bluuebunny/crossref_metadata_2025 huggingface dataset:
Substructure and Crystallography of Degenerate Pearlite in an Fe-C Binary Alloy
Authors: Furuhara Tadashi , Moritani Tomokazu , Sakamoto K. , Maki Tadashi
Published: March 2009

Microstructures formed by degenerate pearlite transformation in an Fe-0.38mass%C
alloy were studied by means of scanning electron microscopy (SEM) and transmission electron
microscopy (TEM). Degenerate pearlite which contains fine cementite particles even at the growth
front was observed with other structures such as proeutectoid ferrite, lamellar pearlite and bainite in
a temperature range between 773K and 923K. As the isothermal transformation temperature is
lowered, a fraction of the degenerate pearlite increases. The degenerate pearlite consists of ‘block’
(a region in which ferrite orientations are nearly the same) and ‘colony’ (a region containing
cementite particles of nearly the same orientation), both of which are similar to those in lamellar
pearlite. Block boundaries within an austenite grain are generally of high-angle type and their
misorientations deviate largely from intervariant relationships for the K-S orientation relationship.
In contrast, colony boundaries are of low-angle type. Cementite films are formed along those ferrite
boundaries in the degenerate pearlite, presumably formed by encounter of the blocks or colonies.
Mechanical and Thermal Properties of Ultra-High Carbon Steel Containing Aluminum
Authors: Syn C.K. , Lesuer D.R. , Goldberg A. , Tsai H.C. , Sherby Oleg D.
Published: March 2009

The properties of ultrahigh carbon steels (UHCS) are strongly influenced by aluminum
additions. Hardness studies of quenched UHCS-Al alloys reveal that the temperature for the start of
transformation increases with increases in aluminum content. It is shown that this change is a
function of the atomic percent of solute and of the valence state when comparisons are made with
UHCSs containing silicon and tin as solutes. The thermal expansion of UHCSs with dilute
aluminum additions shows no discontinuity in the vicinity of the ferrite-austenite transformation
temperature. This is the result of a three phase region of ferrite, carbides and austenite. The slope of
the expansion curve is higher in the austenite range than in the ferrite range as a result of the
dissolution of carbon in austenite with temperature. Processing to achieve a fine grain size in
UHCS-Al alloys was principally by hot and warm working (HWW) followed by isothermal warm
working (IWW). The high temperature mechanical properties of a UHCS-10Al-1.5C material show
nearly Newtonian-viscous behavior at 900 to 10000C. Tensile elongations of 1200% without failure
were achieved in the 1.5%C material. The high oxidation corrosion resistance of the UHCS-10Al
materials is described.
Advanced Technology of Automotive Connecting Rod
Authors: Kubota Tsuyoshi , Yamagata Hiroshi
Published: March 2009

The present requirements for the connecting rod are indicated and the fracture splitting (FS)
technologies for constructing the big end boss are reviewed. Two possibilities of FS for a high
strength Cr-Mo steel and Ti alloys were discussed. The carburized quench-temper FS connecting rod
has a superior fatigue strength with a high dimensional accuracy at the big end boss. The possibility of
using a titanium FS connecting rod was examined and proposed.
Evaluation of Damping Property of Aluminum-Alloyed Cast Iron by Several Methods
Authors: Takamori Susumu , Osawa Yoshiaki , Kakisawa Hideki , Minagawa Kazumi , Halada Kohmei
Published: March 2009

In this research, the effect of the aluminum addition to cast iron on damping property was
investigated by central vibration method, dynamic mechanical analysis, ultrasonic attenuation
measurement and impact sound method. All measurement results indicated that the addition of
aluminum improve the damping property of cast iron.
Intragranularly Nucleated Austenite in a 2205 Duplex Stainless Steel
Authors: Chen C.Y. , Yen Hung Wei , Yu T.H. , Yang Je Rei
Published: March 2009

The effect of the degree of supersaturation in a coarse-grained h-ferrite matrix on the
consequent isothermal transformation of h-ferrite to austenite at 1150‖ in a 2205 duplex stainless
steel has been investigated. The results indicate that rapid cooling (at the cooling rate 100‖/s) to
the ambient temperature after 135P‖ solution treatment of h-ferrite matrix leads to a very high
supersaturated solid solution state, which significantly enhances the formation of the intragranularly
nucleated austenite in the subsequent isothermal transformation at 1150‖. The feature of the
intragranularly nucleated austenite has been revealed; it appears that after the initial nucleation
events for intragranularly nucleated austenite, subsequent small particles of austenite can form
sympathetically on the ferrite/austenite interface.
Effects of Drawing Strain and Annealing on the Mechanical Properties for Heavily Cold Drawn Hyper-Eutectoid Steel Wires
Authors: Yang Yo Sep , Bae Jong Gu , Park Chan Gyung
Published: March 2009

In this study, the effects of drawing strain and annealing at low temperature on the
mechanical properties have been investigated. The mechanical properties, such as hardness and
strength and fatigue, were performed. The fatigue tests of hyper eutectoid steel wires were performed
by the Hunter-type tester, specially designed for ultra thin wires (<0.2mmφ), under the bending stress.
The mechanical properties of the steel wires increased with increase of annealing temperature, and the
increase was more significant with higher drawing strain. Also, as annealing temperature increased,
the hardness and tensile strength gradually increased up to 200 °C and then dramatically decreased at
above temperature. However, bending fatigue limit, including fatigue life, showed the some different
phenomena with increase of annealing temperature. These different behaviors depending on
annealing temperature were discussed in terms of microstructural parameter changes such as pearlite
morphology, rearrangement and coalescence of the dislocations.
Effect of Precipitation on Cryogenic Toughness in N-Containing Austenitic Stainless Steels
Authors: Saucedo-Muñoz M.L. , Hashida Toshiyuki , Watanabe Yutaka , Shoji Tetsuo , Victoria-Hernández V.M.
Published: March 2009

Three types of austenitic stainless steels JK2, JJ1 and JN1 were isothermally aged at temperatures
from 600 to 900°C for 10 to 1000 minutes in order to study the microstructural evolution and its
effect on the fracture toughness at cryogenic temperatures. The Charpy V-Notch fracture energy at
77 K showed a significant decrease with aging time in JJ1 and JN1 steels because of their higher
contents of C and N. In contrast, the fracture energy corresponding to the aged JK2 steel decreased
gradually with aging time. The abundant intergranular precipitation of carbides and nitrides seems
to be the responsible for the fracture toughness deterioration in the aged JJ1 and JN1 steels. On the
other hand, the intergranular precipitation of carbides was less abundant in the aged JK2 steel. The
scanning electron microscope fractographs of the CVN test specimens corresponding to the aged
JJ1 and JN1 steels showed mainly an intergranular brittle fracture and its fraction increased with
aging time and temperature. In general, the presence of a more abundant intergranular precipitation
resulted in a more rapid decrease in toughness with aging time.
Structure Development during ECAP and Subsequent Creep of Aluminium
Authors: Saxl Ivan , Sklenička Václav , Ilucová L. , Svoboda Milan , Král Petr
Published: March 2009

Considerable structural inhomogeneity and anisotropy were found even after eight
ECAP passes in high purity aluminium and the creep loading of ECAP material at 473K, 15MPa
resulted in scattered fracture times ~ 20-60 hours. The structure revealed by orientation imaging
microscopy with different disclination bounds was analysed by stereological methods. The effect of
inhomogeneity and grain orientation on the creep fracture time was assessed.
Stainless Austenitic CrMnCN Steels of Superior Strength Part I: Alloy Design and Properties
Authors: Berns Hans , Riedner Sascha , Tyshchenko A.
Published: March 2009

The solubility of nitrogen is high in stainless austenite of steels with 18 mass% of Cr and
Mn each, but low in the melt. Carbon reveals the opposite behaviour. Instead of producing high
nitrogen steels by pressure metallurgy (PHNS), about 1 mass% of C+N is dissolved in the melt at
ambient pressure. The new cost-effective C+N steel reaches a yield strength of 600 MPa, a true
fracture strength above 2500 MPa and an elongation above 70 %. Conduction electron spin
resonance revealed a high concentration of free electrons. Thus, the ductile metallic character of the
C+N steel is enhanced, explaining the high product of strength and toughness.
Grain Boundary Engineering of High-Nitrogen Austenitic Stainless Steel
Authors: Kokawa Hiroyuki , Jin W.Z. , Wang Zhan Jie , Michiuchi M. , Sato Yutaka S. , Dong Wei , Katada Yasuyuki
Published: March 2009

Large amount of nitrogen addition into an austenitic stainless steel can improve the
mechanical properties and corrosion resistance remarkably as far as the nitrogen is in solid solution.
However, once the nitrogen precipitates as nitride, it results in deteriorations in the properties of the
high nitrogen austenitic stain steel. During welding, a high nitrogen austenitic stainless steel is
ready to precipitate rapidly immense amounts of chromium nitride in the heat affected zone (HAZ),
as intergranular or cellular morphologies at or from grain boundaries into grain interiors. The nitride
precipitation reduces seriously the local mechanical properties and corrosion resistance. The present
authors have demonstrated that a thermomechanical-processing as grain boundary engineering
(GBE) inhibited intergranular chromium carbide precipitation in the HAZ of a type 304 austenitic
stainless steel during welding and improved the intergranular corrosion resistance drastically. In the
present study, the thermomechanical-processing was applied to a high nitrogen austenitic stainless
steel containing 1 mass% nitrogen to suppress the nitride precipitation at or from grain boundaries
in the HAZ during welding by GBE. GBE increases the frequency of coincidence site lattice (CSL)
boundaries in the material so as to improve the intergranular properties, because of strong resistance
of CSL boundaries to intergranular deteriorations. The optimum parameters in the
thermomechanical-processing brought a very high frequency of CSL boundaries in the high
nitrogen austenitic stainless steel. The GBE suppressed the intergranular and cellular nitride
precipitation in the HAZ of the high nitrogen austenitic stainless steel during welding.
Properties of Low Carbon High Nitrogen Martensitic Stainless Steels
Authors: Hamano Shuji , Shimizu Tetsuya , Noda Toshiharu
Published: March 2009

We produced low carbon and high nitrogen martensitic stainless steels that contain less than
0.1 mass% C and more than 0.45 mass% N, through the pressurized induction melting process, in which
nitrogen is introduced from a pressurized N2 atmosphere. The hardness and corrosion resistance of these
steels were investigated under various heat treatment conditions.
The hardness of these steels after spheroidal annealing treatment is approximately 95HRB and the cold
workability is superior to that of AISI440C. The hardness of these steels after quenching and sub-zero
treatment is from 53 to 56HRC. In the tempering process, however, high nitrogen steels show secondary
hardening at approximately 4 points in HRC compared with the quenched hardness after subzero
treatment and have the maximum tempered hardness of 56 to 60HRC around 723K. The corrosion
resistance of quenched and tempered materials under 723K is better than AISI304 evaluated by the pitting
potential in 3.5% NaCl aqueous solution. Both remnant Cr2N in hardening and precipitated Cr2N in
tempering degraded the corrosion resistance of high nitrogen martensitic stainless steels. The best
balanced developed steel has a hardness of 60HRC and better corrosion resistance than AISI304 under
optimal heat treatment conditions.
Effect of Crystalline Phase on Dynamic Deformation Properties of Zr-Based BMG Alloys
Authors: Lee Dong Geun , Lee Yont Tai , Yeon Jong Taek , Kim Jeoung Han , Park Nho Kwang , Lee Sung Hak
Published: March 2009

Dynamic compressive tests were conducted on Zr-based amorphous alloys and
amorphous matrix composite containing dendritic β phases. Dynamic compressive tests were
conducted using a compressive Kolsky bar and then the test data were analyzed in relation to
microstructure and fracture mode. Under dynamic loading, the maximum shear stress and ductility
of the amorphous alloy and composite were considerably lower than those under quasi-static
loading because of the decreased resistance to fracture. Deformation under dynamic loading
lowered strain and compressive strength because of reduced fracture resistance, and the alloy
containing dendritic β phases showed better compressive strength and ductility than the monolithic
alloy.
Chitosan Polyelectrolyte Complexes for Use in Tissue Engineering and Drug Delivery
Authors: Bubeníková Silvia , Lacík Igor , Bakoš Dušan , Vodná Lucia
Published: March 2009

The paper presents the first part of the work focused on preparation of biodegradable
chitosan microcapsules with tailored properties for potential applications in medical field as drug
temporary carriers. In this paper, we aimed to prepare chitosan and chondroitin sulphate
microcapsules using TPP as the second cross-linker and investigate the formation of the capsule
membrane and its permeability in dependence on conditions of polyionic complexation. As a
model, TPP was used to assess an influence of concentration and reaction time on the microcapsule
formation. The method of inverse SEC was used for pores size and permeability limit of capsules
assessment. For chitosan/CHS/TPP capsules, the distribution of pores size in the membrane is rather
broad, which can be suitable for applications in tissue engineering and drug delivery systems.
Electrostatic Nanomechanics of Cantilever Biosensors
Authors: Merlo Manuele , Negretto Fabio , Soncini Monica , Montevecchi Franco Maria
Published: March 2009

Interest in microcantilever based biosensors in the biomedical field has largely increased
during the last years. Potentially, this kind of sensor can provide a considerable contribution to
complex disease diagnosis, which requires the detection of biological molecules.
Microcantilever biosensors allow the detection of complementary DNA fragment hybridization or
specific antibody-antigen binding; it is known that adsorption of specific biological molecules upon
the microcantilever surface induces cantilever deflection due to the interaction of the molecules
with the surface. To date, the phenomena which determine the deflection mechanism are not
completely known.
The present work investigates the electrostatic field within the molecules and the forces
consequently acting on the molecules and on the cantilever in order to provide a description of the
deflection mechanism.
The electrostatic potential of arrays of double strand DNA molecules immersed in an ionic solution
was modelled by means of cylinders negatively charged at the surface and a FE (Finite Element)
continuum electrostatics analysis was implemented in order to numerically solve the second order
non-linear Poisson-Boltzmann equation. Then, a FE structural analysis of the cantilever was
performed coupled with the continuum electrostatics analysis. In this way, the effects of the
molecules’ electrostatic interactions on the cantilever deflection were taken into account.
The model was run to describe the microcantilever deflection due to the electrostatic field under
different design and operating conditions, and it was also set to compare hexagonal and square
disposition of double strand DNA molecules.
Carbon Nanotubes Grown by Catalytic CVD on Silicon Based Substrates for Electronics Applications
Authors: Rizzoli R. , Angelucci R. , Guerri S. , Parisini Andrea , Veronese G.P. , Vinciguerra Vincenzo , Bevilacqua Maria Fortuna
Published: March 2009

To exploit the impressive electronic, mechanical and thermal properties of Carbon Nanotubes
(CNTs) in the nanoelectronics technology, the development of deposition methods enabling the
synthesis of well ordered, properly located and reproducible CNTs structures, is strongly
recommended. We have been developing catalytic CVD synthesis of CNTs in order to get aligned
nanotubes for applications ranging from nuclear particle-position detectors and cold cathode
emitters for storage devices, to interconnects, vias and CNT-FETs.
In this paper, the significant achievements gained on CVD growth processes for the CNTs
deposition are presented. Ni and Fe catalyst nanoparticles have been obtained starting from thin
films evaporated on silicon based substrates. The growth of vertically aligned carpets of MWNTs
and horizontally aligned SWNTs, having a diameter of about 1 nm and bridging between patterned
catalyst islands, has been accomplished. The SEM, TEM, Raman spectroscopy and AFM
characterizations are discussed.
U.S. FDA Perspective on the Regulation of Cyanoacrylate Polymer Tissue Adhesives in Clinical Applications
Authors: Mattamal George J.
Published: March 2009

A brief description of the uses and clinical applications of synthetic
cyanoacrylate polymer adhesive/glues that have been cleared and/or approved as medical
devices by FDA since the Medical Device Amendments of 1976 were enacted. This
includes cyanoacrylate Class I devices (Exempt and not Exempt devices), Class II
cyanoacrylate devices such as Dental Cements and Orthodontic Bracket Adhesives, and
Class III (PMA) devices such as Dermabond™, Indermil™ Tissue Adhesive, and
Trufill® n-Butyl Cyanoacrylate Embolic Agent. By citing an example of recently FDA
approved Class III (PMA) devices in the Cyanoacrylate technology, the author provides a
brief discussion of the FDA approval process of medical devices. It includes the FDA
issues regarding the published guidance document for "Cyanoacrylate Topical Tissue
Adhesives" that will provide guidance to regulatory personnel and manufacturers in the
preparation of IDE applications and in the development of valid scientific evidence to
support PMA applications for cyanocrylate tissue adhesives intended for topical
approximation of skin and others. Also, the author provides a short regulatory
description of US FDA; under what laws its operates, how FDA evaluates new devices
for marketing, and how the device regulatory system works, for example, Class I, Class
II, and Class III cyanoacrylate medical devices.
Alignment of HAp Crystal Using a Sample Rotation in a Static Magnetic Field
Authors: Iwai Kazuhiko , Akiyama Jun , Tanase Tomohiko , Asai Shigeo
Published: March 2009

Formation of crystallographically orientaed hydroxyapatite (HAp) is one of the promising
ways to utilize their anisotropic nature of chemical and biological properties. On the other hand, the
development of super conducting magnet technology enables to introduce a high magnetic field
which can control crystal orientation of non-magnetic materials with magnetic anisotropy. In this
study, a high magnetic field and sample rotation are simultaneously imposed on the hydroxyapatite
during a slip casting process in order to align its c-plane within a horizontal plane. From X-ray
diffraction, it has been found that the HAp crystals in the sample treated with the magnetic field and
the sample rotation were oriented to a particular direction in the slip casting process and it was
enhanced by the subsequent sintering process, while the c-axis crystal orientation of the sample
treated without the magnetic field and with the sample rotation was not observed before and after the
sintering.
Porous Titanium with Porosity Gradients for Biomedical Applications
Authors: Wen Cui E , Yamada Yasuo , Nouri A. , Hodgson Peter
Published: March 2009

Highly porous titanium and titanium alloys with an open cell structure are promising
implant materials due to their low elastic modulus, excellent bioactivity, biocompatibility and the
ability for bone regeneration. However, the mechanical strength of the porous titanium decreases
dramatically with increasing porosity, which is a prerequisite for the ingrowth of new bone tissues
and vascularization. In the present study, porous titanium with porosity gradients, i.e. solid core with
highly porous outer shell was successfully fabricated using a powder metallurgy approach.
Satisfactory mechanical properties derived from the solid core and osseointegration capacity derived
from the outer shell can be achieved simultaneously through the design of the porosity gradients of
the porous titanium. The outer shell of porous titanium exhibited a porous architecture very close to
that of natural bone, i.e. a porosity of 70% and pore size distribution in the range of 200 - 500 μm. The
peak stress and the elastic modulus of the porous titanium with a porosity gradient (an overall
porosity 63%) under compression were approximately 152 MPa and 4 GPa, respectively. These
properties are very close to those of natural bone. For comparison, porous titanium with a uniform
porosity of 63% was also prepared and characterised in the present study. The peak stress and the
elastic modulus were 109 MPa and 4 GPa, respectively. The topography of the porous titanium
affected the mechanical properties significantly.
SLEEM Study of MgAl2O4 at Interface betweeen Al2O3 and Matrix in Al2O3/Al Alloy Composite Materials
Authors: Ikeno Susumu , Matsuda Kenji , Müllerová I. , Frank Luděk
Published: March 2009

In the present talk, MgAl2O4 in the Al2O3/Al-1.0mass%Mg2Si alloy composite was also
observed by a scanning electron microscope equipped with the low energy electron (SLEEM)
adaptation aiming at examination of its morphology and orientation relationships to the Al2O3
particles. Owing to its much smaller interaction volume of signal exciting electrons in the target and
hence more localized information, together with a favorable combination of secondary (SE) and
backscattered (BSE) electron signals, the SLEEM method provided much better readable and
detailed images of all particles, their shapes and mutual orientations, in comparison with
conventional SE and BSE images at the electron energies usually used in the SEM. MgAl2O4
(spinels) were formed on facets of Al2O3 as small particles, and their shape well corresponded to an
octahedron consisting of 8 equiaxial triangles.
Plasticity Mechanisms in Multi-Scale Copper-Based Nanocomposite Wires
Authors: Thilly Ludovic , Vidal Vanessa , Lecouturier Florence
Published: March 2009

Copper-based high strength nanofilamentary wires reinforced by Nb nanofilaments are
prepared by severe plastic deformation (repeated hot extrusion, cold drawing and bundling steps)
for the winding of high pulsed magnets. The effects of microstructure refinement on the plasticity
mechanisms were studied via nanoindentation, in-situ deformation in TEM and under neutron
beam: all results evidence size effects in each nanostructured phase of the nanocomposite wires, i.e.
single dislocation regime in the finest regions of the Cu matrix and whisker-like behaviour in the
Nb nanofilaments. The macroscopic high yield stress is thus the results of the combination of the
different elastic-plastic regimes of each phase that include size effects.
Effect of Milling Condition on Properties and Microstructure of Copper Reinforced with 1% vol. NbC
Authors: López Marta , Jiménez José A. , Benavente R.
Published: March 2009

Composites materials consisting of pure copper reinforced with 1 vol.% of NbC were
prepared by the powder metallurgy route to determine the influence of the milling process on the
mechanical and electrical properties. For comparative purpose different milling times at four
different rotational speeds were used. The resulting powders were consolidated by hot uniaxial
pressing under 90MPa for 2h at 923K to obtain materials with a fine microstructure without residual
porosity. It was found that the microstructure and properties of composite materials could be
principally related to the amount of Fe, Cr, C and O incorporated as impurities during the milling
process. Therefore, the rotational speeds used for milling has an important influence on the
properties of the final product. A lower energy-ball milling is accompanied by a smaller amount of
impurities (Fe, C and O) incorporated during milling. Composites materials combine electrical
conductivity above 40% IACS with high strength. A detailed microstructural analysis by scanning
and transmission electron microscopy and X ray diffraction showed that these properties are related
not only to NbC particles, but also to the presence of very fine particles of carbides and oxides.
Binder-Free Tungsten Carbide Fabricated by Pulsed Current Sintering
Authors: Shimojima Koji , Hosokawa Hiroyuki , Nakajima Takeshi , Mizukami Masahiko , Yamamoto Yoshiharu
Published: March 2009

In this presentation, we show some experimental results of binder-free WC with Nano WC
sintered by Pulsed Electric Current Sintering (PECS) process also known as Field Assisted Sintering
Technology (FAST). The particle size of WC powder is almost 80 nm. These binder-free WC have
extremely hardness and stiffness. However, these mechanical properties are dependent on the
sintering condition, e.g., maximum temperature, applied presssure, etc. We show some relationship
between mechanical properties and sintering condition to improve to sinter the binder-free WC
Mechanical Properties of the MG-Based Amorphous/Nano Zirconia Composite Alloy
Authors: Chang L.J. , Young J.H. , Chiang P.T. , Jang Jason S.C. , Huang J.C. , Tsao Chi
Published: March 2009

Mg-based composites are fabricated through mechanical alloying (MA) the
Mg65Cu20Y10Ag5 amorphous alloy spun and mixed with 1-5 vol.% spherical nano-sized ZrO2 particles
in the planetary mill, after then formed by hot pressing in Ar atmosphere under different pressures at
the temperature 5 K above the glass transition temperature (Tg). The microstructure characterizations
of the resulting specimens are conducted by means of XRD, FEG-SEM, and TEM techniques. It is
found that the nano-sized ZrO2 dispersed Mg-based composite alloy powders can reach to a
homogeneous size distribution (about 80 nm) after 50-hour mechanical alloying. After hot pressing of
these composite alloy powders under the pressure of 1100 MPa at 409K, a 96% dense bulk specimen
can be formed. Throughout the MA and hot pressing, the amorphous nature of the Mg65Cu25Y10Ag5
matrix is maintained. The hardness of the formed bulk Mg-based composites (with 3 vol.%
nano-sized ZrO2 particles) can reach to 370 in Hv scale. In addition, the toughness of the formed bulk
Mg-based composites presents an increasing trend with the content of nano-sized ZrO2 particles and
can reach to 8.9 MPa m .
The Effect of Boron on the Hardness and Fracture Toughness of WC-FeAl-B and WC-Ni3Al-B Composites
Authors: Ahmadian M. , Wexler David , Calka Andrzej , Chandra Tara
Published: March 2009

The hardness and indentation fracture toughness of sub micron WC composites based on aluminide
and cobalt binders were investigated. Doped Fe60Al40 and Ni3Al alloys with boron levels ranging
from 0 to 0.1 wt%, were used as the aluminide binders. The composite materials were processed by
uniaxial hot pressing of milled powder samples at 1500 °C under argon atmosphere. The hardness
of WC-40vol%(FeAl-B) was found to be higher than that of WC-40vol%(Ni3Al-B), and it
approached to the hardness level of the commercial grade of WC-10wt%Co (H10F). The fracture
toughness of both WC-40vol%(FeAl-B) and WC-40vol%(Ni3Al-B) cermets was higher than that of
WC-40vol%Co and the toughness increased with increasing boron content. It is believed that boron
addition to the aluminide binders leads to improvement in the fracture toughness of the intermetallic
matrix composites as a result of increase in the ductility and toughness of the aluminides and also
due to increase in WC solubility in the aluminide binders in presence of boron.
A Study on the Chemical Resistance of GT Composites
Authors: Jeon Han Yong , Lee Y.H. , Seo Jung Min , Hwang Beong Bok , Koo H.S.
Published: March 2009

This paper is concerned with the performance of geo-textile (GT) against chemical
condition. GT is generally adopted for the upper part of geo-membrane (GM) for waste landfills and
thus it is very important to consider the performance of GT against certain chemical environments
until landfill is completed. In this study, PVA geo-textile/HDPE geo-membrane was prepared to
investigate the waste landfill related properties in terms of long-term performance against chemical
conditions imposed. GT composites of PVA GT/HDPE GM, PVA GT and HDPE GM were produced
in thermal bonding process. Polyester and polypropylene GT were also manufactured in needle
punching process. The experiments have been conducted under a modified version of EPA 9090 test
method which is very similar to the method of evaluating chemical resistance of flexible membrane
liner by the US Environmental Protection Agency (EPA). In this testing method, samples immersed
in chemical of different solutions up to 150 days at 30 day interval were obtained to find tensile
strength holding rate and chemical resistance. The analysis in this paper is focused to evaluate the
effect of different pH conditions and temperature environments on geo-synthetics weights strength
retention. It was concluded from the experiments that tensile strength of GT composites against
leachate were reduced by 10 to 20% in both polypropylene and polyester non-woven GT. The
reduction was more significant at temperatures of 50 °C than that at 25 °C. The experiments
conducted in this study demonstrated that PVA GT is excellent in terms of chemical resistance.
Antenna Mechanism and De-Aggregation Concept: Novel Mechanistic Principles for Photocatalysis
Authors: Wang Chuan Yi , Pagel Ronald , Dohrmann Jürgen K. , Bahnemann Detlef Werner
Published: March 2009

TiO2 photocatalysis has attracted a great deal of attention during the last three
decades. One major goal in this field is the design and preparation of TiO2 based photocatalysts
possessing high photocatalytic activity to satisfy the requirements for practical applications. For the
development of successful strategies to achieve this goal it is of utmost importance to improve the
mechanistic understanding of the basic principles of photocatalysis. Therefore, various nanosized
TiO2 photocatalysts including pure TiO2, Fe(III)-doped TiO2 and platinized TiO2 have been
synthesized in our laboratories and their photocatalytic activity has been studied in detail. In
particular, the correlation between the structural characteristics of these newly synthesized catalysts
and their photocatalytic activity has been addressed. To explain the unexpected behavior of these
materials novel mechanistic principles, i.e., the antenna mechanism and the so-called deaggregation
concept have been developed and will be explained in this review.
Characterization and Wettability of TiO2 Films Deposited by Mid-Frequency Magnetron Reactive Sputtering
Authors: Cui Ying , Du Hao , Lee Soo Wohn , Sun C. , Wen Li Shi
Published: March 2009

TiO2 films were deposited by using mid-frequency twin magnetron reactive
sputtering technique at ambient temperature on quartz and Si wafer. The films were
annealed after deposition. The phase composition and surface morphology of the TiO2
films were characterized by X-ray diffraction, Raman spectroscopy, and scanning
electron microscopy, while the optical properties and contact angle were measured using
a UV-Vis spectrophotometer and a contact angle meter. It is indicated that anatase phase
dominates below 900°C and a mixture of rutile and anatase exists in the film annealed at
1000°C. Furthermore, the hydrophilic property depends on phase composition and
morphological change in TiO2 films.
Structure–Mechanical Properties Correlation in a Hydrogenated Ti-Based In-Situ Amorphous Matrix Composite
Authors: Jayalakshmi S. , Fleury Eric , Kim Ki Bae
Published: March 2009

Ti50Zr25Cu25 in-situ composite ribbons consisting of metastable β-Ti crystalline phase in
an amorphous matrix was studied for its structural stability and mechanical properties after
hydrogenation. On annealing, dissolution of the metastable β-Ti phase occurred. On hydrogenation,
upto ~60 at.% hydrogen was obtained and hydrogen-induced amorphization occurred. The fracture
strength of the hydrogenated composite indicated that it was mechanically stable even for high
hydrogen contents.
Effects of Er on Microstructure and Mechanical Properties of Mg-Zn-Er-Zr Magnesium Alloys
Authors: Wang Qu Dong , Li Da Quan , Li Qiang , Ding Wen Jiang
Published: March 2009

Microstructure and mechanical properties of Mg-Zn-Er-Zr alloys were characterized in
detail. The grain size of as-cast Mg-Zn-Er-Zr alloy was greatly decreased by the Mg-Zn-Er phases
formed at grain boundaries. The addition of Er can increase the yield strength (YS) but decrease the
ultimate tensile strength (UTS) and elongation of as-cast Mg-Zn-Zr alloy. The thermally stable
Mg-Zn-Er phases were just partially dissolved into the matrix during solution treatment. And the
addition of Er can prolong the precipitation process of Mg-Zn-Zr alloy. Solution-plus-ageing
treatment can increase the strength of both the Mg-Zn-Zr and Mg-Zn-Er-Zr alloys, but the
strengthening effect of Mg-Zn-Er-Zr alloy was greatly weakened, for the incompletely solution of
Mg-Zn-Er phases. Er can greatly enhance the high temperature elongation of Mg-Zn-Zr alloy, but the
increase of high temperature tensile strength was just a little.
Liquation Cracking in Heat Affected Zone in Ni Superalloy Welds
Authors: Chaturvedi Mahesh C.
Published: March 2009

Precipitation hardened nickel-based superalloys are widely used in aero and industrial gas
turbine engines due to their excellent high temperature strength and remarkable hot corrosion
resistance. A drawback of many of these alloys is that they are very difficult to weld due to their high
susceptibility to heat affected zone (HAZ) cracking, both during welding and post weld heat
treatments (PWHT). Weld cracking in many of these alloys has been attributed mostly to
constitutional liquatioin of grain boundary NbC precipitates. however, HAZ cracking has been
observed in carbon-free superalloys as well, Therefore, research was initiated to examine grain
boundary liquation and cracking in HAZs in a variety of Ni-based superalloys. It was found that
intergranular cracking of grain boundaries involved liquation of several other phases, in addition to
NbC, that were present in pre-weld microstructure of the alloy. These even included the primary
strengthening phase,γ’, in a very widely used superalloy, Inconel 738. In addition, segregation of
melting point depressant element B was also observed at gain boundaries in other superalloys, which
also caused grain boundaries in HAZ to liquate and resulting in their cracking. An overview of
microstructural aspects of different liquation phenomena involved and characteristics of the liquid
film contributing to the HAZ microfissuring of nickel superalloys will be discussed in this
presentation
The Future of Commercial Air Transport and Aeroengines: Challenges and Opportunities
Authors: Khan Tasadduq , Kuentzmann Paul
Published: March 2009

The aeroengines have been the subject of continuous development for the past fifty years
with considerable improvements in fuel efficiency, power density, exhaust emissions, decreased noise
and better reliability. All these changes have been brought due to incremental improvements in engine
cycle, combustion, turbine cooling, acoustics and materials technology.The main challenges for the
future are not only technological and economical but also related to societal concerns. For instance,
noise and emissions are becoming a major concern.In terms of materials, there is a constant need for
developing new affordable materials, or materials systems such as thermal barrier coatings on single
crystal superalloys in order to achieve higher TET but not at the expense of increased NOx, at least in
commercial engines. The use of MMC's and CMC's in some parts of the engine will become possible
due to a considerable improvement in processing and lifing methodologies.
Microstructure Evolution and Strain Features of a Single Crystal Nickel Base Superalloy during Tensile/Compression Creep
Authors: Meng Fan Lai , Tian Su Gui , Wang Ming Gang , Yu Xing Fu , Du Hong Qiang , Shui Li , Wang Ling
Published: March 2009

By means of tensile and compression creep testing and SEM, TEM observation, an
investigation has been made into the microstructure evolution of a single crystal nickel base
superalloy during tensile / compression creep. Results show that the cubic γ′ phase in the superalloy is
transformed into the N-type meshlike structure along the direction vertical to stress axis during tensile
creep. The cubic γ′ phase is transformed into the P-type structure along the direction parallel to stress
axis during compression creep. An obvious asymmetry strain of the alloy occurs during tensile and
compression creep, the formation of the needle-like γ′ rafts during compression creep is a main reason
of the alloy displaying a smaller strain. During compressive creep, the deformation feature of the alloy
is the <110> and (1/3) <112> super dislocations shearing into the γ′ rafts. The deformation
mechanism of the alloy, in the stage state of tensile creep, is dislocation climb over the γ′ rafts.
Microstructure Simulation of Magnesium Alloy
Authors: Fu Zhen Nan , Xu Qing Yan , Xiong Shou Mei
Published: March 2009

A cellular automaton (CA)-based model for two-dimensional simulation of the dendritic
morphology of magnesium alloys was developed. The model considers solving the solute and heat
conservation equations in the modeling domain, including calculation of the solid fraction, the tip
velocity, and the solute diffusion process, all of which have significant influence on the dendrite
evolution. The microstructure of a step-shape die cast part of AZ91D magnesium alloys was
investigated utilizing SEM-EBSD analysis. The microstructure simulation results were compared
with the experimental results and they were in good agreement on grain size.
Phase Transformation in Binary Titanium-Base Alloys with Metals of the I, IV−VIII Groups
Authors: Dobromyslov A.V.
Published: March 2009

Martensitic β→α′(α″) transformation, β→ω transformation and eutectoid decomposition
in a series of Ti-base alloys with d transition metals of Groups I, IV-VIII have been investigated using
the techniques of X-ray diffraction, optical and transmission electron microscopy. Phase and
structural information is given on the non-equilibrium and metastable modifications occurring in
these alloys after quenching from high-temperature β-field and aging. The conditions of the
orthorhombic α″-phase, ω-phase and metastable β-phase formation in binary titanium–base alloys
with d-metals of V-VIII groups were investigated. It was established that the position of the alloying
metal in the Periodic Table defines the presence or absence of the α″-phase in the alloy after
quenching and the minimum concentration of the alloying metal necessary for formation of the
α″-phase, ω-phase and metastable β-phase.
Finite Element Analysis on Superplastic Blow Forming of Ti-6Al-4V Multi-Sheets
Authors: Yoon Jong Hoon , Lee Ho Sung , Yi Yeong Moo , Jang Young Soon
Published: March 2009

Superplastic blow forming with diffusion bonded sheet is an effective forming technology
for the production of multi-cell structures which should have light weight and high stiffness for
aerospace purpose. In the current study, finite element analysis on superplastic blow forming process
has been carried out in order to improve the forming process when manufacturing axi-symmetric
multi-cell structures using diffusion bonded Ti-6Al-4V multi-sheets. The simulation focused on the
reduction of forming time and obtaining finally required shape throughout investigating the
deformation mode of sheet according to the forming conditions, which are diffusion bonding pattern
and die geometry. To reduce forming time, a preforming die was required, and to obtain the final
shape the bonding pattern should be also modified within allowable geometrical margin, so that the
sheet is easy to deform. Moreover, an intermediate simulation result, which was forming pressure
profile, was employed in real forming test to check if the prediction was reasonably on progress. In the
future, a study on the thickness ratio between each sheet should be followed to obtain optimum
process parameters.
Research on Semi-Solid Deformation and Forging Behavior of Ti14 Alloy
Authors: Zhao Yong Qing , Wei J.F. , Wu Wei Lu , Guo P.
Published: March 2009

Titanium and its alloys are widely used in industries due to their excellent comprehensive
properties. However, their high-cost limits their applications in civil, therefore the research on low
cost titanium technology is necessary. In the present study, the semi-solid deformation behavior of
Ti14 burn resistant alloy was investigated. The results indicated that Ti2Cu melting phases within
grains and at grain boundaries grow to form coarse grain boundaries and network structures during
Ti14 alloy semi-solid deformation. Its microstructure was coarse and the grain boundary was wide
after semi-solid forging, leading to low plasticity at room temperature. Recrystallizing heat treatment
leads to fine microstructure, which is similar to that of conventional forging, resulting in
improvement of tensile mechanical properties. The mechanical properties of semi-solid forging are
similar to that of conventional one at high temperature.
In Situ AFM Observation of Mechanical Behavior of Beta Titanium Alloy in Nano-Indentation Test
Authors: Wang Xiao Teng , Fang Hong Yuan , Yoshida Fusahito
Published: March 2009

In this study, depth sensing nano-indntation test combined with in-situ atom force
microscope (AFM) is carried out to investigate the plastic/viscoplastic behavior of beta titanium
alloy. The indentation experiment results show that with the increasing nominal indentation strain
rate, the hardening effect becomes stronger in the loading part, while the creep induced softening
behavior becomes stronger in the unloading part. The residual penetration depth is deeper when the
indentation strain rate increases. A new quantity named nominal hardness/modulus ratio is defined to
characterize the plastic behavior of beta titanium at micro region.
Effect of Sc on Microstructures and Corrosion Properties of AZ91
Authors: Yao Su Juan , Yi Dan Qing , Yang Sheng , Cang X.H. , Li W.X.
Published: March 2009

The microstructures and corrosion properties of AZ91 magnesium alloy with trace
additions of Sc were investigated. The microstructures were observed by OM and SEM, and the
corrosion properties were studied by electrochemical technique. The results show that the alloys with
Sc form a second-phase Al3Sc, the grains become finer with the increasing content of Sc and the
microstructure is the finest when Sc content up to 0.6%, the corrosion resistant of alloy combining
with Sc is improved.
A Novel Canning Technology for Forging of Gamma-TiAl Alloys
Authors: Zhang J. , Kutzsche Anja , Rosenberg K. , Leyens Christoph , Viehweger Bernd
Published: March 2009

A novel canning technology to forge gamma-TiAl alloys was developed at the BTU
Cottbus. A TiAl specimen was encapsulated with multilayer stainless steel foil and glass. The steel
foil layers prevented the heat loss through radiation and the glass layer reduced the temperature
decrease through conduction. First, the effect of steel foil on the cooling rate was investigated.
Cooling curves were recorded for TiAl specimens without steel foil layer, with 1, 2, 3 and 4 layers of
steel foil, as well as with 3 coated steel foil layers, respectively. While the unprotected specimen
cooled from 1200 °C to 1100 °C within 12 s, the specimen with 3 coated steel foil layers needed 52 s
for the same temperature decrease. The efficiency of the glass layer was examined with forging of
steel specimens. The cooling rate during forging of the specimen with a glass layer was only half of
that without a glass layer. Based on the results, Ti-45Al-0.5Mo-0.5Cu-0.2Si specimens, canned with
steel foil and glass, were successfully forged at strain rates of 0.1 s-1 and 0.04 s-1 with warm dies which
were heated to 500 °C. Visual and metallographic examinations revealed no cracks, pores or
micropores. The microstructures are fine-equiaxed grains.
Influence of Rapid Solidification on the Microstructure and Mechanical Properties of NiAl-Based Near Eutectic Alloys
Authors: Guo Jian Ting , Li Hu Tian , Huai Kai Wen , Li Gu Song
Published: March 2009

The effects of rapid solidification on the microstructure and mechanical properties of two
kinds of NiAl based eutectics were investigated. Rapid solidification resulted in the following effects,
which encompass the refinement of the cell size, lamellar spacing and precipitates, deviation from the
equilibrium composition, solubility extension, and a transition from a Heusler phase to an Hf-rich
solid solution phase. Except for the deviation from the equilibrium composition, these microstructural
characteristics are all beneficial to the improvement of mechanical properties. As a consequence, the
room temperature compression yield strength and compression ductility were improved significantly
and high temperature strength improved slightly. The high temperature compressive flow behaviour
can be described by the temperature-compensated power-law equations.
Study on Fracture Behavior of γ-TiAl Based Alloys
Authors: Cao Rui , Chen Jian Hong , Zhang J.
Published: March 2009

Fracture behavior of fully lamellar (FL) and duplex phase (DP) TiAl alloys is reported in
this paper. It was found that the inverse behavior of coarse FL TiAl alloy showing inferior tensile
properties but superior fracture toughness resulted from the different fracture mechanisms of these
two types’ tests. In tensile specimens, the final fracture happened at a section that was most heavily
damaged by the accumulation of large interlamellar microcracks and arbitrarily located within the
gauge-limited volume. In 3PB notch specimens, the propagation of the main crack was constrained
within a narrow strip nearby the centerline where the normal stress was the highest. Large lamellar
grains caused serious damage in tensile tested specimens. However multi-oriented large lamellar
grains formed seriously bifurcated crack tips, which made the crack propagation more difficult in 3PB
notched specimen. The main mechanisms of toughening in FL specimens were the deflection of main
crack, bifurcation and blunting of crack tip and formation of a diffuse zone of microcracks. These
phenomena reduced the driving force for crack extending and then increased the fracture toughness.
NiCr-CrAl Coating for Ni3Al Base Alloy IC6AE
Authors: Li Shu Suo , Zhang Chun Xiao , Kang Yong Wang , Han Ya Fang
Published: March 2009

The effect of NiCr-CrAl coating on the microstructure, oxidation and corrosion resistance,
as well as mechanical properties of Ni3Al base alloy IC6AE has been studied in the present
investigation. NiCr-CrAl coating for alloy IC6AE was prepared by the powder pack cementation
method. The oxidation resistance tests were carried out under the condition of 1050°C/100h, while
the hot corrosion resistance tests were under 900°C/100h. The tensile tests at the room temperature
and the stress rupture life tests under 1050°C/90Mpa have been also conducted. The experimental
results showed that NiCr-CrAl as-coated specimens had excellent oxidation and hot corrosion
resistance compared with the alloy IC6AE blank specimens, and NiCr-CrAl coating has no obvious
effect on the mechanical properties of alloy IC6AE. It may be concluded that NiCr-CrAl coating is
suitable for the alloy IC6AE.