bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival of Goss Grains during Cold Rolling of a Silicon Steel Single Crystal
Authors: Dorner Dorothée , Lahn Ludger , Zaefferer Stefan
Published: March 2009

A silicon steel single crystal with initial Goss orientation, i.e. the {110}<001> orientation, was cold rolled up to 89 % thickness reduction. Most of the crystal volume rotates into the two symmetrical equivalent {111}<112> orientations. However, a weak Goss component is still present after high strain, although the Goss orientation is mechanically instable under plane strain loading. Two types of Goss-oriented crystal volumes are found in the highly deformed material. We suggest that their origin is different. The Goss-oriented regions that are observed within shear bands form during the cold rolling process. In contrast, those Goss-oriented crystal volumes that are found inside of microbands survive the cold rolling.
Texture, Twinning and Uniform Elongation of Wrought Magnesium
Authors: Barnett Matthew R.
Published: March 2009

A small number of crystal plasticity simulations and tensile tests are carried out with the aim of demonstrating that control of twinning can improve the uniform elongation of magnesium based alloys. It is suggested that this can be accomplished through texture manipulation because texture influences both the fraction of grains that undergo twinning and the strain required for the twinning reaction to go to completion.
Representation of Misorientations in Rodrigues-Frank Space: Application to the Bain, Kurdjumov-Sachs, Nishiyama-Wassermann, Pitsch and Greninger-Troiano Orientation Relationships
Authors: Jonas John J. , He You Liang , Godet Stéphane
Published: March 2009

Orientation relationships between individual crystals can be readily represented in
Rodrigues-Frank space because of the one-to-one correspondence between each misorientation and a vector in the fundamental zone of this space. This is done by integrating the rotation angle and axis into a three-component vector. In this study, the three classical orientation relationships describing the γ-to-α transformation, namely the Bain, Kurdjumov-Sachs and Nishiyama- Wassermann, are represented in Rodrigues-Frank space. Also considered are the somewhat less common Pitsch and Greninger-Troiano relationships. The misorientations between these types of
transformation variants are displayed in R-F space based on alternative reference systems to highlight the differences. Examples of the various crystallographic relationships between fcc and bcc crystals during the γ-to-α transformation are given to demonstrate the advantages of the use of this space.
Nucleation of Secondary Recrystallization in Ultra Low Carbon Steel
Authors: Verbeken Kim , Kestens Leo
Published: March 2009

The nucleation stage of secondary recrystallization has never been considered in detail. During the present study, nucleation of abnormal grain growth in ULC steel was studied. A specific nucleation mechanism was identified. This mechanism involved the disappearance of low angle grain boundaries, which gave rise to the onset of a local grain coalescence mechanism that clusters grains that were only separated by low angle grain boundaries. The impact of the nucleation stage remained visible in the texture that was obtained after complete abnormal grain growth.
The Influence of Palladium Addition on the Texture Transition in Silver
Authors: Sekine Kazuyoshi , Zhang Zheng Rong
Published: March 2009

Texture transition in silver introduced by the addition of 10 at% Pd alloying element was analyzed in this study. Experimental results show that the dependence of rolling texture on rolling reduction in thickness rather than on rolling temperature has been mostly detected, and the recrystallization texture transition process in pure silver is so strongly influenced by the addition of alloying element palladium that the final stable state of recrystallization texture has been changed from Brass {011}<211> orientation to Copper {112}<111> orientation. The single cube {001}<100> recrystallization texture in warm rolled silver, Brass {011}<211> recrystallization texture in room-temperature rolled silver, and Copper {112}<111> recrystallization texture in room-temperature rolled or warm rolled Ag-10 at% Pd alloy have been successfully developed for the fabrication of metallic substrates suitable for high-temperature superconducting tapes.
Interactive Texture- and Finite-Element Simulation Including the Bauschinger Effect
Authors: Walde Tom , Riedel Hermann
Published: March 2009

In this paper we describe a rolling simulation considering the main sources of plastic anisotropy, namely the Bauschinger effect and crystallographic texture. For this purpose we coupled the VPSC-model of Lebensohn and Tomé [1] with the hardening model of Peeters et al. [2]. The combined model is implemented in the Finite-Element code ABAQUS/Explicit®. With the combination of finite-element method, VPSC-texture model and the hardening model a rolling process is simulated and the nfluence of the Bauschinger effect on the texture evolution is studied.
Flow Stress Anisotropy - Effect of Microstructure and Texture in Aluminium and IF Steel
Authors: Li Z.J. , Winther Grethe , Hansen Niels
Published: March 2009

The effect of microstructure and texture on the flow stress anisotropy in aluminium and IF steel has been investigated. The samples are recrystallized commercial purity aluminium (AA1050) cold rolled to prestrains of 0.05, 0.11 and 0.2, and recrystallized IF steel cold rolled to a prestrain of 0.28. The flow stress anisotropy was measured by tensile testing of specimens cut along different directions in the rolling plane. Pronounced anisotropy was found in both materials in spite of weak textures. The yield stress increases with increasing angle between the tensile direction and the rolling direction at all prestrains. The effect of microstructure and texture on the flow stress anisotropy was modelled by incorporating into a full-constraint Taylor model the strengthening effect of dislocation boundaries. The modelling and experimental results agree well, leading to a discussion of effect of the microstructure and texture on the flow stress anisotropy.
Plastic Anisotropy and Texture Evolution of Rolled AZ3l Magnesium Alloys
Authors: Hartig Ch. , Styczynski A. , Kaiser F. , Letzig Dietmar
Published: March 2009

The plastic anisotropy was measured for a commercial AZ31 magnesium sheet and compared with results from a model calculation using a self consistent viscoplastic model. The anisotropy of plastic flow stresses can be explained by the off-basal character of the texture and the activation of the  prismatic slip in addition to the basal,  pyramidal slip and the > < 1 1 01 } 2 1 01 { twinning system. The strain anisotropy r ( r = ew/et ; ew, et – strains in width and thickness directions of a sheet material ), as obtained from model calculations, fits qualitatively with in-situ measured values. Results from these model calculations are compared with texture simulations and discussed in further consideration of the microstructure of the sheet material.
Pole Figure Measurement Plan Influence on Accuracy ODF Coefficients Determined by Modified Harmonic Method
Authors: Serebryany Vladimir , Kurtasov Sergey F. , Savyolova T.I.
Published: March 2009

Influences of an X-ray experimental texture plan and of pole figure primary errors on the accuracy of the ODF coefficients are discussed. A modified harmonic method, which is a statistical method of ridge estimates, has been used for ODF restitution from pole figures. The plan of measurement of the pole figures was analysed on the basis of minimization of the primary experimental errors and the errors of the ODF restitution method. Principles of the optimum texture plan construction for hexagonal metals (magnesium example) and for the URD-6 texture diffractometer are considered.
Microstructure and Texture Evolution of Cold Worked 304 Stainless Steel Experimental and Modelling
Authors: Petit B. , Gey Nathalie , Humbert Michel , Bolle Bernard , Cherkaoui M.
Published: March 2009

A micromechanical model was used to simulate the mechanical behaviour, the
transformation kinetic and the texture evolutions of a 304 stainless steel, deformed by tensile tests at T=–60°C. When the transformation strain is calculated with the phenomenological theory, the model does not very well predict the observed transformation rate and the texture evolution of the main γ grain orientations. XRD and EBSD analyses show that the martensitic transformation of γ phase into α’ martensite involves the intermediate ε phase. From these observations, new simulations were performed in which only the γ→ε transformation strain is considered in competition with classical plasticity of austenite. The α’ variants were calculated in a second step, from the ε variants selected in the micromechanical model. Among the 6 potential α’ variants able to nucleate from the same ε variant, the best oriented ones, with respect to the applied stress were selected. Under these conditions, the numerical simulations reproduce the experimental results in a more satisfying way.
Textures in Experimentally Deformed Olivine Aggregates: The Effects of Added Water and Melt
Authors: Heidelbach F. , Holtzman B. , Hier-Majumder S. , Kohlstedt D.
Published: March 2009

The texture development in experimentally sheared aggregates of olivine was monitored as a function of increased water content and added melt. In dry samples, an alignment of {010} with the shear plane and <100> and <001> with the shear direction, respectively, was observed, consistent with intracrystalline glide on the (010)[100] and (010)[001] slip systems. Samples with high water content showed consistently stronger textures of the (010)[100] component for comparable shear strains indicating that water may especially ease glide on this slip system. Samples with added melt showed an increased alignment of {010} and <001> subparallel to shear plane and shear direction respectively, whereby the maxima were consistently rotated 10 to 20° against the sense of shear. This type of texture can be explained by a combination of increased glide on the (010)[001] slip system in combination with a partitioning of the strain between melt rich bands and relatively melt free regions in the sample. Physical anisotropies calculated from the textures indicate that increased water content causes enhanced anisotropy for longitudinal and transverse seismic waves. The addition of melt on the other hand may change the type of anisotropy that develops during deformation, but does not significantly change the magnitude of anisotropy compared to samples of pure olivine.
Role of Deformation Twinning in Cold Rolling and Recrystallization of Titanium
Authors: Chun Y.B. , Semiatin S. Lee , Hwang Sun Keun
Published: March 2009

The evolution of microstructure and texture during cold rolling and recrystallization
annealing of commercial-purity Ti (CP-Ti) was established. Cold rolling to 40% reduction activated mechanical twinning- mostly > 3 2 11 < } 2 2 11 { compressive twins and > 1 1 10 < } 2 1 10 { tensile twins. The formation of twins resulted in an inhomogeneous microstructure, in which only the localized regions containing twins were refined and the regions deformed by slip remained coarse. The twinned grains, containing high stored energy and numerous high-angle grain boundaries, became
the preferential sites of nucleation during subsequent recrystallization. During recrystallization heat treatment at 500~700°C, the cold-rolling texture (ϕ1=0°, Φ=35°, ϕ2=30°) diminished in intensity, whereas a recrystallization texture component (ϕ1=15°, Φ=35°, ϕ2=35°) appeared. The recrystallization heat treatment temperature affected the rate of recrystallization but not the texture
characteristics per se. During the subsequent grain growth stage, the recrystallization texture component increased. This behavior was attributed to the growth of larger-than-average grains of this particular crystal orientation.The evolution of microstructure and texture during cold rolling and recrystallization
annealing of commercial-purity Ti (CP-Ti) was established. Cold rolling to 40% reduction activated mechanical twinning- mostly > 3 2 11 < } 2 2 11 { compressive twins and > 1 1 10 < } 2 1 10 { tensile twins. The formation of twins resulted in an inhomogeneous microstructure, in which only the localized regions containing twins were refined and the regions deformed by slip remained coarse. The twinned grains, containing high stored energy and numerous high-angle grain boundaries, became
the preferential sites of nucleation during subsequent recrystallization. During recrystallization heat treatment at 500~700°C, the cold-rolling texture (ϕ1=0°, Φ=35°, ϕ2=30°) diminished in intensity, whereas a recrystallization texture component (ϕ1=15°, Φ=35°, ϕ2=35°) appeared. The recrystallization heat treatment temperature affected the rate of recrystallization but not the texture
characteristics per se. During the subsequent grain growth stage, the recrystallization texture component increased. This behavior was attributed to the growth of larger-than-average grains of this particular crystal orientation.
Orientation Evolution during Equal Angular Channel Extrusion of Copper Single Crystal
Authors: Wang Gang , Wu Shi Ding , Jiang Q.W. , Wang Yan Dong , Zong Ya Ping , Esling Claude , Zuo Liang
Published: March 2009

The orientation evolution in Copper single crystal during ECAE (in Route C) has been investigated experimentally for 90° die angle by X-ray diffraction and TEM-OIM. It is shown that after the previous three passes of ECAE, orientation evolutes with similar mechanism to the simple shear deformation. The grain subdivision occurs with the appearance of many low angle grain boundaries. After four times extrusions the ED of the samples remains stable, their ND rotates around the ED by about 20°. After five times extrusions the main texture component remains stable.
Texture of Al-Cu Alloys Deformed by ECAP
Authors: Kuśnierz Jan , Mathon Marie Helene , Baudin Thierry , Jasieński Zdzislaw , Penelle Richard
Published: March 2009

Materials of ultra-fine grained microstructure (sub-micrometer grain size) exhibit
large strength, hardness and ductility and also the increased toughness in comparison with conventional coarse-grained ones. In these materials also the super-plastic flow at lower temperatures is observed. This behaviour may be interesting when aluminium alloys like AlCuZr, used in superplastic forming, are considered. In the paper, the methods of preparing such materials by equal-channel angular pressing (ECAP) is proposed and the texture analysis, based on neutron diffraction pole figure measurements and calculated orientation distribution function of two alloys AlCu4SiMn and AlCu5AgMgZr is discussed. The influence of short time recrystallization is discussed in relation with TEM and SEM observations.
Sintering Behavior of Si3N4-TaC Based Composites
Authors: Rumbao Ana Carolina S. Coutinho , Bressiani José Carlos , Bressiani Ana Helena A.
Published: March 2009

Silicon nitride was the first nitride developed for engineering applications. The excellent combination of thermomechanical properties makes silicon nitride a good candidate for applications where high hardness and mechanical properties are fundamental. However, the low fracture toughness of this material limits its use as structural material. The improve of mechanical properties of silicon nitride comes from many factors, like refined microstructure by restraining grain growth, localized stress, crack tip bridging, etc. Within these factors, microstructure formation of the silicon nitride is critically important for the final properties. The design of silicon nitride based composite materials is of particular interest because of their improved high temperature strength and fracture toughness. In this work, Si3N4-TaC particulate composite was investigated. For this study was prepared a basis composition (CB) with 90%wt a-Si3N4, 6%wt and 4%wt Y2O3 and Al2O3, respectively. TaC (20%vol) was added into CB and after mixture, in high-energy milling, the powder was compacted into pellets. The kinetics of sintering was studied by means of dilatometry. The shrinkage rate versus time and temperature curves exhibit two well-defined peaks. The first peak refers to the particle rearrangement process and the second, more pronounced, to solutionreprecipitation process. It is quite clear that the presence of TaC particles has small influence on sintering kinetics of silicon nitride. It was observed the complete a®b-Si3N4 phase transformation. The microstructure shows good homogeneity both in regard of grain size and secondary phase distribution.
Microstructural Evolution of Ti-13Nb-13Zr Alloy during Sintering
Authors: Henriques Vinicius André Rodrigues , Cairo Carlos Alberto Alves , Silva Cosme Roberto Moreira , Bressiani José Carlos
Published: March 2009

With the prolonged average duration of life, there is an increase concern for repair of bone, joints and teeth which deteriorated and lose their functions. Thus, research of artificial materials for implants has assumed an important role in the implants development. The trend of the current research in orthopedic implants is based in the development of titanium alloys with low modulus of elasticity, next to the bone, and toxic elements free. In this work, results of the Ti-13Zr- 13Nb alloy sintering are presented. This alloy due its high biocompatibility and lower modulus of elasticity is a promising candidate for implants fabrication. Samples were produced by mixing of initial metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by sintering between 800 at 1500 °C, in vacuum. Sintering behavior was studied by means of dilatometry. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively. Density was measured by Archimedes method. It was shown that the samples were sintered to high densities and presented homogeneous microstructure from the elements dissolution. Processing parameters were optimized in order to reduce the interstitial pick-up (O, C, N and H) and to minimize grain growth during sintering.
Methodology for Prediction of Desired Mechanical Properties as a Function of Mixture Components
Authors: Nardi J.V. , Hotza Dachamir
Published: March 2009

Preliminary results of the use of electroomosis technique for removal of organic contaminants in ceramic filtration porous structure are presented. The method employed provokes the migration of chemical residue and waste retained or adsorbed on the pore surfaces by applying a controlled tension within an electrochemical system. Porous ceramics have been the most common filtration medium employed within a broad range of applications. Conventional cleaning of a ceramic medium is not entirely effective for organic contaminants since they cannot be excluded by size, but retained through chemical affinity to the oxide surface. Under the influence of an electrical current, adsorbed molecules underwent shear stress due to the diffuse moving layer. In their ionic state the specimens are dragged and thus move towards the opposite charged electrode. Phenol was chosen as a standard contaminant and tests carried out using commercial ceramic filtration candles. Relative contaminant concentration was assessed by optical densities (UV-Vis spectroscopy). The results show that removal is proportional for up to 58% of the contaminant in diluted condition.
Characterisation of Titanium Nitride Thin Films Deposited by Cathodic Arc Plasma Technique on AISI D6 Tool Steel
Authors: Vieira R.A. , Nono Maria do Carmo de Andrade
Published: March 2009

TiN thin film has been produced on the surface of AISI D6 tool steel by using a titanium interlayer. In this work, the morphology, the microstructure and interface depth profile of TiN films deposited at two substrate temperatures (220 oC and 450 oC) in the coating process are presented and discussed. The AISI D6 tool steel substrates were coated with titanium thin film as the underlayer and with TiN thin film as the top layer. They were deposited by conventional cathodic arc process. The surfaces of TiN films were observed by scanning electron microscopy (SEM). The microstructure of these samples was analysed by X-ray diffractometry (XRD). The influence of the substrate temperature on the TiN film-Ti film-AISI D6 interface region were investigated by energy dispersive spectrometry (EDS) and its cross section were observed using backscattered electron image (BEI). The results showed that TiN films deposited at 220 oC formed a film of strongly (111) preferred orientation, while in 450 oC formed a film of (111) and (220) preferred orientation. The thickness of the TiN films increased with increasing substrate temperature. The results show that the interface region of the TiN film-Ti film-AISI D6 substrate system was significantly improved when higher substrate temperature during deposition is used.
Improvement of Low Carbon Steel Properties through V-N Microalloying
Authors: Ali Ibrahim Hamed M. , Moustafa Ibrahim M. , Farid Ahmed Mohamed , Glodowski R.J.
Published: March 2009

To improve the strength properties of vanadium bearing low carbon steel, nitrogen is
often added to the liquid steel. The source of the nitrogen addition can be in many different forms. The recovery of nitrogen from the addition is variable due to the low solubility of nitrogen in steel. In this work, nitrogen-enriched alloy (Nitrovan) was added under open atmosphere. To deduce the nitrogen role, two alloys were chosen that having the same vanadium content. One of them was Ferro-Vanadium as a source of vanadium, whereas Nitro-Vanadium used as a source of vanadium
and nitrogen. Ferro-vanadium as well as Nitro-vanadium was added separately in the ladle after completely melting of carbon steel and proper superheat using 100 Kg induction furnace. The effect of adding nitrogen-enriched alloy on mechanical properties of the steel was investigated. For this purpose, four heats were produced and cast into sand moulds. The general trend of results shows higher mechanical properties through increasing nitrogen content. The experimental work indicates that enhanced nitrogen content promotes the precipitation of V(C,N) and decreases the particles size of V(C,N) precipitates. Also, under the same level of vanadium content, the tensile strength and yield strength of the nitrogen-enhanced steels increases consistently compared to the steels added 80% Ferro-Vanadium. An empirical formula, correlating the mechanical properties of the steel and its composition, was obtained.
The Effect of Thermomechanical Processing on the Structure and Mechanical Properties of Ni, Nb and V-Bearing HSLA Steels
Authors: Kodjaspirov G.E. , Sulyagin R. , Rudskoy A. , Apostolopoulos C.
Published: March 2009

The effect of deformation temperature (800-1000°C) - strain accumulation (number of rolling passes: 3÷5) - cooling rate (8,6 – 25°C/s) parameters on the microstructure and mechanical properties of C-Ni-Nb and C-Ni-V steels after High Temperature Thermomechanical Processing (HTMP) are presented. The experiment planning method was used for the simulation and examination of the above mentioned parameters effect on the mechanical properties. The regression
equations and diagrams describing the qualitative and quantitative effects of HTMP parameters on the mechanical properties of the steels are derived from the experimental results. The Ni-Nbbearing steel with the lower bainite structure that is a result of the HTMP with the maximum number of passes, the highest deformation temperature and cooling rate shows the highest strength (YS=987 MPa) in combination with a high impact strength (W=154 J). It is shown that the Ni- bbearing steel with the fine lower bainite structure that results from the transformation of the hot deformed fragmented substructure of austenite after water cooling has the best resistance to brittle fracture. The Nb-bearing steel has a higher strength compared to the V-bearing one, although it shows a lower impact strength in the negative testing temperature range.
Gears and Springs in Niobium Microalloyed Steels for Automotive Applications
Authors: Mougin Julie , Dierickx Pierre , Robat Daniel , Rofes Vernis Jaime
Published: March 2009

The tensile strength levels required for spring and gear applications are far higher than those commonly associated with other uses of microalloyed steels. In addition, springs and gears are manufactured using highly specific processes. This is why we present first of all a brief overview of the context and objectives of these developments, in order to assess their scope. The work presented here confirms that the effects of Niobium are not simply those usually associated with the precipitation of Nb(CN) carbonitrides: inhibition of recrystallisation, control of austenitic grain coarsening and precipitation hardening . Account must also be taken of the interactions between the Nb and other elements, as well as the slowing down of g => a + carbides transformation observed in certain cases. The number of mechanisms (or interactions) identified clearly shows why there is still a broad range of choices for optimising steel products and processes according to the target application, the production characteristics and the desired value for money ratios.
Relationship between Microstructure and Texture Development during the Early Stages of Annealing in Warm Rolled Low Carbon Steels
Authors: Timokhina Ilana B. , Jonas John J. , Ringer Simon P. , Bulcock S. , Pereloma Elena V.
Published: March 2009

The influence of chromium and phosphorus addition on the microstructure and on texture development was studied during the early stages of the annealing of warm rolled, low carbon steels. The addition of alloying elements led to an increase in the volume fraction of grains containing both shear bands and microbands. Moreover, the alloyed steels displayed lower stored energies and dislocation densities compared with an unalloyed low carbon steel. Two types of carbides were present after warm rolling in the steels containing the alloying additions: (i) coarse carbides; and (ii) fine strain-induced particles. These microstructural differences affected the development of texture during annealing.
Microalloying of Cold-Formable Multi Phase Steel Grades
Authors: Bleck Wolfgang , Phiu-On Kriangyut
Published: March 2009

Microalloying elements like Al, B, Nb, Ti ,V can be used to optimise the microstructure evolution and the mechanical properties of advanced high strength steels (AHSS). Microalloying elements are characterised by small additions < 0.1 mass% and their ability to form carbides or nitrides. They can increase strength by grain refinement and precipitation hardening, retard or accelerate transformations and affect the diffusion kinetics as well as the stacking fault energy. Thus, by their addition the AHSS with their high requirements to process control can be adopted to existing processing lines. Different combinations of microstructural phases and different chemical compositions have been investigated for AHSS in order to combine high strength with excellent formability. The recently developed high manganese steels further improve the formability due to their austenitic microstructure and inherent phase transformations during forming.
Utilization of Generalized Chemical Potential Diagrams for Multi-Component Systems in Understanding Interface Stability
Authors: Yokokawa Harumi , Yamaji Katsuhiko , Horita Teruhisa , Sakai Natsuko , Brito Manuel E.
Published: March 2009

Utilization of chemical potential diagrams is powerful in predicting the chemical stability of dissimilar materials and analyzing the diffusion path when reactions are proceeded. Since practical materials consist of many components so that construction of chemical potential diagrams for the multi-component systems becomes crucial. There is one powerful way of treating phase equilibria for such complicated systems in chemical potential diagrams; that is, a construction of three dimensional diagrams, although all phase relations are not visible in such a diagram. To make phase relations visible, there are several ways; one is to make selected phase transparent. This makes it possible to examine the detailed relations between selected materials. Second one is to make dissections at selected values for the chemical potential of selected chemical species. By swinging the dissected value, the change in phase relations can be examined as a function of given chemical potential. Some examples will be given for the formation of oxide scale on ferritic alloys.
Atomic Mechanisms of Grain Boundary Motion
Authors: Suzuki A. , Mishin Yuri M.
Published: March 2009

We present results of atomistic computer simulations of spontaneous and stress-induced grain boundary (GB) migration in copper. Several symmetrical tilt GBs have been studied using the embedded-atom method and molecular dynamics. The GBs are observed to spontaneously migrate in a random manner. This spontaneous GB motion is always accompanied by relative translations of the grains parallel to the GB plane. Furthermore, external shear stresses applied parallel to the GB and normal to the tilt axis induce GB migration. Strong coupling is observed between the normal GB velocity vn and the grain translation rate v||. The mechanism of GB motion is established to be local lattice rotation within the GB core that does not involve any GB diffusion or sliding. The coupling constant between vn and v|| predicted within a simple geometric model accurately matches the molecular dynamics observations.
Application of Dual-Phase and TRIP Steels on the Improvement of Crashworthy Structures
Authors: Peixinho Nuno , Jones N. , Pinho António
Published: March 2009

The improvements in vehicle crashworthiness observed in recent years have been closely linked to advanced high-strength steels that are currently being produced or in process of development. Amongst these, Dual-Phase and TRIP (Transformation Induced Plasticity) steels have presented excellent properties for use in crashworthy structures. For these steel grades an understanding of material behaviour at relevant strain rates is needed as well as constitutiv eequations suitable for use in analytic and numerical calculations. In this study the crashworthiness of thin-walled sections made of Dual-Phase and TRIP steels was investigated. Tensile tests were performed at different strain rates in a range of interest for crashworthiness problems. The results allowed the determination of parameters of Cowper-Symonds equation. Crush tests were performed at different speeds for top-hat and hexagonal tubes manufactured using laser welding. The experimental results were compared with numerical simulations obtained with LS-DYNA software. The influence of different material parameters on the accuracy of the simulations was examined.
A General Embedded Atom Method and Application to Prediction for Thermodynamic Properties of Fe-Eu System
Authors: Ouyang Yi Fang , Zhong Xiaping , Tao Xiao Ma
Published: March 2009

An analytic embedded-atom potentials was developed. It was applied to calculating mono-vacancy formation energy, divacancy binding energy, elastic constants, energy difference of different structures, the surface energy, and the phonon spectra of iron and europium. The formation enthalpies of Fe-Eu binary alloy were also calculated. The calculated physical properties are in agreement with the experiments available or other theoretical results. The formation enthalpies are in good agreement with the results obtained by Miedema’s theory.
Interatomic Potentials for Metal/Metal Wetting Systems
Authors: Makino Takehiko , Kubo Atsushi , Iida Hiroki , Tanaka Shun Ichiro
Published: March 2009

Considering the uniqueness of wetting systems consisting of three components, namely, the surface, liquid and liquid/solid interface, it is desirable to construct interatomic potentials following a consistent policy. To investigate the physical meaning of the behavior in terms of the interatomic potentials, the wetting systems are modeled by simple two-body interatomic potentials derived using ab initio molecular orbital calculations for hypothetical clusters representing the above three components. For In and Sn liquid atoms, spreading occurs on a Cu (111) surface, while in contrast, liquid atoms penetrate the substrate and form a surface alloy in the case of a Pd (111) surface.
Fundamental Analysis of the New Version of the New Proposed Fracture Theory
Authors: Elshikhy Refat Ahmed
Published: March 2009

New version of new proposed fracture theory called N-N was introduced as concepts and hypotheses. In this research analytical discussions and applications in addition to detailed explanation of physical meaning and conceptual formation of is introduced. The current theory depends mainly on energy approach in LEFM for isotropic brittle materials and can be applied for ductile materials and composites regarding their different properties. This theory represents an extension of the continued efforts to obtain a unified view for all ideas and proposals of the majority of the researchers in the field of development of the fracture theories to predict the mechanism and mechanical aspects of cracking process. Fundamental new concepts and analytical hypotheses are introduced.
Low Temperature Mechanical Properties of Different Commercial Purity Nanostructured Titanium Processed by ECA Pressing
Authors: Tabachnikova Elena D. , Bengus Vladimir Z. , Podolskiy Aleksey V. , Smirnov S.N. , Gunderov Dmitriy , Valiev Ruslan
Published: March 2009

Low temperature mechanical characteristics under quasistatic uniaxial tension and compression have been studied of ultra fine-grained structural state of polycrystalline titanium – nanostructured titanium, processed by the equal channel angular pressing (ECAP). Values of the yield stress and the uniform plasticity at 300, 77, and 4.2 K for nanostructured (NS) and polycrystalline coarse-grained (CG) titanium of different commercial purity have been compared.
An Algorithm for the Kinematic Design of Gear Transmissions with High Reduction Ratio
Authors: Hsieh Long Chang , Lee Hsin Sheng , Chen Tzu Hsia
Published: March 2009

Planetary gear trains can be used as the transmission systems with high reduction ratio for power machinery. The purpose of this paper is to propose an algorithm for the kinematic design of planetary gear trains with high reduction ratio. Based on the concept of train value equation, we propose a new representation to present the kinematic relationship of the members of the train loop. According to this representation graph, we propose an efficient algorithm for the kinematic design of
planetary gear trains with high reduction ratio. Three design examples are designed to illustrate the design algorithm. Based on the proposed algorithm, all planetary gear trains with high reduction ratio can be synthesized.
Effect of Process Parameters on Coating Quality in Surface Coating Processes
Authors: Jou Min , Lo Cheng Chan
Published: March 2009

Coating technologies are widely used in manufacturing processes, to prevent products from deterioration due to the actions of water, air, or an acid, to improve the artistic functions of product. In advance of nano-technologies, the geometry of coating particles will be fabricated as designed. Therefore, the effects of the geometry of materials on the coating quality should be considered in manufacturing processes. Surface roughness is one of the major indicators of coating
quality. The correlation of geometry of coating materials and surface roughness on the performance of coated electrodes is presented in this paper. Three types of geometries are analyzed which are spherical particles, uniformly distributed columns, and random types. Besides the geometry of coating materials, the impact force resulting from spray jet will alter the surface roughness and is
one of the important factors to coating quality. Therefore, the stability of coating jet is also studied. The findings show that high frequency waves can be added into the flow to get neutrally stable condition which will improve the stability of impact force.
Coordinated Motion Control of Large-Scale Transporter for Conveying Heavy Frame Components in Ship-Manufacturing
Authors: Li Yun Hua , Yang Li Man , Yang Gui Lin
Published: March 2009

A large-scale elevating transporter that has multi-wheels to be steered independently is a very complex mechatronic system. Aiming at its real-time coordinated motion control, a multi-mode steering system based on Networked Control System (NCS) is proposed to tackle the problem in the
paper. Through motion synthesis, such as kinematics and dynamics modeling and analysis, and using the inherent real-time data sharing of the NCS, a cross-coupled control algorithm for improving contour accuracy is developed. This control methodology is then applied to the coordinated motion
control of a practical product with multi-steering modes successfully.
Fabrication and Mechanical Properties of MWNTs/Phenolic Nanocomposites
Authors: Yeh Meng Kao , Tai Nyan Hwa , Lin Yan Jyun
Published: March 2009

The multi-walled carbon nanotubes (MWNTs) were added into the phenolic resin to fabricate MWNTs/phenolic nanocomposites. The pressure and temperature were applied to cure MWNTs/phenolic compound by hot press method, then followed by a post curing process. The results showed that post-curing of the nanocomposites specimen is necessary for better mechanical properties. The temperature used for post curing should be higher than the curing temperature. The higher curing pressure improved the Young’s modulus of the nanocomposites. The tensile failure
morphologies of MWNTs/phenolic nanocomposites were examined using field emission scanning electron microscope (FESEM) to evaluate the effects of manufacturing processes on the mechanical properties of MWNTs/phenolic nanocomposites.
Polishing Glass-Ceramic Based Rigid Disk
Authors: Chen S.Y. , Lin Shin Chieh , Cheng Hong Ho
Published: March 2009

In this study, experiments were conducted to reveal effects of polishing parameters on surface characteristics and removal rate when polishing glass-ceramic based rigid disk. The parameters studied including rotational speed, applied pressure, and abrasive concentration. Experimental results show that surface roughness, waviness and removal rate could be improved by adjusting the levels of polishing parameters.
Design, Fabrication and Study of Micro-Electrospray Chips
Authors: Leu Tzong Shyng , Teng Chi Hsiung
Published: March 2009

This paper described design, fabrication and study of micro electrospray chips. The micro electrospray chips are fabricated by using micro-electro-mechanical system (MEMS) technology. The micro electrospray techniques can be used in many applications, including high viscous fluid dispenses for 3D rapid prototyping and biological sample analysis in mass spectrometer. In this study,
micro electrospray chips with different wedge angels are investigated by using microscopic visualization techniques. Four spray modes are identified at various operation voltages and currents. It is found that the voltage for stable cone-jet mode decrease as wedge angle becomes smaller. On the other hand, it is also found that stable cone-jet mode represent a constant current range in current
(I)-voltage(Ф) curve. It allows us to easily identify if the micro electrospray chips operate at cone-jet mode.
A Valveless Micro Impedance Pump Driven by PZT Actuation
Authors: Wen Chih Yung , Cheng Chiang Ho , Jian C.N. , Nguyen T.A. , Hsu C.Y. , Su Y.R.
Published: March 2009

This paper presents the fabrication and preliminary experimental studies of flow
performance on a valveless micro impedance pump actuated by the shear mode PZT actuator, a novel method of pumping fluid on the microscale. The micro impedance pump was constructed of three nickel electroforming components, two glass tubes, a PZT actuator and a glass substrate. The three electroforming components include a bottom structure plate, a channel plate and a top structure plate. The AZ-type positive photoresist was used as the electroforming mould, which was patterned by UV lithography. The top and bottom structure plates were aligned and assembled with the channel plate by epoxy adhesive such that a micro channel with a compressible section coupled at both ends to rigid sections of different impedance was formed. A pressure head can be built up to drive flow through the accumulative effects of wave propagation and reflection originating from the periodic PZT excitation, located asymmetrically along the length of the compressible section of the channel. Experimental results showed that the flow was reversible and pressure heads had a highly non-linear dependence on
the frequency and amplitude of the excitation. Maximum flow rates of 13 μl min-1 have been achieved with the channel size of 15μm high and 4 mm wide.
Modelling of Friction Coefficient in Cold Strip Rolling
Authors: Tieu A. Kiet , Zhu Hong Tao , Lu Cheng , You C. , Jiang Zheng Yi , D'Alessio Giovanni
Published: March 2009

The variation of the friction in the roll bite is of great importance in cold strip rolling. The main interest of the paper is to model the friction coefficient in the roll bite during cold rolling. The deformation resistance of the rolled products and friction coefficient in the roll bite were determined simultaneously by minimizing the error of the measured and calculated rolling forces based on nonlinear least squares optimization algorithm. The neural network was introduced to further
improve the accuracy of friction coefficient calculation in cold strip rolling. The results already obtained shows that friction decreases with roll wear, and the lower the rolling speed, the higher is the friction.
Investigation of Electron Beam Welding on AZ91D-F Extrusive Plates
Authors: Chi C.T. , Chao C.G. , Huang C.A. , Lee C.H.
Published: March 2009

Electron beam welding (EBW) is currently the most advanced jointed technology because of its superior welding precision and larger depth-width ratio than other conjunctive methods. The high vacuum environment of EBW is favorable for the welding of magnesium alloys to prevent the active metals from oxidation. In this study, a home-made 11mm-thick AZ91D extrusive plate was used. By operating and comparing the changeable welding parameters, the optimum condition has been determined as 113mA, 40kV, 73.3mm/s and focal position at bottom. 82% and 89% of the matrix material strength were obtained by stress and non-stress concentration weldments, respectively. Under other worse parameters, the reduction of the strength of EBW for AZ91D-F resulted from four factors, which were undercuts, heat affected zone (HAZ), hot cracking, and
cavities.
Study on Shrinkage of Injection Molding Biodegradable Materials
Authors: Cheng Yih Lin , Lee Ying Wei
Published: March 2009

Due to environmental concerns, biodegradable materials, which are currently used in many medical applications, are being considered as a candidate for replace plastics in the future. One of the most common mass production processes to shape biodegradable materials is injection molding. However, the material manufacturers usually do not provide optimized parameter information. In
this research, two biodegradable materials, PLA 3001D and Biomax, are investigated. Experiments are conducted utilizing the Taguchi method to determine optimal injection molding parameters, which include injection speed, injection pressure, holding pressure, and cooling time. Shrinkage was the major index to evaluate the injection results. As a result, the best combinations of parameters
were determined.
Development of a Drop-On-Demand Micro Dispensing System
Authors: Feng Wei , Fuh Jerry Y.H. , Wong Yoke San
Published: March 2009

This paper presents the development a drop-on-demand micro-dispensing system on which functional devices can be directly printed in a layer-by-layer manner that is commonly used in Rapid Prototyping and Manufacturing processes. The principle is to form micro droplets on substrate that requires accuracy and consistency with the ability to build 3D model. It requires heating of material to a desired temperature and viscosity which allows the piezoelectric the ability to pump out. In order to build a 3D model, a basic XYZ-axis gantry, motion controller and dispenser with temperature controller were developed and integrated. Experiments with different
materials were carried out to understand the influences of the dispensing parameters on continuous frequency output. The results hold attractive potential for the use of this system in fabricating 3D models which meet the accuracy and resolution needs for various industry applications.
A Genetic Approach on the PID Control of VCM for Auto-Focusing Laser Probe
Authors: Torng Jingsyan , Fan Kuang Chao , Lu Tien Fu
Published: March 2009

DVD player is regarded as a mature and low-cost commercial product for multimedia and computer data storage. Fundamentally the pickup head is a key part of the DVD player and it uses focused laser beam to read the data on the DVD disk tracks whose width is approximately 0.74μm. This research focused on the control aspect applied to a DVD pickup head for the development of an auto-focusing laser probe. Practically, the laser pickup head has the S-curve linearity property with
the measuring range of about 7μm [3]. To extend the measurement range, the feedback control of VCM in the focusing direction is needed. This study used Genetic Algorithms (GAs) to search for appropriate PID gains for VCM control. In MATLAB simulation, the GAs tuning scheme could produce the optimised gains within less than 0.02 sec. Moreover, the experimental results demonstrated that the VCM auto-focusing measurement range could be extended to 1350μm.
Valveless Micropumps with One or Two Piezoelectric Buzzers
Authors: Hong Zheng Han , Hwang Shun Fa
Published: March 2009

Valve-less micropumps with one or two piezoelectric buzzers are manufactured and tested. Piezoelectric buzzers are chosen as actuation elements because they are cheap and with high actuation amplitude. The micro-chamber with nozzle and diffuser is fabricated by employing UV photolithography and film mask. A negative photoresistive material, SU8-50, is used as a structure material, and exact angles in the inlet/outlet elements can be obtained. PDMS is chosen to bond
different parts of the micropump. The piezoelectric buzzer does have nice actuation amplitude of 40.4 μm after the assembly with the chamber. The results indicate that the micropump with one piezoelectric buzzer has a maximum flow rate of 90.28μl/min when the buzzer is actuated at 100 V and 20 Hz. A maximum backpressure of 50 mm H2O occurs as the buzzer is actuated at 100 V and 30 Hz. For the micropump with two piezoelectric buzzers, it has a maximum flow rate of 165.32 μl/min when the buzzer is actuated at 100 V and 20 Hz and has a maximum backpressure of 84 mm H2O as the buzzer is actuated at 100 V and 30 Hz.
An Immune Algorithm for Least Cost Advanced Tolerance Design Problem
Authors: Chen Ta Cheng , Hsu Tung-Chou
Published: March 2009

This paper considers nonlinearly mixed integer tolerance allocation problems in which both tolerance and process selection are to be decided simultaneously so as to minimize the manufacturing cost. The tolerance allocation problem has been studied in the literature for decades, usually using mathematical programming or heuristic/metaheuristic optimization approaches. The difficulties encountered for both methodologies are the number of constraints and the difficulty of
satisfying the constraints. A penalty-guided artificial immune algorithm is presented for solving such mixed integer tolerance allocation problems. Numerical examples indicate that the proposed artificial immune algorithms perform well for the tolerance allocation problem considered in this paper. In particular, as reported, solutions obtained by artificial immune algorithm are as well as or better than
the previously best-known solutions.