bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermodynamic Processes and Phenomena Induced by High Current Pulsed Electron Beam
Authors: Qin Ying , Song Zhen Fei , Dong Chuang , Wang Xiao Gang , Hao Sheng Zhi , Zou Jian Xin , Wu Ai Min , Guan Qing Feng
Published: March 2009

Due to the special heating mode of High Current Pulsed Electron Beam (HCPEB)
irradiation, intense stresses such as thermoelastic stress, quasi-static stress, and shock wave stress can
be generated by a dynamic thermal field. A dynamic thermo-stress is the origins of these stresses. The
simulations for non-melting and melting modes are respectively compared with related phenomena
such as bending, surface plastic deformation, and residual stress (non-melting mode, quasi-static
stress-related), crater formation, depth distribution of microhardness, fragmentation of pearlites
(melting mode, shock-stress wave-related).
Fatigue in Ti-6Al-4V at Very High Cycles
Authors: Cao X.J. , Sriraman M.R. , Wang Qing Yuan
Published: March 2009

The importance of determining and understanding the very high cycle fatigue behaviors of
materials has gained strength in recent years. Ti-alloys, in view of their high strength-to-weight ratio,
have a range of structural applications. Of these, Ti-6Al-4V, belonging to the alpha-beta type is the
most widely used. The present paper deals with investigations on the fatigue behavior of TC4, the
Chinese equivalent to Ti-6Al-4V, up to very high cycles. Fatigue testing was carried out on a
piezoelectric ultrasonic fatigue machine operating at 20 kHz frequency. Hourglass shaped resonant
specimens were tested in ambient air at room temperature under completely reversed loading
conditions (R = -1). Failure in the alloy was seen to occur right up to the gigacycle regime, with the
fractures being found to initiate from the surface unlike in steels. The fracture surfaces exhibit brittle
characteristics containing river patterns and cleavage facets, as well as striations.
Influences of Rolling Conditions on Texture and Mechanical Properties of AZ31 Magnesium Alloy Processed by Differential Speed Rolling
Authors: Suzuki Kazutaka , Huang Xin Sheng , Watazu Akira , Shigematsu Ichinori , Saito Naobumi
Published: March 2009

It was reported that the cold and warm press formability of the magnesium alloy was
improved by the application of a differential speed rolling (DSR). However, it can be considered
that the microstructure and the texture of the DSR processed sheets greatly change with the rolling
conditions. In this study, commercial AZ31B magnesium alloy extrusions were processed by DSR
at a differential speed ratio of 1.167 and a reduction per pass of 10% or less, and the effects of the
rolling temperature, the number of rolling passes and reversal of the rolling direction on texture and
mechanical properties were examined. As a result, it was found that the optimal rolling temperature
in terms of the workability and formability of the material was 573 K. And the elongation and
formability were maximal in sheets processed by 4–6 passes of DSR. Moreover, reversing the shear
direction made the microstructure more homogeneous and finer than unidirectional shear, and
improved the mechanical properties and formability. This improvement was greater in samples
where the shear direction was reversed once in the middle than where it was reversed for each pass.
Microstructure and Mechanical Properties of Dual Multi-Phase Intermetallic Alloys Composed of Geometrically Close Packed Ni3X Structures
Authors: Takasugi Takayuki , Kaneno Yasuyuki
Published: March 2009

Dual two-phase intermetallic alloys composed of geometrically close packed (GCP)
structures of Ni3Al(L12) and Ni3V(D022) containing Nb were investigated in terms of the
microstructural evolution during low temperature annealing (aging) and the related mechanical
properties. The eutectoid region, i.e. the prior Al phase (Ni solid solution) is composed of the
lamellar-like structure consisting of Ni3Al(L12) and Ni3V(D022) phases. The lamellar-like structure
tended to align along <001> direction and on {001} plane in the prior A1 phase (or the L12 phase).
In a wide range of temperature, the dual two-phase intermetallic alloys showed high yield and
tensile strength, and also reasonable tensile ductility, accompanied with ductile fracture mode.
Development of a Second Generation TiAl Turbocharger
Authors: Tetsui Toshimitsu
Published: March 2009

In order to expand a market share of TiAl turbocharger a second generation TiAl turbocharger was
newly developed. The characteristic of this turbocharger is its improved turbine wheel material
with excellent creep strength and its low cost manufacturing processes. The usable temperature of
this turbocharger is higher than Inconel713C turbocharger, and the cost is much reduced compared
with current TiAl turbocharger.
High Temperature Oxidation Behavior of MoSi2 under Low Pressure Atmosphere
Authors: Ibano Akira , Yoshimi Kyosuke , Yamauchi Akira , Tu Rong , Maruyama Kouichi , Kurokawa Kazuya , Goto Takashi
Published: March 2009

In this study, the high temperature oxidation behavior of polycrystalline MoSi2 in a
low-pressure atmosphere was investigated. Polycrystalline MoSi2 was produced by the spark
plasma sintering process. Oxidation tests were carried out at 1500°C at either 10Torr or 760Torr in
an Ar-20%O2 atmosphere. For both conditions, the weight change peaked at the initial oxidation
stage, and then their weights gradually increased with increasing oxidation time. The sample weight
became heavier in the ambient pressure than in the low-pressure, but the evaporation oxidation was
not significant in the low-pressure condition. After the low-pressure oxidation tests, the formation
of Mo5Si3 in the MoSi2 substrate was identified. The oxidation resistance of MoSi2 at 1500°C is
discussed based on the obtained results.
Mechanical and Physical Properties of Ni3Al-Based Alloys with Cr Carbides Dispersion
Authors: Miura Seiji , Goldenstein Hélio , Ohkubo Kenji , Sato Hisashi , Watanabe Yoshimi , Mohri Tetsuo
Published: March 2009

Ni3Al-based alloys possess good oxidation resistance, moderate room and high
temperature strength and ductility. Introduction of Cr-carbide particles through a solidification route
is attempted to provide higher hardness and wear resistance. The mechanical and physical
properties are measured at room temperature for several alloys with various carbon concentrations
up to 2.0 wt.%. Hardness and wear resistance as well as compressive strength increase with
increasing carbon concentration, while bend ductility decreases. Adhesion between carbides and
matrix phase is good, and cracks propagate mainly through carbides. The crystallographic
orientation relationships between constituent phases are also attempted using electron
back-scattering diffraction (EBSD) technique. The thermal conductivity is found to be less sensitive
to the alloy composition.
Plastic Deformations in L10-Ordered Single Crystals with their c/a Ratios Less than Unity
Authors: Tanaka Katsushi , Ide Hiromitsu , Sumi Yoshinori , Kishida Kyosuke , Inui Haruyuki
Published: March 2009

Compressive deformation of L10-ordered single crystals of FePd whose c/a ratio less than
unity have been investigated from room temperature to 823 K. The results show that the critical
resolved shear stress (CRSS) for octahedral glide of ordinary dislocations is smaller than that of
super-lattice dislocations in all the temperature range investigated, that is the opposite sense to the
case of Ti-56 mol% Al. The CRSS for ordinary dislocations virtually independent to the temperature.
On the other hand, the CRSS for super dislocations exhibits a weak positive temperature dependence
from room temperature up to 573 K and decreases in higher temperatures.
Hydrogen Permeation Properties of Nb-Based Two-Phase Compounds
Authors: Yamaguchi Yuji , Kishida Kyosuke , Tanaka Katsushi , Inui Haruyuki , Tokui Sho , Ishikawa Kazuhiro , Aoki Kiyoshi
Published: March 2009

Nb-NiTi and Nb-CoTi eutectic alloys were directionally solidified in an optical floating
zone furnace. Rod-type eutectic structures with Nb rods aligned parallel to the growth direction are
obtained for Nb-41Ni-40Ti grown at relatively slow growth rates below 1.0mm/h, while lamellar-type
eutectic structures are obtained for Nb-35Co-34Ti grown at the same condition. The hydrogen
permeability for the Nb-41Ni-40Ti DS alloy with Nb rods perpendicular to the membrane surface is
2.60×10-8mol H2 m-1 Pa-1/2 at 673K, which is about 2.5 times higher than that of as-cast sample. No
hydrogen embrittlement is observed between 573 and 673K, indicating that the Nb-NiTi rod-type
eutectic structure effectively suppresses the hydrogen embrittlement of Nb during hydrogen
permeation.
Improvement of Strength, Weibull Modulus and Damage Tolerance of SiC
Authors: Hirata Yoshihiro , Matsunaga Naoki , Hidaka Nobuhiro , Maeda Tomoyuki , Arima Takashi , Sameshima Soichiro
Published: March 2009

This paper reports the significant effects of addition of 30 nm SiC, polytitanocarbosilane
and SiC fabric to enhance the mechanical reliability of SiC. The flexural strengths of dense SiC
hot-pressed with 800 nm particles (average strength 565 MPa for Y2O3-Al2O3 additives and 640
MPa for Yb2O3-Al2O3 additives) were enhanced to average strength 735-820 MPa by the addition
of 30 nm SiC particles (25 vol%). Addition of polytitanocarbosilane (3 vol%, precursor of SiC
fiber) to the bimodal SiC powder compact with Y2O3-Al2O3 additives provided more excellent
mechanical properties of average strength 910 MPa, fracture toughness 5.2 MPa·m1/2 and Weibull
modulus 11.3. SiC fabric and SiC (60 vol%) - Al2O3 (40 vol%) sheet of 60 micrometer thick were
alternatively laminated and bonded to the surfaces of dense SiC under the pressure of 5 MPa. The
SiC fabric prevented the propagation of the cracks formed by Vickers indentor and showed a
significant nonlinear stress-strain curve. As a result, no change in the strength was measured before
and after the introduction of cracks.
TiNi-Base and Ti-Base Shape Memory Alloys
Authors: Miyazaki Shuichi , Kim Hee Young
Published: March 2009

The basic characteristics of TiNi-based and Ni-free Ti-based shape memory alloys are
reviewed. They include the crystal structures of the parent and martensite phases in both the alloys,
the recoverable strain associated with the martensitic transformation, the transformation temperatures,
the temperature and orientation dependence of deformation behavior, etc. The sputter-deposited
Ti-Ni thin films are also reviewed briefly because of their possibility of expanding into
micromechanical system applications as the most powerful microactuator.
Depth Selective Electronic State Analysis of Implanted Nitrogen in Visible-Light Response TiO2 Photocatalyst
Authors: Yoshida Tomoko , Muto Shunsuke , Wakabayashi Jun
Published: March 2009

Energetic nitrogen ion was injected into a TiO2 photocatalyst in order to investigate the
optimal local concentration of doped nitrogen for visible-light response. N+-implanted TiO2 samples
promoted the photocatalytic activity under visible-light irradiation. N K-edge XANES of the
highest activity sample indicated that N replaces the O sites near the surface, whereas in the
samples of higher N+ fluence, N−O and/or N−N species formed. Depth-resolved N K-edge ELNES
revealed the two types of N, depending on the concentration, and we found the local N
concentration effective for visible-light response was less than ∼1 at%. Further, the spatial
distributions of the different chemical states of N by energy-filtering TEM (FETEM) supported
these findings.
The Study of Inner Surface Crack Formation of Seamless Modified 9Cr-1Mo Tube Rolled on Mandrel Mill and Its Application
Authors: Li Sheng Zhi , Xu Jie , Yin Yuan De , Xue J.G. , Feng Y.
Published: March 2009

The hot workability of modified 9Cr-1Mo, as a grade of heat resistant steels, is inferior to
that of low-alloy steel, so the inner surface crack (ISC) easily occurs in seamless boiler tubes
produced by the Mandrel Mill under improper rolling conditions. With the aid of FEM, the metal flow
status during the rolling process was analyzed in 140mm 8-stand mandrel mill of Bao Steel. Both the
metallographic shape and size of the ISC together with the result from the simulation show that the
ISC of seamless tube forms at the elongation stage of shell. The mechanism of the ISC was discussed.
With its initiation in stand No.1 and No.2 due to poor hot workability of modified 9Cr-1Mo steel, the
ISC develops in subsequent passes. Based upon the mechanism devised was a special roll pass system
which substantially upgraded the yield of qualified products.
Online Wear Monitoring of Polymer Matrix Composites
Authors: Quintelier Jan , Samyn Pieter , De Waele Wim , Degrieck Joris
Published: March 2009

Polymer matrix composites are widely used as bearing materials for heavy load
applications. Still fundamental knowledge about the wear mechanisms of these materials and the
evolution in time of these mechanisms is lacking. Currently these mechanisms are only analyzed by
post mortem analysis.
The Laboratory Soete, based on the well-known pin-on-disc test rig, has developed a new test-setup.
Instead of the standard composite specimen and steel disc, a rotating composite disc and steel pin is
used to be able to have a visible composite wear track. Standard wear and friction measurements
will be further combined with vibration measurements. The vibration measurements give valuable
information about the pin-disc contact.
The combination of all these measurements should yield valuable information on the active wear
mechanisms, the occurrence of fiber and matrix fracture, fiber pull out, generated frictional heat,
formation mechanisms of wear particles, and the interaction between all these effects.
Mechanical Properties Variation with Test Temperature for Liquid Phase Sintered 95W-3.5Ni-1.5Fe Alloys
Authors: Islam Syed Humail , Tufail M. , Qu Xuan Hui
Published: March 2009

The high temperature mechanical properties of dual phase heavy metal of 95W-3.5Ni-1.5Fe alloy
were investigated in tension. The specimens were prepared by liquid phase sintering. Yield strength
decreased and ductility increased as the testing temperature was increased to 300°C, reached a
plateau at between 300 and 500°C and then decreased considerably. The fracture modes of alloys
when deformed at room temperature were a mixture of intergranular fracture and transgranular
cleavage. As the temperature was increased, the percentage of intergranular cleavage increased,
although transgranular fracture also remained. At higher temperatures, substantial reduction in
ductility and in yield strength was a result of loss of bonding strength between tungsten grains and
matrix phase.
Influence of Secondary Electro-Conductive Phases on Sliding Wear Performance of Zirconia Based Ceramic Composites
Authors: Bonny Koenraad , de Baets Patrick , Van der Biest Omer , Vleugels Jef , Lauwers Bert
Published: March 2009

Zirconia-based ceramic composites such as ZrO2-WC, ZrO2-TiCN and ZrO2-TiN, are
suitable for wire-EDM, due to their sufficiently electro-conductive secondary phases inside. Thus,
the material removal technique of EDM to shape complex geometry materials economically and
with high accuracy, irrespective of mechanical properties, could be successfully employed on these
ceramics. Samples of these ZrO2-based ceramics were developed in laboratory and manufactured
and surface finished by wire-EDM. Reciprocative dry sliding pin-on-plate experiments revealed that
the ZrO2-WC composite exhibits better tribological characteristics in comparison with the
composites of ZrO2-TiCN and ZrO2-TiN. Furthermore, topographies and cross-sectional views of
worn surfaces were analyzed by SEM, revealing that the secondary phase inside the investigated
composites governs the wear mechanism.
Metal Coated Functionalized Single-Walled Carbon Nanotubes for Composites Application
Authors: Zeng Qiang , Luna Jennifer , Bayazitoglu Y. , Wilson Kenneth , Imam M. Ashraf , Barrera Enrique V.
Published: March 2009

This study is considered as a method for producing multifunctional metal composite
materials by using Single-walled Carbon Nanotubes (SWNTs). In this research, various metals (Ni,
Cu, Ag ) were successfully deposited onto the surface of SWNTs. It has been found that
homogenous dispersion and dense nucleation sites are the necessary conditions to form uniform
coating on SWNTs. Functionalization has been applied to achieve considerable improvement in the
dispersion of purified single-walled carbon nanotubes. A three-step electroless plating approach
was used and the coating mechanism is described in the paper. The samples were characterized by
using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman
spectroscopy, and energy-dispersive X-ray spectroscopy (EDX). The application of coated SWNTs
in Titanium will be discussed in this paper.
Crystallography of BCC Precipitates at Grain Boundary Corners in FCC Matrix
Authors: Takeuchi T. , Adachi Yoshitaka , Dorner Dorothée , Enomoto Masato
Published: March 2009

This study aims to analyze the potential of grain boundary corners (GBCs) as nucleation
sites of bcc precipitates in an fcc matrix. By combined serial sectioning and electron backscatter
diffraction analysis, the crystallography of GBCs and GBC precipitates was analyzed in a Co-Fe
alloy.
A Relation between Laboratory and Full-Scale Testing of Polyester/Polyester Composites under Static and Dynamic Load
Authors: Samyn Pieter , Quintelier Jan , van Paepegem Wim , De Waele Wim
Published: March 2009

The tribological behaviour of a polymer composite is compared during small-scale and
large-scale sliding tests and it is observed that test results strongly depend on the fibre orientation
and test configuration. Different wear mechanisms are evaluated by optical microscopy and finite
element modelling in relation to a real application of polyester/polyester discs as bearing elements.
Effects of Ti and Nb Stabilization on the Recrystallization and the Pitting Potential in Fe-21%Cr Ferritic Stainless Steels
Authors: Dong Wen Bo , Ma Li , Jiang Lai Zhu
Published: March 2009

Effects of Ti and Nb stabilization on the recrystallization and the pitting potential in
Fe-21%Cr ferritic stainless steels were studied by using optical microscopy, scanning electron
microscopy, transmission electron microscopy and polarization curve measurement. The results show
that both Ti and Nb, either in solution or as precipitates, retard the recrystallization and enhance the
recrystallization temperature. Substitution of Nb for Ti in Fe-21%Cr ferritic stainless steels increases
the recrystallization temperature by 30 to 50°C. Nb and Ti stabilized ferritic steels present higher
pitting potential than Ti stabilized steels.
Bacteria-Templated Synthesis of ZnO Hollow Spheres via a Facile Hydrothermal Method
Authors: Zhou Han , Fan Tong Xiang , Zhang Di
Published: March 2009

Bacterium have evolved a large variety of stunning morphologies controlled at the microor
even nanoscopic level such as cocci, bacillus, vibrios and spirillum acting as templates can lead to
the formation of corresponding hollow inorganic replicas. Here, cocci Streptococcus thermophilus
has been used as a natural biotemplate to synthesize ZnO hollow spheres via a simple hydrothermal
method, followed by calcination. The as-obtained products are characterized by techniques of TG,
XRD, FESEM, TEM and N2 adsorption. A possible formation mechanism is proposed which has an
effect on the bimodal pore structure of the products with pores in the mesoporous range. It has
introduced a new concept to synthesize porous hollow spheres by using bacteria as a biotemplate and
has opened up a new pathway to synthesize hollow nanospheres, nanotubes and other kinds of 3D
hollow nanostructures with bacteria of different morphologies, dimensionalities and sizes as
templates.
In Situ Synthesis of Hierarchical Nanocomposites Utilizing Redox-Active Biofibers by a Novel Biogenic Technique
Authors: Dong Qun , Su Hui Lan , Zhang Di , Cao Wei , Han Jie
Published: March 2009

Biogenic technique for the synthesis of composites with nanopatterns is evolving into an
important branch of nanobiotechnology and materials science. In this work, the biomaterials eggshell
membrane fibers (ESMF) and silk fibroin fibers (SFF) were infused into palladium chloride and silver
nitrate solution at room temperature to actualize the extracellular nucleation of noble metal
nanocrystallites and in situ assembly into composites with hierarchical nanostructures on the
biofibers. The present biofibers not only served as the reacting substrates but also functioned as the
surfactants, so that small-sized but well-crystallized nanocrystallites could be organized into subtle
hierarchy to form inorganic-organic nanocomposites under the direction of the biomacromolecules.
Freeform Fabrication of Non-Metallic Objects by Selective Laser Sintering and Infiltration
Authors: Stevinson B.Y. , Bourell D.L. , Beaman J.J.
Published: March 2009

Silicon infiltrated silicon carbide parts have been manufactured using selective laser
sintering (SLS). The processing route has been defined, including post-processing steps: formation
of a green part from silicon carbide powder using a phenolic binder, infiltration with a transient
epoxy binder, dissociation of the binders thermally to create a brown part, heating the brown part to
the infiltration temperature and infiltrating with molten silicon. A dimensional analysis study was
performed. Cubes 25.4 mm on each side were selective laser sintered and measured after each
processing step. The largest dilatation (volume strain), 7.3%, was associated with creation of the
green part relative to the computer solid model. The smallest dilatation, -6%, was associated with
binder dissociation shrinkage. These volume strains nominally offset, resulting in creation of nonmetallic
parts with small dimensional errors relative to the computer solid model. This research
was funded by the National Science Foundation under grant award DMI-0522176.
Synthesis of 3, 3-Biacenaphthene through Coupling Reaction of Acenaphthene Catalyzed by [Bmim]Cl/FeCl3 Ionic Liquid
Authors: Chen Min , Yuan Xin Hua , Zhang Yan , Zhang Chun Yan , Chen Xiao Nong
Published: March 2009

In order to prepare new functional macromolecule material, the coupling reaction of
acenaphthene catalyzed by [Bmim]Cl/FeCl3 ionic liquid was investigated under mild reaction
conditions and without any additional organic solvent. Pure 3,3’-biacenaphthene, which is used as
intermediate of function aromatic polymer material, was obtained by recrystalling and column
chromatography from the reaction mixture and was determined by GC/MS, 1HNMR and FTIR
analysis. The influence of various reaction conditions on the coupling reaction of acenaphthene were
studied by GC analysis and the optimum synthesis conditions of the reaction were obtain. Under
optimun conditions, the yield of 3,3’-biacenaphthene will be 63.5 % and selectivity of that will be
85.6 %. Further more, [Bmim]Cl/FeCl3 is environmentally benign catalyst and solvent and can be
reused.
Research on the Blank Selection in the Power Spinning Process of Parts with Transverse Inner Rib
Authors: Ma Fei , Yang He , Zhan Mei
Published: March 2009

The advent of high-strength and high-precision thin-walled parts with inner ribs adapts to
the increasing demand of aerospace industry, astronautics industry, military industry, and so on. For a
new metal forming technology, how to determine the reasonable blank is a key problem required
solved firstly in the research of power spinning process of parts with transverse inner rib. In this paper,
based on the platform ABAQUS/Explicit, a reasonable 3D FE model for power spinning of parts with
transverse inner rib has been established, the power spinning process of parts with transverse inner rib
has been simulated under conditions of four typical blanks and the reasonable blanks for different
forming processes have been obtained. The results show the following:(1) Blank with equal half-cone
angle is the best selection to deform workpiece with proper height rib; (2) while for the workpiece
with excessive height rib which exceed the forming limit, blank with rib is the exclusive selection,
although it is difficult to be prepared comparing with non-rib blank.
Microstructure and Mechanical Properties of Titanium Severely Strained by Means of Friction Roll Processing
Authors: Shi Mei Qin , Takayama Yoshimasa , Kato Hajime
Published: March 2009

Severe strain has been introduced to commercially purity (CP) titanium samples by means
of friction roll processing (FRP), which represents an alternative severe plastic deformation technique
by inducing shear strain. FRP has an excellent possibility of controlling surface microstructure
combining with subsequent annealing. The resultant microstructure refinement and texture evolution
has been investigated. Hardness of sample was measured to compare mechanical properties of
samples before and after FRPed. Parameters including the different indentations given to the sample
and sample feeding speed were experimentally conducted to find the optimum condition for
investigating effect on microstructure evolution. After subsequent annealing, the evolutions of
microstructure and texture were observed by field emission scanning electron microscopy (FESEM)
and analyzed by scanning electron microscopy/ electron back scatter diffraction pattern (SEM/EBSP)
technique. Transverse texture was found to be the preferred orientation existing in the thin top layer
of the sample after FRP and annealed at 823K for 1h.
Study on Warm Flow Compacted Tungsten-Based Alloy Powder for Cross-Shape Part
Authors: Xiao Zhi Yu , Wang Jun , Ngai Tungwai Leo , Shao Ming , Li Yuan Yuan
Published: March 2009

Warm flow compaction is a new, simple and economy process that can produce complex
powder metallurgy parts. A special apparatus for measuring the lateral flow capability of the powder
was designed and manufactured. It can be used to analyze the feasibility of forming complex
cross-shaped parts. The preparation of the powder blend and effects of pressing speed, temperature
and axial pressure on the lateral flow capability of a tungsten-base powder mix were investigated.
Results showed that the lateral-pressure increased with increased pressing speed and increased
applied axial-pressure. The lateral-pressure decreased as lateral-distance increased. Biggest
lateral-pressure was obtained when the powder blend was pressed at around 96 °C, at which the
binder start to melt. In this study cross-shaped powder metallurgy parts were successfully prepared by
warm flow compaction.
Ultrasonic Spectroscopy and X-Ray Diffraction Study for ARB Aluminum
Authors: Hirai K. , Ichitsubo T. , Matsubara Eiichiro , Tsuji Nobuhiro
Published: March 2009

It has been reported that accumulative-roll-bonded (ARB) aluminum having ultrafine
grains shows an intriguing mechanical character that it is hardened by annealing and contrarily
softened by deformation. In order to understand the mechanism of such a peculiar phenomenon, we
have investigated the dislocation damping with ultrasonic spectroscopy and total amount of
dislocations with the X-ray diffraction measurement. From the present measurements, we have found
that the dislocations introduced by the ARB process are tangled but can be released with a large stress.
Such dislocations accumulated in ultrafine grains play a significant role in the plastic deformation.
Atomistic Studies of Deformation Mechanism of Nanocrystalline Al-Ti and Al-Fe Alloys from First-Principles
Authors: Uesugi Tokuteru , Takigawa Yorinobu , Higashi Kenji
Published: March 2009

We investigated the contribution to the high yield strength due to the solid solution
strengthening in nanocrystalline Al-Ti alloys produced by a vapor quench method. The misfit strain
due to solute Ti atom in aluminum was obtained from the first principles calculation. Then, the
theoretical result of the contribution to the yield strength due to the solid solution strengthening was
estimated from the misfit strain using the Friedel’s theory. In dilute Al-Ti alloy, the theoretical
results of the solid solution strengthening from the misfit strain was in good agreement with the
analytical result using the measured grain size and yield stress.
Control of Onset of Buckling Lobe in Axial Impact of Square Tube
Authors: Yamashita Minoru , Okuyama Tomohito , Nishimura Naoya , Hattori Toshio
Published: March 2009

The method for prescribing the site of the first buckling lobe in the axial impact of the tubular structure is proposed. The inertia force induced by the solid mass attached to the tube during the impact is exploited to trigger the first buckling lobe. When the tube with the solid mass undergoes a large acceleration, the inertia force of the solid mass is expected to bend on the tube wall. In the experiment, the rectangular solid mass was attached to the aluminum alloy square tube. The tube fixed to the drop-hammer was impacted against the stationary rigid plate at the velocity of 5 or 7.7 m/s. For the case of the tube without the solid mass, the site of the first buckling lobe varied and the slight wavy plastic deformation remained further than the buckling lobes. On the other hand, when the tube with the solid mass was impacted, the onset of the first buckling lobe was observed at the portion where the solid mass was attached and the wavy deformation stated above was suppressed. The corresponding computation was also conducted using the dynamic explicit finite element method. The result showed a good agreement with the experimental one.
Study on the Relationship between Some Foods and Underwater Shock Wave Using the Explosion of the Detonating Fuse
Authors: Oda Asuka , Okamoto Naoki , Itoh Shigeru
Published: March 2009

When an explosive in water is exploded, shock wave from the explosive propagates in
water as underwater shock wave. Using a detonating fuse as an energetic source, an oblique
underwater shock wave with high pressure is obtainable and possible to be utilized for various
applications. It is expected that the use of water can inhibit the heating effect on the shock
processed sample. In the present research, the authors are intended to use underwater shock wave
for the food processing. After loading underwater shock wave against some foods, it is expected to
show some advantageous effects for the food processing, such as, softening, improved permeability,
and grinding foods. However, such advantageous effects are changed depending upon the condition
of the received food. In this research, the foods containing high amount of water were treated by the
underwater shock wave. Japanese radish and apple were used as food samples. The change in their
hardness, permeability and so on were measured. These results were compared with the control
sample in which the underwater shock wave was not applied.
Mechanical Changes in Materials Caused by Explosive Precompression Shock Waves and the Effects on Fragmentation of Exploding Cylinders
Authors: Hiroe Tetsuyuki , Fujiwara Kazuhito , Hata Hidehiro , Watanabe K. , Yamamoto Mitsuharu
Published: March 2009

Explosive driven rapid fracture in a structural body will be preceded by a compression
process, and the compression effects on mechanical properties of the materials are clearly important
to understand shock-induced failure such as spall or fragmentation phenomena. In this study, incident
shock waves in plate specimens of aluminum A2017-T4 and 304 stainless steel are generated by plane
detonation waves in the high explosive PETN initiated using wire-row explosion techniques, and the
compressed specimens are successfully recovered without severe damages due to the reflected
expansion waves with use of momentum trap method. A hydro code, Autodyn-2D is applied to
determine test conditions: thicknesses of explosives, attenuators, specimens and momentum traps and
to evaluate experimental results, simulating time-histories of stress waves in the layers of the test
assembly. Microhardness distributions in cross-sections, tensile strength, fracture ductility and yield
stress are measured for the recovered specimens, using miniature tensile and compression test pieces
machined from them. They are compared with those of virgin specimens, showing significant
increase of hardness, tensile and yield strength and remarkable reduction of elongation and ductility
for shocked specimens. The results are taken into consideration for evaluation of experimental
fragmentation energy in cylinder explosion tests.
Application of Point Sampled Intercept Method in Quantitative Description of Anisotropic Structures
Authors: Maliński Marian , Chrapoński Jacek
Published: March 2009

The point sampled intercept method for estimation of the volume weighted mean volume
of grains has been used. The results obtained for computer generated isotropic and anisotropic (with
different type and level of anisotropy) 3D polycrystalline model structures have been analysed. On
the basis of this analysis methodological recommendations have been formulated.
Microstructure and Mechanical Properties of Electrodeposited Nickel and its Particle-Reinforced Nanocomposite
Authors: Cihlářová Petra , Švejcar Jiří , Sklenička Václav
Published: March 2009

There are two types of experimental material used – pure nickel and its nano-composite
reinforced with nano-sized SiO2. These materials were produced by TU Clausthal, Germany. The
results have shown that the creep resistance of the nickel nano-composite reinforced with nanosized
SiO2 particles is higher in comparison with non-reinforced nickel. The mechanism responsible
for creep behaviour is the dislocation creep at 293 K and at elevated temperatures the dislocation
creep is controlled by grain boundary sliding.
Calculations of Equilibrium Critical Thickness for Non-Polar Wurtzite InGaN/GaN Systems
Authors: Holec D. , Humphreys Colin J.
Published: March 2009

We investigate critical thicknesses of InGaN epilayers grown on GaN substrates with the
growth-plane not being the c-plane. In particular, we focus on non-polar orientations with growth
planes being the m- and a-planes. We have taken into account the proper hexagonal symmetry of
wurtzite GaN. We have found that there is only a small difference in the critical thickness for the cplane
and the a-plane material; however, in the case of the m-plane material, we predict a quite
different behaviour along the (in-plane) c-axis and the perpendicular (in-plane) a-direction.
Intergranular Failure of Roman Silver Artefacts
Authors: Vaníčková Jaroslava , Děd Jiří , Bartuška P. , Lejček Pavel
Published: March 2009

Silver objects obtained from archaeological excavations often exhibit an extended embrittlement.
The causes of this embrittlement were studied on silver artefacts buried for more than one thousand
years in the soil using light and electron microscopy techniques and EDX microanalysis.
Our investigation revealed presence of chlorine, sulphur and oxygen along the grain boundaries
suggesting that most likely, the catastrophic failure of the grave objects made of Ag–Cu alloys is
caused by an intercrystalline corrosion attack. The role of possible grain boundary segregation
and/or precipitation of copper as a path of easy corrosion is discussed.
The Influence of Thermally Sprayed Coatings Microstructure on their Mechanical and Tribological Characteristics
Authors: Houdková Šárka , Zahálka František , Kašparová Michaela
Published: March 2009

The tribological properties of parts surface, namely their wear resistance and friction
properties, are in many cases determining for their proper function. To improve surface properties, it
is possible to create hard, wear resistant coatings by thermal spray technologies. Using these
versatile coatings it is possible to increase parts lifetime, reliability and safety. The thermally
sprayed cermet composite coatings show, thanks to their specific properties, excellent resistance to
abrasive and erosive wear, as well as corrosion resistance. To predict the behavior, lifetime and
application area of thermally sprayed cermet coatings it is necessary to completely understand the
relationships between technology, process parameters, microstructure and properties of the coatings.
The finding of these relationships and use this understanding to develop deposits with improved
wear resistance for coating of various applications is the main aim of the presented work. It was
done by studying the coatings microstructure and mechanical properties. Four different tests of wear
resistance were done to study the mechanism of surface degradation, to confirm the results of
mechanical testing and to predict the lifetime of coated parts - the abrasive wear performance of the
coatings was assessed using a dry/sand rubber wheel test according to ASTM G-65, wet slurry
abrasion test according to ASTM G-75, pin-on-disc test according to ASTM G-99 and erosion wear
resistance for three impact angles. On the basis of obtained data the new possibilities of coatings
application was determined, tested and implemented.
Effect of Anodic Surface Treatment on PAN-Based Carbon Fiber and its Relationship to the Fracture Toughness of the Carbon Fiber-Reinforced Polymer Composites
Authors: Sarraf Hamid , Škarpová Ludmila
Published: March 2009

The effect of anodic surface treatment on the polyacrylonitrile (PAN)-based carbon fibers
surface properties and the mechanical behavior of the resulting carbon fiber-polymer composites has
been studied in terms of the contact angle measurements of fibers and the fracture toughness of
composites. Results from contact angle measurements revealed that the angle of electrolyte solution
largely decreases with increasing current densities of treatments up to 0.4-0.5 A m-2. The results
obtained from the evolution of KIC with flexure of the composites as a function of electric current
density shown that the KIC of the composite continually increases with increased current densities of
the treatments up to 0.5 A m-2, and a maximum strength value is found about 294 MPa cm1/2 at the
anodic treatment of 0.5 A m-2. It can be concluded that the anodic surface treatment is largely
influenced in the fiber surface nature and the mechanical interfacial properties between the carbon
fiber and epoxy resin matrix of the resulting composites, i.e., the fracture toughness. We suggest
that good wetting plays an important role in improving the degree of adhesion at interfaces between
fibers and matrices of the resulting composites.
Effect of Nickel Purity on Self-Diffusion along High-Diffusivity Paths
Authors: Rothová Vĕra , Buršík Jiří , Svoboda Milan , Čermák Jiří
Published: March 2009

In the temperature range 600–1000 °C, the effect of material purity on self-diffusion
along grain boundaries has been studied in both the pure (Puratronic 99.9945%) and the technical
(99.5%) nickel. The penetration profiles were measured by the serial sectioning method using the
63Ni radiotracer. The extensive electron backscatter diffraction (EBSD) analysis was performed on
the same samples in order to reveal possible differences in microstructure induced by the impurity
content. The obtained microstructure characteristics were further interpreted in terms of the
coincidence site lattice (CSL) model.
Influence of Interfaces upon the Self-Diffusion in AZ91 Alloy Reinforced by Saffil Short Fibres
Authors: Stloukal Ivo , Čermák Jiří
Published: March 2009

Diffusion of 65Zn in Mg-based alloy AZ91 with short Saffil fibres was studied by
sectioning method in the temperature interval 648 – 728 K. The results were compared with those
obtained in the measurements made with the same materials without the reinforcement. This
enabled to assess the influence of the interfaces between the matrix and the fibres and to evaluate
the diffusion characteristics of interface self-diffusion.
Plastic Deformation of Metallic Nanostructures
Authors: Champion Yannick , Nowak Sophie , Guérin Sandrine , Duhamel Cecilie
Published: March 2009

Copper nanostructure and aluminum-alumina nanocomposite are studied using the stress
relaxation technique to determine the activation volume involved in the micro-mechanism of the
deformation. These materials exhibiting near-perfect elasto-plastic deformation show similar
behavior in the steady state flow domain. Difference is observed when relaxations are carried out in
the work-hardening domain where dislocations variation occur.
High Resolution Imaging by Means of Backscattered Electrons in the Scanning Electron Microscope
Authors: Wandrol Petr , Matějková Jiřina , Rek Antonín
Published: March 2009

This paper deals with imaging by means of backscattered electrons in the high resolution
scanning electron microscopy. Possible backscattered electrons detection systems are outlined and
one of the most efficient, the high take of angle single crystal scintillation detector, is described in
detail. Its advantages and disadvantages are discussed and the comparison with the secondary
electron detection modes is shown. The high resolution micrographs taken by the backscattered
electron detector as well as by the secondary electron detectors are displayed.
Effect of Thermomechical Pretreatment on Mechanical Properties of Modified Al-Mn-Fe-Si Based Alloys
Authors: Cieslar Miroslav , Slámová Margarita , Hájek Michal , Veselý Jozef
Published: March 2009

Fins in automotive heat exchangers are manufactured from Al-Mn-Fe-Si foils. Since
continuous twin-roll casting (TRC) reduces energy and work consumption, it is the preferred
manufacturing technology. The precipitation processes resulting from annealing of TRC Al-Mn-Fe-
Si based alloys were studied by resistometric measurements during linear heating from room
temperature up to 620 °C, hardness measurements and transmission electron microscopy
examinations. Primary particles and precipitates of the cubic α-Al15(Mn,Fe)3Si2, hexagonal Al8Fe2Si
and orthorhombic Al6(Fe,Mn) phases were identified. Phases of different types prevail in different
alloys depending on composition. The increase of cold rolling prestrain prior to annealing induces a
significant shift to lower temperatures of the start of precipitation. Prestrain accelerates precipitation
kinetics by redistributing solute atoms and favoring their segregation on nucleation sites such as
dislocations, subgrain and grain boundaries.
Stereological Assessment, Mechanical Measurement and Computer Modelling of Smooth Muscle
Authors: Tonar Zbyněk , Kochová Petra , Holeček Miroslav , Janáček Jiří
Published: March 2009

We used mechanical measurements and unbiased statistical morphometry in order to
supply the computer model of smooth muscle cells (SMC) and collagen connective tissue of
a gastropod Arion sp. with sufficient input data. We identified the elasticity modulus for both living
(34 kPa) and formalin-fixed samples (440 kPa). The relative volume proportion of SMC was 57.8%,
their numerical density was 425 925 mm-3, surface density of SMC was 405.9 mm-1 and the mean
cell volume was 1 358 .m3.
Development of High Strength Alloys in the Mg-Ni-Y-RE System
Authors: Pérez P. , González S. , Garcés G. , Caruana G. , Adeva P.
Published: March 2009

The microstructural and mechanical characterization of two alloys within the Mg-Ni-YRE
system prepared by casting and subsequent hot extrusion at 400°C have been carried out. The
microstructure of both materials consists of a fine-grained magnesium matrix embedding a high
volume fraction of second phases; coarse Mg12RE and long period ordered stacking structure (LPS
phase) and fine Mg2Ni particles. Both alloys show high strength values up to 250°C. The yield stress
values at room temperature are 295 and 405 MPa for low- and high-alloyed magnesium alloy,
respectively. Load transfer from the magnesium matrix to coarse Mg12RE and LPS particles account
for the high strength of both alloys at temperatures below 250°C. Above this temperature both alloys
exhibit a superplastic behaviour at low stresses with elongations of 700 and 450 % for the low and
high-alloyed magnesium alloy, respectively.
Degradation of Mechanical and Structural Properties of Steel T23
Authors: Svobodová Marie , Douda Jindřich , Kudrman Jiří
Published: March 2009

This paper deals with changes in mechanical and structural properties of Steel T23 during
long-time annealing at high temperatures. The research is focused on the degradation of the base
material (steel T23), where the samples of steel, after the initial heat treatment, were annealed at
temperatures of 600, 650 and 700 °C for 10 to 10 000 hours in a furnace with air atmosphere. This
contribution summarizes the experimental results of mechanical and structural measurements and
gives the relations between them.
Experimental Techniques in Fracture Characterization
Authors: Tyson W. R.
Published: March 2009

Characterization of fracture toughness is discussed in relation to specification of steels
for northern pipelines. The state of the art and research trends in measurement of CTOD for girth
welds and CTOA for linepipe steel are described.
Effect of Absorbed Hydrogen on the Near Threshold Fatigue Crack Growth Behavior of Short Crack
Authors: Shishime Keiko , Kubota Masanobu , Kondo Yoshiyuki
Published: March 2009

Hydrogen is considered to be a possible energy source in the coming future. However, it
has been recognized that hydrogen has a detrimental effect on the fatigue strength of metal. The
fatigue crack growth characteristic is an important property for the integrity assessment of hydrogen
utilization machine. In this report, the effect of hydrogen on the fatigue crack propagation
characteristic was studied using low alloy steel, carbon steels and A286 alloy. Especially in this study,
very short pre-cracked specimen as small as 0.03 mm deep was used and the near threshold fatigue
crack behavior was studied. As a result, materials whose Vickers hardness was higher than 300 were
found to be susceptible to absorbed hydrogen.
Microstructure Properties and Fracture Behaviors of Tungsten Alloys
Authors: Song Wei Dong , Liu Hai Yan , Ning Jian Guo
Published: March 2009

The plate impact experiments have been conducted to investigate the dynamic behavior of
91W-6.3Ni-2.7Fe with three kinds grain sizes of 1− 3μm, 10 −15μmand 30 − 40μm . The stress-time
history curves at different Lagrangian positions were obtained for tungsten alloys at different impact
velocities. Lagrangian analysis technique was adopted to discuss the mechanical properties of the
tungsten alloys under high strain rate. SEM was introduced to analyze the microstructure properties of
tungsten alloys. The influence of grain size on the dynamic behavior of tungsten alloys under high
strain rate was obtained and the stress-strain curves ( 4 5 1 10 ~ 10 s− ) of the tungsten alloys were given.
The Effect of Grain Size on the Deformation Behaviour of Selected Mg Alloys
Authors: Lukáč Pavel , Trojanová Zuzanka
Published: March 2009

The mechanical properties and deformation behaviour of magnesium alloys are
significantly influenced by the testing temperature, texture and grain size. The paper gives an
overview on the influence of the grain size on the mechanical properties of Mg and Mg-2Al alloys
at various temperatures. The yield stress and the fracture stress increase with decreasing grain size.
It was shown that the elongation to fracture increases with inverse square root of grain size. The
effect of grain size on the tensile strength and the elongation to fracture is influenced by the testing
temperature. The observed grain size dependence of the elongation to fracture is explained by the
activity of non-basal slip systems.
Overview of Fatigue Behaviour of Ultrafine-Grained Copper Produced by Severe Plastic Deformation
Authors: Lukáš Petr , Kunz Ludvík , Svoboda Milan
Published: March 2009

Fatigue behaviour of ultrafine-grained copper of purity 99.9 % produced by ECAP
technique was studied in a broad region of stress amplitudes. Fatigue strength is by a factor of about
2 higher than that of conventional-grain-size copper in the broad region of fatigue lives from 6x103
to 2x1010 cycles. The grain structure is stable and undergoes only very marginal changes during
cycling. Fatigue slip markings on specimen surface follow the trace of the shear plane of the last
ECAP pass. Fatigue notch sensitivity is also higher than that of conventional-grain-size copper, but
not dramatically. The cyclic stress-strain curve of studied copper is temperature insensitive, while
its S-N curve is temperature dependent.