bluuebunny/crossref_metadata_2025 huggingface dataset:
Innovations in Micro Metal Injection Molding Process by Lost Form Technology
Authors: Nishiyabu Kazuaki , Kanoko Yasuhiro , Tanaka Shigeo
Published: March 2009

The production method of micro sacrificial plastic mold insert metal injection molding,
namely μ-SPiMIM process has been proposed to solve specific problems involving the
miniaturization of MIM. The sacrificial plastic mold (SP-mold) with fine structures was prepared by
injection-molding polymethylmethacrylate (PMMA) into Ni-electroform, which is a typical LIGA
(Lithographie-Galvanoformung-Abformung) process. Stainless steel 316L feedstock was injectionmolded
into the SP-mold which had micro structures with multi-pillars. The green compact was
demolded as one component with the SP-mold, which was decomposed along with binder
constituent of feedstock in debinding process. This study focused on the effects of metal particle
size and processing conditions on the shrinkage, transcription and surface roughness of sintered
parts, which were evaluated by SEM (Scanning Electron Microscope) observation.
Effect of Cu and Mg on Forging Property and Mechanical Behavior of Powder Forged Al-Si-Fe Based Alloy
Authors: Lee Dong Suk , Jung Taek Kyun , Kim Mok Soon , Kim Won Yong
Published: March 2009

Two atomized alloy powders, those chemical compositions are Al-10Si-5Fe-1Zr and Al-
10Si-5Fe-4Cu-2Mg-1Zr, were pre-compacted by cold pressing with 350MPa and subsequently hot
forged at temperatures ranging from 653K to 845K and at an initial strain rate of 10-2/s in order to
produce bulk cylindrical type alloys with the diameter of 10 mm. The addition of Cu and Mg into
the present alloy causes a decrease in the eutectic reaction temperature of Al-10Si-5Fe-1Zr alloy
from 841K to 786K and results in a decrease of flow stress at the given forging temperature. TEM
observation revealed that in addition to Al-Fe based intermetallics, Al2Cu and Al2CuMg
intermetallics appeared to display the alloying effect additionally. The volume fraction of
intermetallic dispersiods increased by the addition of Cu and Mg. Compressive strength of the
present alloys was closely related to the volume fraction of intermetallic dispersoids.
3D Printing of Biocompatible PM-Materials
Authors: Dourandish M. , Godlinski Dirk , Simchi Abdolreza
Published: March 2009

The fabrication of complex-shaped parts out of Co-Cr-Mo alloy and 316L stainless steel
by three-dimensional printing (3DP) is studied using two grades of each alloy with average particle
size of 20 and 75 )m, respectively. To produce sound specimens, the proper 3DP processing parameters
were determined. The sintering behavior of the powders is characterized by dilatometric
analysis and by batch sintering in argon atmosphere at 1280°C for 2h. The 3DP process has
successfully produced complex-shaped biomedical parts with total porosity of 12-25% and homogenous
pore structure, which is suitable for tissue growth into the pores.
Effect of the Preparation Methods of Me+Al Powder Blends on the Compaction Behavior, Structure, Phase Transformations, and Properties of the Compacted Aluminides of Transition Metals
Authors: Povarova K.B. , Kazanskaya N.K. , Drozdov A.A. , Morozov A.E. , Nikolaev A.G.
Published: March 2009

The effect of the methods for preparing powder blend by conventional milling (Me+Al
particles), attriting (Me/Al/ Me/Al composite particles), and plating of Me by Al (Me/Al composite
particles) on the structure, internal stress level, and compactability of the powder blends as well as
the structure and phase composition of the MeAl compacts was investigated. The Me+Al→MeAl
exothermic reaction of these powders occurs at T≥650°C. The reaction sintering (RS) or hightemperature
self-propagation synthesis (HTSPS) occurs through the formation of Al melt (liquidphase
reaction) and lower-melting MeAl3, Me2Al3, Me3Al aluminides. An increase in the level of
internal stresses (IS) upon attritting activates RS at lower temperatures and decreases the value of
high-temperature exoeffect. This suppresses the HTSPS development. A large high-temperature
exoeffect ensures the intensity and completeness of the reaction interaction, and the application of
pressure upon RS or HTSPS provides a high, near-theoretical density of the compacted material.
Fabrication of Nanocrystalline TaSi2-SiC Composite by High Frequency Induction Heated Combustion Synthesis and Its Mechanical Properties.
Authors: Shon In Jin , Kim Dong Ki , Ko In Yong , Yoon Jin Kook , Hong Kyung Tae
Published: March 2009

By the high frequency induction heated combustion synthesis (HFIHCS) method, dense nanostructured TaSi2-SiC composite was synthesized within 2 minutes and in a single step from powders of TaC and 3Si. Simultaneous combustion synthesis and densification were accomplished under the combined effects of an induced current and mechanical pressure. Highly dense TaSi2-SiC with relative density of up to 97% were produced under a 60MPa pressure and induced current. The average grain size and mechanical properties (hardness and fracture toughness) of the composite were investigated.
Improvement in Microstructure Homogeneity of Sintered Compacts through Powder Treatments and Alloy Designs
Authors: Hwang K.S. , Wu M.W. , Yen F.C. , Sun C.C.
Published: March 2009

Homogeneous microstructures of the PM compacts are difficult to attain when mixed
elemental powders are used. This study examined the microstructures of pressed-and-sintered and
MIM products that contain Ni and Mo. Ni-rich areas, which were lean in carbon and were soft, were
found easily in regular specimens. Gaps or cracks near the Ni-rich or Mo-rich areas were also
frequently observed. This problem got worse when Ni and Mo particles were large and were
irregular in shape. By using ball milling treatment and ferroalloy powders, the microstructure
homogeneity and mechanical properties were improved. The addition of 0.5wt%Cr further
improved the distribution of Ni because Cr reduced the repulsion effect between nickel and carbon.
With the elimination of Ni-rich areas, more bainites and martensites were formed and mechanical
properties were significantly improved.
A New Technology of Hardening Porous Materials of Titan Powders
Authors: Belyavin K.E. , Minko D.V. , Reshnetikov N.V.
Published: March 2009

A technology of hardening porous materials of titan powders has been elaborated. The
technology is based on passing alternating current with duration of ~10-1…101 s through porous
(35…40%) blanks made by method of Sintering by Electric Discharge (SED) by passing a pulse
of current with duration of ~10-5…10-3 s. The influence of technological regimes of porous blanks
treatment on their structure and properties is investigated. Geometry and dimension of contact necks
between powder particles of obtained samples are evaluated. Variations of porosity and strengths as
well as microstructure of porous samples materials before and after treatment are investigated.
Optimum range of treatment technological regimes is determined within which porosity of
30…35% with maximum strength values.
Effect of Heat Treatment Conditions and Densities on Residual Stresses at Hybrid (FLN2-4405) P/M Steels
Authors: Kafkas Fırat , Karatas Çetin , Saritaş Suleyman
Published: March 2009

The characteristics of residual stresses occurring in PM steel based nickel (FLN2-4405)
was investigated. Residual stresses were measured by electrochemical layer removal technique. The
values and distributions of residual stresses occurring in PM steel processed under various densities
(6.8, 7.05, 7.2 and 7.4 g/cm3) and heat treatment conditions (sintered at 2050 ºF, sintered at 2300 ºF,
quenching-tempered, and sinter-hardened) were determined. In most of the experiments, tensile
residual stresses were recorded on the surface of the samples. The residual stress distribution on the
surface of the PM steels was found to be affected by the heat treatment conditions and density. The
maximum values of residual stresses on the surface showed sinter hardened condition and a density
of 7.4 g/cm3. The minimum level of recorded tensile residual stresses are150 MPa and its maximum
level is 370 MPa.
Fatigue Properties for Sinter-Hardened Fe-Ni-Mo-Cu Materials
Authors: Wang Chong Lin , Wang Ping , Shi Zai Min
Published: March 2009

Fe-4Ni-0.5Mo-1Cu powder was selected as raw material, pressed and sinter-hardened at
1135°C for 30 min with rapid cooling. The density varies in the range of 7.24-7.29 g/cm3. Its fatigue
properties have been tested in axial loading of alternating tensile/compressive stress at R=-1 with a
servo-pulse pump. The fatigue endurance limit was measured to be 260 MPa. The microstructure
showed more homogeneous bainite and martensite. Neither Ni nor Mo rich areas were detected.
Fractography displayed the fatigue cracks initiated from the pore areas near the surface. A nontypical
ductile fatigue striation was found. More dimples occurred on fracture surface due to the
plastic deformation, which can prohibit cracking propagation and improve its fatigue properties.
Functional Relationships between Fatigue Data
Authors: Beiss Paul
Published: March 2009

Most PM components are exposed to cyclic loading over long periods of time, and the
endurable stress amplitude is an important factor considered in many applications. With the
continuously growing volume of experimental test results, functional relationships can be derived
which permit predictions on the effects of density ρ, external notches characterized by a stress
concentration factor Kt, and static mean stresses σm for standardized test specimen geometries.
Rolling Contact Fatigue of Hot-Forged Steels out of Prealloyed Powders and Powder Blend
Authors: Dorofeyev Vladimir , Sviridova Anna
Published: March 2009

Powder forging is used for heavy-loaded parts (rings of rolling-contact bearings, gears
etc.) production. Rolling contact fatigue is material property values of which characterize possibility
of practical utilization of such parts. Rolling contact fatigue of some steels obtained out of prealloyed
powders Astaloy CrM, Atomet 4601, Atomet 4901 and powder blends iron-carbon-nickel by
hot forging is studied in the present paper. Effect of various kinds of heat and thermomechanical
treatment on rolling contact fatigue is determined. Thermomechanical treatment provides optimal
values of rolling contact fatigue. In this case steel structure contains up to 40% of retained metastable
austenite which is transformed to martensite on trials. Thus typically crack is generated on residual
pores and non-metallic inclusions instead of martensite zones in wrought steels.
Mechanical and Microstructural Properties of Titanium Matrix Composites Reinforced by TiN Particles
Authors: Romero F. , Amigó Vicente , Salvador M.D. , Martinez E.
Published: March 2009

Particulate reinforced titanium composites were produced by PM route. Different
volumetric percentages of TiN reinforcements were used, 5,10,15 vol%. Samples were uniaxially
pressed and vacuum sintered at different temperatures between 1200-1300°C. Density, porosity,
shrinkage, mechanical properties and microstructure were studied. Elastic properties and strength
resistance were analysed by flexural strength and tension tests, and after the test, fractured samples
were analysed as well to obtain the correlation between the fracture, interparticular or
intraparticular, and the level of reinforcement addition. Hardness and microhardness test were done
to obtain a better understanding of its mechanical properties. In order to study wear resistance pinon-
disc tests were conducted. In addition, the influence of temperature, the reactivity between
matrix and reinforcement on microstructural development were observed by optical and electron
microscopy.
Softening-Hardening Mechanism in the Direct Hot-Extrusion of Aluminium Compacts
Authors: Zubizarreta C. , Arribas I. , Giménez S. , Iturriza I.
Published: March 2009

Powder compacts from two different commercial aluminium powder grades have been densified by direct hot extrusion. The extrusion runs have been carried out at 425 °C, with an extrusion ratio of 1:16 and a ram speed of 1.5 mm/s. Prior to extrusion, some green compacts were presintered (500 °C). The evolution of the extrusion load during the process and the hardness of the final products have been investigated. Additionally, microstructural characterization by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Electron Backscattered Diffraction (EBSD) was carried out in order to understand the softening-hardnening mechanisms taking place during the process. The obtained results evidence grain refinement. Additionally, inter-metallic precipitation, dynamic recovery and geometric dynamic recrystallization take place depending on the composition of the powder, the heat treatment before extrusion and the strain involved in the process.
Creep Behavior of Hot Extruded Al-5% SiC Composite Powder
Authors: Hosseini Monnazah A. , Simchi Abdolreza , Seyed Reihani S.M.
Published: March 2009

The creep behavior of particulate Al-5vol.% SiC composite was investigated. The
composite powder was produced by mechanical milling and hot extruded at 450°C at the ratio of
16:1. A creep test was carried out at a constant load at 598, 648, and 673 K. Using the existing
equations proposed for the steady-state creep of metals, the threshold stress and the stress exponent
of the creep as a function of temperature were determined. The stress exponent was found to be 3 at
the temperature of 673 K and 8 at the lower temperatures, i.e. 598 and 648 K. The dependency of
the threshold stress to temperature obeys the Arrhenius relationship with the energy term of 29 kJ
mole-1.
Hot Deformation Behavior of P/M Al6061-20% SiC Composite
Authors: Asgharzadeh Hamed , Simchi Abdolreza
Published: March 2009

In the present work, hot workability of particulate-reinforced Al6061-20%SiC composite produced by direct hot extrusion technique was studied. Uniaxial hot compression test at various temperatures and strain rates was used and the workability behavior was evaluated from the flow curves and the attendant microstructures. It was shown that the presence of SiC particles in the soft Al6061 matrix deteriorates the hot workability. Bulging of the specimens and flow lines were observed, which indicates the plastic instability during hot working. Microstructure of the composites after hot deformation was found to be heterogeneous, i.e. the reinforcement clusters were observed at the flow lines. The mechanism of deformation is determined to be controlled primarily by dynamic recrystallization.
Surface Modification of Ag Coated Cu Conductive Metal Powder for Conductive Silicone Sealant Gasket Paste
Authors: Park Seong Yong , Yoon Tae Won , Lee Chung Ho , Jeong In Bum , Hyun Sang Hoon
Published: March 2009

Conductive pastes have drawn significant interest due to their advantageous physical
properties as well as their potential in electronic material industries. Conductive pastes consist of
conductive fillers, organic binders, solvents and additives. Metal powders, such as Au, Ag, Ni, Cu,
etc. are used for conductive filler. Filler dispersion is a very important and yet a difficult process in
conductive paste manufacturing. Meanwhile, there are some metal powders such as copper, nickel
etc that are used for pastes which have serious surface corrosion problems. This problem leads to
change of the color and decrease in conductivity and affect storage stability of conductive pastes.
To overcome these problems, we adopted two kinds of surface modification method. One is a
method involving coating of silane coupling agent to conductive metal powders to overcome the
corrosion stability and the other is a method involving addition of a dispersing agent to increase the
degree of dispersion of metal powders. A coupling agent and dispersing agent are used to reduce the
interfacial energy between filler and organic binder to enhance dispersion and its stability.
By using silane coupling agent and dispersion agent, we can ensure both the corrosion stability and
long term storage stability, and enhance the high performance electrical and mechanical properties
of EMI shielding silicone sealant.
A Study on Kinetics Parameters of Titanium Hydride Powder from Its TPD Spectrum for Metal Foam
Authors: Yang Dong Hui , Kim Sang Youl , Hur Bo Young
Published: March 2009

In this paper, the whole temperature programmed decomposition (TPD) spectrum of titanium hydride was acquired by the special designed set-up. After separating and simulating the TPD spectrum by using Spectrum Superposition Method (SSM), Consulting Table Method (CTM) and differential spectrum technique, the kinetics parameters of titanium hydride and corresponding equations were obtained. Using these kinetics equations, the fabrication parameters of Al alloy foam can be determined and foaming process of Al alloy melt can be predicted.
Bend Deformation Behavior of Silicon Carbide Reticulated Porous Ceramics
Authors: Zhu Xin Wen , Sakka Yoshio , Tan Shou Hong , Jiang Dong Liang
Published: March 2009

This work will report the deformation behavior of silicon carbide reticulated porous
ceramics (SiC RPCs) under three-point bend test. SiC RPCs were fabricated by replication
processing using an open-cell polyurethane sponge with cell size of ~ 13 pores per inch (ppi). It is
shown that the deformation behavior strongly depends on the loading uniformity and the
macrostructure. Using a compliant layer (0.5 mm paper pad), the uniform loading leads to a
significant transition in the load-displacement curve of RPCs from the complex saw-tooth shape
to the one similar to dense ceramics, despite the presence of some macrostructural flaws and
partial clogged cells. However, this dependence of loading uniformity is alleviated by developing
highly uniform macrostructure with fewer flaws and clogged pores. Even, this dependence
becomes less important as the struts become thicker and stronger, leading to an increase in
relative density, accordingly. The bend result of RPCs with highly uniform macrostructure is in
excellent agreement with the GA (Gibson and Ashby) model, but the one with un-uniform
macrostructure deviates from the GA model. This work shows that the macrostructure plays an
important role in deformation behavior of RPCs under bend.
Development of Some New Porous Metal Materials
Authors: Fang Yu Cheng , Wang H. , Zhou Yong , Kuang Chun Jiang
Published: March 2009

Porous metal materials have been widely used in various industrial fields in the world.
This paper describes the recent research achievements of CISRI in the development of porous metal
materials. High performance porous metal materials, such as large dimensional and structure
complicated porous metal aeration cones and tube, sub-micron asymmetric composite porous metal,
metallic membrane, metallic catalytic filter elements, lotus-type porous materials, etc, have been
developed.
Preparation of Titanium Microfiltration Membrane by Field–Flow Fractionation Deposition
Authors: Wang Qiang Bing , Tang Hui Ping , Zhang Qian Cheng , Qiu Qun Feng , Wang Jan Yong
Published: March 2009

The primary aim pursued by the preparation of the separation membrane is to make the membrane thinner as well as have no defects. The field-flow fractionation deposition is a new molding technology which can overcome the traditional disadvantages, such as multi-preparation, to the preparation of a great area of the separation membrane with no defects. Therefore the main ingredients which influence the appearance and performance of titanium membrane layers are investigated by a scanning electricity mirror (SEM) as well as a porous material testing instrument: powder performance prepared and confected; selection of supporting body; sintering system such as temperature and time. It is shown that the membrane thickness can be controlled at 50μm or so.
Production of Titanium Porous Material “Tiporous” and Its Evaluation
Authors: Onishi Takashi , Azuma Kazuomi , Ogasawara Tadashi
Published: March 2009

Gas atomization furnace, Sumitomo Titanium Corporation originally designed, has
been producing spherical and high quality Titanium fine powder, ‘‘Tilop’. Excellent characteristics
of Tilop and property of metal Ti itself (high corrosion resistance, high specific strength) have made
us produce new titanium porous material, ‘‘Tiporous’.
With optimization of green sheet preparation and sintering process, porous sheet of large size and
wide range of thickness are produced and porous pipe and other custom made shape product are
also available. Evaluation of mechanical, chemical, filtration and flow-controlling properties shows
that these products have good characteristics and are applicable to various industrial fields.
Preparation and Characterisation of WO3.1/3H2O Thin Films
Authors: Balázsi Csaba , Zayim Esra Özkan
Published: March 2009

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Development of Composite Structures for Ballistic Protection
Authors: Faur-Csukat Gabriella
Published: March 2009

The mechanical behaviour and ballistic performance of carbon, glass (E and S type),
aramide and polyethylene fabric reinforced composites with different epoxy resins were studied.
The specimens −produced by hand lay-up method− were qualified by low velocity (Charpy and
drop weight tests) and high velocity (two different bores ballistic) impact tests. The energy
absorption capacity of the composites were found to be strongly affected by material properties of
reinforcing fibre, type of fabric structure and elasticity of resin.
The Corrosion Study of ZrO2 Coatings on Metals
Authors: Rotariu Ioana , Turdean Graziella L. , Kormos Fiammetta , Macarovici Dan , Tolnai Gyula , Felhősi Ilona , Nagy Péter M. , Trif László , Kálmán Erika
Published: March 2009

The ZrO2 coatings were deposited by sol-gel techniques on copper and steel. The film
morphology has been investigated by AFM technique. The performance of ZrO2 films as protective
layers was investigated by electrochemical techniques and optical microscopy. Firstly, the
electrochemical behaviour of the uncoated copper and steel substrates was investigated by cyclic
voltammetry in HCl (1 M) and NaOH (0.4 M) solutions having various pH values. Secondly, the
anticorrosion protective effect of sol-gel ZrO2 coatings was evaluated by potentiodynamic
measurements in degrading media in which substrates were immersed for 1-90 days. The
comparisons of electrochemical parameters allow an explanation of the role of the ZrO2 coatings in
the increased resistance of steel and copper against corrosion in moderately aggressive
environments..
Surface Modification of Polyethylene by Nitrogen PIII: Surface Chemical and Nanomechanical Properties
Authors: Tóth A. , Bertóti I. , Mohai M. , Ujvári T.
Published: March 2009

Ultra-high molecular weight polyethylene (UHMWPE) was surface treated by nitrogen
plasma immersion ion implantation (PIII), with the main aim of improving its wear resistance.
Accelerating voltages (U) between 15 and 30 kV, fluences (F) between 1×1017 and 3×1017 cm-2 and
fluence rates (FR) between 3×1013 and 7×1013 cm-2 s-1 have been applied. XPS was used to
characterise the surface chemical composition and structure. Changes induced in the surface
mechanical properties like hardness (H), reduced modulus (E) and in the tribological property of
volume loss upon uniform wear test (V) were studied by nanoindentation and multipass wear
measurements. The evolution of surface topography was followed by measuring the mean
roughness (Ra). The macroscopic temperature (T) developed during the PIII-treatment was also
studied.
Incorporation of N and O took place into the surface layer. With the increase of U the
surface N-content tended to decrease. The bulk plasmon loss energy of the C 1s peak increased
from 20 eV up to about 25 eV, suggesting densification and the formation of amorphous
hydrogenated carbon nitride-like layer. H, T and Ra increased, and V decreased upon PIII treatment,
while E either decreased or increased depending on the actual process parameter set applied. In the
parameter range studied Hmax, Emax and Ra,max values have been observed at Umax, Fmax and FRmin.
Vmin and Tmax have been observed at Umax, Fmin and FRmax, suggesting that the thermal effect is a
dominant factor in determining the extent of reduction in the wear rate.
Raman Analysis of Diamond-Like Carbon Films Deposited onto Corrosion Resistant Alloys Used for Coronary Stent Fabrication
Authors: Veres M. , Tóth Sara , Füle M. , Dobránszky János , Major László , Koós Margit
Published: March 2009

The structure of diamond-like carbon thin films prepared by radio frequency chemical
vapor deposition onto the surface of different corrosion resistant alloys (304, 316L and Iconel 617)
used for coronary stent fabrication was investigated by Raman spectroscopy excited by visible (488
nm) and near-infrared (785 nm) light. The effect of electrochemical polishing of the alloy surface
and that of Ar+ ion pre-treatment on the structure of the forming film was also studied in case of
substrate made of 316L material. It was found that in spite of simultaneous preparation the
character of the formed amorphous carbon films depends on the type of the alloy. The layer
developed on the surface of Fe-rich stainless steels (316L and 304) showed the most diamond-like
character, while the Ni-rich Inconel alloy promoted the formation of layer with high graphitic sp2
cluster content. The Ar+ pre-treatment enhanced the adhesion and the diamond-like properties of the
film while the electrochemical polishing was found to be unfavorable concerning the diamond-like
character of the layer.
AFM Investigation of Steels Surfaces Worn in HFRR Tests
Authors: Aranyi D. , Nagy Péter M. , Oláh Zs. , Kálmán Erika
Published: March 2009

Radical reduction of sulphur content in diesel fuel from the mid 90’s had disastrous
impact on diesel fuel’s lubricity. Due to the desulphurization process the lubricity of diesel
fuel dropped significantly and got crucial nowadays. The lubricity performance of the diesel
fuel is evaluated by the HFRR test in Europe. The HFRR value is determined by measuring
the equivalent wear scar diameter occurred on the steel ball specimen during the test. The
topographies of these wear scars were investigated by AFM and correlation between the
morphology of the worn surfaces and the different HFRR values has been found.
Investigation of Coated Coronary Stents
Authors: Bognár Eszter , Ring György , Dobránszky János
Published: March 2009

In this study the main properties of coated coronary stents are shown, such as recoil,
foreshortening, surface features and failures and the expansion properties. The types and the effects
of active and passive coatings are introduced. The results of our examinations with different coated
coronary stents are shown as well. The quality and the changing of the coatings were examined by
different methods (stereomicroscopy, atomic force microscopy, scanning electron microscopy and
EDS analysis).
On the Temperature Rate Dependent Transformation Processes
Authors: Réti Tamás , Czinege Imre , Felde Imre , Costa Lino , Colás Rafael
Published: March 2009

Kinetic models of new types are suggested which are designated primarily to predict the progress of non-isothermal transformations occurring during rapid heating and cooling in alloys. A common feature of each model outlined is that it takes into account not only the varying temperature but also the rate of temperature change on the transformation rate of the process. The two models represented by differential equations are generated by using the concept of virtual kinetic parameters, which can be determined from non-isothermal experiments only. A key property of the virtual parameter "p" involved in the transformation rate equations is that it quantitatively characterizes the temperature rate dependence of the non-isothermal reaction.
The Strain Dependence of Post-Deformation Softening during the Hot Compression of 304H Stainless Steel
Authors: Jonas John J. , Poliak Evgueni I. , Najafizadeh Abbas
Published: March 2009

Experiments were carried out in which the dependence of the fractional softening on
temperature, time and strain rate was determined in a 304H stainless steel. Three prestrain ranges were
identified pertaining to three different post-deformation softening behaviors: 1) prestraining to below the
DRX critical strain: strongly strain dependent softening by SRX alone with softening kinetics controlled
by growth rate of the nuclei; 2) prestraining to above the DRX critical strain: SRX + MDRX softening
with weaker strain dependence of the kinetics but still controlled by grain growth; 3) at a prestrain of ε*
and beyond: nucleation-controlled MDRX softening with the full inhibition of SRX. The transition
prestrain ε* can exceed the peak strain if the DRX grain refinement ratio g = D0/DDRX > 4. The
transition to MDRX-dominated softening can be attributed to a constant value of the normalized strain
hardening rate independent of the preloading temperature and strain rate. The softening data from the
compression tests show that at ε*, the time for half softening t50 exhibits a minimum. These data differ
somewhat from observations obtained in the torsion testing of solid bars, in which no strain dependence
of t50 was detected at ε* and beyond. Whether or not the strain dependence of t50 vanishes in the MDRX
range is sensitive to the test method employed to study the post-deformation softening.
Novel Processing of Porous Titanium Composite for Producing Open Cell Structure
Authors: Kobashi Makoto , Kanetake Naoyuki
Published: March 2009

Processing technique to produce open-cell porous titanium composite was developed.
One of the outstanding benefits of porous titanium composite is both physical and mechanical
properties can be controlled widely by changing the metal/ceramic fraction and cell structures. In
this work, porous titanium composite was fabricated by a chemical reaction between titanium
powder and boron carbide (B4C) powder. The reactions between titanium and B4C generates a
large amount of latent heat and, therefore, it was a combustion and self-propagating mode.
Precursors were made by compacting the starting powder blend (Ti and B4C), and heated in an
induction furnace to induce the reaction. The reaction was strongly exothermic and, therefore, the
precursor was sintered by its latent heat when the Ti/B4C blending ratio was appropriate. The
reaction products were titanium boride (TiB and/or TiB2) and titanium carbide (TiC). By
controlling the Ti/B4C blending ratio, it was possible to control the volume fraction of reaction
products in titanium matrix. The combustion synthesized titanium composite was porous and its
cell structure was strongly affected by the processing condition of the precursor (porosity and
Ti/B4C blending ratio). High porosity with open pores was obtained with small Ti/B4C ratios and
high porosity of the precursor, while the cell structure was closed and spherical with high Ti/B4C
ratio. The cell-wall size was varied from several tens of microns to about 500 microns by
changing the combustion temperature.
Novel Separation Technique of Particle Reinforced Metal Matrix Composites by Fused Deposition Method
Authors: Mizumoto Masayuki , Ohgai Takeshi , Kagawa Akio
Published: March 2009

To develop a novel separation technique of matrix alloys from metal matrix composite,
separation experiments for various kinds of particle reinforced metal matrix composites (PRMMCs)
were carried out. The Al-4mass%Cu alloy, Al-7mass%Si alloy and cast iron were used as matrix. The
SiC particles (particle size: 75μm) and Al2O3 particles (particle size: 120μm) were used as
reinforcement. The PRMMC specimen was placed in a silica tube container with a small nozzle
(nozzle size: 0.75mm) at the bottom and was melted by H.F. induction heating. Then the molten
PRMMC specimen was forced to flow out through the nozzle by applying a certain pressure of Ar gas.
Most of the molten matrix alloy flowed out through the nozzle and the remainder in the container
consisted of the reinforcements and a part of the matrix alloy. The amount of separated matrix alloy
increased with decreasing the volume fraction of reinforcement particles in PRMMC specimens.
With decreasing the fabrication temperature from 1273K to 1073K, the amount of matrix alloy
separated from SiCP/Al-7mass%Si alloy composites increased. It is considered that a reaction layer
formed on the surface of SiC particles at 1273K improves the wettability between the molten matrix
alloy and SiC particle, which prevents the separation of molten matrix alloy from reinforcements. On
the other hand, the amount of separated matrix alloy from 20vol% Al2O3P/cast iron composites was
very high due to no reaction layer formed at interface between Al2O3 particle and cast iron.
Effect of Al Content on Corrosion Resistance of (Ti1-xAlx)N Coatings under NaCl Deposit in Wet Oxygen at 600°C
Authors: Feng Chang Jie , Li Ming Sheng , Xin Li , Zhu Sheng Long , Wang Fu Hui
Published: March 2009

(Ti1-xAlx)N(x=0, 0.1, 0.3) coatings were deposited on 1Cr11Ni2W2MoV stainless steel
by arc ion plating. The (Ti1-xAlx)N coatings had B1 NaCl structure, however its preferred
orientation change from (111) to (220) with the increase of Al content. A number of nodule-shaped
spots identified as rutile TiO2 by XRD formed on the surface of TiN coating after corrosion beneath
NaCl deposit in wet oxygen at 600 oC. With the addition of Al, a thin scale composed of Al2O3 and
TiO2 formed on the surface of the (Ti1-xAlx)N coatings instead of a scale of TiO2 on TiN coating,
thereby their corrosion resistance was remarkably enhanced.
Development of a Magnesium Recycling Alloy Based on AM50
Authors: Fechner Daniel , Maier Petra , Hort Norbert , Kainer Karl Ulrich
Published: March 2009

Magnesium applications for structural components in the automotive industry are
constantly rising. This is based on the recent development of new alloys, new fabrication processes,
and the ambition of car manufacturers to reduce the vehicles weight and CO2 emissions according
to the EU and US policy [1, 2]. A rising quantity of magnesium per vehicle leads to a rising
quantity of scrap which needs to be recycled according to the European Directive on end-of life
vehicles [3]. So far post consumer scrap has not been used for structural parts. But since the metal is
still expensive compared to aluminium or steel, and remelting saves more than 90 % of the energy
for primary production, magnesium recycling will significantly contribute to cost savings.
In comparison to steel or aluminium a recycling cycle for magnesium has not yet been established.
Concerning post consumer scrap it is likely that many vehicles will end up in the shredder fraction
or at least will be mixed up instead of being dismantled and separated according to their alloy. Thus
it is reasonable to define secondary alloys which allow the use of post consumer scrap for structural
applications. Creep resistant alloys have the potential of a broad application concerning the weight
of the components and therefore a secondary alloy would be reasonable. The aim of this work is to
examine a row of AM50-based alloys, modified with additions of Sr, Ca, and Si due to the
importance of these elements to increase creep resistance and their usage in modern magnesium
alloys. The corrosion properties as well as the mechanical properties and microstructures are
investigated in the as-cast and annealed condition. Salt spray tests (using 5 % NaCl) and
electrochemical corrosion methods are applied to investigate the corrosion properties which are
then compared to the unmodified AM50. Tensile and compression tests at temperatures ranging
from 20 °C to 200 °C are applied to investigate the mechanical properties.
Interface Microstructure and Adhesion of Zinc Coatings on TRIP Steels
Authors: Song G.M. , Sloof Willem G. , Vystavel T. , de Hosson Jeff T.M.
Published: March 2009

Hot-dip galvanized transformation induced plasticity (TRIP) steel sheets were recently
developed for automotive applications. The microstructure and the adhesion of zinc coated CMnSi
TRIP steel alloyed with P were studied. The α-Zn coating adjacent to the steel substrate consists of a
continuous η-Fe2Al5-xZnx inhibition layer with columnar ζ-FeZn13 intermetallic particles on top.
Along the interface between the inhibition layer and the steel substrate Mn/Mn-P oxides were
frequently observed. Although these oxides at the steel surface reduce the adhesion between the zinc
coating and the TRIP steel, they do not cause any bare spots during galvanizing. Upon tensile
deformation of the galvanized steel sheet, cracking along the α-zinc grain boundaries preceded
fracture of the interface between the α-Zn layer and the inhibition layer. After 4 % deformation the
average interface crack length increased linearly with the applied strain. This interface fracture was
strongly influenced by the crystalline orientation of the α-Zn grains.
Plasma Spray Deposition of Hydroxyapatite Coatings from Sol Precursors
Authors: Coyle Tom W. , Garcia E. , Zhang Z. , Gan Lu
Published: March 2009

Plasma spray deposition of hydroxyapatite (HA) coatings is a well established commercial
process. When deposited on metallic substrates, these coatings have been shown to promote bone
fixation and osteconductivity. A concern with current coatings is the formation of relatively large
debris particles during resorption. The size of the debris is related to the particle size of the powder
injected into the plasma during the deposition process. The use of solution precursors or dispersions
of fine particle size powders as the feedstock for plasma spraying has been shown to produce
submicron/nanocrystalline structured coatings from relatively inexpensive precursors.
Nanocrystalline HA coatings may improve the resorption of the coating in the body, avoiding the
irritant effect of large particles which may be seen in current thermal sprayed HA coatings.
We have explored the use of sols prepared from several different precursors as the feedstock for the
plasma spray deposition of HA coatings on Ti6Al4V substrates, employing statistical design of
experiments to establish optimal deposition conditions. We report on the formation and the
characteristics of the coatings as a function of the deposition parameters. The presence of different
Ca-P crystalline and amorphous phases was assessed by X-ray diffraction analysis. The coating
microstructure was characterized by scanning/transmission electron microscopy. The suitability of
the technique to coat biomedical implants is discussed.
Prospective Applications of Gas-Eutectic Porous Materials (Gasars) in USA
Authors: Shapovalov Vladimir
Published: March 2009

The paper summarizes new and published data and also deals with structure, applications, and properties of
gasars – new porous materials based on gas-eutectic reaction which was establish in USSR in 1976-1980.
The method consists of melting a material in an active gas atmosphere and solidifying under controlled
conditions. The materials produced by this method, have a solid matrix and pores of varied geometric
shapes, providing to gasars much higher strength, plasticity, thermal and electrical conductivities as
compared with those of other porous materials. For USA gasars can be recommended for there are many
applications for civil and military industries.
Deposition of Multi-Functional Coatings by Physical Vapour Deposition
Authors: Tillmann Wolfgang , Vogli Evelina , Nebel Jan
Published: March 2009

Multifunctional coatings open new dimensions due to a combination of properties like high
friction and wear resistance, electrical attributes, heat or corrosion protection in one system. In this
study multifunctional coatings for in-situ temperature measurements on cutting inserts as well as
multilayer coatings have been investigated. Corresponding metallurgical analyses together with
mechanical tests are presented.
Effects of Alloying on Deformation Behavior of Low Carbon Steels in the Intercritical Temperature Range
Authors: Poliak Evgueni I. , Bhattacharya D.
Published: March 2009

Industrial thermomechanical processing of hot rolled steel strip products with rolling
operations in the austenite + ferrite (γ + α) range offers, on one hand, unique possibilities for more
precise control of microstructure and mechanical properties of as hot rolled products after
accelerated cooling. On the other hand, there are significant technical problems related to the rolling
stability induced by steel grade dependent non-monotonous variations in deformation resistance and
its sensitivities to temperature and strain rate within the γ + α range. Based on laboratory results, the
deformation behavior of low carbon (up to 0.2 %) steels alloyed with Mn, Si, Al and their
combinations, as well as microalloyed with Nb at the intercritical temperatures is discussed.
High-Temperature Tribological Properties of Barite-Type-Sulfate-Coated Substrates with Different Isoelectric Points
Authors: Murakami Takashi , Umeda K. , Sasaki Shinya , Ouyang Jia Hu
Published: March 2009

In the present study, Al2O3, (ZrO2-3mol% Y2O3)-39.6mass% Al2O3, Si3N4 and MgO
substrates coated with SrSO4 particles were prepared, and their high-temperature tribological
properties were investigated. It was clarified that SrSO4 worked as solid lubricant efficiently against
Al2O3 and (ZrO2-3mol% Y2O3)-39.6mass% Al2O3 substrates in the temperature range of room
temperature to 1073K in air. In addition, thin SrSO4 films were observed on the wear scars formed
on the Al2O3 and (ZrO2-3mol% Y2O3)-39.6mass% Al2O3 substrates.
Analysis on the Microstructure of Ceramic Coating Layer Fabricated by Plasma Electrolytic Oxidation
Authors: Ok Myoung Ryul , Kang Eun Young , Kim Ji Hye , Ji Young Su , Lee Chang Woo , Oh Young Joo , Hong Kyung Tae
Published: March 2009

Plasma electrolytic oxidation (PEO) has drawn attention and been studied intensively all
through the world. The thick ceramic coatings fabricated by the technique exhibit excellent
properties, including hardness and wear resistance, thermal and electrical insulation, and corrosion
resistance, due to the characteristic phase composition and microstructure of the coating layers.
However, most of the studies have dealt with manufacturing process itself and the apparent
properties of coating layers and researches on the microstructural basis including transmission
electron microscopy analysis are limited so far.
In this investigation, a basic approach to PEO process was tried, adapting time-potential behavior
analysis under constant current mode (galvanostatic) oxidation, and microstructural analysis on the
coating structure, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and
transmission electron microscopy (TEM). The time-potential behavior analysis under constant
current DC was carried out, and the resultant evolution of the microstructure was characterized..
Solid Oxide Fuel Cell (SOFC) Development in Denmark
Authors: Linderoth Søren , Larsen Peter Halvor , Mogensen M. , Hendriksen Peter V. , Christiansen N. , Holm-Larsen H.
Published: March 2009

The SOFC technology under development at Risø National Laboratory (RISØ) and
Topsoe Fuel Cell A/S (TOFC) is based on an integrated approach ranging from basic materials
research on single component level over development of cell and stack manufacturing technology to
system studies and modelling. The effort also comprises an extensive cell and stack testing
program. Systems design, development and test is pursued by TOFC in collaboration with various
partners. The standard cells are thin and robust with dimensions of 12 x 12 cm2 and cell stacks are
based on internal manifolding. Production of cells is being up-scaled continuously. The durability
of the standard stack design with standard cells has been tested for more than 13000 hours including
nine full thermal cycles with an overall voltage degradation rate of about 1% per 1000 hours.
Recently, the degradation rate has been significantly reduced by introduction of improved stack
component materials. 75-cell stacks in the 1+ kW power range have been tested successfully. Stacks
have been delivered in a pre-reduced state to partners and tested successfully in test systems with
natural gas as fuel. The consortium of TOFC and RISØ has an extended program to develop the
SOFC technology all the way to a marketable product. Stack and system modelling including cost
optimisation analysis is used to develop multi kW stack modules for operation in the temperature
range 700-850oC. To ensure the emergence of cost-competitive solutions, a special effort is focused
on larger anode-supported cells as well as a new generation of SOFCs based on porous metal
supports and new electrode and electrolyte materials. The SOFC program comprises development
of next generation of cells and multi stack modules for operation at lower temperature with
increased durability and mechanical robustness in order to ensure long-term competitiveness.
Sintering of Mixed-Conducting Composites for Hydrogen Membranes from Nanoscale Co-Synthesized Powders
Authors: Canfield Nathan L. , Crum Jarrod V. , Matyas Josef , Bandyopadhyay A. , Weil K. Scott , Pederson Larry R. , Hardy John S.
Published: March 2009

The potential for highly selective, nongalvanic permeation of hydrogen through dense
mixed conducting composites at elevated temperatures makes them attractive as hydrogen
separation membranes. The glycine-nitrate combustion synthesis technique has been used to
co-synthesize a cation-doped barium cerate protonic conducting phase together with a
metallic nickel electronic conducting phase (15-35 vol% Ni). Co-synthesis of these phases
results in an intimately mixed powder with particle sizes on the order of 10 nm. DTA/TGA
of all as-synthesized compositions determined that a calcination temperature of 1000°C was
required for full reaction of the cerate components. DTA/TGA and sintering shrinkage
dilatometry were performed on calcined powders to determine that a sintering temperature of
1250°C would be adequate for achieving >90% relative density in all compositions. Bars of
the material containing 25 vol% Ni were reduced at three different points in the heat
treatment process (e.g., before, during, or after sintering). It was determined that there was
less porosity in the sample reduced during sintering than any other. It was also seen on SEM
that the primary grain size, regardless of when reduction occurred compared to sintering of
the material, is less than 5 8m.
Texture Memory Effect in Heavily Cold-Rolled Ni3Al Single Crystals
Authors: Demura Masahiko , Xu Ya , Hirano Toshiyuki
Published: March 2009

The paper presented the texture evolution during primary recrystallization and following
grain growth in the heavily cold-rolled Ni3Al single crystals. It turned out that the texture evolution
occurred in the two stages. First, primary recrystallization caused the drastic change of the as-rolled
texture. Then, as grain growth proceeded, the texture returned to the same one as the as-rolled
textures. This texture return can be designated as Texture memory effect. The mechanism of the
texture memory effect was discussed based on the analysis of the orientation relationship between
the as-rolled and the primary recrystallization textures.