bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Zirconia Plasma-Sprayed Coating on Creep of the Ti-6Al-4V Alloy
Authors: Reis Danieli A.P. , Silva Cosme Roberto Moreira , Nono Maria do Carmo de Andrade , Barboza M.J.R. , Neto Francisco Piorino , Vieira R.A.
Published: March 2009

The titanium affinity by oxygen is one of main factors that limit the application of
their alloys as structural materials at high temperatures. Notables advances have been
obeserved in the development of titanium alloys with the objective of improving the specific
high temperature strength and creep-resistance properties. However, the surface oxidation
limits the use of these alloys in temperatures up to 600°C. The objective of this work was
estimate the influence of the plasma-sprayed coatings for oxidation protection on creep of the
Ti-6Al-4V alloy, focusing on the determination of the experimental parameters related to the
primary and secondary creep states. Constant load creep tests were conducted with Ti-6Al-4V
alloy in air for coated and uncoated samples and in nitrogen atmosphere for uncoated samples
at 500°C to evaluate the oxidation protection on creep of the Ti-6Al-4V alloy. Yttria (8 wt.%)
stabilized zirconia (YSZ) with a CoNiCrAlY bond coat was atmospherically plasma sprayed
on Ti-6Al-4V specimens. Results indicated the creep resistance of the coated alloy was greater
than uncoated in air, but nitrogen atmosphere was more efficient in oxidation protection.
Previously reported results about the activation energies and the stress exponents values
indicate that the primary and stationary creep, for both test conditions, was probably
controlled by dislocation climb. Occurred a decreasing of steady state creep in function of the
reduction of oxidation process, showing that Ti-6Al-4V alloy lifetime was strongly affected
by the atmosphere due the oxidation suffered by the material.
Knowledge Based Process Scheduling and Management for Multi-Agent Distributed Collaborative Manufacturing
Authors: He Yan Li , He Wei Ping , Yang Hai Cheng , Zhang Ying , Zhao Kai
Published: March 2009

Agent technology is widely employed to construct dynamic, distributed collaborative
manufacturing systems in which the individual participating agents contribute to execute different
part of the whole manufacturing job, and the final goal is achieved through cooperation. However,
the cooperation among agents is based on message exchange, and the system requires additional
process control and management mechanism to ensure the operation according to a pre-defined
process model. This paper defines the collaborative manufacturing job and related information in
domain knowledge model, and applies knowledge based expert system to build software agents for
process scheduling and management. The system architecture, components and the implementation
methods are discussed. A prototype system is constructed on the basis of JADE agent framework
and Jess rule engine and demonstrated with an industry product as a case study.
The Key Technology Research of Synchronous Collaborative Assembly Based on B/S Framework
Authors: Wan Neng , Mo Rong , Chang Zhi Yong
Published: March 2009

A new model description was proposed which is divided into heavy and light model for
reducing the pressure of the network transfer which is constructed by XML files. The model
description includes the production assembly tree information, part feature information and
geometry information. So it can satisfy the request of browse, query, and annotation with the model.
At the same time, model description is compressed by several methods which avoid the designers
from the long time waiting.
The Validation of the Feasibility of Abnormal Form Patch Winding
Authors: Wang Xian Feng , Fu Hong Ya , Han Zhen Yu
Published: March 2009

The theory of composite material patch winding is proposed to determine the winding
trajectory by a meshed data model. The bridge condition on the concave surface is considered in
this work. This paper puts forward the judgmental principles and corresponsive solutions by
applying differential geometry theory and space geometry theory. To validate the feasibility of the
patch winding method, the winding control code is programmed. Furthermore, the airplane inlet
winding experiments are carried out.
Ultra-Precision Cutting of Brittle Materials with Ultrasonic Vibrated Diamond Tool
Authors: Ma Chun Xiang , Shamoto Eiji , Xu Li Ming , Liu Nan , Moriwaki T.
Published: March 2009

The influence of the ultrasonic vibrated diamond tool on the transition of ductile cutting to brittle cutting of the glasses is investigated by facing turning. It is understood that the critical depth of cut for the ductile cutting of the brittle materials is increased obviously by the ultrasonic vibrated diamond tool. The optical quality surface of the glasses is obtained, the surface roughness of which is less than0.03m. Finally, the relation between the roughness of machined surface and the cutting distance is studied experimentally.
Fabrication of Micro Structure Using EDM Deposition
Authors: Jin Bai Dong , Zhao Wan Sheng , Cao Guo Hui , Wang Zhen Long , Xiao Kai
Published: March 2009

A new deposition method is described using EDM to deposit tool electrode material on
workpiece in air. Then by exchanging the polarities the deposited material can be removed
selectively, thus micro structure can be fabricated. First, the EDD realized conditions are predicted.
Then with ordinary brass, steel and tungsten electrodes and high-speed steel workpiece, EDD
experiments are carried out to obtain micro structure in air. With continuous deposition strategy of
single cylinder, a HIT character type array made up of 15 micro cylinders is deposited. And micro
three-dimensional spiral structure can be obtained with brass electrode using feed of only z axis.
The 19-circle micro spiral structure is 0.19mm in external diameter, 0.1mm in wire diameter and
3.39mm in height. Measurements show that deposited material has obvious delaminating structure
and is corrosion resistant, whose components depend on those of the tool electrode material.
Study on the Method for the Optimization of Cutting Parameters
Authors: Zhang Jing Ying , Pang Si Qin , Yu Qi Xun
Published: March 2009

This article discusses the problem about the method for the optimization of cutting
parameters. A newly developed computational method which is different from the former was used
for the optimization of cutting parameters. This method has its advantages of the controllability of
the precision and higher speed when the precision requirement of the system is not very high. It can
optimize cutting parameters toward the objectives of maximum production rate, minimum
production cost and maximum profit rate.
Breaking Elongation Properties of Hybrid Yarns by Commingling Process
Authors: Herath Chathura Nalendra , Kang Bok Choon , Park Jong Kwang , Roh Yong Hwang , Hwang Beong Bok
Published: March 2009

This paper is concerned the breaking elongation properties of Carbon/Aramid-,
Carbon/Glass- and Aramid/Glass- matrix hybridized commingling yarns. The hybrid yarns produced
by commingling process were investigated in terms of breaking elongation property. In experiments,
carbon (CF), aramid (AF), and glass (GF) filament yarns were combined. In this study, selected
matrix materials include Polyether-ether-Keeton (PEEK), and polyester (PES), or polypropylene
(PP). The volume content of filament in hybrid yarn cross section was maintained at 50% for both
reinforced and matrix, ant hybrid yarns count at 600 tex, respectively. The reinforcement to matrix
filament combination was selected as 1:1 proportion. The effect of different air pressures and material
combinations was investigated in terms of breaking elongation. In experiments, each type of hybrid
yarn sample has been tested 20 times at the testing speed of 10mm/min. under 3 bar of yarn clamping
pressure. Since breaking elongation is one of most important properties in textile fiber, it was
examined closely with reference to the first breaking point of commingling-hybrid yarns. It was
concluded from experiments that hybrid yarns with higher breaking elongation and higher tensile
strength tend to show better force-elongation relationship. It was also known from experiments that
the combination of two reinforcement filament yarns gives always much better results than a single
reinforcement filament yarns in terms of elongation property. GF/AF/matrix is shown very much
better elongation properties. PP and PES gives higher elongation than PEEK as a matrix material.
Study on Fabrication of a Large Al-Cu-Mn Wheel with Indirect Squeeze Casting Process
Authors: Li Yuan Yuan , Zhang Ming , Zhao Hai Dong , Zhang Wei Wen , Cheng Wei Ping
Published: March 2009

The fabrication of a large Al-4.5wt%Cu-0.5wt%Mn wheel with 670mm diameter by
indirect squeeze casting process was studied. The casting system including modified hydraulic press
and die structure was introduced, and the casting procedures was designed and described. The
filling behavior of the casting process was simulated with software Flow3D. It was found that while
flowing from spoke to rim, turbulence flow of liquid melt in the vicinity of free surface was found,
and that at the end of the filling, the unwanted solidification might occur. To reduce the turbulent
flow and the unwanted solidification, a modified injection condition was proposed. The simulation
results with the modified injection indicated that the turbulence was prevented and the unwanted
solidification during the filling was reduced as well. The squeeze wheel castings were fabricated
with the modified injection condition. Cross sections of the castings were checked. A number of
specimens were obtained from different parts of the castings to evaluate microstructure of the wheel,
and both high density and fine grain microstructures were found in the specimens. Mechanical
properties of the tensile samples from the wheels with T5 heat treatment were measured. The
average tensile strength and elongation were 390 MPa and 10%, respectively.
Influence of Cutter’s Helix Angle, Workpiece Hardness, Milling Orientation, and MQL in High-Speed Side Milling of AISI D2
Authors: Iqbal Asif , He Ning , Li Liang , Xia Yu
Published: March 2009

Rapid tool wear is a major demerit of high-speed milling (HSM) applied to cutting of
hardened steels, especially the AISI D2. This paper presents an attempt to maximize the tool life by
experimentally investigating the effects of cutter’s helix angle, workpiece material hardness, milling
orientation, and minimum quantity of lubrication upon tool wear in high-speed side milling of AISI
D2, using coated carbide cutters. Effects of these four parameters were studied also upon surface
roughness. Statistical analysis upon experimental data revealed that milling orientation was the
most significant factor for tool life as well as for surface roughness. The paper also describes the
mechanisms of wear undergone by the tools, by making use of SEM photographs and EDS microanalysis.
The major wear mechanisms were chipping, adhesion, and diffusion.
Manufacturing Technique of High Precision Intricate Diamond Dressing Roller
Authors: Cui Zhong Ming , Liu Zi Ran , Zhang Hong Ying
Published: March 2009

Diamond Dressing Roller is a new kind of diamond tool for profile dressing of grinding
wheel on form grinding. In this paper, internal electroplate method manufacturing process of high
precision intricate diamond dressing roller is introduced. The tolerance of profiler precision degree
of high precision intricate diamond dressing roller by this manufacturing process is less than
0.005mm.
Evolution Trends of Material Usage and Processing in Spectacle Frame
Authors: Fung Mei Ling , Yu Kai Ming , Yuen Man Wah
Published: March 2009

Nowadays’ optical frames are the result of a collaboration between designers and
engineers; it is a combination of high technology and art. Around 250 technical operations are
performed in order to make a high-quality metal frame, and there are 120 to 180 operations to make
a plastic frame. Although the Asian manufacturers of optical frames are prevailing in the world
market, a relatively rudimentary trial-and-error method is being used. A more systematic and
analytic approach is thus needed for them to grasp the evolution trends in the competitive market.
This paper discusses how Gabriel Tarde’s diffusion S-curve and the TRIZ theory can be employed
to analyze the evolution trends in optical frame design and manufacturing.
Diamond Turning of Special Stainless Steel by Applying Ultrasonic Vibration with Gas Shield
Authors: Zhang Yuan Liang , Zhou Zhi Min , Xia Zhi Hui
Published: March 2009

Ultrasonic vibration is applied to diamond turning of special stainless steel to decrease
diamond tool wear and improve the surface quality of the workpieces. It reviews the principle of
diamond turning of special stainless steel by applying ultrasonic vibration combined with gas shield.
Compared with the ordinary machining method, cutting temperature and cutting force are greatly
reduced when machining by application of ultrasonic vibration, and the appetency between a
diamond tool and Ferrous atom of a workpiece is also minimized as gas shield application. The
Experiments of cutting special stainless steel workpieces show that the surface roughness Ra is less
than 0.15μm and flank wear-width is less than 5μm when cutting distance is up to 2000m. It takes
research on the effect of cutting parameters to surface roughness and tool wear. The experiment
result shows that the amplitude is the most important factor which effects tool wear and surface
roughness most.
Studies on the Solid Conveying Process in Micro Injection Molding Machine
Authors: Xu Yan , Yung Kai Leung , Ng Hai Pang
Published: March 2009

Understanding the solid conveying process is important for the optimal design of micro
injection molding machines. To solve problems such as starve feeding and process instability during
plastication of polymers, which deteriorate product qualities, studies have been carried out on the
conveying process of discrete polymer pellets. The effect of screw axis inclination on the speed of
solid conveying is investigated with both simulation and experimental approaches. A discrete
element modeling method (DEM) specially designed for simulating polymer particle movements in
screw channels, which takes into account the effect of gravity while maintaining the simplicity of
calculations, has been developed. The agreements between results of simulations and experiments
verify the integrity of the models developed herein. The proposed modeling method is capable of
optimizing the design of plasticizers of micro injection molding machines.
Damage Analysis of Particulate Polymer Composites Based Structure by Using Micro-Meso-Macro Finite Element Approach
Authors: Tang Chak Yin , Tsui Chi Pong , Chen Da Zhu , Uskoković P. S. , Fan Jian Ping , Xie Xiao Lin , Lee Eric Wai Ming
Published: March 2009

A micro-meso-macro finite element approach has been developed for simulating the
macro-scale damage coupled deformation in a particulate polymer composite (PPC) based structure
under tension. A damage model for the PPC structure was developed to define the debonding
damage behavior of the structure. The computational results determined in our previous studies by
using finite element meso-cell modeling technique were used as the input parameters of the damage
model and definition of the constitutive behavior of PPC. A user-defined subroutine VUMAT
describing the damage-coupled constitutive behaviour of PPC for defining the material properties of
the finite elements for the structure was then built and incorporated into the ABAQUS finite
element code. A case example has been given to demonstrate the proposed approach. The macroscale
damage process in the simulated component was found to be reasonable.
An Investigation of Form Compensation in Fabricating Microlens Arrays by Ultra-Precision Fast-Tool-Servo Technology
Authors: Kwok Tsz Chun , To Suet , Cheung Chi Fai , Wang Su Juan , Lee Wing Bun
Published: March 2009

Microlens arrays are widely used as critical components in a large number of photonics
and telecommunication products. The increasing demand for high-tech products provides an
expanding room for the development of the micro-fabrication technology. This study presents a tool
compensation for correcting the form error of fabricated microlenses in ultra-precision machining
with fast-tool-servo (FTS) system. After presentation of optimal cutting conditions deduced on the
basis of cutting experiments of microlens arrays, a tool radius compensation method will be proposed
and evaluated in this paper. This methodology makes use of form measurement data from a Form
Talysurf system to modify the C program employed in the software of ultra-precision machining FTS
system – SOP. The form error was successfully reduced after implementation of tool compensation.
Finite Element Simulation of High-Speed Cutting Alloy Cast Iron
Authors: Ruan Jing Kui , Ke Ying Lin , Dong Hui Yue , Yang Yong
Published: March 2009

A finite element model (FEM) of high-speed cutting was built to study the mechanism of high-speed machining of alloy cast iron used widely in auto panel dies. The mechanics properties of workpiece material were obtained in the conditions of high strain-rate, high temperature and high strain through high-speed impact compress experiments. Several key technologies are studied such as friction and chip-tool heat conduction. The cutting temperature, stress distribution, and the chip formation process in the process of high-speed cutting alloy cast iron were analyzed based on the finite element model, which was validated through cutting force experiments. It shows that the FEM can simulate the high-speed cutting process of alloy cast iron materials.
Research on Product Systematic Innovative Design Based on TRIZ
Authors: Zhang Fu Ying , Xu Yan Shen , He Qing Ping
Published: March 2009

Many solution tools TRIZ provided, such as innovative principles, technology evolution,
have been widely used for product innovative design in last decade. The key using TRIZ to improve
design is the correct definition and solving of technical problems. However, it’s difficult for
engineers to discover the inherent problems of product, especially for complex engineering systems.
Therefore, this paper proposes a whole process model for product systematical innovation design,
whose objective is to obtain ideal solution and whose technical method is to analyze and solve
conflicts. This model integrates the definition, analysis of problems from top to bottom, with the
resolving of problems from bottom to top, and will contribute to a systematic and operable process
for problems definition, analysis, resolving. A practical application of this work is also presented.
Study on Ultrasonic Vibration Assisted Grinding in Theory
Authors: Zhang Hong Li , Zhang Jian Hua , Huo Meng You
Published: March 2009

In ultrasonic vibration assisted grinding (UAG) along the axial direction, the machining
process of an abrasive grit is introduced in this paper. During the internal UAG, the critical speed is
determined by the amplitude and frequency of ultrasonic vibration. During the surface UAG, the
cutting model of an abrasive grit is established and the cutting trace length of an abrasive grit and
the grinding force making chips deformation is analyzed in theory. The analysis results show that
the cutting trace length is longer by introducing ultrasonic vibration along the axial direction; the
grinding force is decreased, the higher vibration amplitude and frequency is helpful to the decrease
of the grinding force and the higher grinding wheel speed weakens the contributiveness of
ultrasonic vibration to the decrease of the grinding force.
Study on Side Contact Layer Model and Parameters in Quick-Point Grinding
Authors: Xiu Shi Chao , Cai Guang Qi , Li Chang He
Published: March 2009

The main function of the wheel side is to remove the material and the main function of the
wheel edge is to finish the workpiece in quick-point grinding process. So the grinding layer model of
conventional cylindrical grinding process is not fit for quick-point grinding process anymore. Based
on the technical characters and the principle of the process, a new side contact layer model and the
formulas to calculate the contact layer parameters are presented. It is basement to study the
mechanism of materials removal and wheel wear in quick-point grinding process.
A Study on the Process Sequence Design of a Tub for Washing Machine Container by Finite Element Analysis
Authors: Lim Joong Yeon , Jang Dong Hwan
Published: March 2009

A design methodology was applied to manufacturing a tub for washing machine container.
The finite element method was employed to investigate the forming process. The forming process of
sheet metal into a tub for washing machine container was selected as a model process to demonstrate
the design of improved process sequence which has fewer operation stages than in conventional
process. The design procedures made extensive use of the finite element method which can deal with
elastic-plastic modeling. A one stage process sequence to form an initial blank to final product has
been simulated to obtain information on metal flow requirements. Loading simulation for
conventional manufacturing process sequence has been also simulated to evaluate the design criteria.
From the simulation results of conventional process sequence, it is concluded that the design criteria
should include thickness uniformity in finished tub and maximum punch load within the limit of
available press capacity. The newly designed sequence has two forming operations and can achieve
net-shape manufacturing, while the conventional process sequence has three forming operations. The
design procedure proposed in this study could be considered for the method applied to the
development of process sequence design in general.
Elastic-Plastic Contact Analysis of Materials with Gradient Yield Strength
Authors: Xie Qin , Liu Geng , Liu Tian Xiang , Wang Jane Q.
Published: March 2009

Reported in the paper is an elastic-plastic contact model developed to analyze the contact performance characteristics of materials with gradient yield strength. Plastic yielding and the strain-hardening properties of the materials are taken into account. The finite element method, the initial stiffness method, and a mathematical programming technique are utilized to solve the contact model. The von Mises yield criterion is used to determine the inception of plastic deformation. Results indicate that nitrided material with appropriate gradient of yield strength may greatly alter the distributions of contact stress, contact pressure as compared with untreated material in contact. The effects of different yield strength variation path of material on von Mises stress distributions are numerically investigated and discussed.
Study on Non-Interference Normal Tracking Algorithm for NC Quick-Point Grinding of the Curve Parts
Authors: Luo Yu Mei , Wu Qi , Hu De Jin
Published: March 2009

In traditional NC curve grinding, the grinding wheel’s rotary surface is generally not on the
grinding point’s normal direction, which will bring the distortion of grinding wheel and decrease the
machining precision. This paper presents a new technology, which is called the non-interference
normal tracking for NC curve grinding process. By controlling the worktable to rotate in the x-y plane,
the superposition between the rotary surface of the grinding wheel and the normal vector of the
workpiece’s contour is realized, and the interference between the wheel’s body and the workpiece
could be avoided at the same time. A mathematic model is established and an algorithm to calculate
the worktable’s rotary angle is proposed. Finally, the algorithm is applied in a new-type digital curve
grinder successfully. The results show that the method is reliable and effective.
Real-Time Model Building and Experiment Researching of Grinding Force for External Plunge Grinding Process
Authors: Li Guo Fa , Wang Long Shan , Yang Shu Xiang
Published: March 2009

A real-time model of two-direction grinding force for external plunge grinding process
has been built based on the research of grinding system dynamics equation. The two-direction
grinding force can be measured on-line by a force cell sensor developed in this paper. And the
grinding depth and grinding force, which depend on grinding time, were dynamic simulated by
computer simulation. The experimental results are in good agreement with the simulation results,
proved the real-time model’s exactitude. The real-time models showed in this paper not only can
predict and evaluate grinding behave and quality, but also provide the precondition for grinding
optimum, intelligential control, and virtual grinding research etc.
Research on XML-Based Database Integration for Collaborative Design and Manufacture of Space Antenna
Authors: Xiao Yong , Wang San Min , Chen Guo Ding
Published: March 2009

The technique of collaborative design and manufacture is not only very important, but also urgent necessary for space antenna. Building on unicode, XML provides the standard format describing data in various types, so it has the virtue of integrating heterogeneous databases. In this paper, the elementary research has been done on XML-based integrating technique for heterogeneous databases of space antenna. Firstly, the overall flow for collaborative design and manufacture of space antenna shows that five databases should be integrated. Secondly, a XML-based integration system frame is conceived for space antenna databases. Thirdly, an effective XML-based transformation mechanism is proposed for the data integration process between relational database and document-based database. Finally, the implement of XML-based database integration is demonstrated in a space antenna design.
Design of Forming Sheet Electrodes in Electrochemical Finishing of ZDC2 Castings Surface
Authors: Pa Pai Shan
Published: March 2009

This research presents a new modus of electrochemical finishing as a finish process using an effective design of forming sheet electrode on zinc alloys beyond traditional process of die casting on the surface of castings instead of the conventional hand or machines polishing. In the current experiment, the author takes an outer shell of toy vehicle for instance; five types of design electrode are used and supplied with continuous direct current in the experiment of electrochemical finishing. For the design electrodes, a thin plate with small end radius and small wedge angle are associated with higher current density and provides larger discharge space and better polishing effect. The electrode with spherical head performs the best. The electrochemical finishing after die casting saves the need of hand or machines polishing just needs quite short time to make the surface of castings smoothing and bright. An effective and low-cost polishing of the surface of castings is presented.
Effects of Y2O3 Addition on the Microstructure and Electrical Property of TiO2-Excess BaTiO3
Authors: Kim Jong Han , Han Young Ho
Published: March 2009

When Y2O3 was added to Ti-excess BaTiO3 ((Ba+Y)/Ti =1), the the area occupied by Y3+ ion was confirmed by its microstructure development, electrical conductivity behavior and lattice constant. Grain growth inhibition was observed when the content of donor dopant exceeded a critical value (x≈0.01) in BaTiO3+x(0.5Y2O3+TiO2) system. A donor-doped behavior was observed at various Y contents (0.2~3.0 mol% Y) when Y2O3 was added to TiO2-excess BaTiO3. As Y content was increased, (002) and (200) peaks shifted to higher angles and the lattice constant (a and c axis) decreased gradually. These results confirms that Y3+ ions preferentially occupy Ba sites when Ba/Ti < 1.
Diamond Tools with Diamond Grits Set in a Predetermined Pattern
Authors: Sung James C.
Published: March 2009

Although diamond tools have been used for over a century, the diamond grits distribution in the matrix is not uniform. This is because the large and light diamond grits tend to segregate from the small and heavy metal powder during the mixing process, hence diamond distribution in the diamond tools is intrinsically heterogeneous. As a result, the cutting performance of the diamond tools cannot be optimized. In 1997, Dr. James Chien-Min Sung applied two historical patents that can allow the design of diamond distribution according to a predetermined pattern. As the result, the life of diamond tools may be doubled; and the cutting speed, may also be twice as high. The three-dimensional saw segments with arrayed diamond grits were made back in 1999 with the improved performance as predicted. The Sung invention can allow the diamond tools industry to make ideal saw segment that has variable diamond size and diamond separation at different regions. Conventional diamond saws contain diamond grits that are distributed randomly in a metal matrix, as a result, their cutting speeds are slow and their sawing lives are short. In 1997, Dr. James C. Sung applied new patents that revealed revolutionary technology for making diamond tools with diamond grits set in a predetermined pattern. The diamond placement design was first appeared in a series of DiaGrid® products, such as wire saws and grinding wheels. In 1999, DiaGrid® pad conditioners was introduced and it has since become the world's standard for dressing pads, particularly those used for chemical mechanical planarization of semiconductor devices. In 2005, Shinhan adapted the idea and produced saw segments with diamond grits set in a predetermined pattern, their results confirmed that the sawing speed and the life were significantly improved over conventional designs.
Electro Discharge Compaction of WC-Co Composite Material Containing Particles of Diamond
Authors: Grigoriev Evgeny , Rosliakov Alexander
Published: March 2009

In the present paper, the formation of high hardness and large strength structure of WCCo
composite material containing particles of diamond were investigated and optimal operating
parameters were defined. Tungsten carbide - cobalt - diamond composite was produced by the
method of high voltage electrical discharge together with applying mechanical pressure to powder
compact. It was found that the density and hardness of composite material reach its maximum
values at certain magnitudes of applied pressure and high voltage electrical discharge parameters.
We found that there is [a maximum level -Comment: Don’t you mean a maximum level?] for the
discharge voltage and applied pressure beyond which the powder WC-Co-diamond composite
material disintegrates like an exploding wire. Near this level, the cobalt particles are in a fused
condition and are redistributed in the compact volume due to magnetic pressure of discharge current
pulse. [The distribution of magnetic pressure is defined by the distribution of a current density in
the powder compact. The magnetic pressure is more homogeneous in powder compact volume
when the skin effect is strong.-Comment: Are these two statements of fact or conclusions made
based on experimental observations? - Answer: The first statement is fact and the second statement
is conclusion made based on experimental observations.]
Enhancement of Microstructural Homogeneity of W-Cu Pseudo-Alloy by Adding W-Cu Composite Powder in Infiltration Process
Authors: Hong Moon Hee , Choi Jae Ho , Lee Seong , Kim Eun Pyo , Noh Joon Woong , Lee Sung Ho , Kim Young Moo
Published: March 2009

An infiltration technique using W-Cu composite powder has been developed to enhance
microstructural uniformity of W-Cu pseudo-alloy. W-Cu composite powder, manufactured by
reduction from WO3 and CuO powder mixtures, were blended with W powder and then cold isostatically
pressed into a cylindrical bar under 150 MPa. The pressed samples were pre-sintered at
1300 oC for 1 hour under hydrogen to make a skeleton structure. This skeleton structure was more
homogeneous than that formed by using W and Cu powder mixtures. The skeleton structures were
infiltrated with Cu under hydrogen atmosphere. The infiltrated W-Cu pseudo-alloy showed
homogeneous microstructure without Cu rich region.
Neutron Diffraction Analysis of Tungsten-Molybdenum-Disilicide Powders Formed by Self-Propagating High Temperature Synthesis
Authors: Choi Y. , Kim Yong Seog
Published: March 2009

Tungsten-molydiside WxMo1-xSi2 was synthesized by self-propagating high temperature synthesis. The SHS product with the initial composition of (0.5Mo+0.5W+2Si) contains 23.9% MoSi2, 40.89% WSi2 with remaining 9.11% Mo, 9.16% Si and 16.94%W. Lattice parameters of the MoSi2 and WSi2 determined by Rietvelt analysis were a=0.3206 nm, c=0.7841 nm and a=0.3212 nm, c=0.7822 nm, respectively.
Porous Metals of Northwest Institute for Non-Ferrous Metal Research
Authors: Tang Hui Ping , Liao Ji Chang , Zhu Ji Lei
Published: March 2009

In recent years, the research in porous metal got rapid development in China, especial in
Northwest Institute for Non-ferrous Metal Research (NIN). Many porous metals with different raw
material and different shapes were developed, which successfully employed in many fields. We
believe we will earn more rapid development in the future.
Effect of Ba Strate Addition on Magnetic Properties of Ba-System W-Type Ferrite Magnets
Authors: Yamamoto Hiroshi , Nishio Hiroaki , Sawayama Yoshihito
Published: March 2009

Experiment was carried out to investigate the effect of Ba Stearate as a reducing agent on
the magnetic and physical properties of anisotropic BaFe2-W type ferrite magnets. It was found that
the magnetic properties of BaO･8.5Fe2O3 were improved by adding 0.3 wt% of Ba Stearate, 0.5
wt% of SiO2, and 0.5 wt% of CaO together. The optimum conditions for making magnets were as
follows; chemical composition: Ba1.029Ca0.127Si0.097C0.053Fe2+
2.456Fe3+
15.392O27, semisintering
condition: 1350 °C×4.0 h in nitrogen gas atmosphere, drying condition: 180 °C×2.0 h in air,
sintering condition: 1160 °C×1.5 h in nitrogen gas atmosphere. Magnetic and physical properties of
a typical sample were Jm = 0.46 T, Jr = 0.43 T, HcJ = 182.3 kA/m, HcB = 177.2 kA/m, (BH)max =
33.8 kJ/m3, TC = 495 °C and KA = 2.65×105 J/m3 and HA = 1332 kA/m. The lattice constants of this
compound were a = 5.883×10-10 m, c = 32.92×10-10 m, and c/a = 5.596.
Microstructure and Mechanical Properties of Nanostructured Aluminum Consolidated by SPS
Authors: Zadra Mario , Casari Francesco , Molinari Alberto
Published: March 2009

Nanostructured aluminum powders were obtained by means of planetary ball milling
with methanol as the Process Control Agent (PCA). The behavior, during milling, was considered
measuring the microhardness and grain size at different milling times. Bulk near-full density
samples were sintered using the Spark Plasma Sintering technology with different schedules:
temperature of 500°C and 550°C, pressure of 30 MPa and 60 MPa and different modes of applying
the pressure were changed in order to understand the behavior during sintering. The samples
sintered at 500°C showed a density of about 2.4-2.61 g/cm3 while for that sintered at 550°C it was
2.65-2.67 g/cm3 depending on the applied pressure. All the samples retained their nanostructure
with an increase of the grain size from about 46 up to 70-90 nm. Using X-ray diffraction and
metallography the formation of Al4C3 carbides was detected for samples sintered at highest
temperatures.
Development of High Performance Multi-Lobe Fluid Dynamic Bearings Using a Sintered Material
Authors: Tokushima Hidekazu
Published: March 2009

Recently, in spindle motors for hard disk drive (HDD) devices, fluid dynamic bearings
(FDB) with herringbone grooves have come to be used instead of ball bearings due to the demand
for high density recording of the devices, improvement in the speed of data transfer, and the
quietness of the motor. In this study, a 5-lobe bearing with high bearing stiffness using a sintered
material, as a new trial, was developed, and the bearing performance was examined by simulated
calculations and experiments. As a result, it was clarified that the 5-lobe bearing had the required
performance for practical use in the spindle motor for HDD by means of optimizing the bearing’s
dimensions. In addition, bearing loss of the 5-lobe bearing is lower than that of the herringbone
bearing, and the 5-lobe bearing showed clearly that it is effective in being used in the
miniaturization of HDD spindle motors.
Preparation of Ru-C Nano-Composite Film by MOCVD and Electrode Properties for Oxygen Gas Sensor
Authors: Kimura Teiichi , Goto Takashi
Published: March 2009

Ru-C nano-composite films were prepared by metal-organic chemical vapor deposition (MOCVD), and their microstructures and their electrode properties for oxygen gas sensors were investigated. Deposited films contained Ru particles of 5-20 nm in diameter dispersed in amorphous C matrix. The AC conductivities associating to the interface charge transfer between Ru-C composite electrode and YSZ electrolyte were 1000-10000 times higher than that of conventional paste-Pt electrodes. The electro-motive-force (emf) values of the oxygen gas concentration cell constructed from the nano-composite electrodes and YSZ electrolyte showed the Nernstian theoretical values at low temperatures around 500 K. The response time of the concentration cell at 500 K was 900 s.
Elaboration of (Steel/Cemented Carbide) Multimaterial by Powder Metallurgy
Authors: Pascal Celine , Chaix Jean Marc , Dutt A. , Lay Sabine , Allibert Colette H.
Published: March 2009

A steel/cemented carbide couple is selected to generate a tough/hard two layers material. The sintering temperature and composition are chosen according to phase equilibria data. The choice of optimal sintering conditions needs experimental studies. First results evidence liquid migration from the hard layer to the tough one, leading to porosity in the hard region. The study of microstructure evolution during sintering of the tough material (TEM, SEM, image analysis) evidences the coupled mechanisms of pore reduction and WC dissolution, and leads to temperature and time ranges suitable to limit liquid migration. The sintering of the two layer material is then shown to need further compromises to avoid interface crack formation due to differential densification.
The Optimization of Hydrogen Reduction Process for Mass Production of Fe-8wt%Ni Nanoalloy Powder
Authors: Jung S.S. , Kang Yun Sung , Lee Jai Sung
Published: March 2009

The present investigation has attempted to optimize hydrogen reduction process for the
mass production of Fe-8wt%Ni nanoalloy powder from Fe2O3-NiO powder. In-situ hygrometry
study was performed to monitor the reduction behavior in real time through measurement of water
vapor outflowing rate. It was found that the reduction process can be optimized by taking into
account the apparent influence of water vapor trap in the reactor on reduction kinetics which
strongly depends on gas flow rate, reactor volume and reduction.
Thermomechanical Properties of Functionally Graded Al-SiCp Composites
Authors: Song Dae Hyun , Park Yong Ha , Park Yong Ho , Park Ik Min , Cho Kyung Mok
Published: March 2009

A theoretical model is applied to the analysis of thermomechanical properties of Al-SiCp
FGMs in this study. Functionally graded Al-SiCp composites (Al-SiCp FGMs) consisted with 10
layers gradually changing volume fractions of Al and SiCp were fabricated using the pressureless
infiltration technique. Al-SiCp FGMs plates of total thickness of 3mm, 5mm and 7mm with fairly
uniform distribution and compositional gradient of SiCp reinforcement in the Al matrix throughout
the thickness was successfully fabricated. The curvature of Al-SiCp FGM plates was measured to
check the internal stress distribution predicted via a theoretical model for the analysis of thermomechanical
deformation. The evolution of curvature and also internal stresses in response to
temperature variations could be predicted for the different combinations of geometric thickness of
FGM plates. Theoretical prediction of thermally induced stress distribution makes it possible to
design FGM structures without any critical failure during the usage of them.
High Energy Ball Milling of Catalytically Synthesized Carbon Nanotubes
Authors: Ahn Jung Ho , Kim Yong Jin , Hwang S.J. , Chung Hyung Sik
Published: March 2009

This study examines the ball-milling of CVD-processed multi-wall carbon nanotubes for cutting and opening their tips. Results show that dry milling causes nanotubes to rapidly collapse, hence transforming into graphite structure, while wet milling with some organic compounds effectively shortened and opened the nanotubes. Carbon-based milling agents are known to alter surface structure of carbon nanotubes, minimizing an excess algglomeration and consequently improving dispersion of nanotubes. The open tip structure was unstable and quite susceptible to re-close during milling and thermal treatments to minimize their surface energy.
Analysis of Failure Mechanisms during Powder Compaction
Authors: Wu Chuan Yu , Bentham A.C. , Mills A.
Published: March 2009

Powder compaction is a well-established process for manufacturing a wide range of
products, including engineering components and pharmaceutical tablets. During powder
compaction, the compacts (green bodies or tablets) produced need to sustain their integrity during
the process and possess certain strength. Any defects are hence not tolerable during the production.
Therefore, understanding failure mechanisms during powder compaction is of practical
significance. In this paper, the mechanisms for one typical failure, capping, during the compaction
of pharmaceutical powders were explored. Both experimental and numerical investigations were
performed. For the experimental study, an instrumented hydraulic press (a compaction simulator)
with an instrumented die has been used, which enable the material properties to be extracted for real
pharmaceutical powders. Close attentions have been paid to the occurrence of capping during the
compaction. An X-ray Computed Microtomography system has also used to examine the internal
failure patterns of the tablets produced. Finite element (FE) methods have also been used to analyse
the powder compaction. The experimental and numerical studies have shown that the shear bands
developed at the early stage of unloading appear to be responsible for the occurrence of capping. It
has also been found that the capping patterns depend on the compact shape.
Compaction of Ultra-Fine WC Powder by High-Speed Centrifugal Compaction Process
Authors: Suzuki Hiroyuki Y. , Kadono Yuichi , Kuroki Hidenori
Published: March 2009

High-Speed Centrifugal Compaction Process (HCP) is one of slip-using compacting method originally developed for processing of oxide ceramics. In this study, we are going to apply the HCP to ultra-fine (0.1 micron) WC powder. Organic liquid of heptane was chosen as dispersing media to avoid possible oxidation of WC. For slip preparation, addition of sorbitan-monostearate (SMS) dramatically improved state of dispersion. The mixing apparatus also was in consideration. The slips mixed by conventional ball mill or turbula mill were scarcely densified by the HCP. Only the slips mixed by high energy planetary ball mill were packed up to 55% by the HCP, and sintered to almost full density at 1673 K without any sintering aids. This sintered compact marked Vickers hardness of Hv 2750 at maximum.
Plastic Behaviour of Green Powder Metallurgical Compacts
Authors: Prado Jose Manuel
Published: March 2009

The results of monotonic and cyclic uniaxial compression tests, in which the deviatoric component of the stress is predominant, carried out on green and recrystallized iron compacts with different levels of density are presented and discussed in order to analyse the macro and micromechanisms governing the mechanical behaviour of non-sintered PM materials. The plastic deformation of the particles, especially at the contact areas between neighbouring particles, produces an internal friction responsible for the main features observed in the behaviour of green metallic compacts. These experimental results show important discrepancies with the plasticity models, Cam-Clay and Drucker-Prager Cap, used to simulate the powder compaction stage. Possible causes for these discrepancies are pointed out.
Reduced Weight Scatter with Bonded Powder Mixes
Authors: Edman Daniel , Alzati Luigi , Pozzi Giovanni , Frediani Carlo , Crosa Riccardo
Published: March 2009

Organically bonded P/M mixes have been developed to improve the stability of
dimensional properties by reducing the segregation of the mix constituents and improving the filling
characteristics. Robustness and reliability are key factors for the promotion of P/M as cost effective
substitute of competing manufacturing technologies. Based on the production of four different belt
pulleys, this paper presents the achievement of reduced weight scatter and close dimensional control
realizable by using a StarmixTM that is organically bonded.
A Study of Ceramic Injection Molding of Watch Case Composed of ZrO2 Powder
Authors: Kwak Te Su
Published: March 2009

This study is focused on the manufacturing technique of powder injection molding of
watch case made from zirconia powder. A series of computer simulation processes were applied to
the prediction of the flow pattern in the inside of the mould and defects as weld-line. The material
properties of melted feedstock, including the PVT graph and thermal viscosity flowage properties
were measured to obtain the input data to be used in a computer simulation. Also, a molding
experiment was conducted and the results of the experiment showed a good agreement with the
simulation results for flow pattern and weld line location. On the other hand, gravity and inertia
effects have an influence on the velocity of the melt front because of the high density of ceramic
powder particles during powder injection molding in comparison with polymer’s injection molding
process. In the experiment, the position of the melt front was compared with the upper gate and
lower gate positions. The gravity and inertia effect could be confirmed in the experimental results.
Effect of Particle Size in Feedstock Properties in Micro Powder Injection Molding
Authors: Baek Eung Ryul , Supriadi Sugen , Choi Chul Jin , Lee Byong Taek , Lee Jae Wook
Published: March 2009

Micro powder metal injection molding has received attention as a manufacturing
technology for microparts. Small powder size is very useful in achieving detailed structures. STS
nanopowders with an average diameter of 100 nm and STS micropowders with an average diameter
of 5 micron were utilized to produce feedstock. The mixing behavior of the feedstock was indicated
that the nanoparticle feedstock produce highest mixing torque at various powder_loading than the
micropowder feedstock. Ares rheometer was utilized to examine visco-elatic flow behavior. The
nanoparticles feedstocks showed that elastic properties are dominant in flow behavior and high
viscosity. Whereas the micropowders feedstocks, viscous properties are dominant in flow behavior
and less viscosity.
Influence of the Morphology and Particle Size on the Processing of Bronze 90/10 Powders by Metal Injection Moulding (MIM)
Authors: Contreras José M. , Jiménez-Morales Antonia , Torralba José M.
Published: March 2009

The MIM technology is an alternative process for fabricating near net shape components
that usually uses gas atomised powders with small size (< 20 μm) and spherical shape. In this work,
the possibility of changing partially or totally spherical powder by an irregular and/or coarse one that
is cheaper than the former was investigated.
Different bronze 90/10 components were fabricated by mixing three different types of powder: gas
atomised spherical powder (usual MIM powder < 22 μm) and two water atomised irregular powders
(size < 35 μm and < 140 μm). The blends were made by using only two types of powder in each
mixture with the following volume proportions (100/0, 67/33, 33/67, 0/100).
The influence of the particle size and shape on the powder packing density and sintering stage was
analyzed through the apparent density of the powder blends, as well as, densification, hardness and
porosity of the sintered parts.
The addition of irregular and/or coarse powder was found to affect the moulding process, although
good densifications and hardnesses were obtained in the sintering step. Therefore it could be a
promising way to diminish production costs in this technology.