bluuebunny/crossref_metadata_2025 huggingface dataset:
Processing Defects and Nanoindentation Mechanical Properties in Tape Cast Alumina/Zirconia/Mullite Layered Composites
Authors: Yoon Seog Young , Stevens Ron , Park Hong Chae
Published: March 2009

Symmetric three-layer alumina/zirconia/mullite composites have been prepared by tape
casting and hot-pressing (20 MPa) at 1500°C for 2 h in argon. The hardness and Young’s modulus of
the layered materials were evaluated using low load continuous depth-sensing indentation equipment
(nanoindentation), appear to be affected by the formation of processing defects and residual stress.
Crystallography and R&D for Material Science from Our Research: Electroceramics
Authors: Ohsato Hitoshi
Published: March 2009

This article summarizes the work of the author’s lab based on crystallography. The topics are categorized in the following three fields: The first category is crystallographic analysis of materials, the second one is correlations between crystal structure and their properties, and the third one is crystallography for processing such as epitaxy, topotaxy and templates. The examples for these categories are: (1) multilayer ceramic capacitor (MLCC); (2) microwave dielectrics of tungstenbronze-type like solid solutions, and piezoelectric materials langasite (La3Ga5SiO14); (3) thin film growth of GaN or AlN on sapphire for example of epitaxy, hydroxy-apatite grown on diopside for topotaxy, and template growth of microwave dielectrics for template. Crystallography is useful in all studies, but is not almighty. Interdisciplinary study between crystallography and solid state physics is necessary to make clear the mechanism of the properties.
Detection of Corrosion Damage on Pressure Equipment with Acoustic Emission
Authors: Lackner Gerold , Tscheliesnig Peter
Published: March 2009

Acoustic emission testing (AT) is in Europe an already well established non-destructive
testing (NDT) method. Qualification requirements as well as certification of testing personnel are
laid down in European standard EN 473. A widespread application of AT deals with testing of
unfired pressure vessels for re-qualification after a certain period of service (repetition test). The
advantages of applying AT compared to the traditional procedure of hydrostatic test plus visual
inside inspection are numerous. Just to name the most important: reduction of downtime, omitting
of residual humidity and no risk of product contamination with water. It is a fact that AT provides
much more useful information concerning the condition of the pressure vessel under test than a
simple ‘passed’ or ‘not passed’ obtained usually by a hydrostatic test. This contribution gives two
examples of practical experience, where severe corrosion defects have been detected by AT. The
defects have been found in both cases on the vessel’s shell under the thermal insulation, where they
have been hidden undetected for years. It can be assumed that even the vessel with the most severe
damage (loss of more than 50% of the nominal wall thickness) would have passed the traditional
repetition test procedure and that failure within the following service period would have occurred.
In contrary to this scenario, AT enabled the vessel operator to perform appropriate repair in time.
Monitoring of Rail-Wheel Interaction Using Acoustic Emission (AE)
Authors: Thakkar N.A. , Steel John A. , Reuben R.L. , Knabe G. , Dixon D. , Shanks R.L.
Published: March 2009

This work presents the results of field measurements and laboratory studies carried out
with a view to developing ways to monitor rail-wheel interaction using Acoustic Emission. It is
known that impact, wear and cracking generate AE and it is therefore expected that axle loads,
wheel out-of-roundness, speed and traction will influence the AE generated by an interaction. It is
hoped that the extent of the effect might be sufficient to permit a measure of “interaction intensity”
that could be used to quantify cumulative damage by wear and contact fatigue.
In the field measurements, AE was acquired as a train with 20 moving sources of AE (20 wheels)
passed a single sensor position and a laboratory rig has been devised which uses a single wheel
whose condition, speed and loading can conveniently be modified. Simulated source tests have
indicated that the AE wave characteristics on real rails are similar to those in the laboratory rig.
A simplified analytical model, devised for AE waves propagating from a moving source(s),
based on a ‘vehicle’ speed and wave damping coefficients, has been compared to measured results.
As a wheel rolls towards a sensor and then away from the sensor the measured AE generally rises
and falls in a predictable way. The effects of wheel and rail surface features appear to complicate
the results by introducing sharp spikes in the signals. The numerical model for AE wave
propagation from the moving sources (wheels) shows good agreement with the more slowly
changing envelope of the signals.
Acoustic Emission (AE) and Nonlinear Elastic Wave Spectroscopy (NEWS) for Online Monitoring of Concrete Curing
Authors: Van Den Abeele Koen , Desadeleer W. , de Schutter Geert , Wevers Martine
Published: March 2009

An integrated system of dynamic nondestructive experiments for material process
monitoring is proposed, consisting of a combination of the AE technique with Nonlinear Elastic
Wave Spectroscopy (NEWS). Using this system, we evaluate the microstructural properties of
freshly poured concrete during hydration, with the ultimate goal to correlate these properties to its
long-term behavior. The integrated system allows online monitoring of the condition parameters, of
the internal microstructural activity by continuously triggering AE events and of the linear and
nonlinear elastic properties of the microstructure through ultrasonic pulsed and continuous wave
transmission measurements at regular time intervals. The internal temperature readings, the
evolution in the acoustic emission events and the behavior of the linear and nonlinear elastic
properties can be related to the different stages in the hydration process of concrete. The data are
analyzed as a function of the degree of hydration for various concrete compositions during the first
three days of the hydration process.
Detection of Stress Corrosion Cracking of Type 304 Stainless Steel Using Acoustic Emission and Corrosion Potential Fluctuation
Authors: Yonezu Akio , Cho Hideo , Takemoto Mikio
Published: March 2009

This paper discusses the mechanism of chloride SCC of sensitized and non-sensitized
Type-304 stainless steel based on the data obtained by simultaneous monitoring of AE and corrosion
potential fluctuation (CPF). The steel produced transgranular SCC via corrosion pits filled with
corrosion product (chromium oxy-hydroxides) in 35 mass % MgCl2 solution. Both the pitting
corrosion and transgranular SCC did not produce primary AEs due to anodic dissolution, while they
generated rapid drop (RD) type CPF. We, however, detected the secondary AEs from hydrogen gas
evolution and fracture of corrosion products. Hydrogen gas was found to produce AE with single
frequency component, while the fracture of corrosion products produced AEs with broad frequency
components. The sensitized steel produced primary AEs due to the falling-off of grains as well as the
secondary AEs. Microscopic progression of SCC was consistently interpreted by the timing and
time-lag of AEs and CPFs.
Initial Studies for AE Characterisation of Damage in Composite Materials
Authors: Venturini Autieri M.R. , Dulieu-Barton Janice M.
Published: March 2009

Some initial studies for an AE characterisation of damage in composites are presented in
this paper. A PAC AE PCI-2 based system and four PAC WD AE broadband sensors are used.
Pencil lead breaks (PLB) were used to introduce a source of elastic waves. An initial validation of
the system based on PLB on an aluminium plate showed that there was a large difference in
sensitivity of the four nominally identical sensors. It is shown that the AE parameters are so
strongly related to the sensitivity of the sensors that they tend to describe the AE system more than
the actual sources. To characterise damage in composite materials alternative AE parameters are
required that are not dependent on the sensitivity of the sensors. In the paper, it is shown that the
frequency spectra of the sources have relatively little variability with respect to the sensor. A
frequency-based approach that examines the spectrum of each source is proposed in the paper. The
procedure is demonstrated using PLBs on a CFRP plate and it is demonstrated that the approach can
indicate the position of the source in relation to orientation of the fibres and the plate edge.
Application of Laser AE to Microfracture at Elevated Temperature
Authors: Enoki Manabu , Nishinoiri Satoshi
Published: March 2009

An AE measurement system that uses a laser interferometer has been developed to
evaluate microfractures at elevated temperatures in various materials. This technique has the
advantage that it can estimate the temperature where microfractures were generated. The results give
useful information to control process conditions. AE during sintering ceramics and thermal spying of
ceramic powder on metal substrates were successfully detected by this laser AE measurement system.
Effect of process conditions on damage process was discussed from the detected AE behaviour
during in-process monitoring.
Acoustic Emission Testing of a Landing Gear Component
Authors: Pullin Rhys , Holford Karen M. , Evans S.L. , Baxter M.G.
Published: March 2009

Acoustic emission (AE) monitoring was performed on an aluminium landing gear
component that was undergoing testing to investigate its fracture resilience. The type of component
was identified from FE analysis and previous fatigue testing. The component was loaded in fatigue
for 500 flight cycles before re-greasing of the bearings. After 2,000 cycles the component was
removed for NDT inspection. The AE investigations were implemented after 83,000 flight cycles
had been completed. NDT at this point had shown that the component contained no damage. This
paper presents the findings of the final 2,000 cycles monitored. The AE investigation detected and
located, using both linear and planar location approaches, one region of activity around the grease
pin. Fretting damage at this location was confirmed using dye pentrant testing. It was also shown
that the increase in rate of detected activity is a significant tool in the identification of damage in
landing gear components.
Acoustic Emission Monitoring during Solidification Processes
Authors: Crha Jan , Havlíček J. , Molínek Jiri , Kozelský Petr
Published: March 2009

The paper summarizes the experiences acquired from on-line acoustic emission
monitoring (herafter AE) of heavy castings during their manufacturing (solidification and following
cooling in the mould). They are usually monitored elastic waves generated above all by stress
changes in the solid state. In order to exactly determine plastic-elastic transition state the
investigation was focused on raising the sensitivity of detection. The suitable experimental
technique is discussed in the first part of this article. The main problem of the measurement by high
temperatures was solved by using waveguides. It is very important in this case to select useful
signal sources from mechanical and electromagnetical disturbances. Some laboratory experiments
were done for studying the signal origin in the first state of solidification.
The results from on-line monitoring of two types cast rolls during manufacturing were
compared. Each type of casting has its typical AE histogram. For the quality evaluation ( in our
case) is significant the time period of approximate 5 days after pouring . The time delayed stress
induced cracking generates high level AE signal in this time period and the presence of such signal
indicates defective product. The study of high temperature tensile tests, structural phase
transformation and solidification processes using AE is very important for analysis of AE sources.
The use of the laboratory results for the AE source analysis on real products will be subject to
futher research.
Me and AE -The Early Years 1962 – 1982
Authors: Green Allen T.
Published: March 2009

The author has been involved in acoustic emission technology (AET) for over forty
years, since 1962. Activity in AET for these many years has provided the author with a unique
insight into a technology that has seen many successes and also many failures. Much anecdotal
material has been circulated. The author separates legend from fact and shares some little known
anecdotes of his own.
Correlation between Acoustic Emission and Internal Friction in Materials
Authors: Vinogradov Alexei
Published: March 2009

The relationship between acoustic emission and internal friction is investigated during
cyclic deformation of copper single- and poly-crystals at intermediate amplitudes. Good agreement
between these two phenomena has been demonstrated in all materials tested as long as the stress
relaxation occurs uniformly within the sample whereas the difference between them becomes
pronounced when strain/fracture localisation takes place. The similarity between acoustic emission
and internal friction can be extended to materials deforming without appreciable plastic deformation,
such as metal matrix composites where the main source of stress relaxation and strain accumulation is
the particle breakage. The significance of the relation between internal friction and acoustic emission
for understanding of fundamentals of AE is discussed.
Detection of the Broken Wires in the Cables’ Hidden Parts (Anchorings) by Acoustic Emission
Authors: Zejli Hasnae , Laksimi A. , Tessier C. , Gaillet L. , Benmedakhene S.
Published: March 2009

Steel cables play an indispensable role in a number of rather diverse fields of
applications. They are extensively used in suspension and stay cables bridges. It is important to be
able to detect as precociously as possible the defects affecting their performance. They can present
a healthy aspect over their observable lengths and be damaged in the hidden parts (anchorages). In
this present study, Acoustic Emission (AE) is used in order to detect and to locate broken wires in
the anchorage zones.
The study of the behaviour of a broken wire in a cable under dynamic bending contribute to
understand the origin of AE source and to discuss the necessary conditions of vibrating for
detection. In this case, the phenomene source of AE is related to interwire friction caused by the
redistribution of elastic energy on the recovery length of the broken wire and the repetition of the
process joining-slip between wires.
AE parameters are very influenced by the change of surface conditions, contact strength between
wires and the recovery length of the broken wire. Several cables are evaluated in different surface
conditions i.e. corroded, dry and oiled.
Acoustic Emission Monitoring of Leaks in Pipes for Transport of Liquid and Gaseous Media: A Model Experiment
Authors: Brunner Andreas J. , Barbezat Michel
Published: March 2009

In order to explore potential applications for Active Fiber Composite (AFC) elements
made from piezoelectric fibers for structural integrity monitoring, a model experiment for leak
testing on pipe segments has been designed. A pipe segment made of aluminum with a diameter of
60 mm has been operated with gaseous (compressed air) and liquid media (water) for a range of
operating pressures (between about 5 and 8 bar). Artificial leaks of various sizes (diameter) have
been introduced. In the preliminary experiments presented here, commercial Acoustic Emission
(AE) sensors have been used instead of the AFC elements. AE sensors mounted on waveguides in
three different locations have monitored the flow of the media with and without leaks. AE signals
and AE waveforms have been recorded and analysed for media flow with pressures ranging from
about 5 to about 8 bar. The experiments to date show distinct differences in the FFT spectra
depending on whether a leak is present or not.
Estimation of Rock In-Situ Stress by Acoustic and Electromagnetic Emission
Authors: Mori Yasuhiko , Sedlak P. , Sikula Josef
Published: March 2009

The Kaiser Effect in acoustic emission is often used for an estimation of the stress to which
rocks have been subjected. However, there are cases in which the Kaiser Effect is not clear, since the
noises due to the contact and/or the stick slip between the pre-induced fracture surfaces are measured
during the reloading process. In such cases, estimation of previous stress is difficult by the
conventional method which is based on the acoustic emission activity observed under reloading
process. In the tests for the Kaiser Effect on rocks, therefore, the noises must be eliminated from the
acoustic emission generated from newly created cracks during the second loading process. Such
techniques as analysis of the difference between the acoustic emission activity observed in the first
and second reloading and the analysis of the change in the slope of the acoustic emission amplitude
distribution have been proposed. In this paper we present a new method by which the maximum
previous stress in rocks can be directly estimated without any post signal analysis. In the new method,
simultaneous measurement of acoustic and electromagnetic emission during loading test of rock
sample is employed. The electromagnetic emission in the deformation of rock sample generates only
when the fresh surfaces due to cracking are created in the material, and the source of electromagnetic
emission is the electrification between the fresh crack surfaces. This paper describes the
simultaneous measurement of acoustic and electromagnetic emission useful for estimating the rock
in-situ stress.
More than a Quarterly Century of Acoustic Emission Testing (AT) at TÜV Austria
Authors: Tscheliesnig Peter
Published: March 2009

The TÜV Austria (formerly TÜV Vienna) has been testing different structures, mainly
pressure equipment, since 1977 with Acoustic Emission. I will not enumerate all the different tests,
which are more than 20.000 till today, but I will point out, how the test method has changed on
some typical tests over the years. I will also remind you on the different possibilities, which have
been offered by the rapid development of the electronic data acquisition and treatment, especially
during the last 10 – 15 years.
Damage Monitoring in Cyclic Loaded C/C Woven Composites Using the Acousto-Ultrasonics Approach
Authors: Loutas Theodoros , Kostopoulus V.
Published: March 2009

Non-destructive monitoring of damage accumulation in woven-fabric carbon/carbon
composites is a topic of high interest due to the increased use of such materials in structural
components for the aerospace, automobile and defense industries.
Acousto-ultrasonics (AU) is a non-destructive technique that utilizes two typical acoustic
emission sensors one as a pulser and the other as a receiver. During tensile load-unload-reload tests
the pulser emits an ultrasonic pulse, which in the form of elastic wave propagates through the test
specimen and is captured by the receiver.
As damage accumulates into the material structure the ultrasonic pulse interacts with the
damaged microstructure and changes its characteristics often in a subtle not obvious manner.
Consequently, sophisticated signal processing methods are needed to extract the hidden information
from the recorded AU waveforms in order to identify the type of damage and quantify its severity.
The diffuse field decay rate method and wavelet-based methods were applied in order to process
the AU waveforms and extract damage sensitive parameters.
Two types of C/C composites with different interface concepts were tested and the applied
technique elucidates the damage evolution developed during cyclic loading and associated with the
different interface concepts.
Micro- and Nanoscaled Titanium Surface Structures Textured by Electrolytic Plasma and Etching Methods
Authors: Beck Ulrich , Lange Regina , Neumann Hans Georg
Published: March 2009

The surface topography of Titanium implants modulates bone response and implant
anchorage. For this reason great efforts yet will be made for new surface refinements.
In this work Ti samples were surface structured by corundum blasting firstly and then chemically
etched to remove the remaining corundum particles and further surface structuring. In following steps
these samples were electrochemically etched or additionally structured and coated with various
micro-plasma processes. As result we got various typical surface structures in micro- and nanoscale
and also different coating layers in dependence on the composition of the electrolyte for the
micro-plasma process.
In all steps the properties of the modified Ti surfaces were characterised mechanically by surface
profiling, optically by SEM and electrochemically by CV- (for testing the corrosion parameters), CA-
(to give the enlargement of the real surface) and EIS-measurement in range of 100 kHz to 1 mHz (to
give a survey of the changing of surface capacities and structures). A comparison of the measuring
results demonstrated their reliability.
Properties of Cu-TiB2 Composites Fabricated by In-Situ Liquid Melt Mixing Process
Authors: Yun J.H , Kim J.H. , Park J.S. , Park Young Do , Park Yong Ho , Cho Kyung Mok , Park Ik Min
Published: March 2009

A Cu-TiB2 composite was successfully fabricated by in-situ liquid mixing process, and its
microstructure, mechanical properties as well as electrical conductivity were evaluated. For
Cu-2vol.%TiB2 composite, the hardness was as high as 5GPa and the Young’s modulus was 130GPa.
And hardness and Young’s modulus of Cu-6vol.%TiB2 composite was 5.6Gpa and 138GPa,
respectively. With the increase of the TiB2 content, hardness and Young’s modulus of
Cu-10vol.%TiB2 composite were 20 and 12%, respectively, which was higher than that of
Cu-2vol.%TiB2 composite. Young’s modulus of the Cu-TiB2 composite in this paper was in good
agreement with the prediction by Hashin-Shtrikman (H-S) model. Furthermore, the electrical
conductivity of the Cu-TiB2 composite showed its maximum value of about 78%IACS and decreased
with the increase of the TiB2.
(TiB+TiC) Hybrid Titanium Matrix Composites Shot Sleeve for Aluminum Alloys Diecasting
Authors: Choi Bong Jae , Sung Si Young , Kim Young Jig
Published: March 2009

The aim of this study is to fabricate an α-case free (TiB+TiC) hybrid titanium matrix
composites (TMCs) shot sleeve for aluminum alloy diecasting by in-situ synthesis and investment
casting. Granular 1.88 wt% B4C was added to a titanium matrix in a vacuum induction melting
furnace. The synthesized (TiB+TiC) TMCs were examined using electron probe micro-analysis and
transmission electron microscopy. The results of the in-situ synthesis and investment casting of the
TMCs show that our casting route constitutes an effective approach to the economic net-shape
forming of TMC sleeves.
Processing of Ce1-xGdxO2-δ (GDC) Thin Films from Precursors for Application in Solid Oxide Fuel Cells
Authors: Rose Lars , Menon Mohan , Kammer Kent , Kesler Olivera , Larsen Peter Halvor
Published: March 2009

Extensive interfacial reactions are known to occur between Fe-Co based perovskite cathode materials
and the standard solid oxide fuel cell (SOFC) yttria stabilized zirconia (YSZ) electrolyte. Thin films
of gadolinia doped ceria (GDC) could be used as a diffusion barrier between the cathode and the
electrolyte. The present work investigates spin coating thin diffusion reaction inhibiting films onto
SOFC electrolytes. The chemical and structural evolution of ethylene glycol based precursor solution
is studied by means of rheology, x-ray diffraction (XRD), high temperature XRD (HT-XRD),
Fourier-transformed infrared spectroscopy (FTIR) and differential thermal analysis (DTA). The
studies show that cerium formate is formed as an intermediate resin. Thin films, up to 500 nm thick,
of gadolinia doped ceria (GDC) are successfully produced by multiple spin coating of polymerized
ethylene glycol derived solutions on 200 1m thick YSZ tapes. The GDC and YSZ interfacial surface
morphology and film thickness are studied by scanning electron microscopy (SEM) and atomic force
microscopy (AFM). These films are shown to successfully prevent the creation of non-conducting
reaction phases at the cathode-electrolyte interface by blocking interdiffusion.
Air Plasma Spraying of LSM/YSZ SOFC Composite Cathodes
Authors: White B.D. , Kesler Olivera
Published: March 2009

Porous composite cathodes containing (La0.8Sr0.2)0.98MnO3 (LSM) and yttria stabilized
zirconia (YSZ) for use in solid oxide fuel cells (SOFCs) have been produced by air plasma
spraying. Deposition was carried out using axial powder injection for increased deposition
efficiency and composition control. A number of composite cathodes were produced using different
combinations of parameter values within the identified range. Successful coatings were then
characterized for composition and porosity using EDX and SEM. As a result of these tests,
combinations of input parameter values were identified that are best suited to the production of
coatings with microstructures appropriate for use in SOFC composite cathodes.
Water Transport through Proton Exchange Membranes
Authors: Romero-Castañon Tatiana , Mérida W.
Published: March 2009

The presence of water within the polymeric ionic conductor and catalyst
layers is indispensable for proton exchange membrane fuel cell (PEMFC) operation.
The water transport within the membrane is always a balance between at least two
competing mechanisms (water back-diffusion from the cathode to the anode, and
electro-osmotic drag from the anode to the cathode). We present an experimental
technique for the analysis of water transport within and through the membrane. Mass
spectrometry was used to investigate diffusion and electro-osmotic drag in real time
(detection rates < 100 ms). We present data on the net water transport resulting from the
analysis at room temperature in Nafion115.
Evaluation of the Fe(III)/Fe(II) Redox Fuel Cell Cathode Couple in a Bioelectrolytic Solution
Authors: Moraw Franz , Fatih Khalid , Wilkinson David , Girard François
Published: March 2009

The use of redox fuel cells, in which oxygen is replaced by other oxidants
such as ferric ions, can have significant advantages. The redox fuel cell can achieve
high efficiencies and has other fuel cell advantages. Bioregeneration is one method of
creating a closed cathode system with efficient catholyte regeneration. In the work
discussed here, a Fe3+/Fe2+ redox simulated bio-electrolyte catholyte is characterized
over a range of electrolyte concentrations and fuel cell operating conditions using
cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).
The Analysis and Design of Microchannel Reactors
Authors: Bellemare-Davis C.A. , Karan K. , Pharoah J.G. , Zak G.
Published: March 2009

This investigation considers the development of microchannel reactors with catalystcoated
walls for fuel-processing applications. In particular, the focus is to study the possibility of
direct etching of microchannels into aluminum and alumina using a solid-state UV laser.
Microchannels of a scale between 10μm-200μm across and 10μm-100μm have been ablated into
aluminum and alumina bases. It was found that single scans resulted in narrow channels (20μm-
30μm in width) with shapes described by a Gaussian-like distribution. Multiple scans allowed
fabrication of channels with a larger width, but of a similar depth. The surface quality was
observed to be quite uneven, with roughness on the order of 1μm-2μm.
Linear Friction Welding of IN-718 Process Optimization and Microstructure Evolution
Authors: Mary Caroline , Jahazi Mohammad
Published: March 2009

Linear Friction Welding (LFW) of IN-718 Superalloy was investigated under several
processing conditions. The influence of process parameters such as frequency (60Hz to 100Hz),
amplitude (2mm to 3mm) and frictional pressure (50MPa to 110MPa) on the microstructure and
mechanical properties of welded specimens was determined. Optical and scanning electron
microscopy, and micro-hardness testing were used to characterize the welded areas as well as the
Thermo-Mechanically Affected Zones (TMAZ). In-situ thermocouple measurements were performed
to follow temperature evolution in the specimens during the different phases of the LFW process. The
analysis of the results indicated that for some specific conditions (f=80Hz, a=2mm and P=70MPa) a
maximum temperature of 1200°C was attained during the last stage of the welding process, the
burn-off phase. This temperature, very close to the alloy melting range, would be sufficient to cause
partial liquation in this zone. Microscopic examinations revealed the presence of oxide particles
aligned around the weld interface. Their concentration and distribution, varying with process
parameters, affect the weld integrity. The TMAZ characterised by a global loss of strength (from
334HV to 250HV) is associated with temperatures exceeding 800°C and causing γ’ and γ’’ reversion.
A narrow band of the TMAZ, exposed to high strains and temperatures, showed evidences of dynamic
recovery and recrystallization (up to 67% of reduction in the matrix grain size). Visual and
microscopic examination of the flash layer, revealed two distinct zones. Microstructure evolution and
microhardness variations were associated to process parameters and the optimum conditions for
obtaining defect free weldments were determined.
High Temperature Corrosion of Al3Ti-Cr Intermetallics in SO2 Atmosphere
Authors: Choi Jee Hoon , Lee Dong Bok
Published: March 2009

L12-type Al65.5Ti24.4Cr10.1 alloys were prepared by induction melting followed by
thermomechanical treatment. Corrosion tests were performed between 1173 and 1373 K in a
flowing Ar-1% SO2 atmosphere for up to 150 hr. The corrosion proceeded mainly via the
oxidation reaction. The oxide scale was primarily composed of Al2O3, together with a small
amount of TiO2 that appeared mainly in the lower part of the oxide scale during the latter stages
of corrosion. The formation of the highly stoichiometric, slowly growing alumina scale on the
surface significantly improved the corrosion resistance of the alloys. Neither internal corrosion
products nor sulfides were detected.
Influence of the Cooling Rate on the Iron Solubility in High Purity Aluminum Maked by the Melt Spinning Method Using the Rotating Single Roller
Authors: Shimizu Shouhei , Furui Mitsuaki , Anada Hiroshi
Published: March 2009

It makes use of that excellent nature, high purity aluminum is being used as a function
material in the electron, the high technology industry and information. Generally that material is
molded as a slab, and processed through such as metal rolling is given after that, and it is being
made. It is increase demand that it use for condenser. Condenser capacity is increase by making a
(100) oriented cube texture crystal. It is known effective to increase a solid solubility of iron to
aluminum that make increase the condenser capacity. Therefore, the cooling rate of Al-10,100 and
1000ppm content Fe was controlled by single roller equipment. Research was done about the
relations of the amount of solid solubility of iron to aluminum and the cooling rate. It is result that
the amount of solid solubility of iron to aluminum becomes 800ppm at the cooling rate of 2×103 K/s.
When the cooling rate rises, the amount of solid solubility increases. The change appears in the
separation thing as well because the amount of iron changes by this when the cooling rate is high.
When iron is solid solubled in aluminum, it is bigger than the case of solid solubility formed by
other general metal elements. Hardness is four times rose more than pure aluminum by solid
solubility of iron to aluminum about 800ppm.
Porous Metals Produced by Spacer Method as Ecomaterials
Authors: Hakamada Masataka , Yamada Yasuo , Kuromura Tetsumune , Asao Yuuki , Chen Y. , Kusuda Hiromu , Mabuchi Mamoru
Published: March 2009

Porous metals, or metallic foams, are emerging ecomaterials that can be applied to
structural use, shock absorber, filter, heat exchanger, etc. Their very low densities and peculiar
deformation behaviors will facilitate the application. The control of pore characteristics such as
porosity and pore size distribution can be successfully achieved by spacer method. In this paper,
fabrication of porous aluminum via the spacer method is introduced and their excellent properties due
to homogeneous pore characteristics are exhibited
Low Frequency Damping Behaviors of Magnesium Alloys
Authors: Hu Xiao Shi , Wu Kun , Zheng Ming Yi
Published: March 2009

The effect of different alloying elements including Ni, Si and Al and various mass
contents of these elements on the low frequency damping behaviors of magnesium alloys were
investigated. The measurements of strain dependent and temperature dependent damping capacities
of these magnesium alloys were carried out using dynamic mechanical analyzer (DMA), and the
very different damping behaviors of these magnesium alloys were found. The hypoeutectic
magnesium alloys with low solubility alloying elements such as Si and Ni shown extremely high
damping capacities. But the Mg-Al alloys exhibited very low damping values. The tensile
properties of these magnesium alloys were also illustrated in this study. It was found that
hypoeutectic Mg-1.0%Si alloy possess the excellent overall properties with high damping capacity,
relatively high tensile properties and good corrosion resistant ability.
Experimental Study of In-Line Heat Treatment for Twin Roll Casting of Magnesium Alloy AZ31
Authors: Ju Dong Ying , Hu Xiao Dong , Zhao Hong Yang
Published: March 2009

Strip casting is a promising route to directly produce magnesium alloy sheet by twin
roll casting method. As-cast strips with proper microstructure and good surface quality are
requested to serve as next rolling feedstock. In order to restrain the coarse dendrite growth and get
uniform grain, a new method of in-line heat treatment was proposed. The as-cast strip was dipped
into an oil tank after exiting the rolls and then was quenched with oil at various temperatures. The
effect of oil temperature, casting speed and pouring temperature on microstructure and mechanical
properties of cast strip was investigated.
Microstructure Evaluation of High Chromium Ferritic Steels Based on Hydrogen Desorption Profile Analysis
Authors: Honda T. , Komazaki Shinichi , Sugimoto Takayuki , Kohno Yutaka
Published: March 2009

The thermally aged 10Cr-1Mo-1W-VNbN steels were charged with hydrogen by cathodic
electrolysis and then were subjected to the thermal desorption spectroscopic analyses to examine an
applicability of hydrogen as a tracer for evaluating the microstructure. The variation in hydrogen
desorption characteristics with aging was discussed from the view points of microstructural changes.
Experimental results revealed that the amount of hydrogen desorbed, CH, decreased monotonously as
the aging proceeded and there was a relatively good correlation between the CH and Vickers hardness.
The CH was expected to be a useful indicator for the material degradation. Additionally, the
decomposition of the profile was attempted to understand the metallurgical meaning of hydrogen
profile and apply the present method to the microstructural evaluation. As the result, it was suggested
that the changes in two decomposed profiles with aging might reflect the variation of dislocation
density and the precipitation process of M23C6 carbide and/or Laves phase, respectively.
Mechanical Alloying and Properties of ODS Ferritic Steels
Authors: Ahn Jung Ho , Lee Sang Hyun , Jang Jin Sung
Published: March 2009

Oxide-dispersion strengthened (ODS) ferritic stainless steels have been considered as
promising high-temperature materials such as interconnects for oxide-fuel cells and nuclear
materials for Liquid Metal Fast Reactors or Super-Critical-Water-Cooled Reactors. In the present
work, we have prepared Fe-14Cr-2Al-1Si-0.3Ta-1Y2O3 ferritic stainless steels which were
dispersion-strengthened by nano-sized Y2O3 via mechanical alloying of elemental powder mixtures
and subsequent hot consolidation. A comparison was made with MA 957 and DY-01 alloys. The
mechanically alloying behaviour and consolidated mechanical properties of the Fe-14Cr-2Al-1Si-
0.3Ta-1Y2O3 ferritic steels were strongly influenced by processing parameters, especially milling
atmosphere. The stability of yttrium oxides and oxidation resistance at high temperatures were
examined. The preliminary result shows that the mechanically alloyed Fe-14Cr-2Al-1Si-0.3Ta-
1Y2O3 ferritic stainless steel exhibits interesting properties to be exploited as high temperature
materials.
Physically Based Model for Static and Dynamic Behaviour of TRIP Steel
Authors: Bouquerel Jérémie , Verbeken Kim , De Cooman Bruno C. , Houbaert Yvan , Verleysen Patricia , Van Slycken Joost
Published: March 2009

Low alloy multiphase TRansformation Induced Plasticity (TRIP) steels offer an excellent
combination of a large uniform elongation and a high strength. This results from the composite
behaviour of the different phases that are present in these steels: polygonal ferrite, bainitic ferrite
and a martensite/austenite constituent. In order to obtain a clear understanding of the behaviour of
the different constituents within the multiphase steel, they were prepared separately.
The stress-strain relationship of the different single phase and multiphase steels were simulated with
physically based micromechanical models. The model used to describe the stress-strain curves of
the separate phases is based on the Mecking-Kocks and Seeger-Kocks theories and uses physical
properties such as the microstructural properties and the chemical composition of the different
phases. Strain-induced transformation kinetics, based on a generalized form of the Olson-Cohen law,
were used to include the influence of the transformation of the metastable austenite.
Static stress-strain properties of multiphase steels were modelled by the successive application of a
Gladman type mixture law for two-phase steels. The model yields detailed information of stress and
strain partitioning between the different phases during a static tensile test. A model for the dynamic
stress-strain properties of ferritic steels is also proposed.
Lotus-Type Porous Nickel-Free Stainless Steel with High Temperature Nitriding
Authors: Alvarez Kelly , Hyun Soong Keun , Nakajima Hideo
Published: March 2009

Lotus-type porous Fe-25wt.%Cr and Fe-23wt.%Cr-2wt.%Mo alloys were fabricated by
continuous zone melting technique in pressurized hydrogen gas. After applying a high temperature
nitriding treatment, the fabricated Lotus-type porous nickel-free stainless steel absorbed larger
amount of nitrogen compared with non-porous alloy of the same composition since the surface area
exposed to the gas is larger in the porous samples. In the Lotus-type porous Fe-25wt.%Cr and
Fe-23wt.%Cr-2wt.%Mo alloys the nitrogen concentration after the nitriding achieved was
approximately 1.2 wt.%. Only austenite peaks were detected in the profile of both Fe-Cr-N alloys
after the nitriding treatment. Neither CrN nor Cr2N were identified by XRD in any specimen after
the nitriding.
Deformation Behaviour of Martensite in a Low-Carbon Dual-Phase Steel
Authors: Mazinani M. , Poole Warren J.
Published: March 2009

The deformation behaviour of martensite and its effect on tensile properties of a lowcarbon
dual-phase (DP) steel were investigated. DP steel samples with different martensite contents
and morphologies were produced after intercritical annealing at different temperatures using low
and high heating rates. Two distinct martensite morphologies were obtained for low and high
heating rates. The investigated steel showed the unusual results that the true fracture stress and
strain were found to increase with the martensite volume fraction. The plastic deformation of
martensite was considered to be responsible for these results. Experimentally, it was observed that
the martensite in DP steels with greater than 25-30% martensite can deform plastically during
tensile straining. Finally, the effect of tempering on the martensite plasticity was also evaluated. It
was found that the tempering process and an increase in the martensite content have a similar effect
on promoting martensite plasticity.
Oxide Scales Grown on Stainless Steels during Simulated Reheat
Authors: Jepson M.A.E. , Verona C.L. , Higginson Rebecca L.
Published: March 2009

including, external oxide layers, internal grain boundary oxidation structures as well as many other
forms of internal oxidation. During the present study, needle like grains of hematite have been
observed within the top layers of a number of external oxide scales formed during simulated reheat
of 316L stainless steel. It is believed that these needles are caused by the decomposition of an iron
rich spinel (approximated to magnetite) along a preferred crystal direction within the spinel grains.
The needles have been studied using optical microscopy, scanning electron microscopy (SEM),
energy dispersive x-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD).
Change in Stress Axis with Creep Deformation in γ-Single Phase Ni-20mass%Cr Single Crystal within Standard Stereographic Triangle
Authors: Yuge Kentaro , Terada Yoshihiro , Matsuo Takashi
Published: March 2009

The creep deformations of γ-single phase Ni-20mass%Cr single crystals with stress
axes within standard stereographic triangle and at the three pole positions have been investigated.
The most of the creep life is occupied by the transient stage, which consists of Stage I and Stage II.
In Stage I, the creep rate just after loading remains constant. In Stage II, the creep rate decreases
continuously. Except for the single crystals with stress axes of [001] and [1,–11] poles, the single
crystals make the creep deformation using the primary slip plane of (111). As a result, the cross
section of the specimens turns from circular to elliptical in shape. However, there are marked
difference in deformation manner among single crystals with the stress axes within standard
stereographic triangle. The single crystals whose angle between stress axis and primary slip plane
of (111), θ. is more than 45° shows the heterogeneous deformation during creep. While, the
homogeneous deformation will be expected in the single crystals with θ less than 45°. In this
study, by using the four single crystals with θ less than 45°, the change in the stress axis with the
creep deformation at 1173K-29.4MPa, is investigated and the deformation manner due to the
primary slip plane of (111) is estimated by conducting the creep interrupting tests. In the two
single crystals with stress axes in the standard stereographic triangle where the moving range of θ is
narrow, comparing to the others, the spot of the stress axis in the inverse pole figure moves for <1,–
01> direction by using (111)<1,–01> slip system, and after arriving at the [001]-[1,–11] line, the
spot turns to its direction for [1,–11] pole using (111)<1,–10> slip system. While, in the other two
single crystals whose stress axes located in the area with wider moving range of θ, the spot of stress
axis only move for <1,–01> direction. And, the widely spread spot of the stress axis is confirmed
after subjecting the small strain.
Change in Stress Axis with Creep Deformation in Ni-20mass%Cr Single Crystal with Orientation of [011]
Authors: Mitsutake Masaomi , Terada Yoshihiro , Matsuo Takashi
Published: March 2009

The features of the creep deformation of γ-single phase single crystals with the
composition of Ni-20mass%Cr are characterized by the extended transient stage, which consists of
Stage I and Stage II. In the Stage I, the creep rate just after loading remains unchanged, while the
creep rate decreases continuously in Stage II.
In the single crystals except for the single crystals with the stress axis of [001] and [1,
–
11], the
predominant creep deformation using the primary slip plane continues. By this deformation, the
cross section of specimen turns to elliptical in shape. However, in the single crystals with the
angle between stress axis and primary slip plane (111) is more than 45°, the deformation using the
primary slip plane does not continue, as a result, the duration of Stage II turn to shorter one. The
single crystal with the stress axis of [011] has the largest angle of 55°.
In this study, the deformation manner during transient stage of single crystal with the stress axis
of [011] orientation is investigated from the two viewpoints. The first one is to clarify the change
in deformation manner with decreasing the stress. As a result, with decreasing the stress, the Stage
I become clear and strain during Stage I and Stage II become small, furthermore, the decreasing
ratio of creep rate with definite strain becomes larger. While, the second viewpoint is to
investigate the change in crystallographic orientation of the [011] single crystals with creep
deformation using the inverse pole figure obtained by the EBSD method. As a result, at the stress
of 29.4 MPa, the spot of stress axis turns from the [011]-[1,
–
11] line to the <1,
–
01> direction.
While, at the stress of 19.6 MPa, the stress axis moves for the [1,
–
11] pole along the [011]-[1,
–
11]
line from the [011] pole. And, it is noteworthy that the spot widely spread from the [011] pole
during transient stage. This indicates the large distortion in the primary slip plane and the
evidence of heterogeneous deformation.
TLP Bonding of DS Ni Base Superalloy, GTD-111 Using Mixed Powder of Base Metal and Filler Metal
Authors: Lee Bong Keun , Han Tae Kyo , Song Woo Young , Ye C.H. , Kang Chung Yun
Published: March 2009

The effect of a mixed powder on the wide gap transient liquid phase diffusion bonding of
a directionally solidified Ni base superalloy, GTD-111 was investigated. The mixed powder
consisted of a mixture of a powdered Ni base filler (GNi-3) and powdered base metal (GTD-111).
The range of the base metal powder was 40 to 70wt%. Bonding was performed at a temperature of
1463K, using various holding time. In the case of a lower 50wt%, the base metal powders
completely melted and base metal mating at the interface dissolved at an early time, and extent of
dissolution of base metal decreased with increasing mixing ratio. Liquid was eliminated by
isothermal solidification, which was controlled by the diffusion of B into the base metal. The solids
in the bonded interlayer grew epitaxially from the mating base metal inward from the insert metal
and the number of grain boundaries formed at the bonded interlayer corresponded with those of the
base metal. The finishing time for isothermal solidification was about 74ks. In the case 60wt% and
higher, the base metal powders partially melted and remained in the vicinity of bonded interlayer.
The solid was formed from the remaining powder and base metal mating at the interface. Finally,
the bonded interlayer underwent the poly-crystallization when isothermal solidification was
complete. The contents of Al and Ti in the bonded interlayer with a holding of 74ks were equal to
that of the base metal.