzed systematically based on
experimental observations. The residual compressive strengths of the recycled aggregate concrete
(RAC) at elevated temperatures are studied and evaluated in details. Some differences between the
recycled aggregate concretes with different replacement percentages of the recycled coarse aggregates
are observed. On the basis of the experimentally measured residual compressive strengths of the
recycled concrete, relationships between the residual compressive strengths of the recycled aggregate
concrete and the elevated temperature are derived. The results presented in this paper have direct
applications in the design and structural analysis of reinforced concrete structures consisting of
recycled aggregate concrete.
Structure and Electric Property of BaTi2O5 Film by Laser Ablation
Authors: Wang Chuan Bin , Tu Rong , Goto Takashi
Published: March 2009

BaTi2O5 film was prepared on MgO (100) substrate by laser ablation, and the structure and electric
property of the film were investigated. The film was b-axis oriented and epitaxially grown on the
substrate along two in-plane directions with the a-axes ([100]-orientation) perpendicular to each
other. The b-axis oriented BaTi2O5 film exhibited a sharp permittivity maximum (~ 2000) and had
a high Curie temperature (750 K). The electrical conductivity increased with temperature and
showed the Arrhenius relationship having an activation energy of 1.25 eV.
Improvement of Orientation and Characterization of Dielectric Property for (Y,Yb)MnO3/HfO2/Si Structures
Authors: Suzuki Kazuyuki , Nishizawa Kaori , Miki Takeshi , Kato Kazumi
Published: March 2009

Y0.5Yb0.5MnO3 ferroelectrics/HfO2 stacking layers were successfully constructed on Si(100)
substrates through the chemical solution deposition. The degree of c-axis orientation and
microstructure of Y0.5Yb0.5MnO3 ferroelectrics was improved by the control of concentration of
precursor solutions. Capacitance of Pt/Y0.5Yb0.5MnO3/HfO2/Si structure was almost constant over
104 s on the retention property.
Electrochemical Properties of Lithium Titanate Synthesized by Reassembly of Nanosheets
Authors: Sato Keigo , Suzuki Shinya , Miyayama Masaru
Published: March 2009

The electrochemical properties of titanate nanosheets and layer-structured lithium titanate obtained
by restacking of titanate nanosheets were investigated in comparison with those of layer-structured
lithium titanate obtained by ion-exchange. Restacked lithium titanate was synthesized by
reassembling titanate nanosheets with LiOH aqueous solution. The nanosheets were 50-200 nm
wide and 1.7 nm thick. The crystal structure inside the nanosheets was the same as that the of parent
material. The oxidation current peaks observed in cyclic voltammograms of titanate nanosheets and
restacked material were 1.6 V (Li/Li+), which was lower than that of ion-exchanged material by 0.3
V. The discharge capacity of restacked material was 96 mAh g-1, indicating that 32% of the titanium
ions were reduced.
Magneto-Optical Effects in Superlattice Assemblies of Ferromagnetic Nanosheets
Authors: Osada Minoru , Ebina Yasuo , Takada Kazunori , Sasaki Takayoshi
Published: March 2009

We have demonstrated a fabrication procedure for spin-electronic devices by using two-dimentional
titania nanosheets. Magneto-optical Kerr measurements demonstrate that Co-substituted titania
nanosheets (Ti0.8Co0.2O2) act as nanoscale ferromagnetic layers at room temperature, and their
multilayer-assemblies exhibit robust magnetic circular dichroism (104–105 deg/cm) near the
absorption edge at 260 nm, an operating wavelength being the shortest attained so far. The
availability of ferromagnetic nanostructures and their molecule-level assembly allow the rational
design and construction of high-efficiency magneto-optical devices by forming superlattices.
Preparation of C-Ru-RuO2 Nano-Composite Films by Plasma-Enhanced CVD and their Electrode Property
Authors: Sakata Masato , Kimura Teiichi , Goto Takashi
Published: March 2009

C-Ru-RuO2 nano-composite films were prepared by plasma-enhanced chemical vapor deposition
and their microstructure and electrode properties were investigated. Ru-C nano-composite films
consisted of Ru nano-particles of 3 nm in diameter and an amorphous C matrix. With increasing
oxygen gas flow rate (FRO2), the volume fraction of C decreased from 0.91 to 0 and Ru
nano-particle size increased from 2.5 to 4.5 nm. At high FRO2, the film consisted on the fibrous
RuO2 and Ru-C nano-composite layer. Ru-C nano-composite containing 91 vol% C showed the
highest interfacial electrical conductivity below 673 K, and Ru-C/RuO2 composite containing 0 – 5
vol% C showed the highest interfacial electrical conductivity at 873 K. Electro-motive-force
(EMF) values of an oxygen concentration cell constructed from a YSZ electrolyte and Ru-C or
Ru-C/RuO2 composite electrodes responded to the change of oxygen gas partial pressure at more
than 473 K. The response time of the concentration cell with Ru-C nano-composite electrodes at
573 K was less than 10 s, and that with Ru-C/RuO2 composite electrodes was about 300 s.
Fabrication and Characterization of Alkoxy-Derived (Na, K)NbO3 Series Powder
Authors: Tanaka Kiyotaka , Kakimoto Kenichi , Ohsato Hitoshi
Published: March 2009

Various KNbO3 powders have been derived from sol-gel process by using different preparation and
heating conditions. KNbO3 powder derived from ethanol solution and fabricated at 800oC was most
suitable as the raw material of KNbO3 bulk ceramics, because of the small grain size of about 250
nm and its homogeneous size distribution.
Dielectric Measurement for Barium Titanate Nanoparticles Using Far Infrared Reflection Method
Authors: Hoshina Takuya , Kakemoto Hirofumi , Tsurumi Takaaki , Wada Satoshi
Published: March 2009

Barium titanate (BaTiO3) nanoparticles with various particle sizes from 20 to 430 nm were prepared using a 2-step
thermal decomposition method. Powder dielectric measurement clarified that dielectric constant of BaTiO3 particles
with 140 nm exhibited a maximum around 5,000. To explain this high dielectric constant, THz-region dielectric
properties of BaTiO3 nanoparticles, especially Slater transverse optic (TO) mode frequency, were estimated using the
far infrared (FIR) reflection method. As the result, it was found that the Slater TO mode of BaTiO3 particles with 140
nm exhibited a minimum. Therefore, the high dielectric constant around 5,000 at 140 nm can be originated
from the softening of the Slater TO mode.
The State and Optical Properties of Crystalline BaTiO3 Nanoparticles Dispersed in Various Suspension Media
Authors: Koyama Mikiko , Murakami Sachi , Iwaji Naoki , Takebe Hiromichi , Kuwabara Makoto
Published: March 2009

An investigation has been made on the state of barium titanate (BaTiO3; BTO, hereafter) nanoparticles of 10-15 nm in diameter dispersed in various suspension media, such as 2-methoxyethanol (ethylene glycol monomethyl ether: EGMME) with and without acetylacetone (Acac), ethanol, and isopropanol. The state of the nanoparticles dispersed in these suspension media is deduced from the behavior pattern of their optical transmittance (T), in the wavelength (λ) range of 300-900 nm; the concentration (c) of BTO nanoparticles in the suspensions was varied from 0.01 to 0.25 mol/L. T-c plots obtained for EGMME+Acac and EGMME suspensions at various wavelengths indicate that BTO nanoparticles take two and three different states in the suspensions, respectively, from mono-dispersed to agglomerated states with increasing c.
Defects and Leakage Current in PbTiO3 Single Crystals
Authors: Tamada Minoru , Noguchi Yuji , Miyayama Masaru
Published: March 2009

Single crystals of PbTiO3 (PT) were grown by a self flux method, and effects of lattice defects on the leakage current properties were investigated. While PT crystals annealed in air at 700 oC showed a leakage current density of the order of 10-5 A/cm2, annealing under a high oxygen partial pressure of 35 MPa increased leakage current density to 10-4 A/cm2. The increase in leakage current by the oxidation treatment provides direct evidence that electron hole is a detrimental carrier for the leakage current property of PT at room temperature. The vacancies of Pb are suggested to act as an electron acceptor for generating electron holes.
Phase Transition Temperatures of Divalent and Trivalent Ions Substituted (Bi1/2Na1/2)TiO3 Ceramics
Authors: Hiruma Yuji , Watanabe Yoshinori , Nagata Hajime , Takenaka Tadashi
Published: March 2009

The phase transition temperatures of divalent and trivalent ions substituted (Bi1/2Na1/2)TiO3
ceramics were investigated in detail by electrical measurement. BNT ceramics substituted by
divalent (Ca2+, Sr2+ and Ba2+) and trivalent (La3+, Nd3+, Ho3+ and Yb3+) ions were prepared by
conventional ceramic fabrication process. For these ceramics, the depolarization temperature, Td,
the rhombohedral-tetragonal phase transition temperature, TR-T, and the temperature of the
maximum dielectric constant, Tm, were determined on the basis of the temperature dependences of
dielectric and piezoelectric properties. In this study, we demonstrated the relationship between
phase transition temperature and ionic radius of ions substituted in the A-site of BNT ceramics.
Microstructure Characteristics of Spray-Formed and Melt-Spun Al85Nd5Ni10 and Al89La6Ni5 Bulk Hybrid Composites
Authors: Guo M.L.T. , Tsao Chi Y.A. , Huang J.C. , Jang Jason S.C.
Published: March 2009

The microstructure characteristics of the spray-formed and melt-spun Al85Nd5Ni10 and Al89La6Ni5 alloys were studied. The spray forming process was demonstrated to produce a bulk scale hybrid composite consisting of amorphous and nanostructured phases directly without the need of an amorphous precursor. The spray-formed Al89La6Ni5 deposit (~1 mm in thickness) were partially amorphous, and the amorphous phase came from the undercooled liquid droplets upon deposition. The as-spray-formed Al85Nd5Ni10 deposit (~20 mm in thickness) was completely crystallized due to the devitrification of the retained amorphous phase to nano-scale secondary crystals upon deposition. Primary crystals (~1 μm) are dispersed uniformly in the bulk spray-formed amorphous/or partial amorphous composites and many distinctive deformation twins also are observed in the crystals, however, not twins found in the corresponding completely devitrified ribbon. This is mainly because of the stirring and impacting force offered by high velocity droplets during spray forming and the mismatch of thermal expansion coefficient between primary crystals and adjacent amorphous matrix.
Thermodynamics of the Effect of Alloying Additions on In-Situ Reaction to Synthesize TiC/Mg Composites
Authors: Cao Wei , Zhang Cong Fa , Fan Tong Xiang , Zhang Di
Published: March 2009

The effect of the alloying element additions on in-situ chemical reaction to synthesize particulate reinforced TiC/Mg composites was evaluated from the viewpoint of thermodynamics. The influences of alloying elements on the changes of the activity coefficient and the excess free energy in molten magnesium were calculated. The results show that additions, such as Nd, La, Ca, Cu and Zr can promote TiC formation, at the same time hinder the brittle TiAl3 phase formation.
Spark Plasma Sintering of α-Si3N4 Ceramics with MgO-Al2O3 as Sintering Additives
Authors: Yan Fa Qiang , Chen Fei , Shen Qiang , Zhang Lian Meng
Published: March 2009

In the present study, α-Si3N4 is prepared by using MgO and Al2O3 as the sintering additives and spark plasma sintering (SPS) technique. The SPS sintering mechanism is discussed. The relationship between the content of sintering additives, sintering temperature and relative densities of the samples is analyzed. The results suggest that when the sintering temperature is 1300-1500°C, the content of sintering additives is 6wt.%-10wt.%, the relative density of sintered samples is 64%-96%. When the sintering temperature reaches 1400°C, the content of sintering additives is 10%, the samples can be fully dense sintered and the relative density can be up to 95%. The sintering mechanism is liquid phase sintering. The bending strength of the sintered samples is 50-403MPa and has a close correlation with the relative density.
Study on the Thermodynamics and Kinetics in the Combustion Reaction between Titanium and Boron Powders
Authors: Wang K. , Fu Zheng Yi , Wang Wei Min , Wang Yu Cheng , Wang H. , Zhang Jin Yong , Zhang Qing Jie
Published: March 2009

Combustion synthesis of titanium diboride(TiB2) from titanium(Ti) and boron(B)
powders was studied by theoretical calculation and experimental analysis. In high temperature
range or in low temperature range, the calculated activation energies are 140KJ/mol or 355KJ/mol
respectively, which is described by a change from dissolution-precipitation controlled process to
diffusion-controlled process. With the increase of particle size of the raw materials, combustion
temperature and propagating rate will both reduce. The propagating rate decreases with the addition
of diluents. Further increase of diluents may result in a stop of the combustion wave halfway or
even a failure of ignition.
Fabrication CNTs/SiO2 Laminated Structure from Aqueous Tape Casting
Authors: Zhu Yong , Xiang Chang Shu , Xu Heng , Pan Yu Bai , Guo Jing Kun
Published: March 2009

Well-dispersed SiO2 slurry with high solid content for aqueous tape casting was obtained by selecting the appropriate dispersant, binder, plasticizer and other additives. However, it is difficult to prepare well-dispersed CNTs/SiO2 slurry because CNTs tend to aggregation and the bulk density disparity of CNTs and SiO2 is obvious. In addition, the contradiction between removing organic additives and retaining the properties of CNTs should be considered. Some methods are provided to solve the as-mentioned difficulties.
Materials Characterization in Continuous Fiber-Reinforced Ceramic Composites Served in Simulating Environment
Authors: Li Jian Zhang , Zhang Li Tong , Cheng Lai Fei , Xu Yong Dong , Qiao Sheng Ru , Jiao Gui Qiong , Zhang Jun , Luan Xin Gang
Published: March 2009

Materials characterization is a crucial issue in the development and application of new materials. Materials characterization aims to mine and acquire characteristic information and their evolution in the materials. It mainly includes three important topics which are microstructural characterization, properties characterization, and environmental degradation. In this paper, characterization techniques about these topics were discussed for C/SiC composites and a characterization system was preliminarily established. All these characterization research and their results further the better understanding of the relationship between microstructure and properties and of the failure mechanisms in the C/SiC composites.
Rate Equations for Material Transport Driven by Excess Free Energy in Solid
Authors: Tanaka Hidehiko
Published: March 2009

Diffusion phenomena in solid particles were analyzed with the new material transport
concept. It was assumed that total excess free energy in a system acted as a driving force for
material transport so that the system changed to an equilibrium state. The new rate equation was
adopted to analyze shape change, sintering and growth of grains. It was found that surface energy or
ratio of grain boundary energy to surface energy was key factor for shape changes in these
processes.
Two-Dimensional Heat Transfer Model for Rapid Solidification of Ceramic Alloys
Authors: Nikolic Zoran S. , Yoshimura Masahiro
Published: March 2009

A finite difference method based on control volume methodology and interface-tracking
technique for simulation of rapid solidification accompanied by melt undercooling will be described
and applied to analyze the solidification of alumina sample on copper substrate.
Innovation in SiAlON Ceramics
Authors: Thompson Derek P.
Published: March 2009

The discovery of sialons in 1971 was a significant step in the history of nitrogen ceramics, because it broadened the field into a wider range of chemistry, and simultaneously increased the flexibility to modify microstructure and properties. During the last 35 years this has resulted in the development of a spectrum of materials, mainly based on the α- and β- structural forms. However, the subject has remained broadly within the scope of structural ceramics. During the 1990s, a range of new sialon derivatives were prepared with a more varied starting chemistry, and the corresponding final materials demonstrated a correspondingly wider variety of structural complexities. In response, many sialon researchers have started to broaden their interests beyond the limiting horizon of structural applications, and considerable progress has been made in the development of transparent and coloured materials, and also derivatives with useful electronic properties.This enlargement of the sialons field is still in its infancy, but promises to generate a much wider spectrum of materials, which can be tailored to meet the increasingly multifunctional requirements of modern day engineering applications.
Sintering Mechanism of Fine Zirconia Powders with Alumina Added by Various Ways
Authors: Matsui Koji , Yamakawa Takanori , Uehara Masato , Enomoto Naoya , Hojo Junichi
Published: March 2009

Small amounts of Al2O3 were added to fine zirconia powder by different ways: powder
mixing, hydrolysis of alkoxide, and homogeneous precipitation. During a constant rate heating
process, the Al2O3 addition slightly raised the starting temperature of densification of powder
compact, and the densification was remarkably stimulated by Al2O3 at temperatures above about
1100oC. According to an isothermal analysis of densification, the densification rate was retarded by
Al2O3 addition just after the start of sintering and then the densification rate increased significantly
during sintering compared to Al2O3-free powder. These results mean that Al2O3 particles pinned the
shrinkage of zirconia powder compact at the initial stage, and diffuse toward zirconia surface to
enhance the sintering. The sintering mechanism was explained by the grain-boundary diffusion for
the Al2O3-free powder and the volume diffusion for Al2O3-added powder. When the Al2O3 was added
to zirconia powder by homogeneous precipitation and alkoxide methods, the densification rate was
more stimulated compared to powder mixing method. The sintering mechanism did not change by
the way for Al2O3 addition. The Al2O3 addition by the chemical process tended to enhance the grain
growth of zirconia, while the uniform microstructure was achieved because of homogeneous
addition of Al2O3 by these chemical processes.
A.C. Impedance Spectroscopy of B-Axis Oriented SrO Substituted BaTi2O5 Prepared by Arc-Melting
Authors: Yue Xin Yan , Tu Rong , Goto Takashi
Published: March 2009

b-axis oriented SrO substituted BaTi2O5 (Ba1-xSrxTi2O5) was prepared by arc-melting. The effect of SrO substitution on the dielectric properties of BaTi2O5 (BT2) was investigated by A.C. impedance spectroscopy. The Cole-Cole plot of Ba1-xSrxTi2O5 showed a distorted semi-circle which was deconvoluted into two semicircles corresponding to the bulk BT2 and a second phase. The complex impedance, modulus and capacitances from the ferroelectric bulk matrix and the paraelectric second phase of Ba1-xSrxTi2O5 were simulated by a Maxwell-Wagner model.
Hydrothermal Synthesis of TiO2/SiO2 Hybrid Photocatalyst from Rice Husk Ash
Authors: Sujaridworakun P. , Jinawath Supatra , Panpa W. , Nakajima Akira , Yoshimura Masahiro
Published: March 2009

Photocatalyst materials were prepared as a hybrid between TiO2 /SiO2 via low temperature
hydrothermal method (150oC) without further heat treatment. Porous silica from rice husk ash was
used as a support for fine TiO2 particles which acted as a photocatalyst when radiated with a UV light.
TiO2-deposited SiO2 was successfully prepared through hydrolysis of TiOSO4 solution by controlling
synthesis parameters such as pH ,concentration of TiOSO4, temperature and time under hydrothermal
treatment. The obtained products were characterized for physical and chemical properties by means of
XRD, XRF, BET and TEM . It was found that pH had an influence on the crystallization of TiO2, and
under an appropriated pH, only anatase presented along with amorphous phase. High crystallinity of
nano-crystalline anatase ( about 5 nm) deposited on silica surface was observed through TEM.
Adsorption and photocatalytic performances of the prepared catalyst were evaluated in methylene
blue aqueous solution in the dark and under ultraviolet ray irradiation, respectively. Due to the
synergetic functions of adsorption by porous substrate and decomposition by TiO2 photocatalyst, an
enhancing of photocatalytic activity for decomposition of organic pollutants in water under UV rays
was obtained.
Epitaxial Growth of B-Axis Oriented BaTi2O5 Films by Laser Ablation
Authors: Wang Chuan Bin , Tu Rong , Goto Takashi
Published: March 2009

A new lead-free ferroelectric BaTi2O5 film was first prepared by laser ablation. BaTi2O5
films in a single phase were obtained at substrate temperatures (Tsub) from 900 to 1050 K and oxygen
partial pressures (PO2) from vacuum (10-6 Pa) to 30 Pa. The films exhibited a (710) and/or (020)
preferred orientation, depending on Tsub and PO2. At PO2 = 12.5 Pa and Tsub = 950 - 1000 K, the
BaTi2O5 film was b-axis oriented and epitaxially grown on MgO (100) substrate with a rectangularly
crossed texture. The epitaxial growth relationship between the film and the substrate were BaTi2O5
(020) [100] // MgO (100) [001] and BaTi2O5 (020) [100] // MgO (100) [010].
Measurement of Indentation Fracture Toughness of Silicon Nitride Ceramics: II, Effect of the Experimental Conditions
Authors: Miyazaki Hiroyuki , Hyuga Hideki , Yoshizawa Yuichi , Hirao Kiyoshi , Ohji Tatsuki
Published: March 2009

The influence of two measuring conditions, the elapsed time after indentation and the condition of edge of an indenter, on the indentation fracture toughness of silicon nitrides was assessed. No slow crack-growth after unloading was confirmed by optical microscopic observation of a crack tip induced by the indentation, which led to the negligible difference in fracture toughness measured at 1 and 30 min after the indentation. Measurements with relatively new and used indenters gave almost the same fracture toughness data, indicating that the crack lengths were hardly affected by the slight damage of the corner of the indenter. It was suggested that the large scattering of the indentation fracture toughness reported by the round-robin tests such as VAMAS was not originated from these factors.
Computer Study of Skeletal Settling Combined with Extrication of Solid Phase Domains during Liquid Phase Sintering of Tungsten Heavy Alloy
Authors: Nikolic Zoran S. , Yoshimura Masahiro
Published: March 2009

In this paper, we investigated numerically gravity induced skeletal settling during liquid phase sintering. The microstructural evolution will be simulated by simultaneous computation of displacement of the center of mass and mass transport due to dissolution and precipitation at the interfaces between solid-phase and liquid matrix. Common to this study based on domain methodology for definition of regular multi-domain model will be the need to relate some diffusional phenomena to essential geometric and topological attributes of the W-Ni porous microstructure influenced by skeletal settling combined with extrication of some solid-phase domains during liquid phase sintering.
Study on Micro-Mechanism of Crack Initiation and Propagation Induced by Inclusion in Ultra-High Strength Steel
Authors: Zeng Yan Ping , Fan Hong Mei , Wang Xi Shu , Xie Xi Shan
Published: March 2009

Specially designed SEM in-situ tensile and fatigue tests have been conducted to trace the
entire process of crack initiation and propagation till fracture in an ultra-high strength steel MA250.
TiN is a typical inclusion and its average size is in the range of 8~10μm in MA250 steel. The
micro-mechanism of the effect of TiN inclusion on crack initiation and propagation at tensile and
fatigue tests both have been studied in detail. Experimental results show the harmful effect of TiN
on tensile and fatigue properties both. This work is helpful to establish the practical life prediction
model for the characteristic inclusion parameters in ultra-high strength steel components. It also
enlightens us to eliminate TiN in the further development of ultra-high strength steels.
Synthesis of Boron Carbonitride Films by Plasma-Based Ion Implantation
Authors: Xu Shu Yan , Ma Xin Xin , Sun Ming Ren
Published: March 2009

BCN films were prepared with unbalanced magnetron sputtering boron carbide film
followed by nitrogen plasma-based ion implantation at different voltages on Si substrate. The
implantation voltages vary from 10 kV to 50 kV. The chemical states of B, C and N of the films were
studied with X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy
(FTIR). The nano-hardness and elastic modulus of films were measured by Nano-Indenter. The
results showed that amorphous BCN films formed in the nitrogen implanted layer. The amorphous
peak becomes obvious with increasing of the implanted voltage when the voltage is under of 40 kV.
The Nano-Indenter measurement showed that the B-C bond content and the disorder degree affect the
hardness and modulus.
Development of Cu Brazing Sheet with Cu-P Composite Plating
Authors: Shohji Ikuo , Arai Susumu , Kano Naoki , Otomo Noboru , Uenishi Masahisa
Published: March 2009

A Cu brazing sheet has been developed using a Cu-P composite plating method. A Cu-P
composite plating layer, which contains 7mass%P, was formed on a Cu plate with a copper sulfate
solution including P particles. The melting start temperature of the Cu-P composite layer was
determined to be approximately 765°C. Microstructure and joint strength of a brazed joint with the
Cu-P composite layer were investigated and compared with those of the joint with a conventional
Cu-7P filler foil. As the results of the study, it was clarified that the Cu-P composite layer
developed is feasible to use as a brazing material for Cu and Cu alloys.
Wavelet Denoising of the Horizontal Vibration Signal for Identification of the Guide Rail Irregularity in Elevator
Authors: Du Xiao Qiang , Yao Zhe He , Chen Zi Chen
Published: March 2009

Wavelet denoising method was introduced to improve the validity of identifying the guide
rail irregularity in elevator. The horizontal acceleration signal measured from a test elevator was
processed by wavelet denoising. Then the denoised signal was decomposed up to four levels using
Daubechies 4 mother wavelet to identify the guide rail irregularity. The results indicate that the
impulses due to the guide rail irregularity are prominent in wavelet decompositions. And the causes
resulting in those characteristics of the vibration signal can be well revealed. So discrete wavelet
transform (DWT) can be used as an effective tool for denoising the horizontal vibration signal of
elevator and diagnosing faults in the guide rail.
Study on the Control and Test of High Precision Honing Machine for Injection Nozzle
Authors: Shi Lun
Published: March 2009

Because of the high precision in roundness, straightness and roughness, it is very difficult
to machining the inner surface of injection nozzle. Honing machine is the main equipment for
machining the injection nozzle. The key honing control techniques and honing test for injection
nozzle on the developed high precision vertical honing machine are analyzed. The quantitative
expansion，which is one of the most important feeding styles in honing process, is discussed in
detail. Some machining tests on the developed honing machine are made and the work pieces of
injection nozzles with inner surface Φ11mm are honed successfully with roundness tolerance less
than 0.4μm, straightness tolerance less than 1μm and roughness tolerance less than 0.04μm.
A Calculating Method of the Least Feeding Times in Cylinder Cam’s Grinding
Authors: Zhang Yi Tong , Hu Zhan Qi , Zhang Hong Li
Published: March 2009

The accurate calculation and the approximate calculations of the cylinder cam’s curve
enveloping surface in single-tool-position-compensation are compared. It is proved that the
approximate formula is enough precision for engineering purpose. Based on the analyses for the
approximate formula, the calculating method of the least feeding times of the
multi-tool-position-compensation is proposed. This method provides theoretical foundation for
complex surface’s high efficiency and great precision grinding as well as optimal machining
control.
Research on Nanoscale Material Removal Process Using Atomic Force Microscopy
Authors: Zhang Fei Hu , Zhang Hua Li , Yan Yong Da , Wang Jing He
Published: March 2009

Nanomachining tests have been conducted on single-crystal Al using atomic force
microscope to simulate single-blade machining process of single gain. The influences of
nanomachining experimental parameters (lateral feed and velocity) on the properties of engineering
surface, material removal and chip formation were studied. Results indicated that the cutting depth
of nanomachined surface increased as the lateral feed decreased. Insensitivity of cutting depth to
velocity at same normal load was revealed. The different chip behaviors of nanomachined surface
were investigated through scanning electron microscope (SEM). Results indicated that different
lateral feeds caused different chip behaviors. Three typical chip behaviors were characterized as the
lateral feed increased. In addition, the chip behavior and the volume of material removed were
observed having no evident linear transformation with the evolution of the velocity by SEM
graphics. Furthermore, it was concluded from the chip behaviors in nanomachining process that the
material at high loads was removed by plastic deformation with no fracture or crack happened.
Influences of Machining Parameters on Silicon Wafer Polished with Gel-Coupled Ultra-Fine Abrasive Polishing Pads
Authors: Liu Juan , Xu Xi Peng
Published: March 2009

In this paper, a newly developed ultra-fine abrasive polishing pad by gel technology was
adopted to polish silicon wafer on a nano-polishing machine. In order to evaluate the machining
performances of the polishing pad, the influences of abrasive sizes, abrasive concentration and
polishing parameters (pressure, rotating speed and machining time) on the silicon wafer were
investigated respectively. Optical microscope and ZYGO 3D surface analyzer were applied to
examine the surface morphologies and surface roughness of the polished silicon wafer respectively.
The experimental results showed that the surface roughness of silicon wafer decreased with the
decreasing of abrasive grits and the increasing of abrasive concentration and polishing parameters
(pressure, rotating speed and polishing time) when polishing silicon wafer with the polishing pad
containing Al2O3 abrasive. When abrasive concentration, polishing pressure and polishing time
reached certain values, few changes would happen for the silicon wafer.
Surface Texturing Technology by Laser Honing Based on Hydrodynamic Lubrication
Authors: Zhang Yong Kang , Yang Chao Jun , Fu Yong Hong , Zhou Jian Zhong , Hua Xin Jun , Ji Jing Hu
Published: March 2009

The laser honing technique is a new surface texturing technique. As the piston ring at the
top or lower oil attachment point works under worse lubrication condition, its wear increases
severely, laser texturing was used to the piston ring/liner, lineary extending grooves and regular
arranged dimples with predetermined parameters was well-matched with the needs of lubrication.
The effects of different dimple shapes, such as sphere coronal, combined sphere coronal ,columnar,
hexahedral, and trapezoidal dimples was analyzed by the theory of hydrodynamic lubrication. It
was deduced that trapezoidal dimples are fit for only single running orientation and sphere coronal
and combined sphere coronal dimples are fit for double running orientations. The experimental
researches show that laser texturing not only can reduce the oil consumption and the cost of engine
but also can prolong its work life.
Basic Experimental Research on the NC-Contour Evolution Ultrasonic Assisted Grinding Ceramic Blade Surface
Authors: Zheng Jian Xin , Xu Jia Wen
Published: March 2009

Ultrasonic machining is a practical process for advanced ceramic machining. Usually, ceramics with complex surfaces are machined with two common ultrasonic assisted contour machining methods, which may be classified as surface/point contact machining mode. While these methods are not suitable to machine some complex surfaces such as blade surface, so an ultrasonic assisted contour machining method using a simple shaped diamond grinding wheel to machine ceramic blade surface is presented, which is named as Numerical Control-Contour Evolution Ultrasonic Assisted Grinding (NC-CEUAG) method. In the NC-CEUAG process, the contour evolution motion of the grinding wheel is controlled by the NC system and the blade surface is the enveloping surface formed by the grinding wheel’ cutting edges when they cut into the ceramic specimen. In this paper, the relative motion between the grinding wheel and the specimen in the process of NC-CEUAG ceramic blade surface is analyzed. The mathematical models of ruled surfaces are constructed. The ceramic blades with ruled surface are machined with selected machining parameters on the retrofitting NC-CEUAG machine tool.
A Study of Micro Machining with Instantaneous Tiny-Grinding Wheel Based on the Fe3O4 Magnetorheological Fluid
Authors: Lu Jia Bin , Yan Qiu Sheng , Yu Juan , Tian Hong , Gao Wei Qiang
Published: March 2009

In this study, Fe3O4 particles were used as magnetic particles to form Fe3O4 magnetorheological (MR) fluid, and experiments were conducted to polish optical glass using this Fe3O4 MR fluid. The machining characteristics of glass surface with different MR fluids that are added diamond abrasives and short fibres are studied. Experimental results indicate that the tiny-grinding wheel based on the Fe3O4 MR fluid can effectively polish optical glass and that the maximum diameter and depth of machined region increase obviously in the presence of diamond abrasives and short fibres. When both of diamond particles and short fibres are added to the Fe3O4 MR fluid, the removal efficiency of the tiny-grinding wheel is markedly enhanced due to the synergetic effect of diamond abrasives and fibres.
Study on Dynamical Characteristics of Catenary Transformer in Gear Honing
Authors: Wang Shi Ying , Lv Ming , Ya Gang
Published: March 2009

Ultrasonic vibration can reduce honing forces efficiently. As the honing wheel can be washed by ultrasonic cavitations of cooling liquid, its jams are decreased and the higher honing efficiency has obtained. Therefore, the combination of ultrasonic machining and gear honing is a method for gear fine machining with its wide application future. However, the gears with big diameter and thickness machined by ultrasonic honing are special loads, which influence the machining frequency of vibration system heavily. Hence, the horn and gear must be considered at the same time while designing the vibration system. In this paper, the frequency equations are derived according to stress match, wherein, the gear is considered as a thin disc and catenary horn is adopted. Then the influences of vibration of transformer that consists of horn and gear are investigated with the variety of the horn length and the machining frequency. The theoretical analysis shows that the resonance frequency of the horn and detune frequency of transformer have the different value. The results are proved by FEM, too.
Modeling of Material Removal Rate in Two-Dimensional Ultrasonic Grinding Complex Ceramics
Authors: Gao Guo Fu , Zhao Bo , Kong Qing Hua , Liu Chuan Shao
Published: March 2009

Based on the machining pattern, mechanics of material removal and theory of
micro-indentation, in previous studies the models of material removal rate of hard-brittle materials
was discussed through the relatively influencing factors of machining parameters from various
aspects, reflecting the research advances on mechanics of material removal of hard-brittle materials.
However, those models of material removal rate have limitations, which results from impercipient
theory of fracture of new kinks of materials, randomicity of practical machining process,
inappropriate assumptions and simplification of the machining conditions and so on. In this work
firstly, previous models of material removal rate of hard-brittle materials machining with ultrasonic
assistance were reviewed briefly. Subsequently, the models of material removal rate of complex
ceramics machining with two-dimensional ultrasonic vibration assistance were established based on
fracture theory of micro- indentation in fracture regime and plastic removal mechanics in ductile
regime respectively. The material removal rate is affected not only by the properties of material and
machining parameters, but also by the character of grinding wheel and parameters of ultrasonic
vibration.
Study on Removal Mechanism of Fixed-Abrasive Diamond Wire Saw Slicing Monocrystalline Silicon
Authors: Gao Yu Fei , Ge Pei Qi , Hou Zhi Jian
Published: March 2009

The physical model of fixed-abrasive diamond wire-sawing monocrystalline silicon was founded to analyze the elastic deformation of the wire, supposing that every grit was connected to the surface of the wire by a spring. Ignoring lateral vibration of the wire, the geometrical model of wire-sawing was founded; the average cut depth of single grit was calculated theoretically. Based the indentation fracture mechanics and investigations on brittle-ductile transition of machining monocrystalline silicon, the removal mechanism and surface formation was studied theoretically. It shows that in the case of wire-sawing velocity of 10m/s or higher, infeed velocity of 0.20mm/s and diamond grain size of 64μm or smaller, the chip formation and material removal is in a brittle regime mainly, but the silicon wafer surface formation is sawed in a ductile regime. The size of the abrasives, the wire-saw velocity and infeed velocity can influence the sawing process obviously.
Study on the Wear Mechanism of Brazed Diamond Grains
Authors: Zhang Guo Qing , Huang Hui , Xu Xi Peng
Published: March 2009

Plenty of studies on wear mechanism of diamond grains show that the specific failure form of single diamond grit has a close relationship with its load. Monolayer diamond grinding wheels and samples for shearing test are prepared by a high frequency induction brazing technique in this paper. The normal abrasion mechanism of diamond grains has been found through the comparison between the single grain tangential load during grinding and the shearing failure-load of the single grit of the test samples. The result shows that the dynamic strength of diamond grains is relative to the static strength after being brazed. Most of the grains are micro-broken during grinding, and only a few of them are pulled-out or broken-off.
Mechanism of Material Removal and the Generation of Defects by MD Analysis in Three-Dimensional Simulation in Abrasive Processes
Authors: Chen Jia Xuan , Liang Ying Chun , Bai Qing Shun , Tang Yu Lan , Chen Ming Jun
Published: March 2009

Molecular dynamics (MD) simulations of nanometric scratching with diamond tip are conducted on single crystal copper crystal plane (010), and MD simulations are carried out to investigate the mechanism of material removal and the generation of defects on the surface, subsurface and inner of material. During the process of diamond tip scratching the surface of single crystal copper on conditions of different scratching speeds, depths and widths. We achieved the forming details of the chip. While the generation and moving process of defects, such as dislocation, are recorded. The different times of atomic displacement and interaction force are also shown through MD simulation. The evolvement of the lattice pattern in the abrasive processes are analysed by radial distribution function (RDF) and computing the changes of workpiece’s atomic displaces and forces. At the same time, the lattice reconfiguration and the onset and the evolvement process of defects and are analysed by RDF and atomic perspective method, respectively. The simulation results show that scratching speed play role in the course of the form of removing chips, and that different scratching widths and depths of tool have effect on onset and evolvement of lattice defects of workpiece in abrasive processes. This study can give more fundamental understanding of nanosconstruction from atomistic motions and contribute to the design, manufacture and manipulation of nano-devices
Passivation Model of Diamond Grinding Wheel in Constant-Force Grinding of Si3N4 Ceramic
Authors: Tian Xin Li , Wu Zhi Yuan , She An Ying , Hu Zhong Xiang
Published: March 2009

Grinding wheel passivation is an inevitable phenomenon during grinding process. It has
important guiding significance for the formulation of grinding technique to unveil the passivation rule
and generation mechanism. Taking grinding efficiency as evaluation indicator, the passivation curve
of grinding wheel during full passivation period under the constant-force grinding condition is
established through experiments in this dissertation, which is divided into three stages according to
passivation speeds and passivation patters, i.e. early passivation stage, stable passivation stage and
sharp passivation stage. Of which, the passivation speed is the slowest but with the highest grinding
efficiency in early passivation stage. The change of passivation curve with the time is a process from
concave to convex, which is totally different from the wearing process of grinding wheel in this stage.
With combination of experiment conditions and wearing characteristics of grinding wheel, the
passivation rule and its generation reasons are discussed deeply. Furthermore the exponential
function y = abx is adopted to make fitting for passivation curve based on the scatter plot of stable
passivation stage and regression equation is derived through the fitting result of origin thus to testify
the correctness of the inference.