bluuebunny/crossref_metadata_2025 huggingface dataset:
Organic-Inorganic Nano Composite Membranes of Sulfonated Poly(ether Sulfone-Ketone) Copolymer and SiO2 for Fuel Cell Application
Authors: Lee Dong Hoon , Park Hye Suk , Seo Dong Wan , Kim Whan Gi
Published: March 2009

Novel bisphenol-based wholly aromatic sulfonated poly(ether sulfone-ketone) copolymer and organic-inorganic composite membranes were prepared for operation 80°C in polymer electrolyte membrane fuel cell (PEMFCs). The copolymer were synthesized by direct aromatic nucleophilic substitution polycondensation of 4,4-difluorobenzophenone, 2,2’-disodiumsulfonyl- 4,4’-fluorophenylsulfone (40mole% of bisphenol A) and bisphenol A. Polymerization proceeded quantitatively to high molecular weight in N-methyl-2-pyrrolidinone at 180°C. Organic-inorganic composite membranes were obtained by mixing organic polymers with hydrophilic SiO2 obtained by sol-gel process. The polymer and a series of composite membranes were studied by FT-IR, 1HNMR, differential scanning calorimetry (DSC) and thermal stability. The proton conductivity as a function of temperature decreased as SiO2 content increased, but methanol permeability decreased. The nano composite membranes were found to poses all requisite properties; Ion exchange capacity (1.2meq./g), glass transition temperatures (164-183), and low affinity towards methanol (4.63-1.08x10-7 cm2/S).
Development of Self-Supporting Polycrystalline Diamond Bridge
Authors: Csorbai Hajnalka , Kovách Gergely , Fürjes P. , Csíkvári P. , Sólyom A. , Hárs G. , Kálmán Erika
Published: March 2009

Polycrystalline diamond layers are mostly used in various fields of industrial application.
Mechanical tension is generated due to the different heat expansion coefficients of the
substrate and the layer, which leads to fracturing in some cases. In this work a homogeneous
polycrystalline diamond structure has been deposited on Si/SiO2 substrate by microwave
assisted CVD method (MW-PECVD). An selective etching technique has been used to
remove the silicon below the 2.5 micron thick diamond layer. A self-supporting diamond
structure has been created this way. Polycrystalline diamond based heaters and thermometers
can be made from doped diamond materials, which can resist corrosive and radiative
environment.
Crystallization of Fe-Ni Based Amorphous Alloy
Authors: Janovszky Dóra , Sólyom Jenő , Roósz András , Czigány Zsolt
Published: March 2009

The devitrification of the Fe-Ni-B-Si amorphous ribbon was investigated by the differential scanning calorimetry (DSC) with scanning and isothermal methods. The devitrification of rapidly quenched ribbons is a multilevel process. On the basis of DSC investigations it was determined that crystallization occurs in three processes up to 700°C in the Fe40Ni40B16Si4 alloy. In the present work the first and second steps have been discussed. The first crystallization step involves the segregation of the Fe-Ni crystalline solid solution from the amorphous matrix. During the second crystallization phase, in addition to austenite, nickel silicide and two types of iron borides crystallize as well. The ribbons were relaxed at 380°C for 2 hours, following the pre-annealing at different temperatures. Pre-annealing was performed in the DSC within the temperature range elapsing from 395°C to 420°C. The preannealing at temperatures below the first exothermal DSC peak has an effect on the crystallization processes. After the pre-annealing the samples were investigated by DSC. The DSC peak of the first crystallization step shifts to higher temperatures and decrease its enthalpy. The scanning DSC measurements, applied after the isothermal pre-annealing, were performed in order to determine the fraction of the ribbon transformed in the primary crystallization step. The second DSC peak shifts to lower temperatures with a maximum of 4°C. The X-ray diffraction (XRD) analyses reveal that the lattice constant changes with the pre-annealing temperatures. Such observation was also supported by the circumstance that the composition of the Fe-Ni solid solution undergoes certain modifications.
Thin Film Carbon Layers with Continously Changing Bonding Properties
Authors: Kovách Gergely , Pető Gábor , Karacs Albert , Veres M. , Csorbai Hajnalka , Sólyom A.
Published: March 2009

Polycrystalline diamond and diamond-like carbon (DLC) films were deposited by microwave chemical vapor deposition (MW-CVD) and by pulsed laser deposition (PLD) respectively. Ar ion bombardment was used to change the properties of these layers. The sp2 bonds were determined directly by reflected electron energy loss spectroscopy (REELS) and further characterization was made by Raman scattering. The polycrystalline diamond showed only very slight π-π* transition at 6.5 eV, but after Ar ion bombardment strong peak was formed but definitely shifted to lower energy compared to the well known π-π* transition of graphite. The as deposited PLD carbon films showed broad peak around 5eV clearly different than the π-π* transition (6.5eV). After Ar+ ion bombardment the peak was shifted also to lower energy range (4-5eV) with a remaining part at 6.5eV. The lower energy part of the peak can be correlated to the transition of sp3 sites, while this change in peak position was not detectable after ion bombardment of the reference HOPG sample, which does not contain sp3 hybridized carbon atoms.
Barkhausen Noise Measurements in Amorphous and Nanocrystalline FINEMET Type Alloys
Authors: Balogh Z. , Daróczi Lajos , Erdélyi Z. , Szabó S. , Juhász R. , Beke Dezső L.
Published: March 2009

Barkhausen noise properties of amorphous and nanocrystallized FINEMET type
soft magnetic materials are investigated. It is obtained that the amorphous-nanocrystalline
tranformation has a well observable effect on both the root main square, RMS, values and the
critical exponents of the probability distributions of peak heights and durations.
Characterisation of Solid Supported Nanostructured Thin Films by Scanning Angle Reflectometry and UV-Vis Spectrometry
Authors: Deák András , Hild Erzsébet , Kovács Attila L. , Hórvölgyi Zoltán
Published: March 2009

Nanostructured Langmuir-Blodgett (LB) films of Stöber-silica nanoparticles have been prepared on silicon and quartz glass substrates. The deposited layers were investigated using scanning angle reflectometry and UV-Vis spectroscopy. The reflectivity and the transmittance spectra of the LB films were evaluated using a model based on thin layer optics. Film thickness and effective refractive index of the films were determined. From the refractive index values the volume fraction of the particles in the film was estimated by effective medium approach.
The Sodium Transport in Polycrystalline Alumina
Authors: Lovas Henriett , Josepovits V. Katalin , Tóth Zoltán , Tóth M.
Published: March 2009

In this work we present the investigations on the determination of the mechanism of sodium loss in High Pressure Sodium (HPS) lamps. The transport through the ceramic arc tube consists of several steps (solution in the ceramics, diffusion through the ceramics, leaving the bulk phase, evaporation from the surface). Among the listed processes the mechanism of the diffusion was investigated by model-experiments. A ceramic arc tube was applied as a reactor chamber, in which polycrystalline ceramic plates were heated at 600-1100°C in controlled Na and Xe atmosphere. The sodium diffusion profiles developed by the heat-treatment were measured by XPS and SIMS and from the measurements we tried to draw a conclusion about the mechanism of sodium diffusion through the ceramic discharge tube. The ceramic discharge tube were measured by X- ray diffraction, too. We found traces of some Na-O-Al compound.
Fatigue Properties of Welded Joints of High-Carbon Steels
Authors: Magasdi Attila , Dobránszky János , Tusz F. , Ginsztler János
Published: March 2009

The typical tool steels of the wood-cutting industry are the unalloyed and
chromium and nickel containing, low-alloyed eutectoid steels. These materials, in tempered
condition have a very high, 1200-1400 MPa tensile strength. One of the major failure forms
of these tools is the fatigue fracture of the tool. The high pretension and the cyclic load,
caused by the cutting and the bending of the tool, easily can cause high-cycle fatigue fracture,
especially at the welded area and at the heat affected zone. Thus, one of the most critical part
in the manufacturing process of the bandsaw blade is the welding. We have examined the
fatigue properties of three types of joints: conventional and cold wire TIG welding, MIG
welding, and resistance-butt welded joints. The structure at the weld and at the heat affected
zone could highly affect the life-span of the tool. Therefore the welding parameters (preheat,
post welding heat treatment (PWHT), shield gas, backing gas), affecting the microstructure of
the weld, also have serious affects on the fatigue properties. The influence of welding
parameters on the fatigue properties were examined by low-cycle fatigue test.
Virtual TTT Diagrams Generated by Multi-Linear Regression Analysis
Authors: Dudás Zoltán
Published: March 2009

The TTT (Time-Temperature-Transformation) phase transformation diagrams based on
FEM based phase elements make it possible to create virtual TTT diagrams. In this case the virtual
TTT diagrams are results of multiple linear regression calculations. The basic TTT diagrams are
created on the basis of measured published data. Two created virtual TTT diagrams are presented
for two different austenitisation temperatures. The results of calculations are compared to the
measured ones.
On the Topological Characterization of 3-D Polyhedral Microstrutures
Authors: Réti Tamás , Csizmazia Agnes , Felde Imre
Published: March 2009

To characterize topologically the polycrystalline microstructure of single-phase alloys
computer simulations are performed on 3-dimensional cellular models. These infinite periodic
cellular systems are constructed from a finite set of space filling convex polyhedra (grains). It is
shown that the appropriately selected topological shape factors can be successfully used for the
quantitative characterization of computer-simulated microstructures of various types.
Choosing a Laser-Cutting Technology to be Applied to a Deep-Drawn Product
Authors: Grum Janez , Kek Tomaž
Published: March 2009

Residual stresses are an inevitable result of mechanical and heat treatments of steel. The stress field
generated at the surface and through the cross section of a product is usually non-uniform, and there
can be important stress gradients. In general residual stresses can be defined as self-balanced
internal stresses existing in a free body on which no external forces are acting. In the present study
the focus was on the residual stresses occurring in a steel deep-drawn product of a complex form.
The residual stresses occur mainly because of different degrees of plastic deformation at different
locations. The residual stresses occurring in the product as a result of the manufacturing process of
deep drawing can be comparatively strong. In slitting or cutting a useful product out of a deepdrawn
part by laser cutting, a portion of the residual stresses will get relieved and produce distortion
of the deep-drawn product. The studies made showed that the distortion of the deep-drawn product
depended on the mode of cutting-out. Also the state of the residual stresses after slitting or cuttingout
of the deep-drawn product will depend on the mode of cutting-out, i.e., on the sequence of
individual cuts chosen.
The product used in the analysis made was a deep-drawn steel mud-guard, which makes a
component part of a working machine. The various modes of cutting-out a useful product of
1260x800x370 mm in size were performed with laser cutting using cutting oxygen. The residual
stresses in the mud-guard were determined with a semi-destructive hole drilling strain gage method.
The EAF Slag as Construction Material
Authors: Márkus Róbert , Grega Oszkár
Published: March 2009

The metallurgical slag is a normal building material in Europe but not in
Hungary. I prove by my own researches that the electric arc furnace slag isn’t harmful
to the nature especially the ground water and their physical aspects are similar to the
natural rocks. It means that we can use slag to replace them to save our environment
and to clear away the old slag dumps.
Carbon Nanotubes as Ceramic Matrix Reinforcements
Authors: Balázsi Csaba , Czigány Zsolt , Wéber Ferenc , Kövér Zsuzsanna , Kónya Zoltán , Vértesy Zófia , Biró László Péter , Kiricsi Imre , Arató Péter
Published: March 2009

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Thermodynamic Assessment of the Al-Cr System by Combining the First Principles and CALPHAD Methods
Authors: Tokunaga T. , Ohtani Hiroshi , Hasebe Mitsuhiro
Published: March 2009

Thermodynamic assessment of the Al-Cr system has been carried out by incorporating
first-principles calculations into the CALPHAD approach. A regular solution approximation was
adopted to describe the Gibbs energy of the solution phases. The several phases appearing in the
composition range between about 30 and 42 at.%Cr were treated as a single homogeneous γ-phase,
based on recent experimental results, and the Gibbs energy of the γ-phase was represented using the
four-sublattice model with the formula (Al,Cr)8(Al,Cr)8(Cr)12(Al)24. The calculated results enable the
reproduction of experimental results on both the phase equilibria and thermochemical properties. In
addition, a B2 ordered bcc phase, which was suggested to form as an equilibrium phase in a previous
X-ray diffraction study, is not likely to form in either the stable state or metastable state based on our
first-principles calculations.
Brazing of CP-Titanium / CP-Titanium and Titanium Alloy / Stainless Steel with Laminated Ti-Based Filler Metal
Authors: Miyazawa Y. , Chang C.S. , Sato H. , Suda Jun , Hiraoka T. , Kanda Kiichi , Ariga T.
Published: March 2009

Joining technology of CP-Titanium and Titanium alloy is very important for manufacturing
field. In that case of titanium brazing, chemical compositions of brazing filler metal and brazing
atmosphere are very important. In this study, CP-Ti/CP-Ti and Ti alloy/Stainless Steel were brazed
with Ti-based laminated brazing filler metal by using continuous type furnace under Ar gas
atmosphere containing extremely low oxygen.
Laminated filler was fabricated by roll bonding technology. Chemical compositions of
laminated filler metal used in this study were Ti-15Cu-15Ni and Ti-20Zr-20Cu-20Ni. Brazing
temperature employed in this study was 850, 900, 950, and 1000 C. These brazing temperatures were
based on thermal analysis results and alpha-beta transformation temperature of the base metal used in
this study. Firstly melting properties of laminated brazing filler metal was investigated with DTA and
DSC. Secondary joint characteristics were estimated by micro-structural observation at the joint and
mechanical properties measurement.
Sound joint was obtained in this study according to outside appearance of the specimen.
Ti-20Zr-20Cu-20Ni filler had low melting point as compared with Ti-15Cu-15Ni according to
thermal analysis results and fillet form-ability. Ni and Cu were diffused from molten brazing filler to
base metal during brazing and Ti-Cu-Ni eutectoid reaction was took placed at the based metal during
cooling after brazing.
Evaluation of Capping Materials for the Stabilization of Contaminated Sediments
Authors: Yun Sang Leen , Kim So Jung , Park Yong Jin , Kang Sung Won , Kwak Pill Jae , Ko Jae Jung , Ahn Jae Hwan
Published: March 2009

With the development of economic status and living standard, eutrophication of lakes has
become serious problem. Due to continuous inflow of external nutrients into lakes, phosphorus, a
critical nutrient for lake production, has been accumulated in large amount in the sediment. Thus
phosphorus rich sediment acts as an internal nutrient source and reduction of phosphorus release from
the sediment is very important for restoring eutrophied lakes. Among the various strategies to restore
lakes, in-situ capping is known as an attractive and cost-effective method for remediation of
contaminated sediments. In this paper, lab-scale batch column test was conducted to evaluate the
characteristics of capping materials on reduction of phosphorus release from the sediment. Three
different types of capping materials including sand, zeolite, and natural gypsum (CaSO4·2H2O) were
used. Each column was filled 7 cm with sediment and covered by 1 cm of sand, zeolite, and natural
gypsum, respectively. The change of water quality in supernatant solution was monitored for 10 days
in each column. From the results, addition of gypsum showed higher treatment efficiency than sand
and zeolite. In case of the capping with gypsum, it was found that the phosphorous release from the
sediment could be reduced by around 90% as compared with untreated column. On the contrary,
phosphorus reduction efficiencies of sand and zeolite were 60% and 14%, respectively. Moreover, in
case of the capping with sand and zeolite, sudden increase of phosphorus concentration was observed
with the generation of CH4 gas from sediment. Methanobacterial ebullition is one of the important
factors for transporting phosphorus from sediment into water column. It was reported that the
addition of gypsum could reduce the progress of methanogensis by supplying sulfate into sediment,
which enhances the activity of sulfate-reducing bacteria (SRB) and mineralization rate of organic
matter.
Utilization of Waste Tires to Reduce Railroad Vibration
Authors: Cho Sam Deok , Kim Jin Man , Kim Ju Hyong , Lee Kwang Wu
Published: March 2009

This study proposes a means to recycle waste tires as a material to reduce ground vibration.
A series of field experiments was carried out to assess the reduction effect of railroad transport
vibration by utilizing waste tire chips. The ground vibration during the railroad transport operation
was measured in two railroad lines to investigate the vibration characteristics prior to field model
tests. Test results showed that the frequency of vibration induced by railroad transport ranged from
5Hz to 100Hz, while the dominant frequency was within the range of 20Hz to 40Hz. A series of field
model test was carried out by using tire chips (5cm×5cm in size) as a reduction material for railroad
vibration. The field experiment results showed that the reduction effect of waste tires for railroad
vibration increased with increasing thickness of the waste tire layer and increasing frequency of the
vibration source. From these experimental results, it can be concluded that waste tires can be recycled
effectively for reduction of railroad.
New Perspectives for Wrought Magnesium Alloys
Authors: Bohlen Jan , Letzig Dietmar , Kainer Karl Ulrich
Published: March 2009

In view of the increasing needs for efficient usage of natural resources and environmental
protection in our modern society, weight reduction in transportation such as cars, trains or aircrafts is
of fundamental interest. In order to solve this major issue, improved concepts are necessary which
also emphasize the usage of light weight materials in construction. Especially magnesium and its
alloys as the lightest available constructional metals have a major potential in this regard. Since
magnesium cast components have found their application, interest is now spreading towards wrought
alloys for use as structural components. However, the use of wrought magnesium alloys in the
transportation industry is still limited at present. In this paper we give an overview on the present state
of the art as well as on specific requirements for the processing of wrought magnesium alloys. We will
show the technical potential in terms of improved economic aspects for wrought magnesium and
discuss research topics such as process-specific alloy design.
Exfoliation Corrosion Behavior of 2524 Aluminum Alloy
Authors: Yang Sheng , Yi Dan Qing , Yao Su Juan , Hou Ya Ping
Published: March 2009

The exfoliation corrosion behavior of 2524 aluminum alloy was studied by Transmission
Electron Microscope (TEM), hydrogen evolution and Electrochemical impedance spectroscopy (EIS)
. The results showed that 2524 aluminum alloy was very susceptible to exfoliation corrosion and the
exfoliation corrosion appeared after 24 h. EIS could better explain the exfoliation corrosion than
hydrogen evolution. Exfoliation corrosion kinetics included accelerated formation of pitting, quick
development of pitting, retarded formation of exfoliation and steady development of exfoliation.
Effects of Particle Size on Microstructure of the Matrix Alloy in Aluminum Matrix Composites
Authors: Jiang Long Tao , Wu Gaohui , Zhao Min , Zhang Qiang , Kouno Norio , Saito Hideo
Published: March 2009

Aluminum matrix composites, reinforced by 0.15μm and 5μm Al2O3 particles with 40%
volume fractions were fabricated by squeeze casting technique. The microstructure characterization
near the interfaces of Al2O3p/1070Al composites was investigated by SADP and HREM techniques.
Results showed that high-density dislocations were generated in the 5μm-Al2O3p/Al composite due
to the thermal mismatch stress. In contrast, the matrix of the 0.15μm-Al2O3p/Al composite appeared
to be nearly free dislocations and some “micro distortion areas” of 1-5nm were observed, which
was attributed to the dispersion of fine sub-micron particles and uniform distribution of the stress
near the interfaces.
Formation and Characterization of the Quasicrystal Films
Authors: Zhou Xi Ying , He Liang , Liu Yan Hui
Published: March 2009

Al-Cu-Fe quasicrystals powder was used to prepare the thin films on the surface of the A3
steel by the means of DMD-450 vacuum evaporation equipment. The thin films with different
characterization were obtained through different parameters. The microstructures of the thin films
were analyzed by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Additionally,
the nano-hardness and the modulus of the films are tested by MTS and Neophot micro-hardness
meter. The results showed that the modulus of the films was about 160GPa. Nano hardness of the
films was about 7.5 Gpa. The films consisted of CuAl2, AlCu3. The thickness and the micro-hardness
of the films are improved. In same way, with the increase of the electric current, the thickness and the
hardness of the films are also improved. Along with increase of the time and the electric current, the
wear behavior of the films was improved. To some extent, the microstructure of films contained the
quasicrystal phase of Al65Cu20Fe15.
Optimizing Solution Heat Treatment to Improve Mechanical Properties of Al Alloy 7055
Authors: You J.H. , Liu Sheng Dan , Huang Z.B. , Zhang Xin Ming
Published: March 2009

The influence of one- and two- stage solution heat treatment on the microstructure and
mechanical properties of aluminum alloy 7055 was investigated. The results showed that in the case
of one-stage solution heat treatment in the range of 450 °C to 470 °C, the strength increased while the
ductility decreased with temperature. Further increasing temperature led to more dissolution of
soluble constituents but a large amount of recrystallization, therefore, the strength decreased while
ductility increased. The two-stage solution heat treatment, which included first stage of
low-temperature-long-duration and second stage of high-temperature-short-duration heating was
suggested for improvement of mechanical properties.
Multiple Forging Textures and Microstructures in Al Alloys
Authors: Ringeval S. , Driver Julian H.
Published: March 2009

The development of deformation substructure and texture has been studied up to large plastic strains in some simple Al base alloys by multiple forging. The experiments involve successive forging strains on near-cube samples along 3 orthogonal axes up to cumulative strains of 3 or more (and temperatures from 20 to 400°C). The alloys include the commercial AA 3103 (Al- 1%Mn) and a laboratory Al-3%Mn-Sc-Zr alloy for the high temperature tests. Some complementary experiments have been carried out on oriented single crystals of Al-0.3%Mn. During 3D cross forging of fcc metals a clear texture composed of three symmetrical components is formed; they are the 3 possible variants of the <110> <110> <100> crystal axes along the 3 forging axes. This macroscopic texture is demonstrated by X-ray pole figure analysis, EBSD mapping and confirmed by crystal plasticity (CP) simulations. At room temperature the alloys (particularly Al-Mn) exhibit significant grain refinement by grain fragmentation leading to "grain sizes" of less than 103m. However, at temperatures ≥ 300°C in the stable Al-3%Mn-Sc-Zr alloy the lattice rotations towards just 3 texture components leads to a high frequency of grain "fusions"; each grain becomes surrounded by 3-5 neighbours of the same orientation so that long interpenetrating chains of the texture components are formed; they are also confirmed by FEG-SEM EBSD and spatially resolved texture simulations. The behaviour of stable (Goss) and unstable (cube) single crystal orientations during the same deformation processing is also investigated and shown to agree with the CP simulations.
Recent Progress in the 3D Experimentation and Simulation of Nanoindents
Authors: Zaafarani N. , Roters Franz , Raabe Dierk
Published: March 2009

This work studies the rotations of a (111) Cu single crystal due to the application of a conical nanoindent. With the aid of a joint high-resolution field emission SEM-EBSD set-up coupled with serial sectioning in a focused ion beam (FIB) system in the form of a cross-beam 3D crystal orientation microscope (3D EBSD) a 3D rotation map underneath the indent could be extracted. When analyzing the rotation directions in the cross section planes (11-2) perpendicular to the (111) surface plane below the indenter tip we observe multiple transition regimes with steep orientation gradients and changes in rotation direction. A phenomenological and a physically-based 3D elastic-viscoplastic crystal plasticity model are implemented in two finite element simulations adopting the geometry and boundary conditions of the experiment. While the phenomenological model predicts the general rotation trend it fails to describe the fine details of the rotation patterning with the frequent changes in sign observed in the experiment. The physically-based model, which is a dislocation density based constitutive model, succeeded to precisely predict the crystal rotation map compared with the experiment. Both simulations over-emphasize the magnitude of the rotation field near the indenter relative to that measured directly below the indenter tip. However, out of the two models the physically-based model reveals better crystal rotation angles
Evolution of the Deformed Substructure Obtained by Cold-Rolling in IF Steel
Authors: Wauthier Aurelie , Réglé Hélène , Brenner Rénald
Published: March 2009

The aim of this study is to acquire more quantitative data on the cold-deformed state, in order to determine the key parameters for nucleation (like orientation gradient, dislocation density, degree of fragmentation…) and to correlate these to parameters which can be predicted by a mean field deformation model. Experimentally, a Ti-IF hot band has been deformed by cold rolling up to 51%. The deformed microstructures are finely characterised using EBSD inside the SEM. It appears then that the heterogeneity of deformation inside the grains begins very early. Some grains undergo fragmentation whereas some others deform very homogeneously. Misorientation and degree of fragmentation are found to be orientation and rolling level dependent. These deformation parameters are plotted against the Taylor factor, calculated in each grain.
Deformation Processing of Sheet Metals by Continuous Frictional Angular Extrusion
Authors: Huang Yan , Prangnell Philip B.
Published: March 2009

The feasibility of a novel continuous severe plastic deformation (SPD) technique, continuous frictional angular extrusion (CFAE), for producing ultra-fine grained strip material, has been studied. The CFAE technique takes advantage of facets of rolling and equal channel angular extrusion (ECAE) and is designed to produce bulk ultra-fine grained (UFG) metals with high productivity and low cost. A process setup was established through the modification of a standard rolling mill. CFAE processing of commercially pure aluminium AA1050 sheets was successfully carried out at room temperature, using a 120o die angle. A uniform UFG structure with an average grain size of ~0.6μm was achieved after 10 CFAE passes, at an equivalent strain of ~ 6.6. Evolution of the deformation structure and texture during processing was examined as a function of strain and characterized using high resolution EBSD.
General Principles of Substructure Inhomogeneity, Arising in Metal Materials under Plastic Deformation
Authors: Perlovich Yuriy , Isaenkova Margarita , Fesenko Vladimir
Published: March 2009

The substructure inhomogeneity of real textured metal materials was studied by use of
the X-ray method of Generalized Pole Figures. Main regularities of substructure inhomogeneity
were revealed for the first time. Substructure conditions of grains in rolled material form an
extremely wide spectrum and vary by passing from texture maxima to texture minima, where
residual deformation effects are most significant. The distribution of residual elastic microstrains in
the orientational space of rolled material shows the distinct cross-wise system, consisting in
alternation of quadrants with predominant microstrains of opposite signes.
The Role of Austenite Grain Misorientation on Ferrite Nucleation in an Fe-Cr-Ni Alloy
Authors: Landheer H. , Offerman S. Eric , Petrov Roumen H. , Kestens Leo
Published: March 2009

The relationship between the misorientation of the austenite crystallites and the favoured
sites for ferrite nucleation has been investigated. Ex-situ EBSD measurements were performed on
an especially developed high purity ternary iron alloy with 20 wt.% Cr and 12 wt.% Ni with both
austenite and ferrite present at room temperature to measure the misorientation between the
austenite crystallites. The experimental results are compared to the nucleation models of Clemm and
Fisher and Aaronson and co-workers.
Recrystallisation Behavior of Cold Rolled Zr702: Influence of Rolling Direction and Thickness Reduction
Authors: Gerspach Francois , Bozzolo Nathalie , Wagner Francis
Published: March 2009

Zirconium alloys are widely used for different applications in nuclear industry. Precise knowledge of their texture is of great relevance since this hcp metal exhibits a strong crystal anisotropy. Despite that, the mechanisms of texture change during its deformation and subsequent annealing are still not precisely known. Thus, there is a need for a better understanding of the fundamental mechanisms of recrystallisation. Earlier works on Zr702 [1-3] suggested that the kinetics and local mechanisms of recrystallisation after cold-rolling was controlled by the heterogeneity of the deformed microstructure and that, at the end of recrystallisation (corresponding to the disappearance of the deformed matrix), the position of the major texture components remained almost unaffected. The aim of the present work is to confirm whether these statements can be generalized for various deformation conditions or not.
Study of Grain Growth Kinetics in Submicrocrystalline Armco-Iron
Authors: Aleshin A.N. , Arsenkin Alex M. , Dobatkin Sergey V.
Published: March 2009

The paper is devoted to the problem of thermal stability of ultra-fine grained
(submicrocrystalline) materials prepared by severe plastic deformation. A basis of the paper lies in a
fact that there is practically no grain growth in submicrocrystalline materials when annealing
temperature is less than 0.35Tm. Reasons of high thermal stability of submicrocrystalline materials
at low temperatures are widely discussed in literature. One of them is the affect of triple junction
drag on grain boundaries motion. During annealing at a low temperature triple junction drag
controls microstructure evolution in submicrocrystalline materials, and this phenomenon can be
used to improve their thermal stability at high temperatures. The aim of this paper is to investigate
grain growth kinetics in a two-step regime, low temperature and high temperature annealing. The
experiments on grain growth were performed in submicrocrystalline Armco-iron fabricated by high
pressure torsion. It is established that long-time low temperature pre-annealing reduces the grain
growth rate in following high temperature annealing by a factor greater than two.
Overview of Texture Evolution during Friction Stir Welding of Stainless Steel Using Crystal Plasticity and EBSD
Authors: Cho Jae Hyung , Boyce Donald E. , Dawson Paul R.
Published: March 2009

Texture evolution during friction stir welding of stainless steel was investigated using both
predictions by crystal plasticity and EBSD measurements. Two- and three-dimensional Eulerian
formulations are used to model friction stir welding. Plane strain deformation is assumed in a
two-dimensional model, and an initial uniform texture changes into a torsion texture with monoclinic
sample symmetry after deformation. Around the tool pin, the texture strengthens, weakens and
restrengthens repeatedly. It is found from a simple circular streamline model that the relative
magnitudes of the deformation rate and spin along the streamlines decide textural stability. In order to
consider more complicated material behaviors, such as movement along the thickness direction due
to a threaded tool pin and a tool shoulder, a three-dimensional Eulerian formulation is also
implemented. Materials starting under the tool shoulder travel down to the bottom, producing the
longest material streamlines. Those material points are predicted to have stronger texture components
than others. EBSD results are compared with the predictions.
Tracing the Goss Orientation during Deformation and Annealing of an FeSi Single Crystal
Authors: Dorner Dorothée , Adachi Yoshitaka , Tsuzaki Kaneaki , Zaefferer Stefan
Published: March 2009

A Goss-oriented single crystal was cold rolled up to 89 % thickness reduction, and
subsequently annealed at 550°C or 850°C. During deformation most of the initially Goss-oriented
material rotated into the two symmetrical {111}<112> orientations. In addition, Goss regions were
observed related to microbands or microshear bands. Goss regions in microshear bands formed
during straining, whereas Goss regions between microbands were retained from the initial Goss
orientation. The recrystallisation texture for annealing temperatures of both 550°C and 850°C is
characterised by a Goss texture. However, the origin of the Goss recrystallisation nuclei appeared to
be different for the different annealing conditions. In the material annealed at 550°C, the Goss
texture originated from the Goss regions in the microshear bands. In contrast, for an annealing
temperature of 850°C, the Goss grains between the microbands are likely to form recrystallisation
nuclei.
Deformation Structure and Texture Transformations in Twinned Fcc Metals: Critical Role of Micro- and Macro- Scale Shear Bands
Authors: Paul Henryk , Driver Julian H.
Published: March 2009

Microstructure and texture development in twinned fcc metals is investigated in order to
characterize the influence of micro- and macro-scale brass-type shear bands (SB) on structural and
textural changes at large deformations. TEM and SEM analyses are focused on bands developed by
plane strain compression in twinned C{112}<111> oriented single crystals. The proposed
crystallographic model of the shear banding phenomenon refers to the idea of local lattice reorientation
within narrow areas. Most of these rotations occur around the TD||<110> axis with
significant further rotations about <112> poles. These two rotations explain the influence of SB’s on
the formation of Goss{110}<001> and brass{110}<112>-S{123}<634> texture components clearly
observed in highly deformed low SFE metals. At high deformations symmetrically equivalent
crystal lattice rotations inside narrow areas lead to the formation of positive and negative
macroscopic SBs.
A Study of Texture Evolution during Deformation and Annealing in Fe 3 wt.-% Si by Orientation Contrast Microscopy
Authors: Rodriguez-Calvillo Pablo , Petrov Roumen H. , Houbaert Yvan , Kestens Leo
Published: March 2009

Electrical steels, in particular Fe-Si alloys, are used as magnetic flux carrier in transformers and motors because of their excellent magnetic properties. They owe these magnetic properties in part to the presence of specific texture components such as the Goss ({110} <001>) or the cube components ({001} <010>), but also to the chemical composition which is optimum with 6.5 wt. % Si. This high silicon content provides a stable BCC lattice structure to the alloy over the entire solid state domain, but also renders the material more brittle. This embrittlement, which is induced by ordering phenomena, makes it impossible to produce the alloy in a conventional rolling process unless a specific thermomechanical route at high temperature is applied. In order to examine the working behaviour of high Si electrical steels, a series of room temperature plane strain compression tests was carried out on a Fe-3%Si alloy in hot band condition. The samples were compressed with a constant strain rate of 20 s-1 to a reduction of 10, 35 and 70% and subsequently annealed for different times at 800 and 900°C in an electrical furnace without protecting atmosphere. The hot rolled microstructure displayed an average grain size of 195 7m and the texture showed on the cube component ({001} <010>) of maximum 5x random levels. After plane strain compression the samples developed the conventional α (<110> // RD) / γ (<111> // ND) fibre texture by plastic shear which was also accommodated, in part, by mechanical twinning. With regard to the annealed material, it was observed that the recrystallisation started in grains with the higher stored energy and within the shear bands. After a reduction of 70% the samples that were annealed at 800°C for 4 hours displayed an average grain size of 27 7m and a relative maximum of 4x random on the cube component. Also other less intense components such as the rotated cube ({001} <110>) and the Goss ({110} <001>) were present in the annealing texture. The samples that were annealed at 900°C, after a reduction of 70%, were characterized by an average grain size of 36 7m and by the appearance of the {111} <121> γ fibre component with an intensity of 4.7.
Plastic Deformation of Zr-Based Alloys at Temperatures of Phase Transformations
Authors: Isaenkova Margarita , Perlovich Yuriy , Fesenko Vladimir , Htike Thant Zaw , Kropachev S. , Akhtonov S. , Filippov V.
Published: March 2009

Deformation behavior of Zr-Nb alloys under uniaxial compression, accompanied by
phase transformations, is considered by the example of Zr-1%Nb and Zr-2.5%Nb alloys. Model
samples were deformed at temperatures of β- and (α+β)-regions of the phase diagram Zr-Nb.
Mechanisms, responsible for plastic deformation of alloys by different temperature-rate regimes,
were determined on the basis of textures, arising in deformed samples. Among these mechanisms
there are crystallographic slip in grains of β-Zr and α-Zr as well as mutual displacements of
crystallites along interphase boundaries. The latter mechanism sharply intensifies under conditions
of α↔β phase transformations and lies in the basis of superplasticity. An input of each mechanism
into plastic deformation of material depends on the temperature-rate regime of compression and
determines its anisotropy.
Correlating Microstructural Features and Surface Roughening in Ferritic Stainless Steel
Authors: Knutsen R.D.
Published: March 2009

The surface ridging behaviour during tensile straining has been characterised for two ferritic stainless steels possessing different austenite potentials (0.1 and 0.6 respectively). Microstructural and texture heterogeneities have been detected to different levels in each steel and are used to explain the extent of surface ridging by considering a ridging mechanism arising from differential transverse strains. Orientation images are presented to trace the development of orientation clusters during recrystallisation.
Analysis of Different Specimen Geometries for Tensile Tests in Superplastic Conditions for an Aluminium Alloy
Authors: Sorgente Donato , Tricarico Luigi
Published: March 2009

Different geometries of tensile test specimens have been analyzed to get information about
the variability of the measured physical quantities during tensile tests in superplastic conditions. A
commercial aluminium alloy (AA5083) sheet has been used for the experimentation. The influences
of main geometrical parameters on the elongation to failure, the measured stress and other test
responses have been investigated using a universal testing machine and a split furnace. A numerical
model has been used to better understand deformation phenomena involved in tensile tests.
Two Different Approaches for the Effective Conductivity Investigation of 2D Porous Materials with Temperature Dependent Material Properties
Authors: Pesetskaya Ekaterina , Fiedler Thomas , Öchsner Andreas
Published: March 2009

The effective conductivity of 2D porous materials with temperature dependent
matrix properties is investigated by two different approaches: namely, a numerical and an
analytical method. A model with disjoint parallel cylindrical pores in a representative cell is
considered. The numerical method is represented by the finite element method. In the scope
of the analytical method, the nonlinear boundary value problem which describes conducting
properties of the materials is solved by the methods of complex analysis, and the effective
conductivity is represented in an explicit form via the solution of this problem. The values of
the effective conductivity obtained by two these methods are compared.
SPH as an Inverse Numerical Tool for the Prediction of Diffusive Properties in Porous Media
Authors: Sousa Antonio C.M. , Jiang Fangming
Published: March 2009

Heat and mass transfer and fluid flow in porous media are usually characterized by, or
associated with, the effective thermal conductivity, the effective mass diffusivity and the
permeability, respectively. All these macroscopic quantities are conceptually established on a
phenomenological “equivalence” basis. They may contain the influence of porous micro-structures
upon the corresponding diffusive process; however, the detailed nature inside the porous medium is
lumped and neglected. Pore scale numerical modelling has the potential of providing adequate
meso-/micro- scale insight into the transport process in porous medium, as well as obtaining
macroscopic properties, which can encompass the complex pore-structure details. Modelling
heat/mass transfer and fluid flow in complicated porous micro-structures presents a major challenge
to numerical methods due to their multiscale and multiphysics nature. A relatively-novel numerical
technique - the meshless Lagrangian-based Smoothed Particle Hydrodynamics (SPH) method is
thought to be capable of making a significant contribution to this research field. This work deals
primarily with the SPH modelling of heat conduction and fluid flow in 2-D isotropic porous media.
The porous matrix is formed by randomly including a different component into a base component.
Various pore-structures are realized by changing the inclusion shape/size, or the relative
arrangement condition between inclusions. Pore-scale heat transfer and fluid flow streams are
visualized, and both heat transfer and fluid flow always follow, as expected, the paths of least
resistance through the porous structures. In what concerns the effective thermal conductivity, for
the porous media with the base component of larger bulk thermal conductivity, the “flexible” EMT
model, which can accommodate, to some extent, the influence from the porous micro-structures on
the effective thermal conductivity by adjusting the so-called flexible factor ff, gives effective
thermal conductivities agreeable to the SPH predictions across the whole composition range if ff is
taken to be ~ 4.5; the effective thermal conductivity shows a weak dependence on the inclusion
shape/size and the relative arrangement condition between inclusions; however, for porous media
with dispersed inclusions, which component has larger bulk thermal conductivity presents a strong
effect upon the effective thermal conductivity. The SPH fluid flow simulation results confirm the
macroscopic Darcy’s law to be valid only in the creeping flow regime; the dimensionless
permeability (normalized by the squared characteristic dimension of the inclusions) is found to have
an exponential dependence on the porosity within the intermediate porosity range, and the derived
dimensionless permeability /""porosity relation is found to have only a minor dependence on either
the relative arrangement condition between inclusions or the inclusion shape/area.
Investigation of Evaporation and Diffusion Phenomena in Porous Media
Authors: Bennacer Rachid , Sefiane Khellil
Published: March 2009

Many industrial and biological phenomena involve the evaporation of liquids in porous media. In drying processes the evaporation of a liquid meniscus from the solid is the key mechanism in the process and its efficiency. After a first steady stage of evaporation the meniscus becomes unsteady and recedes inside the pore. Diffusion of vapour becomes the controlling mechanism for evaporation in a later stage. In this work an experimental investigation is undertaken to study the various stages of evaporation of different liquids in capillary tubes (pores) of various sizes. The analysis of the data obtained from this investigation reveals some interesting behaviours and emphasizes the role played by vapour diffusion in the case of unsteady interface. The preliminary transient regime allowing the thermal field establishment, is followed by the first stage of evaporation is found to be dominated by thermocapillary effects associated with non-uniform evaporation and temperature gradients. The laste stage is a molecular diffusion-limited mode. The liquid volatility and the effect of the size of the tube (ranging from 200 to 900 μm) are also analysed to show the interaction between the various effects at different scales.
Modeling and Simulation of Resin Filling and Cure Processes in Molds Partially Filled with Porous Media
Authors: Costa Vítor A.F.
Published: March 2009

The complete and simultaneous simulation of the overall filling and curing processes is presented. Fluid flow in the porous medium is described by the Brinkman-Forchheimer flow model, and fluid flow in the clear fluid domain is described by the Navier-Stokes equations. The flow front is captured using the volume fraction concept and a compressive convective scheme. Energy conservation equation and resin conversion equation give the equations to obtain the temperature and degree of cure, respectively. The physical model is solved using a control volume based finite element method. A limited set of results is presented, showing the usefulness of the information obtained from the complete and simultaneous simulation of the overall real process.