bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Surface Topography and Tribological Characteristics Finished by Abrasive Jet with Grinding Wheel as Restraint
Authors: Li Chang He , Cai Guang Qi , Xiu Shi Chao
Published: March 2009

The abrasive jet finishing process with wheel as restraint is a kind of compound precision
finishing process that combined grinding with abrasive jet machining, in which inject slurry of
abrasive and liquid solvent to grinding zone between grinding wheel and work surface under no
radial feed condition when workpiece grinding were accomplished. The abrasive particles are
driven and energized by the rotating grinding wheel and liquid hydrodynamic pressure and
increased slurry speed between grinding wheel and work surface to achieve micro removal
machining. The micro removal machining with grinding wheel as restraint, not only to attain higher
surface form accuracy but also to can acquire efficiently defect-free finishing surface with Ra0.15～
1.6μm and finally achieve high efficiency, high precision and low roughness values, furthermore,
integrating grinding process and abrasive jet process into one features. In the paper, surface
topography and tribological characteristics finished by abrasive jet with grinding wheel as restraint
were analyzed. Experiments were performed with plane grinder M7120 and workpiece material
Q235A. The machined surface morphology was studied using SEM and the microscope and
microcosmic geometry parameters were measured with TALSURF5 instrument. The experimental
results show that microcosmic geometry parameter values were diminished comparing with ground
surface. The tribological characteristics of finished surface were also investigated with pin on disk
wear tester of MG-2000. The experimental results show that the friction coefficient and wear
amounts of finishing machining surface were obviously decreased comparing with ground surface.
As a result, life and precision consistency of finished workpiece were improved.
Research on the Microfluidics Control Method Based on the EOF Technology
Authors: Jiang Hong Yuan , Yang Hu Kun , Wang Yang , Jiang Tao
Published: March 2009

Electroosmoticflow (EOF) applied in micropump is a novel technology, which will be widely applied in micro total analysis systems (μTAS) and drug delivery systems. EOF velocity in microchannel depends on the zeta potential (ζ), the electric field (E) parallel to the microchannel and so on. Electric field can be decreased if ζ can be increased, which can reduce the disadvantage caused by the high electric field voltage. This paper discusses the relationship between EOF velocity and ζ, E, to realize this concept. Through building mathematical model, this paper analyzes the effects of changing ζ and E on EOF velocity, which provides the microfluidics control theory basis to design EOF micropump and presents a new subject of manufacturing micropump process.
Design and Production of Wind Tunnel Testing Models with Selective Laser Sintering Technology Using Glass-Reinforced Nylon
Authors: Daneshmand Saeed , Adelnia R. , Aghanajafi S.
Published: March 2009

In this study, the ability of Selective Laser Sintering (SLS) Technology for production of wind tunnel testing models are evaluated. It has been undertaken to determine the suitability of the Model constructed with SLS method in subsonic and transonic wind tunnel testing. Two models were evaluated in this study. The first model was fabricated from aluminum 5086-H32 by a CNC machining technique. The other model had the same section but was fabricated by the selective laser sintering (SLS) process. Aerodynamic characteristics and times as well as costs of both models were measured in 0.3 to 1.2 Mach and the results were compared. The longitudinal aerodynamic data and the normal force data obtained from SLS model showed good agreement with data obtained from the aluminum model. The greatest difference in the aerodynamic data between two models is the total axial force. The time and the cost of production are considerably reduced with use of SLS model.
3D Rigid-Viscoplastic FEM Simulation of Forging Process of a Gas Turbine Rotor Blade
Authors: Lv Cheng , Zhang Li Wen , Wang Zhao Kun , Zheng Qu Ying , Wang Dan
Published: March 2009

Analysis of the forging of gas turbine rotor blades is a complex operation because of the
complicated three-dimensional geometry and the non-steady state contact between the workpiece
and the die surface. As a result, the simulation of blade forging performed so far has been restricted
to two-dimensional plane-strain problems or simplified three-dimensional deformational cases
throughout which some simplifications and assumptions are employed. In this paper a
three-dimensional analysis of the non-isothermal multi-stage forging process of a gas turbine rotor
blade from a cylindrical billet to a complicated product is presented, using 3D rigid-viscoplastic
FEM. The simulation results of the blade forging processes are summarized in terms of deformed
configurations, the material flow net pattern of typical cross-sections, the distribution of different
field variables such as strain and stress, and the load-stroke relationships for each operational stage,
in this way the forming laws during forging process of a gas turbine rotor blade being revealed. The
validity of simulation results has been verified through comparisons with forging tests, which show
good agreements with numerical simulation results. The simulation results may be effectively
applied to other types of three-dimensional turbine blade forging processes.
Optimization of the Clamping Scheme of the Aero Monolithic Component Based on Even-Bedded Residual Stress Distribution
Authors: Lu Dong , Li Jian Feng , Sun Jie , Xin Bo
Published: March 2009

Uneven distribution of the residual stress is the main factor causing the distortion of a
workpiece. Different clamping scheme may cause different clamping stress. Clamping stress
coupling with the residual stress inside the part induces different stress distribution, which affects
components’ machining distortion and service life. To reflect the relationship between clamps and
residual stress , finite element model with different clamping schemes were bulit and the clamping
process was simulated. And the chip removal effect was taken into account using a material removal
approach based on element death technique. Stress distribution in the workpiece is analyzed and
compared under different clamping conditions. It is verified that clamping position has a significant
effect on the residual stress. Otherwise the clamping sequence has a little effect on the stress
redistribution.
Cutter Location Generation Via Development of UG/OPEN API for Turbine Blades Machining
Authors: Li Tian , Chen Wu Yi , Wang Rui Qiu
Published: March 2009

The CAD/CAM software UGNX3 was used to implement tool positioning strategy in
CNC milling. The Sturz strategy embedded in UG was replaced by curvature matching strategy
using the interface of the UG/OPEN API. The feed direction was constrained along u direction of
the machined surface. An extra angle was added to eliminate the interference between the cutter and
the surface and some additional cutter locations were calculated to ensure the whole face to be
machined. After the previous algorithms applied in computer program, an optimized tool path was
generated. By the method of ZIG-ZAG mode, the efficiency was increased. The new strategy was
verified by the simulation and machining experiment. It showed that combining the new strategy in
UG was feasible. The precision and efficiency could thus be improved.
Research on Machinability and Evaluation Methods of Feature-Based Part under Concurrent Engineering Environment
Authors: Liu Hong Jun , Mo Rong , Fan Qing Ming , Chang Zhi Yong , Li Xiao Peng
Published: March 2009

Part manufacturability under Concurrent Engineering (CE) environment was analyzed in detail. An evaluation system of Design For Manufacturing (DFM) was proposed according to CE ideas. The evaluation methods for part manufacturability feature-based are intended to present in this paper. Product design can be guided according to feedback information by evaluating the part manufacturability. Finally an example of rabbet-feature manufacturability of a turbine blade was given to show the method available and practicable.
Cutting Force Experiment and Simulation by Hard Turning GCr15 Bearing Steel with High Speed Considering Cutting Edge Preparation
Authors: Wang Yu , Yan Fu Gang , Hu Jing Shu , Chen Tao , Chang Zhen , Liu Xian Li
Published: March 2009

In this study, hard turning GCr15 bearing steel with high cutting speed is experimental investigated the influence of the CB7015WH insert with chamfer edge and Safe-Lock and the CB7015 insert with a combination of hone radius and a chamfer edge on cutting forces and surface roughness of machined surface. Experimental results show that the cutting forces of the chamfer edge and Safe-Lock is smaller than that of the combination of hone radius and a chamfer edge. Moreover, surface roughness of machined surface with the CB7015WH insert is better. A coupled thermo-mechanical 2D finite element model with general finite element analysis software Deform 2D.8.1 is developed for the influence of two kinds of inserts on cutting forces and effective stress. The simulation results are compared with experimental data and found to be in good agreement.
An Optimal Feed Interpolation Algorithm for High-Speed Five-Axis Machining
Authors: Wang Yu Han , Feng Jing Chun , Li Yu Hao , Chen Ming
Published: March 2009

To alleviate the feed fluctuation and maintain a smooth feed in five-axis machining, this paper takes the following two constraints into account: (1) the machining dynamics, including the constraints of power, velocity and acceleration represented by upper bounds for each axis (2) the contour constraints of the tool path, including the linear distance of the segment and sharp corner at the segment junctions. With the analysis of these constraints, the optimal feed is derived and the corresponding adjusted interpolation algorithm is presented such that a smooth motion during the machining can be obtained. The presented algorithm is demonstrated by the simulation result.
Research on Integration Technology of Numerical Engineering Collaborative Design and Simulation Platform
Authors: Wang Hai Wei , Liu Geng , Wu Li Yan
Published: March 2009

In the advanced manufacturing technology, how to integrate CAD/CAE software has
become a very important research issue. After analyzing the function framework of collaborative
design and simulation platform, the management model of collaborative design and simulation
platform for numerical engineering is proposed in this paper. Moreover, workflow management
technology, collaborative running management, collaborative development model database,
database management, and Win32 API message interception technology are studied in detail. An
object-oriented software integration method is presented. The method is divided into three lays:
interface integration, data integration, and operation integration. A C/S structural prototyping
system is developed by using C# and XML under .NET development environment. The system can
support customizing engineering design and simulation task, which integrates various design and
simulation tools, including some self-developed application tools.
Decision Model in Selecting Engineering Materials for Pump Manufacture
Authors: Chan Joseph W.K.
Published: March 2009

This paper presents a decision model that applies the Superiority and Inferiority Ranking
(SIR) method in identifying the best material option. It has the strength to handle imprecise
information, in different units of analysis, for the evaluation process that ranks the material options in
preference order. It is demonstrated with an example of selecting materials for a pump.
Surface Characterization in Diamond Turning of Highly Anisotropy Brittle Crystals: A Multi-Spectrum Analysis Approach
Authors: Cheung Chi Fai , Lee Wing Bun , To Suet
Published: March 2009

This paper presents a multi-spectrum analysis method for the characterization of the
surface generation in single-point turning of brittle single crystals. The features on the diamond
turned surfaces were extracted and analysed by the power spectrum analysis of the surface
roughness profiles measured at a number radial sections of the workpiece. By the analysis of the
variation of the spectral patterns in the multi-spectrum plots, the surface roughness and materials
effect on surface generation are found to be strongly related to the power spectrum. This provides an
important means to explain quantitatively the effect of factors affecting the surface generation in
diamond turning brittle crystals.
A Web-Based Cost Estimation System for Collaborative Development of Injection Mould
Authors: Lan Hong Bo , Ding Yu Cheng , Zhang Cheng Rui , Jiang Zhuang De
Published: March 2009

To satisfy the increasing requirements in the collaborative development and price
quotation for injection mould from the customers and companies, this paper presents a web-based
cost estimation system of injection mould which can aid mould designers to evaluate the different
design alternatives, implement the collaborative development of injection mould, and provide a
reference for mould quotation. The overall architecture of the system based on a logical structure of
four layers is established. Approach to cost estimation for injection mould is described in detail.
Furthermore, a java-enabled solution together with the JESS 4.4 expert system shell and Microsoft
Access 2000 is employed to develop such a networked cost estimation system. Finally, an actual
example is given to demonstrate the use of the online cost estimation system of injection mould. The
practical results from engineering application indicate the system can provide an effective and
feasible tool to aid the evaluation of design alternatives and price quotation at the early development
stages of injection mould.
High Temperature Stability of Bulk Ti3SiC2 Materials in Air
Authors: Lee D.H. , Han Jae Ho , Kim Young Do , Park Sang Whan , Lee Dong Bok
Published: March 2009

The Ti3SiC2 materials were synthesized by hot pressing TiCx and Si powder mixtures. The matrix grains were lamellar, having a small amount of TiCx. The high-temperature stability was investigated by subjecting Ti3SiC2 to high-temperature oxidation up to 1200oC in air. Ti3SiC2 began to oxidize appreciably above 850oC. The oxidation resulted in the formation of the oxide layer that consisted of TiO2 and SiO2. The scales formed were adherent.
Sinetring of Cobalt - (3-25 wt.%) Iron Materials
Authors: Romanski Andrzej
Published: March 2009

The kinetics of sintering of Co-Fe materials was studied. The main objective of the work was to establish the effects of iron content and sintering parameters on the microstructure and phase composition of the as-sintered materials. Specimens containing from 3 to 25 wt.% iron were sintered in a dilatometer for one hour at 900, 1000 and 1150OC in either hydrogen or nitrogen atmosphere. The length of specimens during the heating, hold at the temperature and cooling steps were monitored to establish the sample’s shrinkage. Microstructural observations were carried out on polished and etched transverse sections which were also subjected to the X-ray phase analysis.
Development of High Corrosion Resistant Mo2NiB2 Boride Base Cermets for Plastic Injection Molding Machine Parts
Authors: Hirata Koro , Iwanaga Kengo , Yamasaki Yuji , Takagi Kenichi
Published: March 2009

Injection molding of corrosive super engineering plastics and engineering plastics with various fillers is conducted under severe conditions and causes corrosion and wear problems. Hence, in orde to apply Mo2NiB2 boride base cermets into plastic molding machine parts, the effects of V substitution for Cr on the mechanical properties, corrosion resistance and microstructure of Ni- 5.0B-51.0Mo-(17.5-X)Cr-XV (mass%) model cermets were investigatied. Both transverse rupture strength (TRS) and hardness increased monotonically with increasing V content and reached 2.94GPa and 87.2RA at 10.0%V, respectively. The improvements of TRS and hardness were attributed to microstructural refinement. The excellent corrosion resistance for a molten fluorocarbon resin was obtained up to 5.0%V.
Effect of Sinter/HIP Technology on Properties of TiC-NiMo Cermets
Authors: Kollo Lauri , Pirso Jüri , Juhani Kristjan
Published: March 2009

The present work is a study on the argon gas pressure effects of Sinter/HIP sintering on
microstructure and strength of different grades of TiC-NiMo cermets. Titanium carbide in the
composition of different grades of TiC-NiMo cermets was ranged from 40 to 80 wt.% and the ratio
of nickel to molybdenum in the initial powder composition was 1:1, 2:1 and 4:1 respectively. On
the sintered alloys, the main strength characteristic, transverse rupture strength (TRS) and erosion
wear resistance were measured. Furthermore, the microstructure parameters of some alloys were
measured and the pressure effect on pore elimination was evaluated. All the results were compared
with common, vacuum sintered alloys. The TRS values of TiC-NiMo cermets could be
considerably improved by using Sinter/HIP technique, for high-carbide fraction alloys and for
alloys sintered at elevated temperatures. The results provide new possible application fields for
Sinter/HIP-ed TiC cermet materials to areas where, in addition to wear performance, higher strength
properties are demanded.
Structural and Mechanical Properties of Multilayered CVD TiC/TiCN Coatings with Variations of Multilayer Period
Authors: Park Geun Woo , Kwon Hyuck Sang
Published: March 2009

Multilayered coatings on tungsten carbide cutting tools are widely used for enhancing
cutting performance. In this paper, we review the CVD TiC/TiCN multilayer as a function of the
multilayer period. The TiC/TiCN multilayers in initial stage show preferred (220) orientation but
shifts to (200) orientation with decreasing multilayer period. The nanohardness of TiC/TiCN
multilayers were found to increase with decreasing multilayer period and shows a maximum of 23.8
GPa at a period = 33.5 nm.
Fine-Grained Tungsten Heavy Alloy by Mechanical Alloying with Yttrium Oxide Addition
Authors: Fan Jing Lian , Cheng Hui Chao , Huang Bo Yun , Liu Tao , Wang Deng Long
Published: March 2009

In this paper, the microstructure and mechanical properties of yttrium oxide dispersed
90W-7Ni-3Fe alloy were studied. The 90W-7Ni-3Fe nano-crystalline composite powder dispersed
with Y2O3 addition was firstly fabricated by MA process, and then the powder was pressed and
sintered at 1480°C for 30 min. A fine-grained 90W-7Ni-3Fe alloy with high tensile strength and
elongation properties was obtained, in which the tungsten grain size was 8-12μm, the maximum
tensile strength was 1050 MPa and the elongation was 30%. The Influence of rare earth oxide Y2O3
on the mechanical properties and microstructure characteristics is discussed in detail herein.
Powder Metallurgy of Tungsten Alloy
Authors: Zhang Ke , Chun Ge Chang
Published: March 2009

This paper describes the preparation of tungsten powder and the various types of tungsten
alloys and their application.
Polyamine Group Assembled Silica Coated Ferrite Nanoparticle or Lambda DNA Detection
Authors: Park Moo Eon , Chang Jeong Ho
Published: March 2009

This study describes the development of a high throughput purification process of nucleic acid using amino-functionalized silica coated ferrite nanoparticles. The magnetic ferrite nanoparticles were synthesized and coated by a silica precursor in controlling the coating thicknesses and sizeses. The surface modification was performed with amino-functionalized organic silanes on silica coated magnetic nanoparticles. The spectroscopic measurements such as a FT-IR (ATR-method) and Vibrational Sample Magnetometer (VSM) were used to characterize the chemical structures and magnetic strengths. To elucidate the relationship between surface area, pore size distribution and reactivity of the materials, BET and Zeta potential were used. The use of functionalized self-assembled magnetic ferrite nanoparticles for a nucleic acid separation process provides a lot of advantages compared to the conventional silica based process.
Fabrication of Nanostructured Fe-Co Alloy Powders by Hydrogen Reduction and Its Magnetic Properties
Authors: Lee Young Jung , Lee Baek Hee , Kim Gil Su , Lee Kyu Hwan , Kim Young Do
Published: March 2009

Magnetic properties of nanostructured materials are affected by the microstructures such
as grain size (or particle size), internal strain and crystal structure. Thus, it is necessary to study the
synthesis of nanostructured materials to make significant improvements in their magnetic properties.
In this study, nanostructured Fe-20at.%Co and Fe-50at.%Co alloy powders were prepared by
hydrogen reduction from the two oxide powder mixtures, Fe2O3 and Co3O4. Furthermore, the effect
of microstructure on the magnetic properties of hydrogen reduced Fe-Co alloy powders was
examined using XRD, SEM, TEM, and VSM.
Metal Plasma Source Ion Implantation Using a Pulsed Cathodic Arc
Authors: Chun S.Y.
Published: March 2009

Combining nano-designed plasma source ion implantation and deposition (PSII&D) method has been developed with the pulsed cathodic arc plasma to make a processing system suitable for surface modification of materials such as metals, plastics and ceramics. By controlling the arc plasma pulse and the target pulse, the surface modification can be changed from plasma deposition to ion implantation. Various versions of applying high-voltage pulse bias are described and compared with other methods. Microstructural changes of the nanometered gold films with/without a high voltage bias, concentration profiles of implanted aluminum ions on the surfaces of complex-shaped trench are discussed.
Graded Powder Composites by Freeze Drying, Electrophoretic Deposition and Sintering
Authors: Olevsky Eugene , Wang Xuan
Published: March 2009

Two approaches for the fabrication of tailored powder composites with specially distributed pore-grain structure and chemical composition are investigated. Electrophoretic Deposition (EPD) followed by microwave sintering is employed to obtain functionally graded materials (FGM) by in-situ controlling the deposition bath suspension composition. Al2O3/ZrO2 and zeolite FGM are successfully synthesized using this technique. In order to fabricate an aligned porous structure, unidirectional freezing followed by freeze drying and sintering is employed. By controlling the temperature gradient during freezing of powder slurry, a unidirectional ice-ceramic structure is obtained. The frozen specimen is then subjected to freeze drying to sublimate the ice. The obtained capillary-porous ceramic specimen is consolidated by sintering. The sintering of the graded structure is modeled by the continuum theory of sintering.
Effect of Processing Factors on Critical Current Density in Bi2212/Ag Wires
Authors: Kim Sang Cheol , Ha Dong Woo , Oh Sang Soo , Han Il Yong , Ha Hong Soo , Sohn Ho Sang
Published: March 2009

Five kinds of double stacked 385 (55ⅹ7) filamentary Bi2212/Ag round wires and 55
filamentary tapes with different Ag ratios (silver area/superconductor area) have been fabricated via
PIT method, and the effects of Ag ratio and processing factors on critical current density were
studied. The effects of the maximum temperature and average filament diameter on critical current
density were also studied. The wire of 0.74 mm diameter having Ag ratio 3.7 showed critical
current density of 2,218 A/mm2 at 4.2 K, 0 T.
Fabrication of Ti-6Al-7Nb Alloys by Metal Injection Molding
Authors: Itoh Yoshinori , Miura Hideshi , Sato Kenji , Niinomi Mitsuo
Published: March 2009

The metal injection molding process was applied to produce Ti-6Al-7Nb alloys using 3
types of mixed powders. The first is a mixture of Ti and Al-Nb pre-alloyed powders, the second is a
mixture of Ti, Ti-Al alloy and Nb powders, and the third is a mixture of elemental powders of Ti,
Al and Nb. The sintered compacts using the first and second powders showed higher density and
mechanical properties than the compacts using the third powder which showed many large pores
formed due to the dissolution of Al particles during the sintering steps. Eventually, the compacts
using a mixture of Ti+Al-Nb or Ti+Ti-Al+Nb powders showed tensile strength of above 800MPa
and elongation of above 10%, which are similar to the properties of wrought materials.
Micro Metal Injection Molding Using Hybrid Micro/Nano Powders
Authors: Nishiyabu Kazuaki , Kakishita Kenichi , Tanaka Shigeo
Published: March 2009

This study aims to investigate the effects of hybrid micro/nano powders in a micro metal
injection molding (μ-MIM) process. A novel type of mixing-injection molding machine was used to
produce tiny specimens (<1mm in size) with high trial efficiency using a small amount of feedstock
(<0.05cm3 in volume). Small dumbbell specimens were produced using various feedstocks prepared
by changing binder content and fraction of nano-scale Cu powder (130nm in particle size). The
effects of adding the fraction of nano-scale Cu powder on the melt viscosity of the feedstock,
microstructure, density and tensile strength of sintered parts were discussed.
An Empirical Method to Evaluate the In-Flight Particle Behaviors within a Cross Section of Mass Flux during Atmospheric Plasma Spraying
Authors: Choi Han Shin , Joo Hye Sook , Lim Kyoung Mook , Jo Hyung Ho , Lee Chang Hee
Published: March 2009

In order to enhance understandings of the coating formation in the plasma spraying, an empirical method known as the spot spraying bead formation, was designed. This study is focused on the applicability of the proposed empirical method to explain the microstructural inhomogeneity during the process. Based on the in-flight particle diagnostics using DPV-2000, two different plasma gas compositions were chosen to evaluate the plasma gas effect on the microstructural evolution of Al2O3-TiO2 composite feedstock. A blended NiCr-Cr2O3-Ag-Ca/BaF2 feedstock was sprayed in order to examine the effects of particle parameters on the particle trajectory and the coating microstructures. Through the empirical approach, impacting particle properties and particle trajectory depending on process parameters could be directly shown and coating microstructures could be deduced from the characteristics of the spot spraying bead.
Correlations between In-Flight Particles, Splats and Coating Microstructures of Ni20Cr Thermally Sprayed by Flame and Arc Spray Processes
Authors: Apichayakul Pisit , Wirojanupatump Sittichai , Jiansirisomboon Sukanda
Published: March 2009

Correlations between in-flight particle, splat and coating microstructure of thermally
sprayed Ni20Cr were investigated. Flame spray and arc spray systems were employed for spraying
Ni20Cr powder and Ni20Cr wire, respectively. The results showed that the arc spray process
produced a broader size distribution for both in-flight particles and splats compared to flame
process. Flower-like splat morphology was obtained from the arc spray whereas a pancake-like
splat was obtained by flame spray. Ni20Cr coating sprayed by arc process had a denser
microstructure, lower porosity and better adhesion at the interface. This could be due to the higher
temperature and velocity from the arc spray process enhancing the melting and adhering for coating
formation.
The Effect of In-Flight Bulk Metallic Glass Particle Temperature on Impact Behavior and Crystallization
Authors: Kim Soo Ki , Yoon Sang Hoon , Lee Chang Hee
Published: March 2009

NiTiZrSiSn bulk metallic glass powder was produced using inert gas atomization and
then was sprayed onto a SS 41 mild steel substrate using the kinetic spraying process. Considering
the principle of kinetic spraying and the temperature dependent deformation behavior of the bulk
metallic glass, an attempt to change the in-flight particle temperature was tried by modifying the
kinetic spraying apparatus. Through this study, the effects of thermal energy of in-flight particle and
crystallization degree by powder preheating temperature were evaluated. The deformation behavior
of bulk metallic glass is very interesting and it is largely dependent on the temperature and the
strain rate. The crystalline phase formation at impact interface was dependent on the in-flight
particle temperature. In addition, variations in the impact behavior need to be considered at high
strain rate and in-flight particle temperature.
Direct Metal Laser Sintering – New Possibilities in Biomedical Part Manufacturing
Authors: Kotila Juha , Syvänen Tatu , Hänninen Jouni , Latikka Maria , Nyrhilä Olli
Published: March 2009

Direct Metal Laser Sintering (DMLS) has been utilized for prototype manufacturing of
functional metal components for years now. During this period the surface quality, mechanical
properties, detail resolution and easiness of the process have been improved to the level suitable for
direct production of complex metallic components for various applications.
The paper will present the latest DMLS technology utilizing EOSINT M270 laser sintering machine
and EOSTYLE support generation software for direct and rapid production of complex shaped
metallic components for various purposes. The focus of the presentation will be in rapid
manufacturing of customized biomedical implants and surgical devices of the latest stainless steel,
titanium and cobalt-chromium-molybdenum alloys. In addition to biomedical applications, other
application areas where complex metallic parts with stringent requirements are being needed will be
presented.
High-Throughput Preparation and Characterization of Powder and Thin-Film Library for Electrode Materials
Authors: Fujimoto Kenjiro , Onoda Kazuhiro , Ito Shigeru
Published: March 2009

Powder library of pseudo four components Li-Ni-Co-Ti compounds were prepared for
exploring the composition region with the single phase of the layer-type structure by using
combinatorial high-throuput preparation system “M-ist Combi” based on electrostatic spray
deposition method. The new layer-type compounds were found wider composition region than the
previous report. This process is promising way to find functional multi-component materials.
Densification Behaviors of Fe-TiC System during Spark Plasma Sintering
Authors: Lee Yong-Hee , Park Dong Kyu , Bea Sung Yeal , Ahn In Sup
Published: March 2009

The SPS process is a synthetic technique which enables sinter-bonding to occur at low
temperature and within a short sintering time. Furthermore, it produces finer grain size than
conventional sintering methods. Fe-TiC system is a relatively light material and is one third the size
of tungsten carbide and less than half weight of tool steel. It is cost effective when used in Fe-TiC
system due to high mass effect with low density and relatively low cost of changing tools and
bearings. Fe-TiC system can be machined easily with conventional equipment. In the present work,
SPS was conducted at the temperatures of 1200, 1250 and 1300°C at the sintering time of 3, 5 and
10min. As the sintering temperature and holding time increased, the relative density decreased and
the hardness reached the lowest at 1250°C. These are attributed to the more pore being generated by
liquid Pool at 1250°C and 1300°C. The result of the microstracture observation showed more M6C
and MC carbide by liquid Pool as sintering temperature and holding time increased.
Expansion Behavior of Iron-Copper Compact from (FeCu) Pre-Alloyed Powder
Authors: Kim Youn Che , Suk Myung Jin
Published: March 2009

Dilatometric curves of iron-copper compact made from elemental or pre-alloyed powder
were compared in order to study its expansion mechanism.
The compacts from a mixture of elemental iron and copper powders showed the maximum
expansion at the copper powder content of 7.44mass% and at the sintering temperatures above the
copper melting-point. In the case of the compacts from a mixture of iron pre-alloyed powder of (Fe-
3.44mass%Cu) and copper powder, the maximum expansion which is lower than the former case
was obtained at the additive copper powder content of 4.00mass%. But the compact from a mixture
of iron pre-alloyed powder of (Fe-7.18mass%Cu) and copper powder showed only shrinkages at
any additive copper powder content. The penetration of liquid copper into the interstices between
solid grains was observed in all sintered compacts. The iron-copper compacts containing the same
content of copper powder showed a very different expansion behavior depending on the amount of
copper content in the starting iron raw powder.
In Situ Observations of Sintering Process during Pulsed Current Sintering of Al2O3, ZnO and WC Alloy
Authors: Kawakami Yuji , Tamai Fujio , Enjoji Takashi , Shikatani Noboru , Misawa Tatsuya , Otsu Masaaki , Takashima Kazuki
Published: March 2009

Pulsed Current Sintering (PCS) process possesses some problems that need to be
resolved. We, therefore aims at understanding phenomena of PCS process by presenting some basic
data on in situ sintering behavior of PCS. In order to observe in situ sintering behavior of PCS, a
special graphite mold equipped with thermo couple and electrodes were designed to measure the
temperature, electric current and voltage inside the powder during PCS process. We apply three
types of raw materials, especially for ZnO (thermoelectric material) as semiconductor, Al2O3 as
non-conductor and WC (Tungsten Carbide) as good conductor. The observation succeeded and
some valuable data were obtained. The results showed that the temperature in the Al2O3 powder is
100 K higher than the graphite mold at the temperature of 1473K and ZnO powder is 150 K higher
than the graphite mold at the temperature of 1373K. The electric current and voltage were measured
for each powder during PCS process. In addition, their electric resistance properties were calculated.
The electric resistance showed different behavior.
Low-Temperature Sintering and Electromagnetic Properties Evaluation of (Ni/Mn)CuZn Ferrite
Authors: Ju Dong Ying , Bian Pei
Published: March 2009

Low temperature sintering (Ni/Mn)CuZn ferrite was employed at most cases due to its
co-firability with Ag (below 960 °C).The purpose of this study is to fabricate (Ni/Mn)CuZn ferrite
sintered body with high-strength and high-frequency magnetic properties. Following is the
procedure: firstly, (Ni/Mn)CuZn ferrite powder was synthesized under CO2 atmosphere at 500 °C
from the mixed doxalate synthesized by co-precipitation method; then a small amount of boric acid
[H3BO3] was added to the powder, and the (Ni/Mn)CuZn ferrite powder compact was prepared with
Newton press and CIP methods; finally, (Ni/Mn)CuZn ferrite sintered body was fabricated by
sintering at 900 °C under CO2 atmosphere. By this method, NiCuZn and MnCuZn ferrite sintered
bodies with 0.5 mass% boric acid were obtained, the strength are 430 and 530 MPa respectively.
The effect of various Mn addition on NiCuZn electromagnetic properties were studied.
Model Calculation of Grain Growth in a Liquid Matrix
Authors: Jung Yang Il , Yoon Duk Yong , Kang Suk Joong L.
Published: March 2009

Growth behavior and kinetics of grains in a liquid matrix has been studied by computer simulation for various physical and processing conditions. The kinetics of growing and dissolving grains is considered to follow that of single crystals in a matrix. Depending on the crystal shape, i.e. rounded or faceted, different kinetic equations were adopted for growing grains and a single equation was assumed for dissolving grains. Effects of critical parameters such as step free energy, temperature, and liquid volume fraction were evaluated.
Preparation and Sintering Behavior of Fe Nanopowders Produced by Plasma Arc Discharge Process
Authors: Choi Chul Jin , Yu Ji Hun
Published: March 2009

The nano-sized Fe powders were prepared by plasma arc discharge (PAD) process
using pure Fe rod. The microstructure of the prepared nanopowders was evaluated and the effect of
hydrogen gas in the chamber atmosphere was investigated. In addition, the sintering behavior of
nanosized Fe powders was analyzed and compared with those of conventional micron powders. The
prepared Fe nanopowders had nearly spherical shapes and consisted of metallic core and oxide shell
structures. In PAD nanopowder sintering, the higher volume shrinkage at low sintering temperature
was observed due to the reduction of surface oxide. The PAD nanopowders showed 6 times higher
densification rate and more significant isotropic shrinkage behavior than those of micron sized Fe
powders.
A Preliminary Study of the Development of 9Cr Fe-Base ODS Alloys: The Effects of Minor Elements and Cooling Rate
Authors: Jang Jin Sung , Jang Young Moon , Shen Yin Zhong
Published: March 2009

Three 9Cr Fe-base ODS alloys were prepared by MA (mechanical alloying) and HIP (hot
isostatic processing) processes. The addition of Ti was confirmed to have a significant effect on the
tensile properties at high temperature as well as at room temperature, while the V addition did not
clearly show its effect on the microstructure or on the mechanical porperties at both temperatures.
Fine and evenly distributed Y and Ti containing complex oxide was detected in the Ti added ODS
alloy. They were attributed to the good high temperature strengths. Different cooling rates from the
normalizing temperature did not result in a significant change in the grain boundary characters, but
rather significant differences were observed in the mechanical properties. This is mainly attributed
to the difference of the matrix phase rather than to the grain size distribution or the grain boundary
characters.
Development of PM Stainless Steels with Improved Properties through Liquid Phase Sintering
Authors: Tojal C. , Gómez-Acebo T. , Castro F.
Published: March 2009

The use of boron for successfully obtaining high density PM stainless steels with improved mechanical properties and corrosion resistance is presented. Boron is added as part of master alloys which have been specifically designed to provide the formation of wetting liquid phases with excellent characteristics for producing controlled densification and alloying of 316L and 304L austenitic stainless steels. The as-sintered density and properties of these alloys is determined by the amount of master alloy, the chemical composition of the stainless steel powder, the sintering temperature and time. The microstructural development and alloy homogenisation are determined by the chemical composition of the Fe-based powder and the chemical reactions taking place between the basic powder and the master alloy particles during high temperature sintering. The use of this master alloy is shown to lead to stainless steels with outstanding combinations of strength and ductility. The influence of alloying and the sintering conditions on the final microstructure, density, corrosion resistance and tensile properties is also discussed.
Gigacycle Fatigue Crack Initiation in Cr-Mo Prealloy Sintered Steel
Authors: Xu Chen , Danninger Herbert , Khatibi Golta , Weiss Brigitte
Published: March 2009

Crack initiation and short crack propagation was studied on the polished notched surfaces
of Cr-Mo prealloy sintered steels with 7.35 g.cm-3 sintered density. An ultrasonic resonance test
system operating in push-pull mode at 20 kHz and R=-1 was used. It showed that crack initiation
took place in several places, small cracks growing oriented to the local pore structure rather than to
stress orientation. Their growth rate is markedly higher than the corresponding one of long cracks.
Finally, several microcracks join to form a dominant crack.
Rolling Contact Fatigue Property of Sintered and Carburized Compacts Made of Molybdenum Hybrid-Alloyed Steel Powder
Authors: Unami Shigeru , Ozaki Yukiko , Uenosono Satoshi
Published: March 2009

A new molybdenum hybrid-alloyed steel powder has been developed. The powder is
based on a molybdenum prealloyed steel powder to which molybdenum powder particles have been
diffusion bonded. The sintered compact made of the developed powder has a finer pore structure
than that of the conventional molybdenum prealloyed steel powder, because the ferritic iron phase
(α-phase) with a high diffusion coefficient is formed in the sintering necks where molybdenum is
concentrated resulting in enhanced sintering. The rolling contact fatigue strength of the sintered and
carburized compacts made of this powder improved by a factor of 3.6 compared with that of the
conventional molybdenum prealloyed steel powder. The improvement in the rolling contact fatigue
strength should result from the fine pore structure without coarse pores acting as stress
concentration points.
SCC Inhibitors for SG Tube Materials in Nuclear Power Plants
Authors: Kim Kyung Mo , Lee Eun Hee , Kim Uh Chul
Published: March 2009

Several chemicals were studied to suppress the damage due to stress corrosion cracking
(SCC) of steam generator (SG) tubes in nuclear power plants. The polarization curves showed that
the electrochemical properties on the surface of Alloy 600 MA changed with the addition of
inhibitors. The SCC tests were conducted by using a m-RUB specimen in a 10% NaOH solution at
a temperature of 315°C. The effects on the SCC of the compounds, TiO2, TyzorLA and CeB6, were
tested for several types of SG tubing materials. The test with the addition of TiO2 (P25) and CeB6
showed an effect in decreasing the SCC for the SG tubing material. However, CeB6 caused some
more SCC for Alloy 800. The penetration property into a crevice of the inhibitors was investigated
by using Alloy 600 specimens with different gap sizes and an AES analysis was performed on the
oxide layer of the specimen.
Effect of High-Energy Ball Milling on the Mg Alloy Powders under Alcohol Protection
Authors: Li Gang , Liu Xing Xing , Guo Qi , Tang Jian Ren , Yan Biao
Published: March 2009

Study about the feasibility and effect of high-energy ball milling on a specific Mg alloy
under protection medium of alcohol was presented via comparing with conventional vacuum
milling. More fine particles with wider powder size distribution but more irregular shape were
shown from image analysis of the SEM pictures of the powder milled under alcohol. No obvious
oxide was revealed from the X-ray diffraction of the two kinds of Mg alloy powders with limited
milling time. And since slip induced in a preferential direction, the (002) texture was formed in the
Mg alloy powders at the initial stage of alcohol milling. With deformation occurred randomly, the
texture disappeared regularly. More O and Fe contaminants were introduced into the powders
milled under alcohol according to the EDS analysis, for which the hot-pressed Mg alloy samples
fabricated with that powders exhibited lower UTS.
Fabrication of TiAl Target by Mechanical Alloying and Applications in Physical Vapour Deposition Coating
Authors: Gabbitas Brian , Cao Peng , Raynova Stella , Zhang De Liang
Published: March 2009

The research involves the development of a powder metallurgical route for producing
good quality TiAl targets for making physical vapour deposition (PVD) coatings. Mixtures of
elemental titanium and aluminium powders were mechanically milled using a novel discus milling
technique under various conditions. Hot isostatic pressing (HIP) was then employed for
consolidation of the mechanically alloyed powders. A cathodic arc vapour deposition process was
applied to produce a TiAlN coating. A microstructural examination was conducted on the target
material and PVD coatings, using X-ray diffractometry (XRD), X-ray photoelectron spectrometry
(XPS) and scanning electron microscopy (SEM). It has been found that combining mechanical
alloying and HIP enable us to produce a fairly good quality of TiAl based target. The PVD coatings
obtained from the TiAl target showed very high microhardness values.
Macro-Interface Characteristics of Bimodal-Structured Al Materials Produced by Ball-Milling
Authors: Chang Si Young , Cho Han Gyoung , Kim Jin Chun , Lee Seong Hee , Song Byung Heum
Published: March 2009

The bimodal-structured materials composed of Al-5wt%Mg alloy and its composites
reinforced with SiC and Al2O3 particles were prepared by ball-milling and subsequent compaction
under the pressure of 350MPa and sintering at temperatures ranging from 973K to 1173K for 1h, 3h
and 5h. The macro-interface between Al-Mg and Al-Mg/ Al2O3 composite was macroscopically
well-bonded compared to that between Al-Mg and Al-Mg/SiC composite under same sintering
conditions. The bonding of macro-interface became better as the sintering time and temperature
increased, resulting in that the bimodal-structured materials sintered at 1173K for 5h showed the
relative density of nearly 100%. In addition, the higher sintering temperature was, the more
irregular macro-interface was. The microhardness of macro-interface area was in between the Al-
Mg and composites, which was independent of the sintering temperature.
Study of TiCn Additions to an 2xxx Series Aluminium Alloy
Authors: Ruiz-Navas E.M. , Delgado M.L. , Benito Gonázles S. , Gordo Elena
Published: March 2009

The increasing demand of PM parts for automobile and aerospace applications has
caused a strong development of the aluminium based metal matrix composites (MMCs).Aluminium
alloys are one of most widely used materials as matrix in MMCs, both in research and development
as well as in industrial applications. The main reason is the combination of good specific properties,
the first requirement in most applications, and the competitive price compared to other low density
alloys such as Mg or Ti alloys.
In the present work, the influence of the ceramic reinforcement addition to a 2xxx series
aluminium alloy is studied. Several percentages of TiCN have been added to the Al-Cu alloy using
PM techniques, in order to analyze its influence on the liquid phase sintering process and also on
the final properties of the material. The materials have been uniaxially compacted using two
different pressures to determine the optimal pressing condition. They have been subsequently
sinterized in a N2-H2 atmosphere.
Analysing the results obtained, it can be concluded that the addition of TiCN allows a better
distribution of the liquid phase up to the 10 %wt, where the optimal results are observed: For higher
quantities of reinforcement, elemental copper is observed in the microstructure with the consequent
decrease in densification.
Shock-Wave Synthesis of Titanium Diboride in Copper Matrix and Compaction of TiB2-Cu Nanocomposites
Authors: Lomovsky O.I. , Mali Vjacheslav I. , Dudina Dina V. , Korchagin M.A. , Kwon Dae Hwan , Kim Ji Soon , Kwon Young Soon
Published: March 2009

TiB2-Cu composites in a nanostructured state are candidates for high-strength conductive
and erosion-resistant materials. In this work, we studied formation of nanostructured TiB2-Cu
composites under shock wave conditions. We investigated the influence of preliminary mechanical
activation (MA) of Ti-B-Cu powder mixtures on the peculiarities of the reaction between Ti and B
under shock wave. In the MA-ed mixture the reaction proceeded completely while in the nonactivated
mixture the reagents remained along with the product – titanium diboride. The size of
titanium diboride particles in the central part of the compact was 100-300 nm. This research shows
that shock wave synthesis in mechanically activated powder mixtures with simultaneous
compaction of the composite is a promising way to materials with submicron and nanostructures.
Fabrication of Porous Material Using Glass Abrasive Sludge
Authors: Chu Yong Sik , Kwon Chun Woo , Lee Jong Kyu , Shim Kwang Bo
Published: March 2009

agents. The glass abrasive sludges were mixed with expanding agents and compacted into pellets. These pellets were sintered in the range of 700-900oC for 20min. The sintered porous materials had a surface layer with smaller pores and inner parts with larger pores. The surface layer and pores controlled the absorption ratio and physical properties. As the expanding agent fraction and the sintering temperature increased, the porosity and pore size increased. The porous materials with Fe2O3 and graphite as the expanding agents had a low absorption ratio of about 3% or lower while the porous material with CaCO3 as the expanding agent had a higher absorption ratio and more open pores.