bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Characteristics of Efficient-Ground Alumina and Zirconia Ceramics for Dental Applications
Authors: Kasuga H. , Ohmori Hitoshi , Watanabe Y. , Mishima T.
Published: March 2009

Progress of new dental materials such as biocompatible metal, ceramics is being accelerated because of aging society and sophistication of medical treatment. In addition, the demand for dental implant treatment is increasing. Currently, dental implant crowns (superstructures) are formed by cutting semi-sintered ceramics and then sintering the ceramics at a high temperature. So, there is some concern that to maintain the form accuracy of the workpiece is difficult. Meanwhile, it is usually difficult to machine sintered ceramics with high precision and high efficiency. In this paper, we tried to apply grinding with metal bonded superabrasive wheels, and investigated the grinding and surface characteristics of an alumina and zirconia ceramics for dental implant superstructure due to lack of such data. As a result of experiments, sintered dental ceramics can be ground with high precision and Fe, it has harmful effect to human body, was not detected in sintered dental ceramics.
Preparation and Application of High-Rise Building for Pumping Lightweight Aggregate Concrete
Authors: Wang Jun , Gao Yu Xin , Hu Guo Fu , Zhou Jie Gang , Yang Wen , Zhang Heng Chun
Published: March 2009

As large flow pattern lightweight aggregate concrete is float up easily, slump loss quickly under the pumping pressure, and pumped hard. Improving the homogeneous and Reducing the slump loss will be the key technology of pumping lightweight aggregate concrete. Researched on the technology of large flow pattern lightweight aggregate concrete, and prepared the concrete, whose strength is over 50MPa, was suitable for high-rise building. The concrete has been succeeded in pumping on high-rise building, and the height of pumping is 181.4m.
Improvement of Concrete Durability by Composite Cement
Authors: Feng Nai Qian , Niu Quan Lin , Li Chong Zhi
Published: March 2009

Mineral powders play positive role in improving the durability of concrete subjected to alkaline and saline corrosion, where sulphate ion and chloride ion coexisted may cause serious deterioration to the reinforced concrete structures. Metakaolin, slag, fly ash and natural zeolite mixed in appropriate proportion were tested in inhibiting the deterioration. It is found that the composite powder might decreased AAR and the charge passed of concrete effectively，the while the 7d and 28d strength of cement and concrete are improved as well.
Characteristics of Zeolite Plasticizer
Authors: Feng Nai Qian , Shi Yun Xing , Niu Quan Lin
Published: March 2009

Absorption and d esorption of super plasticizer by zeoltie were investigated, and zeolite superplasticizer with zeolite as carrier was produced. The addition of zeolite superplasticizer in cement and concrete increases the paste fluidity and concrete slump, while the loss of fluidity and slump are effectively controlled.
Evaluation of Concrete Permeability by Monitoring Alkali Saturated Conductivity of Concrete Incorporating Mineral Admixtures
Authors: Niu Quan Lin , Feng Nai Qian
Published: March 2009

Concrete conductivity is the reflection of the micro pore structure and the pore solution conductivity of concrete, but the conductivity of pore solution changes considerably as different mineral admixtures are added, though the change is not always relevant to permeability and Cl- diffusivity. Saturation of concrete capillary pore system with 1 mol/l KOH solution through vacuum processing was tempted to maintain the pore solution conductivity constant, after which the concrete conductivity was a reflection of concrete porosity and tortuousity that closely related to Cl- diffusivity. Charge passed of concrete was also measured for comparison. It is shown that the conductivity of alkali saturated concrete without mineral admixtures was the biggest, followed by the concrete with natural zeolite（20％）, fly ash（30％）, slag（40％）metakaolin 20% and 10% of silica fume.
Influence of Polypropylene Fiber and Silica Fume on the Chloride Penetration of High Performance Concrete with Fly Ash
Authors: Liu Jing , Deng De Hua , Yin Ming , Hu Xu Li
Published: March 2009

In this paper, the influence of polypropylene fibers (PPF) and silica fume (SF) on chloride penetration of high performance concrete (HPC) containing fly ash (FA) was examined. Three different HPC in which the amount of ordinary Portland cement is 360 kg/m3, via., A concrete with 120 kg/m3 of FA, B concrete with 0.9 kg/m3 of PPF and 120 kg/m3 of FA, C concrete with 0.9 kg/m3 of PPF and 96 kg/m3 of FA and 24 kg/m3 of SF were used for the study. Chloride resistance of concrete was evaluated. From the tests, it is found that the incorporation of PPF and no SF has less influence on the chloride resistance of the fly ash concrete at the age of 28 days. SEM examines B and C concretes specimens illustrating that just incorporating PPF induced more porous fiber-matrix interfacial zone (FMIZ) in B concrete which is detrimental to the chloride resistance, but the microstructures of both the matrix and FMIZ in C concrete with PPF and SF are denser. The plastic shrinkage cracking test proves that the cracking areas on the surface of B and C concrete with PPF are 12.2% and 20.7% of A concrete without PPF respectively.
The Study of Mixing for Underground High Performance Concrete in Coastal Environment
Authors: Xing Feng , Huang Zhan , Dong Bi Qin , Yin Hui , Liu Jun , Zhang Ming
Published: March 2009

The paper discussed the mix principle, performance target and the technical demands for the underground high performance concrete combined the Shenzhen side-connection item of Shenzhen-Hong Kong West Channel project. The better mix proportion of underground high performance concrete is brought forward, which can direct the construct units and the concrete servers to produce the high quality concrete that fit for the underground project.
Ultra High Performance Cementitious Hybrid and Flexural Analysis of the UHPCC-NC Hybrid Structure with Full Shear Connection
Authors: Wu Xiang Guo , Xu Shi Lang
Published: March 2009

The analysis of material variables and curing procedure design are the key techniques of UHPCC. Material variables include cement-water ratio, silica fume content, sand’s content and size, filling powder’s content and type. Based on the objective of compressive strength, UHPCC with compressive strength 180MPa was developed based on the influence analysis of material variables on its performances and the substitution of silica fume by lime stone powder. By the analysis of the influences of early curing method, initial time, duration time and high temperature curing, curing procedure design was proposed, i.e. early water curing at first after 24 hours of casting and then high temperature steam curing. Based the simplified constitutive relation of UHPCC, the ultimate flexural of UHPCC hybrid girder was analyzed. This paper can be a basis of UHPCC-NC hybrid structure analysis.
The Effect of Specimen Dimensions on Obtained Tensile Properties of Sheet Metals
Authors: Han Li , Reynolds Neil C. , Dargue I. , Williams G.
Published: March 2009

A pilot study has been carried out to examine the effect of specimen dimensions on the obtained tensile properties of aluminium and steel sheet. The materials used were DP600 grade steel and AA5754 grade aluminium sheet. Four types of dog-bone samples with varying dimensions were tested for both materials. Standard tensile test procedures were performed using a universal test machine together with contacting extensometry. The GOM Aramis photogrammetric 2D strain mapping technique was also applied. The results suggest that for both steel and aluminium sheet materials, differing specimen dimensions have little effect on the obtained mechanical properties. Depending on the gauge length of extensometer chosen and the position at where necking occurred on the sample, the extensometry results and 2D strain mapping results slightly differed towards to the end of stress-strain curve. The failure mode between the chosen grades of steel and aluminium samples was observed to differ, as did the percentage of failures that occurred within the gauge length. All steel samples fractured across the specimen perpendicularly to the test direction; whilst fracture of aluminium samples occurred approximately 30 degrees from the perpendicular.
Springback Compensation by Superposition of Stress in Air Bending
Authors: Weinrich Andres , Ben Khalifa Nooman , Chatti Sami , Dirksen Uwe , Tekkaya A. Erman
Published: March 2009

In the sheet metal processing industry bending is one of the common metal forming processes. Depending on the process state, a differentiation has to be made between free bending (air bending) in the die and coining (die bending). Because of its flexibility the air bending process is nowadays one of the widely applied processes for sheet metal bending, but the springback phenomenon is still a great challenge for the industrial application. At the Institute of Forming Technology and Lightweight Construction (IUL) of the Technische Universität Dortmund, Germany, a new method has been developed allowing the compensation of springback effects in air bending of sheet metals. This method is based on the incremental and local superposition of stresses in the forming zone. The superposition occurs after the bending operation but before unloading along the sheet metal width. The advantage of this new method is that a minimal force is required to compensate the springback. This paper describes the springback compensation method in detail and presents first experimental results.
Grain Surface Relaxation and Grain Interaction in Powder Diffraction
Authors: Leoni Matteo
Published: March 2009

The role of grain surfaces and interfaces in nanocrystalline materials is investigated by X-ray diffraction (XRD). Two apparently distinct aspects show the importance of the interaction of a single grain with the environment in which it is placed: the role of grain-grain interaction in determining the residual stress in a polycrystalline thin film and the surface effects in single powder grains on the macroscopic average cell parameter determined by powder diffraction. A brief theoretical introduction of the phenomena and their possible modelling is presented together with a discussion of practical examples.
128-Channel Silicon Strip Detector Installed at a Powder Diffractometer
Authors: Zięba A. , Dąbrowski W. , Gryboś P. , Pawroźnik W. , Słowik J.R. , Stobiecki T. , Świentek K. , Wiącek P.
Published: March 2009

Silicon strip detectors represent a new class of one-dimensional position-sensitive single photon counting devices. They allow a reduction of measurement time at the powder diffractometers by a factor up to 100 compared to instruments with a single counter, while maintaining comparable count statistics. Present work describes a 128-channel detector working with a standard diffractometer. The detector is 12.8 mm long and covers the angular range of 3.2 deg. We discuss the diffraction geometry in real and reciprocal space, the FWHM of diffraction peaks, and the
background level. Measurements were made on standard samples and on complex samples of industrial importance (e. g., portland clinker). Applications of the detector to diffraction measurements of single crystals and thin films are discussed briefly.
New Principles of the Substructure Development in Metal Materials under Plastic Deformation, Revealed by Advanced X-Ray Methods
Authors: Perlovich Yuriy , Isaenkova Margarita
Published: March 2009

The substructure inhomogeneity of real textured metal materials was studied by use of the X-ray method of Generalized Pole Figures and the computer data treatment. Main regularities of substructure inhomogeneity were revealed for the first time. Substructure conditions of grains in rolled material form an extremely wide spectrum and vary by passing from texture maxima to texture minima, where residual deformation effects are most significant. The distribution of residual elastic microstrains in the orientational space of rolled material shows the distinct system.
Quantitative Texture Analysis and Phase Fraction of Nickel-Titanium Shape Memory Alloys by Means of Neutron Diffraction
Authors: Sitepu H. , Brokmeier Heinz Günter
Published: March 2009

The orientation distribution function (ODF) of the textured polycrystalline nickel
titanium (NiTi) shape memory alloys (SMAs) was determined from the measured austenitic (B2)pole-figures by neutron diffraction. The texture results showed that neutron diffraction is an excellent tool to investigate the minor variation in the texture of NiTi alloys, which is very sensitive to the variation of the content of nickel in the materials. Moreover, the alloys crystallographic phase fraction and texture were calculated from Rietveld refinement with generalized spherical harmonic
(GSH) description for the measured complete neutron powder diffraction (ND) spectrum, rather than a few isolated peaks, during in-situ temperature-induced martensitic transformation. The phase fraction results are consistent with the differential scanning calorimeter (DSC) curves.
Calibration of Diffractometers: A Test Method to Monitor the Performance of Instruments
Authors: Berti Giovanni , Bartoli U. , D'Acunto M. , De Marco F.
Published: March 2009

Reproducibility of diffraction experiments provides an indication of data
consistency with respect to different variables. The level of reproducibility and accuracy of the diffraction measurements is increased when using calibrated instruments. The paper presents most significant results of the 'Calibration Monitoring of Diffractometers', a project using a systematic approach to the Round Robin tests. At the present stage, the results suggest that instrumental performances and other related experimental effects in a diffraction the
experiment can be summarised through 'characteristic curves'.
Neutron and X-Ray Diffraction Studies of Piezoelectric Materials under Non-Ambient Conditions
Authors: Haines J. , Cambon O. , Rouquette J. , Bornand V. , Papet Ph. , Léger J.M. , Hull S.
Published: March 2009

In depth study of the crystal structures of piezoelectric materials as a function of
temperature, pressure and composition allows for the design and optimization of such materials and defines the conditions of their use in technological applications. Results from studies on two classes of piezoelectric materials are described, the α-quartz group and the ferroelectric perovskite group.
The structures of α-quartz-type germanium dioxide and iron phosphate were refined at high temperatures by the Rietveld method using time-of-flight neutron powder diffraction data. The α-β phase transition occurs at 980 K in FePO4, whereas for GeO2, no β phase is observed. The intertetrahedral bridging angle θ and the tilt angle δ in GeO2 exhibit thermal stabilities that are significantly greater than α-quartz. The temperature dependence of these angles is found to be a function of the initial structural distortion in α-quartz homeotypes with the notable exception of α-quartz-type FePO4, which appears to be dynamically unstable. The stability of α-quartz and α-quartz-type germanium dioxide was investigated at high pressure by x-ray powder diffraction. New six-fold coordinated forms were found in both materials.
The important, perovskite-type, piezoelectric material PbZr0.52Ti0.48O3 was studied up to 18 GPa by angle-dispersive, x-ray diffraction using an imaging plate and by Raman spectroscopy. A novel phase transition was found in this system at close to 5 GPa. Whereas the x-ray diffraction data indicated no deviation from cubic symmetry above this pressure, a strong Raman signal was present in this phase, which is similar to those observed for ferroelectric relaxors.
The Hunt for Hydrogen in the High-Pressure Phase of Ca(OH)2 and Ca(OD)2: Neutrons Versus X-Rays
Authors: Papoular Robert J. , Kunz Martin
Published: March 2009

A recent measurement on the high-pressure phase of Ca(OH)2 using high-resolution synchrotron X-ray powder diffraction has been carried out on a hydrogenated sample at high-temperature. It complements an earlier time-of-flight neutron measurement carried out in the US on a deuterated sample at low temperature. The two protons are found by Rietveld refinement using a new suitable non-Fourier based strategy, for which GSAS and FullProf yield very similar results.
Our X-ray result agrees with the previous neutron study for one proton site only, prompting us to reinvestigate the neutron data. A second new and distinct non Fourier-based strategy coupled with GSAS is used to tackle the latter data and indeed confirms the US results. Whilst the reasons for this X-Ray vs Neutron discrepancy can only be guessed at this stage, the use of the two related
proton-finding strategies could be extended beyond our specific study.
FOX: Modular Approach to Crystal Structure Determination from Powder Diffraction
Authors: Favre-Nicolin V. , Černý R.
Published: March 2009

Program FOX for ab initio crystal structure determination from powder diffraction uses global optimization algorithms to find the correct structure by making trials in the direct space. It is a modular program, capable of using several criteria for evaluating each trial configuration, e.g. combining neutron and X-ray diffraction patterns. The program describes the structural building blocks (polyhedrons, molecules etc.) with their internal coordinates (Z-matrices), thus allowing
natural constraints on interatomic distances and angles. Identical atoms shared between neighboring building blocks, and special positions are handled with an automatic, adaptive method (Dynamical Occupancy Correction). Several algorithms (Simulated Annealing, Parallel Tempering) are currently
available. The program is based on an object-oriented crystallographic library ObjCryst++(programming language c++). The program and the library are available for Linux and Windows on http://objcryst.sourceforge.net. Inorganic and organic structures with the complexity up to 26 independents atoms are routinely solved from laboratory X-ray, synchrotron or neutron data.
A Neutron Diffraction Study of Magnetically Ordered Ferroelectric Materials
Authors: Ivanov S.A. , Eriksson S.-G. , Tellgren Roland , Rundlöf Håkan
Published: March 2009

Structural, magnetic, dielectric properties and Mossbauer effect were
investigated on complex perovskite with composition AFe2/3B1/3O3 (A=Ca,Sr,Pb,Ba;
B=W,Te). The most striking feature of this type of complex perovskites is the coexistence of magnetic and antiferroelectric types of ordering in a certain temperature interval. It was found that ferrimagnetic Ca and Sr compounds belong to a partially ordered perovskite structure, and antiferromagnetic Pb phase to a disordered one. The possible models for nuclear and magnetic structures were proposed in accordance with the observed dielectric and magnetic properties.
X-Ray Scattering from Thin Films and Multilayers
Authors: Rafaja David
Published: March 2009

Capability of the X-ray scattering for study of low-dimensional structures is illustrated on few examples. They are focused to the phase analysis, residual stress measurement, calculation of the stress-free lattice parameters, investigation of the anisotropic lattice deformation and preferred orientation in UN thin films. Further, the study of concentration profiles in functionally graded hard-metals and investigation of the multilayer degradation caused by soft annealing are discussed.
Ultrafine Grained Bulk 5083 Al Alloy Produced by Cryogenic Rolling Process
Authors: Nam Won Jong , Lee Young Bum , Shin Dong Hyuk
Published: March 2009

The large deformation at cryogenic temperature would be one of the effective methods to produce large bulk UFG materials. The effects of annealing temperature on microstructure and mechanical properties of the sheets received 85% reduction at cryogenic temperature were investigated for the annealing temperature of 150 ~ 300°C , in comparison with those at room temperature. Annealing of 5083 Al alloy deformed 85%, at 200°C for an hour, results in the considerable increase of tensile elongation without the great loss of strength and the occurrence of equiaxed grains less than 300nm in diameter.
In-Situ Orientation Rotation Behavior Study during Tensile Deformation of Aluminum Single Crystal and Polycrystal
Authors: Han Jun Hyun , Kim Dong Ik , Jee Kwang Koo , Oh Kyu Hwan
Published: March 2009

Orientation rotation behaviors taking place in aluminum single crystal and polycrystal
were studied during uniaxial tensile deformation at room temperature. Specimens were elongated in an in-situ deformation stage equipped on a high resolution electron backscattered diffraction (HREBSD)system. A series of crystallographic evolution and deformation behavior of concerned areas in the specimens during deformation was directly analyzed using HR-EBSD.
Dry Sliding Wear Characteristics of Severely Deformed 6061 Aluminum and AZ61 Magnesium Alloys
Authors: Kim Yong Suk , Ha J.S. , Kim Woo Jin
Published: March 2009

Dry-sliding-wear behavior of ultra-fine grained 6061 Al alloy and AZ61 Mg alloy was investigated. The accumulative roll bonding (ARB) and the equal channel angular pressing (ECAP) processes were employed to obtain refined microstructures in the Al and Mg alloys, respectively. Pin-on-disk wear tests of the processed alloys were carried out with various applied load against a 304 stainless steel counterpart. In spite of the increased hardness and strength, wear resistance of the ultra-fine grained 6061 Al alloy was lower than that of the coarse-grained starting alloy. The strength and wear resistance of the ECAP processed AZ61 Mg alloy did not change appreciably despite the refined microstructure. Recrystallization was found to occur during the ECAP process of the Mg alloy. Worn surfaces and cross-sections of the wear-tested specimens were examined to investigate the wear mechanism of the ultra-fine grained Al and Mg alloys.
Molecular Dynamics Simulation of Stress Induced Grain Boundary Migration during Nanoindentation Experiments
Authors: Yoon Jang Hyuk , Kim Seong Jin , Jang Ho
Published: March 2009

Molecular dynamics (MD) simulation was performed to study the stress induced grain boundary migration caused by the interaction of dislocations with a grain boundary. The simulation was carried out in a Ni block (295020 atoms) with a Σ = 5 (210) grain boundary and an embedded atom potential for Ni was used for the MD calculation. Stress was provided by indenting a diamond indenter and the interaction between Ni surface and diamond indenter was assumed to have a fully
repulsive force to emulate a traction free surface. Results showed that the indentation nucleated perfect dislocations and the dislocations produced stacking faults in the form of a parallelepiped tube. The parallelepiped tube was comprised of four {111} slip planes and it contained two pairs of parallel dislocations with Shockley partials. The dislocations propagated along the parallelepiped slip planes
and fully merged onto the Σ = 5 (210) grain boundary without emitting a dislocation on the other grain. The interaction of the dislocations with the grain boundary induced the migration of the grain boundary plane in the direction normal to the boundary plane and the migration continued as long as the successive dislocations merged onto the grain boundary plane. The detailed mechanism of the
conservative motion of atoms at the grain boundary was associated with the geometric feature of the Σ = 5 (210) grain boundary.
Finite Element Simulations of 3D Zener Pinning
Authors: Couturier G. , Maurice Claire , Fortunier R. , Doherty R. , Driver Julian H.
Published: March 2009

An original model, based on a variational formulation for boundary motion by viscous
drag, is developed to simulate single grain boundary motion and its interaction with particles. The equations are solved by a 3D finite element method to obtain the instantaneous velocity at each triangular element on the boundary surface, before, during and after contact with one or more particles. After validation by comparison with some simple, analytical and numerical cases, it is adapted to model curvature driven grain growth. For single phase material, the single grain boundary model closely matches the grain coarsening kinetics of a 3D multi boundary vertex model.
In the presence of spherical incoherent particles the growth rate slows down to give a growth exponent of 2.5. When the boundary is anchored there is a significantly higher density, by a factor of 4, of particles on the boundary than the density predicted by the classic Zener analysis, and many particles exert less than this Zener drag force. As a result the Zener drag is increased by a factor of about 2.2. The limiting grain radius is compared with some experimental results.
Simulating the Interaction between a Straight Boundary and a Particle
Authors: Radhakrishnan B. , Sarma G.B.
Published: March 2009

The paper describes large scale, three-dimensional, Potts model simulations of the interaction between a coarse particle and a straight boundary driven by a bulk stored energy difference across the boundary. It is shown that the variation of the interaction energy as a function of the interface position is significantly affected by the choice of the lattice temperature. The maximum force offered by the particle on the grain boundary decreases with increasing lattice temperature and approaches the theoretical limit at high lattice temperatures. The boundary velocity responds appropriately to changes in the magnitude and direction of the interaction force only at high lattice temperatures.
Monte Carlo Method for Simulating Grain Growth in 3D Influence of Lattice Site Arrangements
Authors: Solas Denis , Gerber Ph. , Baudin Thierry , Penelle Richard
Published: March 2009

A three-dimensional Monte Carlo computer simulation technique has been applied to the problem of normal grain growth. A continuum system is modelled employing a discrete lattice. In this paper we investigate the connectivity of the points that represent the discretized microstructure. The lattice can have a strong influence on the result of the simulation. Only the BCC lattice with 14 neighbours gives similar results than the traditional simple cubic model with 26 neighbours. If we consider the computing time and the required computer memory, the BCC-14 model is a good
alternative to the SC-26 model for simulating normal grain growth.
Synchrotron Radiation Investigation of Thermal Stability and Grain-Growth in Pure and Metal-Doped Nanocrystalline TiO2
Authors: Nicula R. , Stir M. , Burkel E.
Published: March 2009

The crystallization and coarsening of pure and metal-doped (M: Ag, Fe, Co) TiO2 amorphous specimens were studied during in-situ synchrotron radiation diffraction experiments. The temperature and time dependence of the average grain-size of TiO2 anatase and rutile constituent phases was determined. Excess vacancies, secondary phases or solute elements cause the pinning of the grain-boundary motion, control the onset of the anataserutile transition and control the thermal stability of ultrafine microstructures in nanocrystalline TiO2 ceramics.
Thermal Stability of Electrodeposited Ni and Ni-Co Layers; an EBSD-Study
Authors: Rasmussen A.A. , Gholinia Ali , Trimby Patrick W. , Somers Marcel A.J.
Published: March 2009

The influence of heat treatment on the microstructure and the microtexture of electrodeposited Ni and Ni-Co layers was investigated with Electron Backscatter Diffraction (EBSD) with high resolution. Samples were annealed for 1 hour at 523 K and 673 K, the temperature region wherein recrystallisation occurs. The results are discussed in relation to the resolution of EBSD for the very fine grained electrodeposits and previous X-ray diffraction investigations.
3DXRD – Mapping Grains and Their Dynamics in 3 Dimensions
Authors: Poulsen Henning Friis , Fu Xing , Knudsen Erik , Lauridsen Erik M. , Margulies L. , Schmidt S.
Published: March 2009

3-Dimensional X-Ray Diffraction (3DXRD) microscopy is a tool for fast and non-destructive characterization of the individual grains, sub-grains and domains inside bulk materials. The method is based on diffraction with highly penetrating hard x-rays, enabling 3D studies of millimeter - centimeter thick specimens. The position,
volume, orientation, elastic and plastic strain can be derived for hundreds of grains
simultaneously. Furthermore, by applying novel reconstruction methods 3D maps of
the grain boundaries can be generated. With the present 3DXRD microscope set-up at the European Synchrotron Radiation Facility, the spatial resolution is ~ 5 µm, while
grains of size 100 nm can be detected. 3DXRD microscopy enables, for the first time, dynamic studies of the individual grains and sub-grains within polycrystalline
materials. The methodology is reviewed with emphasis on recent advances in grain
mapping. Based on this a series of general 3DXRD approaches are identified for
studies of nucleation and growth phenomena such as recovery, recrystallisation and
grain growth in metals.
Effect of the Degree of Order and the Deformation Microstructure on the Kinetics of Recrystallisation in a Fe3Al Ordered Alloy
Authors: Kobayashi Satoru , Zaefferer Stefan , Schneider André , Raabe Dierk , Frommeyer Georg
Published: March 2009

A Fe3Al based single phase alloy was rolled at 600 °C and 400 °C and the kinetics of recrystallisation in A2 and B2 phase regions was determined in conjunction with the kinetics of the A2-B2 ordering and recovery. At 700°C and 800°C the recrystallisation kinetics depends strongly on the temperature of rolling while at 900°C only a small influence is visible. These results are attributed to the high stored energy in the sample rolled at 400 °C and its high recovery rate at 900 °C, leading to a similar level in stored energy as for the sample rolled at 600 °C in the beginning of annealing. At lower temperatures, in contrast, the difference in stored energy is conserved over longer times in the annealing process. Almost half the apparent activation energy was observed in the ordered state compared to that in the disordered state.
Cold Rolled Microstructure and Its Evolution during Recovery and First Recrystallisation Stages in Low Carbon Steels
Authors: Díaz-Fuentes M. , Novillo E. , Iza-Mendia Amaia , Gutiérrez Isabel
Published: March 2009

During annealing of cold rolled steel sheets, the evolution of the texture, to produce the characteristic texture of a recrystallised material, depends on a series of factors, including the starting deformation texture, composition and processing conditions. In the present work, electron backscattered diffraction (EBSD) techniques have been used to investigate the deformation substructures being developed by cold rolling into grains belonging to different texture components. The strain localisation, the deformation banding, the spread in orientation into grains with different orientations are some of the aspects that have been considered. Annealing cycles at different temperatures have also been carried out in order to promote recovery and initial stages of recrystallisation . The obtained substructures have been compared to the as-cold rolled ones. It has been observed that recovery induces the dislocation structures to arrange into subgrains. Associated to the ND fibre, a network of relatively high angle boundaries develop within the subgrain structure. The recrystallisation nuclei have been observed to evolve from such a network.
Microstructural Parameter-Based Characterization of Annealing Behaviour in Metals Deformed to High Strains
Authors: Liu Qing , Cao W.Q. , Godfrey Andrew
Published: March 2009

The transition from discontinuous recrystallization to a continuous recovery process
during annealing of aluminium deformed to high plastic strains has been investigated by following several different microstructural parameters. Samples were examined following equal channel angular extrusion (ECAE), accumulated roll bonding (ARB) and high-strain conventional rolling (HSCR). Local variations in the uniformity of coarsening have been characterized by an analysis of grain size distributions, obtained from electron backscatter pattern investigations. Except for at the lowest strains the distributions were not obviously bimodal. Methods of separating the distributions into two parts based on the mean value have therefore also been examined. The results suggest that the presence of a high fraction of high angle boundaries (>15o) in the microstructure may be a necessary but not sufficient condition for continuous recovery during annealing. The annealing
behaviour can be related in part to the heterogeneity of the deformed microstructures, which can be pronounced even after strains of ≈ 10 (ECAE). The presence of oxide particles in the ARB sample has a beneficial effect in limiting the grain growth.
Grain Growth Texture Evolution in Zirconium (Zr702) and Commercially Pure Titanium (T40)
Authors: Bozzolo Nathalie , Dewobroto N. , Grosdidier Thierry , Barbéris Pierre , Wagner Francis
Published: March 2009

Primary recrystallization of a 80% cold–rolled T40 or Zr702 sheets leads to equiaxed microstructures. Subsequently, only normal grain growth takes place in T40 while a few grains can grow abnormally after sufficient time at high annealing temperature (close to the transus) in Zr702. The grain sizes reached after extended grain growth at moderate temperatures in Zr702 are smaller than in T40. The presence of precipitates in Zr702 is probably responsible for this and also for the abnormal phenomena observed at high temperature in this material. The texture changes occurring in both materials under normal grain growth conditions (often roughly described as “30° rotation around c axes”) are due to the development of the largest grains produced by the primary recrystallization. These large grains are preferentially oriented around {j1=0°, F=30°, j2=30°} for T40 and around {j1=0°, F=25°, j2=30°} for Zr702, orientations which become predominant after extended grain growth.
Investigation of Subgrain Rotation Recrystallization in Dry Polycrystalline NaCl
Authors: Pennock G.M. , Drury M.R. , Spiers C.J.
Published: March 2009

NaCl is plastically anisotropic and forms a well developed substructure during deformation at 0.3-0.5Tm. EBSD was used to assess subgrain misorientations up to 0.5 true strain in dry NaCl. Equiaxed subgrains were ubiquitous but misorientations along segments of subgrain boundaries differed. Three types of subgrain boundary were identified: boundaries that surrounded equiaxed subgrains, boundaries that partly surrounded mantle subgrains, and extended subgrain boundaries, longer than the equiaxed subgrains. All of these subgrain features were recognised at low strains, <0.15. Misorientations of the majority of equiaxed subgrains were generally <2° at 0.5 strain, although segments could reach higher misorientations along kink-like boundaries. Mantle subgrains along grain boundaries tended to develop higher misorientations than in core subgrains. Long subgrain boundaries reached very high misorientations along segments of their length by 0.5 strain. Small new grains formed at triple points and more rarely within grains. Microstructures in NaCl are similar to those found in aluminium. Therefore, the dominant mechanism of high angle subgrain development at 0.5 strain and at 0.4Tm is probably an orientation splitting mechanism rather than equiaxed subgrain rotation.
The Effect of Initial Grain Size on the Microstructures Developed during Cold Rolling of a Single-Phase Aluminium Alloy
Authors: Jazaeri H. , Humphreys John F.
Published: March 2009

High resolution Electron Backscatter Diffraction (EBSD) in a field emission gun scanning electron microscope (FEGSEM) was used to study substructural development during the deformation by cold rolling of a single-phase Al-0.1Mg alloy with initial grain sizes between ~3µm and 120µm. In the coarse-grained material, bands of elongated cells aligned at approximately 35º to the rolling direction were formed at low strains. However, as the grain size was reduced, fewer of these aligned microstructural features were formed, and at the smallest grain sizes, there was little evidence of significant substructure within the deformed grains. The alignment of low angle boundaries was analysed from EBSD data and shown to be a function of grain size, strain and boundary misorientation.
Evolution of Non-Oriented Silicon Steel Texture on Recrystallization and Grain Growth
Authors: Da Cunha Marco Antônio , Da Costa Paolinelli Sebastião
Published: March 2009

The evolution of annealing texture of non-oriented grain silicon steel as a function of annealing temperature was investigated from hot rolled samples taken from industrial production. Hot band samples were annealed at 900°C, cold rolled to final thickness of 0.5mm in a single stage cold rolling process or in two stages with intermediate annealing at 900°C, and final annealed in the temperature range from 540°C to 980°C. The results show that the [001]||RD fibre is an important recrystallization texture component, but it may be consumed by further grain growth and become a minor component. The effect of grain growth in the temperature range investigated seems to be that of strengthening the main components at the expenses of the others. The results suggest that to avoid the reduction of the [001]||RD fibre on grain growth a volume fraction ratio between the texture components (111)[112] and (110)[001] close to unity is necessary after recrystallization. This can be obtained under conditions that enhance [001]||RD fibre on recrystallization, such as: strong [111]ND fibre in the deformation texture, large initial grain size and enhanced grain boundary mobility, by proper composition and purity.
Consideration of Crystallographic Neighbourhood in Magnetic Sheets of Fe3%Si. Behaviour Prediction of Grain Growth from the Texture Function
Authors: Rouag N. , Afer H. , Penelle Richard
Published: March 2009

The abnormal grain growth is related to the material texture, in the magnetic sheets
Fe3%Si of HiB type, with AlN and MnS inhibitors. The onset of abnormal growth of Goss grains seems to be linked to the existence of a local favourable crystallographic neighbourhood. The grains which abnormally grow do not have a size greater than the average size in the matrix, their ability to grow in an abnormal way can be related to the local evolution around that considered grain, the whole effect of the matrix can hide the effect of matrix heterogeneity.
Nucleation During Recrystallisation in Ti-SULC Steel
Authors: Seaton N.C.A. , Prior David J.
Published: March 2009

This work is part of a PhD study which investigates mechanisms of nucleation during recrystallisation in steels. A specially built SEM with EBSD and heating stage allows us to observe static recrystallisation in situ. Changes in samples of Ti-stabilised ultra low carbon steel heated to 550°C are documented via still images, videos and automated EBSD maps. Recrystallisation begins rapidly but slows down within an hour. A temperature increase to 850°C forces complete recrystallisation. EBSD mapping shows that the ‘new’ grains appear first on the boundaries of deformed {111} grains and have high angle misorientations with the deformed grains, although the new grains are also of {111} type. {111} type deformed grains are recrystallised first due to their higher stored energy relative to {001} grains. Mapping of a section through the sample along the rolling direction reveals intragranular shear bands. Future work will look at these sites in more detail to determine their role as sites for nucleation.
A Neural Network Approach for Milling Process Control
Authors: Yang Z. , Huang T. , Yang Y.M.
Published: March 2009

One of key approaches to improve the productivity is to control with constant force in the milling process by adjusting the feed rate. In order to overcome the mismatch model occurred in adaptive control and inaccurate deducing regulation in fuzzy logic control, a three-layer BP neural network is designed for tracing reference force. First of all, control arithmetic is given, and a series of simulation work is achieved to determine the study factor. At last, aimed at two working conditions with abrupt and gradual change of cutting depth, the correctness and effectiveness of the neural network controller are proved by experiments.
Molecular Dynamics Simulation on the Mechanism of Nanometric Machining of Single-Crystal Silicon
Authors: Wu Hui , Lin Bin , Yu S.Y. , Zhu Hong Tao
Published: March 2009

Molecular dynamics (MD) simulation can play a significant role in addressing a number of machining problems at the atomic scale. This simulation, unlike other simulation techniques, can provide new data and insights on nanometric machining; which cannot be obtained readily in any other theory or experiment. In this paper, some fundamental problems of mechanism are investigated in the nanometric cutting with the aid of molecular dynamics simulation, and the single-crystal silicon is chosen as the material. The study showed that the purely elastic deformation took place in a very narrow range in the initial stage of process of nanometric cutting. Shortly after that, dislocation appeared. And then, amorphous silicon came into being under high hydrostatic pressure. Significant change of volume of silicon specimen is observed, and it is considered that the change occur attribute to phase transition from a diamond silicon to a body-centered tetragonal silicon. The study also indicated that the temperature distributing of silicon in nanometric machining exhibited similarity to conventional machining.
Effects of Tool Geometrical Parameters on the Chip Formation and Cutting Force in Orthogonal Cutting
Authors: Fang Gang , Zeng P.
Published: March 2009

The tool plays an important role in cutting process. The aim of this paper is to investigate the effect of tool geometrical parameters on the chip formation and cutting force with orthogonal cutting models. The large deformation Rigid-visco-plastic FEM program DEFORM-2DTM is used, and thermo-mechanical coupling effect are considered. The chip separation from workpiece is implemented by remeshing. Contrary to traditional cutting simulation, the workpiece is moved and the tool is fixed, which is consistent with actual process. The effects of tool rake angle on the chip geometry and cutting force are analyzed. The simulated cutting forces are compared with results in other references. The research results are a help to cutting process study and cutting tool design.
The Assessment of Cutting Temperature Measurements in High-Speed Machining
Authors: Wan Yi , Tang Zhi Tao , Liu Zhan Qiang , Ai Xing
Published: March 2009

High-speed machining has received important interest because it leads to an increase of productivity and a better workpiece surface quality. However, the tool wear increases dramatically in high-speed machining (HSM) operations due to the high cutting temperature at the tool-workpiece interface and chip-tool interface. Cutting temperature and its gradient play an important role in tool life and machined part accuracy. This paper reviews different methods of the measurements of cutting temperature, which include: (1) thermocouples---tool-work thermocouple, embedded thermocouple, combination thermocouple and compensation thermocouple (2) optical infrared pyrometer, (3) infra-red photography, (4) thermal paints, (5) microstructure or microhardness observation. Each method has its advantages and limitations. The fundamental principles and application fields of each measurement method are presented, which is useful for the selection of the measurement methods for high-speed cutting temperature.
Theoretical and Experimental Study on Optimum Design of Gear Profile Modification Curves
Authors: Zhang Sheng Sheng , Zheng J.Z. , Cheng L.
Published: March 2009

Gear profile modification is an important method for reducing system vibration and noise of a gear transmission. In this paper, three kinds of gear profile modification curves are studied, and relevant experiments are conducted. Some useful conclusions based on the theoretical analysis and experimental results have been obtained. Line, parabola and sinusoid modification curves are very useful in improving the dynamic performance of a gear transmission system by reducing system vibration and noise. In order to design the optimal tooth profile modification curve, the curve type must be decided firstly according to the specific working condition, and the curve parameters can be determined by means of optimum programming.
Study on the Mechanism of High Speed Small Hole Drilling by EDM
Authors: Ye S.L. , Su J. , Jia Z.X. , Hua R.
Published: March 2009

In this paper, a single-pulse discharge experimental device has been developed to study the mechanism of high speed small hole EDM drilling. It is found that the emulsion used in high speed small hole EDM drilling as dielectric fluid is easier to be broken down than the kerosene which is always used in the traditional EDM. The injection flushing is contributive to the ejection of molten material in the crater produced by discharge, and can greatly improve the evacuating condition.
Additionally, the effective quenching ability of emulsion and injection flushing can greatly reduce the necessary pulse interval and increase the effective pulse frequency.
Effect of Cutting Parameters on Integrality of Machined Surface in Hard Cutting
Authors: Liu Xian Li , Yan Fu Gang , Li Y.F. , Wang Yong Jun , Pen H.M.
Published: March 2009

There is a bright future for hard cutting technique because of good machining flexibility, high efficiency, no pollution. This paper presents effect rules of cutting parameters (cutting speed, feed, depth of cutting) on integrality of machined surface (surface roughness, surface hardness, surface hardened depth, residual stresses, surface texture) based on orthogonalization test. Optimal cutting parameters are selected according to these rules. Surface roughness (Ra) is up to 0.6µm in terms of selected optimal cutting parameters.
A New Model for Predicting Small Crack Growth Rates
Authors: Zhang Hong Cai , Huang K.Z. , Cheng J.H.
Published: March 2009

A new model for predicting the small-crack growth rates is proposed under the constant amplitude loading. With the use of two important parameters, the transition crack length a0 and the barrier characteristic parameter d*, the new model can reflect the abnormal feature of small-crack growth. The effect of crack closure is considered in the model as well. The model is shown to provide a better correlation to the experimental results for the Ti-6Al-4V alloy under various stress levels at a stress ratio of R = 0.4.
Investigation on Material Removal Rate in Rotation Grinding for Large-Scale Silicon Wafer
Authors: Tian Y.B. , Kang Ren Ke , Guo Dong Ming , Jin Zhu Ji , Su Jian Xiu
Published: March 2009

In this paper, the formula of material removal rate (MRR) in wafer rotation grinding
process is deduced based on kinematics. The main effect on MRR of the grit size and the process parameters, including the rotational speed of the cup grinding wheel, the down feed rate of the grinding wheel spindle and the rotational speed of the chuck table, is both theoretically and experimentally investigated. The influence on MRR of the cup wheel grinding status, the geometric dimension of the cup-grinding wheel, the rigidity of the grinding machine and the coolant is also analyzed. The investigating results show that, the increase of the grit size and the down feed rate of the cup grinding wheel results in great increase of the MRR; the MRR increases as the rotational speed of the cup wheel increases whereas the MRR reduces and the ground surface becomes bad due to size effect if the rotational speed of the cup wheel is overlarge; in normal grinding, the MRR decreases as the rotational speed of the chuck table increases. The results provide a theoretical basis
to improve grinding efficiency, reduce grinding cost and select the proper parameters of grinding process.