bluuebunny/crossref_metadata_2025 huggingface dataset:
The Correlation of Texture and Microstructure to the Corrosion Resistance of Tin Coatings
Authors: Wen Shixue , Szpunar Jerzy A.
Published: March 2009

The influence of current density and temperature on the macrotexture, the orientation and size of grains, and the corrosion resistance of tin deposits was studied. Tin coatings with two different textures, (100) and (301) fiber textures were produced by electrodeposition at 20°C by varying current density. At a lower current density of 100A/m2, (301) fibre was obtained. At the current densities of 100 and up to 400 A/m2, only (100) fibre texture was observed. An increase in current density leads to a decrease in grain size. At the same current density, the grain size of tin coatings increases with increased temperature. The influence of temperature (20, 40, 60 and 80 °C) on texture is relatively negligible. The corrosion resistance of tin coatings increases with a decrease in grain size. The corrosion resistance of tin coating with (301) fibre is higher than that of tin coating with (100) fibre texture. The results suggest that texture and microstructure play an important role in controlling corrosion rate of tin based coatings.
Texture Development during Mechanical r-Value Determination
Authors: Klinkenberg Christian , Klein Helmut , Gerlach Jörg
Published: March 2009

This investigation aimed at the understanding of texture development during r-value determination by uniaxial tensile testing. Special emphasis was given to examine the texture evolution in the deformation zone of the tensile test specimen during mechanical r-value determination. The textures of different sheet steel grades were investigated in different deformation stages by the orientation distribution function (ODF) and mechanical testing.
Simulation of Earing during Deep Drawing of bcc Steel by Use of a Texture Component Crystal Plasticity Finite Element Method
Authors: Raabe Dierk , Roters Franz , Wang Yan Wen
Published: March 2009

We present a numerical study on the influence of crystallographic texture on the earing behavior of a low carbon steel during cup drawing. The simulations are conducted by using the texture component crystal plasticity finite element method which accounts for the full elastic-plastic anisotropy of the material and for the explicit incorporation of texture including texture update. Several important texture components that typically occur in commercial steel sheets were selected for the study. By assigning different spherical scatter widths to them the resulting ear profiles were calculated under consideration of texture evolution. The study reveals that 8, 6, or 4 ears can evolve during cup drawing depending on the starting texture. An increasing number of ears reduces the absolute ear height. The effect of the orientation scatter width (texture sharpness) on the sharpness of the ear profiles was also studied. It was observed that an increase in the orientation scatter of certain texture components entails a drop in ear sharpness while for others the effect is opposite.
Texture-Based Explicit Finite-Element Analysis of Sheet Metal Forming
Authors: Ristić Svetlana , He S. , Van Bael Albert , van Houtte Paul
Published: March 2009

An explicit integration algorithm using a texture-based plastic potential and isotropic hardening has been developed and implemented into a commercial explicit finite-element software program through a user material subroutine (VUMAT in ABAQUS/Explicit). Simulations of cup drawing of an IF-steel are presented and compared to both experimental data and calculation results obtained with a previously developed fully implicit approach (UMAT in ABAQUS/Standard). The explicit formulation has the advantage of being more stable, but local sheet thickness variations cannot be reproduced with the same accuracy.
Texture Evolution and Earing in Aluminium Can Sheet
Authors: Hirsch Jürgen
Published: March 2009

The texture evolution during hot and cold rolling of AlMg1Mn1 can body sheet is described and the related anisotropy effects during deep drawing are analysed quantitatively. The typical textures of rolled aluminium show the transition between ß-fibre orientations and cube recrystallization texture, depending on rolling temperature and strain. These correlate with transitions between 45° and 0°/90° ear heights in deep drawn cups which are described by a new method of Fourier series expansion. Processing parameters to achieve low anisotropy are discussed.
Effect of Annealing Temperature on Texture and Creep Anisotropy in Ti3Al2.5V Alloy
Authors: Linga Murty K. , Kishore R. , Yan J. , Scattergood Ron O. , Helsel A.W.
Published: March 2009

Effect of annealing temperature is investigated on texture and creep anisotropy in a thinwalled tubing of titanium alloy. Creep anisotropy is studied under equibiaxial loading using internally pressurized tubing superimposed with axial load while monitoring in-situ the time variations of both hoop and axial strains. Relatively weak hoop direction in the cold-worked material became stronger following complete recrystallization. The analyses of the data reveal that the anisotropy parameter, P which is the contractile strain ratio for testing along hoop direction increases from around 0.6 for the cold-worked material to around 1.5 following complete recrystallization. Results indicate that planar isotropy should occur following annealing at around 800K. Work on the effects of annealing on the textures and deformation microstructures is in progress. We summarize here results from some of our earlier work on a different lot of Ti3Al2.5V tubing in the recrystallized states where the ODFs were used in conjunction with crystal slip models to predict creep anisotropy.
Orientation Maps Derived from TEM Diffraction Patterns Collected with an External CCD Camera
Authors: Rauch Edgar F. , Duft A.
Published: March 2009

An automatic crystallographic orientation indexing procedure is developed for
transmission electron microscopes. The numerical identification is performed by mapping the spot diffraction patterns with pre-calculated templates. The diffraction patterns are acquired thanks to an external CCD camera that points to the fluorescent screen through the TEM window. Orientation maps with spatial resolution better than 10 nm were obtained with this low cost equipment.
On Probability - Statistical Representation of Pole Figures for Materials with Hexagonal Symmetry
Authors: Borovkov M.V. , Savyolova T.I.
Published: March 2009

A new method of computing of normal distributions [1] on rotation groups is suggested. Monte Carlo method allows to calculate the orientation of grains function (ODF) and correspondent pole figures (PFs) using approximation by normal distributions [2]. The developed Monte Carlo method is applied for construction of PFs mathematical statistical model corresponding to experimental measurement. This model is based on statistical simulation of normal distributions on SO(3) group for discrete representation of pole figures. It is possible to calculate effective physical properties of polycrystals using the given discrete representation. The mathematical simulation for texture with two components of polycrystalline sample with hexagonal symmetry is developed. Two experimental PFs } 0 1 10 { and } 0002 { for Be measured by X-ray experiment are being used. For this case the effective property as a tensor of elastic compliance was calculated. The mathematical simulation of PFs also allows to determine the statistical errors of pole figures measurement.
Texture Development during Final Annealing in Nonoriented Electrical Steels
Authors: Park Jong Tae , Szpunar Jerzy A. , Kim Jae Kwan
Published: March 2009

Nonoriented electrical steels have been widely used as core materials in motors and generators. For these applications low core loss and high permeability are required. The magnetic properties of these steels depend on the grain size and crystallographic texture of the annealed final products. The problems related to grain size control have been extensively investigated, while texture control has received much less attention. The technologies used to control the grain size in nonoriented electrical steels have approached to their limits. However, there is still some possibility for improvement of the magnetic properties through texture control. In order to explore this possibility, the evolution of recrystallization texture for nonoriented electrical steels with 2% Si was systematically studied. Texture change during grain growth was additionally analyzed. The formation of recrystallization texture is explained by oriented nucleation. This is supported by the fact that the area fraction of nuclei or recrystallized grains with specific orientation to all new grains remains almost constant during the progress of recrystallization. Most nuclei have a high misorientation angle of 25~55° with the surrounding deformed matrices. During the progress of grain growth, Goss and {111}<112> components are weakened and the random texture is strengthened. The grains of the Goss and {111}<112> orientations have smaller grain size than those of random orientation.
Study of Texture Development and Anisotropy of Mechanical Properties of API-X80 Line Pipe Steel for Spiral-Welded Pipe
Authors: Bae Jin Ho , Choi Shi Hoon , Kim Ki Soo , Kang Ki Bong
Published: March 2009

This study has been conducted to analyze the effect of texture and microstructure on the anisotropy of yield strength and Charpy fracture toughness of an X80 line pipe steel. The texture and microstructure were investigated by X-ray diffractometer and electron backscattered diffraction (EBSD). The yield strength and impact energy were measured along 0o (longitudinal), 30o and 90o (transverse) to the rolling direction. It was found that the microstructure of the developed steel
consisted of fine acicular and polygonal ferrite with small pearlite and martensite or retained austenite (MA constituents). The major components of textures were {332}<113> and {113}<110> orientations. In order to investigate the effect of both morphological and crystallographic texture on yield strength anisotropy, the prediction of the plastic property was carried out by using a viscoplastic self-consistent (VPSC) polycrystal model. The predicted anisotropy of yield strength with VPSC model assuming ellipsoidal grain shape was in a good agreement with experimental observation. EBSD results showed that the density of {001} cleavage planes of Charpy specimen, 30 degree to rolling direction, was the highest compared with that of other specimens. Therefore, the highest susceptibility to the cleavage fracture, i.e. increased ductile-brittle transition temperature, can be seen in the 30 degree direction.
Modelling of Recrystallisation Kinetics and Texture during the Thermo-Mechanical Processing of Aluminium Sheets
Authors: Engler Olaf , Löchte L. , Karhausen Kai F.
Published: March 2009

Computer-based alloy and process development requires integration of models for simulating the evolution of microstructure, microchemistry and crystallographic texture into process models of the thermo-mechanical production of Al sheet. The present paper focuses on recent developments in linking softening modules that simulate the progress of recovery and recrystallisation with the following texture changes to deformation and microchemistry models. The potential of such coupled simulations is illustrated by way of the thermo-mechanical processing of Al-Mg-Mn alloys. In particular, the progress of recrystallisation during coil cooling (“self-annealing”) as well as the texture differences between production on a reversible rolling mill and a high-speed tandem line are explored.
Evolution of Texture in Zirconium Alloy Tubing during Processing
Authors: Allen V.M. , Preuss Michael , Robson Joseph D. , Comstock R.J.
Published: March 2009

Electron backscattered diffraction (EBSD) has been used to determine microtexture in a zirconium alloy tube subject to interrupted pilgering and therefore exhibiting varying amounts of deformation as a function of axial position along the transition between the initial and final size. Texture and hardness measurements have been made as a function of the distance through the tube wall thickness and along the tube length. Texture results have been compared with co-located hardness
measurements. The results show a systematic variation in the deformation texture with changes in Q (the ratio of the reduction in thickness to reduction in diameter). This is consistent with previous observations of the effect of Q on texture evolution in zirconium alloys. It is demonstrated that the texture measurements can be correlated well with the anisotropy in strength determined from
hardness measurements.
Heterogeneity of Deformation in Pure Ni Single Crystal of Cube Orientation Deformed by Equal Channel Angular Extrusion
Authors: Goran D. , Fundenberger Jean-Jacques , Suwas Satyam , Bouzy Emmanuel , Tóth László S. , Skrotzki Werner , Grosdidier Thierry
Published: March 2009

Texture and microstructure were investigated after 1 pass equal channel angular extrusion (ECAE) of a single crystal cube oriented Ni billet. Neutron and X-ray diffraction were used to determine global and local textures, respectively. EBSD and TEM investigations were also carried out in order to study fine scale microstructural features. Substantial variations in texture and microstructure, resulting from different efficiencies in the shearing process, were locally recorded through the billet height. The deformation was heterogeneous on both micro and macro scales.
Equal Channel Extrusion Heterogeneities in Recrystallized Copper
Authors: Necker C.T. , Alexander D.J. , Beyerlein Irene J.
Published: March 2009

Various processing routes have been studied to develop the most efficient route toward microstructure refinement and texture homogenization. Most studies have focused on the central shear zone in round or square cross-section rods. However, the utility or application of these materials is subject to conditions across the entire rod. This study begins to investigate the development of recrystallization textures and microstructures across copper ECAE processed via route Bc through 16 passes. Although the recrystallized condition appears to be reasonably homogeneous after 4 or 8 passes, additional passes lead to stronger, heterogeneous recrystallization textures and coarsened microstructures.
Analysis of Textures of Wires Drawn in Pressure and Roller Dies with ODF
Authors: Pilarczyk Jan W. , Nitkiewicz Zygmunt , Kucharska Barbara , Małecki T.
Published: March 2009

In the work orientation distribution functions (ODF) were determined for wires drawn in pressure and roller dies from a high carbon steel wire rod with a diameter 5.5 mm to wires with a diameter 3.8 mm and 3.0 mm. For a comparison ODFs for wires drawn conventionally were also determined. The texture was measured on the cross sections of investigated wires prepared in a form of squares to eliminate the effect of the surface layer. In the first stage of a drawing with a total reduction of 54.3% it has been found that in wires drawn conventionally (KI), in pressure dies (HI) and in roller dies (RI) a strong <110> fibre-texture exist with a value of the ODF equal to about 3.2 for all tested wires. At an increase of the total reduction from 54.3% to 71.5% values of ODF were different for different methods of drawing. For wires with a diameter 3.0 mm drawn conventionally (KF) it was equal 4.25 and for wires drawn in pressure dies (HF) the ODF value was the highest and equal to
4.4. For wires drawn in roller dies the ODF value was the lowest and equal only to 2.6. It means that in spite of the increase of the total reduction roller die drawing results in a decrease of the sharpness of the fibre texture <110>. In conventional drawing and in pressure dies drawing an increase of the <110> texture has been noticed with the increase of the total reduction. In addition to a strong <110> texture component, specimens K and H also featured weak <311> and <310> components. In R specimens there were more of such additional components after the first stage of drawing i.e. <311>, <310>, <210>, <211> and after the second stage of drawing (total area reduction 71.5%) - <311>, <310>.
The Alignment of Low Angle Boundaries during Deformation
Authors: Humphreys John F. , Bate Pete S.
Published: March 2009

Two methods of automatically determining boundary alignments from EBSD maps are discussed and shown to produce comparable results. Measurements of Al-0.1Mg and IF steel, deformed at room temperature, confirm that the alignment of low angle boundaries is primarily a function of the deformation mode, rather than the crystallography. During the high temperature deformation of aluminium, the lagbs maintain a large angle of inclination to the rolling direction (>35o) even at large strains, which is consistent with the boundaries being of transient character during
deformation.
Computational Fluid Dynamics Techniques for Flows in Lapple Cyclone Separator
Authors: Lacerda A.F. , Vieira Luiz Gustavo Martins , Nascimento A.M. , Nascimento S.D. , Damasceno João Jorge Ribeiro , Barrozo Marcos A.S.
Published: March 2009

A two-dimensional fluidynamics model for turbulent flow of gas in cyclones is used to evaluate the importance of the anisotropic of the Reynolds stress components. This study presents consisted in to simulate through computational fluid dynamics (CFD) package the operation of the Lapple cyclone. Yields of velocity obtained starting from a model anisotropic of the Reynolds stress are compared with experimental data of the literature, as form of validating the results obtained through the use of the Computational fluid dynamics (Fluent). The experimental data of the axial and swirl velocities validate numeric results obtained by the model.
Computational Fluid Dynamics Applied to Bradley Hydrocyclones
Authors: Vieira Luiz Gustavo Martins , Damasceno João Jorge Ribeiro , Barrozo Marcos A.S.
Published: March 2009

Hydrocyclones are centrifugal devices employed on the solid-liquid and liquid-liquid separation. The operation and building of these devices are relatively simple, however the flow inside them is totally complex and its prediction is very difficult. The fluid moves on all possible directions (axial, radial and swirl), the effects of turbulence can not negligible and an air core along the center line of the hydrocyclone can appear when the operational conditions are favorable. For that reason, the most models that are used to predict the hydrocyclone performance are empirical and require the collection of the main operational and geometric variables in order to validate them. This work objectified to apply Computational Fluid Dynamics (CFD) on Bradley Hydrocyclone and compare the results from this technique to empirical models. The numerical simulation was made in a computational code called Fluent® that solves the transport equation by finite volume technique. The turbulence was described by Reynolds Stress Model (RSM) and the liquid-gas interface was treated by Volume of Fluid Model (VOF). In agreement with the results from the simulation, it was possible to predict the internal profiles of velocity, pressure, air core, particle trajectories, efficiencies, pressure drop and underflow-to-throughput ratio.
Characterization of Strontium Ferrites Powders Obtained by High Energy Milling
Authors: Paulin Filho P.I. , Corrêa R.R.
Published: March 2009

Strontium ferrites powders were obtained by high energy milling process after calcinations of iron oxide and barium carbonate. Phase formations and crystallite size was determined using X-ray diffraction. Morphology, particle size and agglomeration stages were analyzed using scanning and transmission electron microscopy. Results show particles in the range of 14 to 40 nanometers, large agglomerates and crystalline phases formation.
Characterization of Ti-35Nb-7Zr-5Ta Alloy Produced by Powder Metallurgy
Authors: Taddei Elisa B. , Henriques Vinicius André Rodrigues , Silva Cosme Roberto Moreira , Cairo Carlos Alberto Alves
Published: March 2009

Abstract: Titanium and titanium alloys present the highest biocompatibility among metallic biomaterials. The ideal titanium alloy for orthopedic applications should have low modulus of elasticity (near the bone), excellent mechanical strength, high corrosion resistance, formability and no potential toxic elements. Among titanium alloys, the Ti-35Nb-7Zr-5Ta alloy, due its high biocompatibility and lower Young’s modulus is a promising candidate for implants material. The titanium alloys production by powder metallurgy, starting from the elementary powders, is a viable route due at the smaller costs and larger operational facilities. The Ti-35Nb-7Zr-5Ta samples were manufactured by blended elemental method from a sequence of uniaxial and cold isostatic pressing with subsequent densification by sintering between 900 at 1700 °C, in vacuum, under a heating rate of 20 °C×min-1 for 1h. The objective of this work is the analysis of alloy microstructural evolution from the powders dissolution under the increase of the sintering temperature. For the alloy microstructural characterization, scanning electron microscopy and Vickers microhardness measurements, were used. Density was measured by Archimedes method. The samples presented high densification, an homogeneous microstructural development, with complete dissolution of alloying elements in the titanium matrix with the temperature increase.
Alkaline Activation of Kaolinitic Soils for the Production of Special Binders
Authors: Dias D.P. , Soares Amilcar , Viana C.E. , Soares J.C. , Azevedo P.H.B.
Published: March 2009

The alkaline activation of Portland cement based materials, ground granulated blast furnace slag and pozzolans has been accomplished with success since the decade of 40, in several countries. The practicability of the use of the alkalis opens new opportunities for the production of special binders with properties different from those presented by the ordinary Portland cement.
Besides the chemical composition, the mechanical strength of these alkali-activated materials depends a lot on the reactivity of the raw material, property that is influenced mainly by the specific surface area and crystalline degree of the raw material.
Thus, an experimental program was carried out aiming at evaluating the influence of these variables in the compressive strength, at 3, 7 and 28 days of age, for mortars manufactured using alkaline activation of kaolinitic soils.
The results have shown that the most suitable combination, in terms of mechanical strength and economy of energy, was the mortar manufactured with soil receiving a ½ hour grinding time and calcined at 650oC during four hours.
Clays from Southern Brazil: Physical, Chemical and Mineralogical Characterization
Authors: Correia Sivaldo Leite , Curto K.A.S. , Hotza Dachamir , Segadães Ana M.
Published: March 2009

Fore knowledge of the characteristics of ceramic raw materials is of utmost importance during the development, processing and production stages of any ceramic product. This work describes the characterization of clays commonly used in the ceramics industry. Two different clays were selected: clay A, from Tubarão-SC and clay B, from Porto Alegre-RS. Their chemical composition was obtained by X-ray fluorescence and their mineralogy by X-ray diffraction, coupled with numerical rational analysis. Their thermal behaviour was studied by differential thermal analysis and thermogravimetry. Their particle size distribution and plasticity were also determined. Clay A showed circa 47.5 % quartz (by weight), 40.2 % kaolinite and 9.9 % muscovite mica. Clay B showed a high kaolinite content (circa 72 wt.%), accompanied by montmorillonite (circa 10 %) and potash feldspar (circa 10 % microcline). Clay B was found to be much more plastic than clay A, and both are suitable for pottery, tiles and brick making.
Mechanism of Microstructural Banding in Hot Rolled Microalloyed Steels
Authors: Cai S. , Boyd J.D.
Published: March 2009

Pilot-scale plate rolling experiments and laboratory thermomechanical processing
experiments were carried out to understand the mechanism of microstructural banding in low-carbon microalloyed steels. The microstructural banding originates with large elongated austenite grains, which are present at the roughing stage of rolling. The large austenite grains develop when conditions favour abnormal grain growth during reheat and/or strain induced grain boundary migration (SIBM) in the first few rolling passes. Microstructural banding is eliminated by designing TMP schedules to avoid abnormal grain growth and SIBM.
Austenite Decomposition in Low Carbon Steels with Microalloy Additions
Authors: Gomez G.R. , Bühler M. , Perez T.
Published: March 2009

A metallurgical model to describe the formation of ferrite, perlite and bainite during continuous cooling was developed. The model uses classical nucleation and early growth theories to calculate the beginning of the reaction, and Avrami-type equations to evaluate the transformation progress. The materials studied were plain carbon steels with different Mn contents, and microalloyed steels with Nb, Ti and/or V additions. The model predictions were adjusted and validated with experimental results obtained from dilatometric tests. The range of cooling rates considered was between 5°C/sec and 50°C/sec. From the comparison with the experimental data it was found that the model correctly describes the dependence of the reaction kinetic on the cooling rate, as well as on the steel chemistry.
Multiphase Steels: Structure-Mechanical Properties Relationships in the Cold Rolled and Continuous Annealed Condition
Authors: Verdeja J.I. , Pero-Sanz J.A. , Asensio J.
Published: March 2009

The present work describes the correlation between the microstructure and the
mechanical properties of multiphase steels processed through a Continuous Annealing Process Line (CAPL). The mechanical and microstructural properties of one of the former experimental steel compositions was also processed via Batch Annealing (BA) and the results have been included for comparison reasons.
FE-SEM Study of Fine Nb Precipitates in Carbon Extraction Replicas
Authors: Varano Rocco , Elwazri A.M. , Siciliano Fulvio , Bai D.Q. , Gauvin Raynald , Yue Steve
Published: March 2009

Precipitation strengthening is an important parameter controlling the mechanical properties of low carbon steels. These precipitates are very fine and are normally analyzed using either thin foils or carbon extraction replicas under a transmission electron microscopy (TEM). In this work, field emission gun scanning electron microscope (FE-SEM) was applied successfully in the characterization of niobium (Nb) carbo-nitride (C,N) precipitates using carbon extraction replicas. FE-SEM observation of high strength linepipe steel replicas before and after aging at 400°C for 1 hr confirmed the presence of Nb(C,N) precipitates in ferrite. The FE-SEM could analyze small particles (below 50 nm) embedded in the steel but the analysis had to be carried out at low voltages to maximize spatial resolution resulting in a poor signal. However, carbon extraction replicas in the FE-SEM can be analyzed using high voltages, since the interaction volume effect is no longer a problem.
Effect of Pearlite Structure on the Mechanical Properties of Microalloyed Hypereutectoid Steels
Authors: Elwazri A.M. , Yue Steve
Published: March 2009

The relationship between mechanical properties and pearlite microstructure was investigated using various heat treatments on a hypereutectoid steels containing 1% carbon with different levels of vanadium and silicon. Specimens were heat treated at various temperatures ranging from 900 to 1200°C and transferred to salt bath conditions at 550, 580 and 620°C to examine the structural evolution of pearlite. The results show that the thickness of the cementite network increases with increasing reheat temperature. This is likely due to the larger austenite grain size reducing the grain boundary area available for proeutectoid cementite nucleation. It was found that the vanadium and silicon additions increased the strength of hypereutectoid steels through refinement of the microstructure and precipitation strengthening.
New Microalloyed Steel Applications for the Automotive Sector
Authors: Matlock David K. , Krauss George , Speer John G.
Published: March 2009

Developments related to the use of microalloy additions, primarily of Ti, Nb, and V, and controlled processing are reviewed to illustrate how steels with tailored microstructures and properties are produced from either bar or sheet steels for new automotive components. Microalloying additions are shown to control the necessary strengthening mechanisms to produce high strength materials with the desired toughness or formability for a specific application. Selected examples of direct cooled forging steels, microalloyed carburizing steels, and advanced high strength sheet (AHSS) steels are discussed.
Current Status of Welding Technology & The State Key Lab of Welding in China
Authors: Wu Lin , Zhang Guang Jun , Gao Hong Ming
Published: March 2009

In the near twenty years, with the rapid increase of Chinese economy, Chinese welding technology developed very fast. In 2003, the annual output of steel in China has reached 230 megatons and above 40 percent was manufactured by welding process. The main welding engineering projects include: the Three Gorges power station, bridges over the Changjiang River, high pressure heavy-duty chemical container, pipeline project of transferring natural gas from West to East and manned spacecraft etc. Meanwhile, Chinese annual output of welding materials exceeds 1,200 kilotons, welding equipments exceed 200,000 sets and the welding automation rate reached 40 percent.
The State Key Laboratory of Advanced Welding Production Technology in Harbin Institute of Technology is the only welding laboratory of national level in China. It is the base of applied fundamental research and high quality welding technicians training. It has completed many projects of welding technology development and some significant applied engineering tasks. Every year, about 15-20 Doctors, 40-50 Masters and 70-100 Bachelors graduate from the Laboratory. Also, it is opened to the whole world.
Microstructures of Oxidized Primary Carbides on Superalloy Inconel 718
Authors: Hong Jae Keun , Park Nho Kwang , Kim Seong Jun , Kang Chung Yun
Published: March 2009

The oxidation behavior of carbides on Inconel 718 surface was investigated. Oxidation tests were performed at the temperature range of 300 to 650°C. Two types of carbide, NbC and TiC were detected, and the amount of NbC was significantly higher than that of TiC. The oxidation of NbC started at the carbide surface and the matrix interface, and propagated into the interior of the carbide and eruption subsequently occurred with increasing oxidation time. In case of TiC, the oxidation occurred at the outer surface of the carbide and the matrix interface, but did not propagated into the interior of the carbide. Oxides formed on the outer surface of the TiC contained a relatively large amount of elemental Nb. The cross-section of oxidized specimen was investigated. NbC was oxidized more easily due to the significantly lower Gibbs free energy of oxidation than that of TiC. Eruption occurred mainly at the NbC because the Pilling-Bedworth ratio of Nb is higher than the critical value of 2.3 where eruption typically occurs.
In Situ Neutron Diffraction Analysis of Phase Transformation Kinetics in TRIP Steel
Authors: Zrník Jozef , Muránsky O. , Lukáš Petr , Šittner Petr , Nový Z.
Published: March 2009

The precise characterization of the multiphase microstructure of low alloyed TRIP steels is of great importance for the interpretation and optimisation of their mechanical properties. In-situ neutron diffraction experiment was employed for monitoring of conditioned austenite transformation to ferrite, and also for retained austenite stability evaluation during subsequent mechanical loading. The progress in austenite decomposition to ferrite is monitored at different transformation temperatures. The relevant information on the course of transformation is extracted from neutron diffraction spectra. The integrated intensities of austenite and ferrite neutron diffraction profiles over the time of transformation are then assumed as a measure of the volume fractions of both phases in dependence on transformation temperature. Useful information was also obtained on retained austenite stability in TRIP steel during mechanical testing. The in-situ neutron diffraction experiments were conducted at two different diffractometers to assess the reliability of neutron diffraction technique in monitoring the transformation of retained austenite during room temperature tensile test. In both experiments the neutron investigation was focused on the volume fraction quantification of retained austenite as well as on internal stresses rising in structure phases due to retained austenite transformation.
Fabrications and Corrosion Resistance of Iron-Aluminum Alloy/High Carbon Steel Composites Prepared by Clad Rolling
Authors: Masahashi Naoya , Komatsu K. , Kimura G. , Watanabe Sadao , Hanada Shuji
Published: March 2009

The composite steel of iron-aluminum alloy and high carbon steel was fabricated by clad rolling, which process conditions were determined by the flow stress ratio between the constituents. Flow stress ratio of iron-aluminum alloy to carbon steel exhibits near unity at temperatures ranging from 873K to 1273K. Composite steel consisting of alloy/steel/alloy is successfully fabricated with about 70 % reduction in thickness, which demonstrates distinctive bending deformability. Clad plate is further rolled at room temperature to 150 µm in thickness with 98.3 % in reduction, and it is capable of winding without damage. The composite has shown significantly better high temperature oxidation resistance and corrosion resistance in a sulfuric acid than carbon steel. The dependency of corrosion resistance upon aluminum content of iron-aluminum alloy in an oxidation atmosphere is positive, whereas that in a sulfuric acid is negative. These results provide a strategy for the fabrication of functional composite steel.
Microstructure and Mechanical Properties of Hyper-Interfacial Bonded Joints of Ultra-Fine Grained High Strength Steels
Authors: Nishimoto Kazutoshi , Saida Kazuyoshi , Jeong Boyoung
Published: March 2009

A new conceptual bonding technique, " hyper-interfacial bonding" has been proposed as the most effective bonding technique for ultra-fine grained steels. The hyper-interfacial bonding process was characterized by the instantaneously surface-melted pressure-bonding which involved a series of steps, namely, surface heating by high frequency induction, rapid removing of a heating coil and simultaneously pressing of specimens together by an oil pressure system. All equences were typically completed within a second under vacuum/gas atmosphere. An ultra-fine grained high strength steels with the average grain size of 1.0-1.5µm were used for bonding. A bainitic structure and MAconstituents were confirmed in the HAZ, while the base metal indicated the fine ferrite-cementite/ pearlite texture. The maximum hardness in HAZ was limited at HV320-400 and the softening in the HAZ did not occur consequently. Prior austenitic grains were coarsened at the vicinity of the bond interface, however, the grain growth in the bond layer could be depressed below about 11-16µm attributed to the dynamic recrystallization during pressure-bonding process. The tensile strength of joints attained to 83% of the base metal strength. The upper-shelf absorbed energy and DBTT were improved to approx. 60J/cm2 and 223K respectively in the case of Ni-plated UFG steel joints. It could be resulted that the hyper-interfacial bonding technique was a feasible joining method for ultra finegrained steels.
Microstructure of SiC / TiAl Interface Formed by Solid-State Diffusion Bonding
Authors: Maeda Masakatsu , Tenyama Kazuyuki , Shibayanagi Toshiya , Naka Masaaki
Published: March 2009

The microstructure of the solid-state diffusion bonded interfaces of silicon carbide (SiC) and titanium aluminide (TiAl) were investigated. A 100-µm-thick Ti-48at%Al foil was inserted between two SiC specimens and then heat-treated in vacuum. The interfacial microstructure has been analyzed by scanning electron microscopy, electron probe microanalysis and X-ray diffractometry. Four layers of reaction products are formed at the interface by diffusion bonding: a layer of TiC adjacent to SiC followed by a diphase layer of TiC+Ti2AlC, a layer of Ti5Si3CX containing Ti2AlC particles and a layer of TiAl2. However, the TiAl2 layer is formed during cooling. The actual phase sequence at the bonding temperatures of 1573 K and 1673 K are described as SiC/TiC/(TiC+ Ti2AlC)/(Ti5Si3CX+Ti2AlC)/Ti1-XAl1+X/TiAl and SiC/TiC/(TiC+Ti2AlC)/(Ti5Si3CX+Ti2AlC)/Ti5Al11 /Ti1-XAl1+X/TiAl, respectively. The phase sequences are successfully expressed on the basis of the Ti-Al-Si-C quaternary chemical potential diagram.
Laser Beam Welding of Automobile Materials for Lightweight Car Body
Authors: Hirose Akio , Kobayashi Kojiro F.
Published: March 2009

This paper presents laser beam welding (LBW) of an age-hardened aluminum alloy and a bake-hardening (BH) steel, which are promising materials for lightweight car body, compared with conventional arc welding. The LBW of the aluminum alloy had a significantly narrower fusion zone and heat affected zone (HAZ) than the arc weld and the hardness of the softened zones was almost completely recovered to the base metal hardness after a post weld aging treatment. This advantage of LBW is due to a low overall heat input resulting from its high energy density. This is also beneficial for welding of the BH steel. In the LBW of the pre-strained BH steel, both the fusion zone and HAZ were bake-hardened after a heat-treatment and the fracture occurred in the base metal in the tensile test. In contrast to this, the arc weld had a large softened zone in the HAZ and fractures in this region.
Evaluation of Fracture Behavior of Ceramic Composite Joints by Using a New Interface Potential
Authors: Serizawa Hisashi , Lewinsohn Charles , Singh Mrityunjay , Murakawa Hidekazu
Published: March 2009

In order to examine mode-I & II type fracture behavior of ceramic joints, the interface element was proposed as a simple model which represents the mechanism of failure in an explicit manner. It was applied to the analyses of four point bending test and asymmetrical four point bending test for SiC/SiC composite specimen joined by ARCJoinTTM. By using a new type interface potential, which is a coupled function of opening and shear deformations, both the bending and asymmetrical bending tests were simulated. From comparison with experiments, surface energy at the interface between the joint and composite was estimated to be about 30 N/m regardless of the fracture mode. Also, from the comparison between the predicted strength and the experiments for the tensile test of lap joint of SiC/SiC composites, it was found that the proposed method was considered to have a great potential as a tool to study the failure problems whose fracture type was a mixture of mode-I & II.
Challenges in Joining Advanced Ceramic Materials: Interface Formation of Ceramic/Metal High-Temperature Brazes
Authors: Indacochea J.E. , Polar A. , McDeavitt S.M.
Published: March 2009

This paper describes the metallurgical interfacial reactions at elevated temperatures between reactive zirconium metal and stable oxide ceramics, specifically beryllia, yttria, and magnesia- zirconia composite ceramic. The ceramic/metal systems were preheated at 600°C, and then heated to peak temperatures of 1800°C or above, depending of the system, in ultra pure Argon atmosphere. After a short stay at the peak temperature, each system was cooled to room. The interaction was monitored during heating by a video camera and the interfaces were microscopically examined after the thermal cycle. The microstructure and chemical changes at the interface were evaluated via SEM and EDS. During heating of the beryllia/Zr system, the ceramic was initially reduced and Be alloyed the Zr metal in solid solution, causing Zr to melt locally at the interface at about 1600°C instead of 1855°C. The alloy Zr-Be liquid is what later dissolved the beryllia and infiltrated partially into the ceramic substrate. It seems that there was no solid state reaction between the Zr metal and yttria since Zr melted at its melting temperature of 1855°C; it is evident, however, that the liquid Zr partially dissolved yttria at the interface; yttrium and oxygen segregated to the grain boundaries. The solidified metal tightly bonded to the ceramic substrate as the system cooled to room temperature. In the Zr-MgO/ZrO2 system, Zr melted at 1855°C and it reduced the magnesia, but at the same time the magnesium was volatilized.
Developing a Nanowriter System: Simulation and Experimental Set-Up of a Plasmonic-Based Lens Design
Authors: Lee Chih Kung , Lin C.L. , Lin D.Z. , Cheng T.D. , Chang Ching Kao , Yu L.B. , Yeh C.S.
Published: March 2009

The aim of this article is to introduce a nanowriter system that could lead to a
sub-micrometer spot size using a visible light source under ambient conditions. The key component of the system is a focusing optical head, which incorporates a plasmonic-based lens instead of a conventional lens. Based on knowledge of the physical origin of extraordinary transmission and directional beaming, we theorize that the directional beaming phenomenon can be explained simply as a surface plasmon (SP) diffraction along the corrugations as long as the multiple scattering effects are taken into account to modify the dispersion relationship of the surface
plasmon. We introduce a Rigorous Coupled Wave Analysis (RCWA) formulation to pursue a precise dispersion relationship needed for the lens design. Comparing the resultant theoretical data between Finite Difference Time Domain (FDTD) simulations and RCWA results, we found good agreement and the many important characteristic parameters needed for an innovative lens design. We also set up a writing-test optomechanical system to examine the photoresist exposure ability of
the plasmonic-based lens.
An Intelligent Tool Post in a Lathe
Authors: Wu C.L. , Wang K.S.
Published: March 2009

An Intelligent Tool Post (ITP) used in lathe is proposed in this study. ITP is designed from the basis of two different cutting force characteristics produced from abnormal cutting generated by tool crashing workpiece and from normal cutting. ITP is capable of sensing and distinguishing the normal cutting signals from the abnormal ones. During normal cutting, ITP is able to resist the cutting torque and continue the cutting. As abnormal cutting occurs, the tool would move away from the
workpiece without any damage. The equations for design and operation have been established. With the threshold and the design equation, one can design appropriate ITP. The threshold can be calculated and set up by the operating equation and the cutting conditions. Furthermore, Taguchi method was employed to conduct the experiments and analyze the experimental results. The results
showed that the ITP’s functions met the design requirements completely.
Stability Analysis of the New Repetitive Learning Controller for Cutting Systems
Authors: Her Ming Guo , Chen Jih Ming , Ho Ming In
Published: March 2009

The new repetitive learning for the control of the periodic motion has already been
developed. The structure and parameters of the dynamic system don’t need to be known exactly by using this controller, in advance. And it will be shown the new repetitive learning controller is more efficiency than the traditional controller. In this study, it will be proved the system using new repetitive learning controller is global asymptotic stability under the ideal condition. It will be also shown the system is robust stability under the nonideal condition. Lastly, the noncircular cutting
system that will be illustrated to show the efficiency of stability for the repetitive learning controller is conducted.
Manufacturing of Cardiac Models Through Rapid Prototyping Technology for Surgery Planning
Authors: Cheng Yih Lin , Chen Shyh Jye
Published: March 2009

Rapid Prototyping (RP) Technology is capable of fabricating 3D freeform solid models from CAD models and has been widely used in communicating design concepts. Due to its distinctive characteristics, RP is very suitable in aiding surgery planning. Typical medical software used to display cardiac images can delineate both inner and outer structure but its images are virtual. Therefore, solid cardiac models made by RP technology provide a touchable reality to compensate
for this deficiency. In this research, RP technology is utilized to assist cardiac surgery planning. CT-scanned image data were first processed to obtain RP-acceptable STL file format, and then solid cardiac models were constructed by Objet QuadraTempo, a commercial RP system made in Israel. These models proved extremely helpful in cardiac surgery planning. In addition, several commercial
RP systems are compared by their process capabilities for cardiac surgery planning application.
Design and Implementation of Emulators for a Real-World Automated Manufacturing Systems Using Scenario
Authors: Huang Yi Sheng , Chung Ta Hsiang , Wen Yuan Lin
Published: March 2009

This paper demonstrates how to design and implement the emulators for a real-world
automated manufacturing system (AMS). In order to develop and validate system control software for managing AMSs, most laboratories have constructed an experimental test using actual manufacturing equipment. These experimental systems typically occupy a large amount of lab space and require considerable human expertise to operate. In this paper, a scenario-based development
environment for the equipment design and implementation are described. The intended advantage of the proposed environment is that, the designer can make an experimental test in a computer and does not need the actual manufacturing equipment. The proposed environment can be used to design and
implement a real-world automated manufacturing cell controller at National Taiwan University of Science and Technology (NTUST). We start with a new methodology to model the operation sequences of the system’s equipment (i.e., machine) called scenario. Modeling methodology is the key to the application of scenarios to automated manufacturing systems. The scenarios methodology
is able to clearly depict the communication signals for the equipment. And it also can be used to model the resource utilization features within a manufacturing system. Using scenario, we have developed an emulator for an automated manufacturing cell which faithfully replicates the operating characteristics of an ensemble of physical equipment that would typically comprise an AMS.
Accelerated Life Testing under Variable Synthetic Stresses for Hydraulic Pump
Authors: Wang Shao Ping , Shi Jian
Published: March 2009

Life testing is an important technique to assess the reliability and lifetime of components with long life and high reliability. To some expensive products, it is difficult to supply a large of samples and long test time to carry out the life testing, so this paper investigates the accelerated model and presents statistical method based on hybrid Weibull distribution under variable synthetic stresses. Based on the cumulative exposure theory, the failure probability can be cumulated with transform rate that can convert the fault proportion at certain stress into another stress. Using the genetic algorithm, the parameters of accelerated model can be estimated according to the accelerated stress profile. Then the lifetime at normal stress can be calculated with accelerated life model under normal stress profile. Application of hydraulic pump indicates that this method can reduce test time and test samples greatly.