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Showing papers on "Texture (crystalline) published in 2005"


Book
23 Dec 2005
TL;DR: Birkholz et al. as discussed by the authors proposed a line profile analysis for X-ray diffraction and showed that line profiles can be used to detect residual stress gradients in thin films.
Abstract: Preface Symbols 1 Principles of X-ray Diffraction 11 The Basic Phenomenon 12 The &theta /2&theta Scan 13 Intensity of Bragg Ref lections 14 Applications 2 Identification of Chemical Phases 21 Histogram-Based Techniques 22 Linear Attenuation Coefficient &mu 23 Determination and Interpretation of the &mu t Product 24 Analysis of Phase Mixtures 25 Amorphous Thin Films 26 Accurate Determination of Lattice Parameter 27 Applications 3 Line Profile Analysis 31 Model Functions and Peak Parameters 32 Instrumental Line Profile 33 Deconvolution by Fourier Techniques 34 Ref lection Broadening by Small Crystallite Size Only 35 Concomitant Occurrence of Size and Strain Broadening 36 Applications 4 Grazing Incidence Configurations 41 Grazing Incidence X-ray Diffraction (GIXRD) 42 Penetration Depth and Information Depth 43 Depth-Dependent Properties 44 Refractive Index for X-rays 45 Total External Ref lection and Critical Angle 46 X-ray Reflectivity (XRR) 47 Grazing Incidence Diffraction (GID) 48 Applications 5 Texture and Preferred Orientation 51 Texture Factors 52 Pole Figures 53 Measurement of Pole Figures 54 Directions, Orientations and Inverse Pole Figures 55 Fiber Textures or Layer Textures 56 Biaxial and Fully General Textures 57 Depth Dependence of Thin-Film Textures 58 Applications 6 Residual Stress Analysis (Mario Birkholz and Christoph Genzel) 61 Ceiiinnosssttuv 62 Fundamental Equation of XSA 63 Measurement of d&Psi Distributions 64 Diffraction Elastic Constants (DECs) s 1 and 1/2s 2 65 Grain Interaction Models 66 The Effect of Texture 67 Classification of Stresses 68 Effect of Residual Stress Gradients 69 Detection of Residual Stress Gradients in Thin Films 610 Applications 7 High-Resolution X-ray Diffraction (Mario Birkholz and Paul F Fewster) 71 Strain, Strain Relaxation and Composition in Epitaxial Layers 72 High-Resolution Rocking Curves 73 Mosaicity and Extinction 74 Dynamical Theory of Ewald and Extensions 75 High-Resolution Rocking Curves and Profiles from Layer Structures 76 Reciprocal Space Mapping 77 Diffuse Scattering 78 Extensions to High-Resolution Diffraction

671 citations


Journal ArticleDOI
TL;DR: The components of the macroscopic mechanical stress tensor of a stressed thin film, coating, multilayer or the region near the surface of a bulk material can in principle be determined by X-ray diffraction as discussed by the authors.
Abstract: The components of the macroscopic mechanical stress tensor of a stressed thin film, coating, multilayer or the region near the surface of a bulk material can in principle be determined by X-ray diffraction. The various analysis methods and measurement strategies, in dependence on specimen and measurement conditions, are summarized and evaluated in this paper. First, different X-ray diffraction geometries (conventional or grazing incidence) are described. Then, the case of macroscopically elastically isotropic, untextured specimens is considered: from the simplest case of a uniaxial state of stress to the most complicated case of a triaxial state of stress. The treatment is organized according to the number of unknowns to be determined (i.e. the state of stress, principal axes known or unknown), the use of one or several values of the rotation angle φ and the tilt angle ψ of the sample, and one or multiple hkl reflections. Next, the focus is on macroscopically elastically anisotropic (e.g. textured) specimens. In this case, the use of diffraction (X-ray) elastic constants is not possible. Instead, diffraction (X-ray) stress factors have to be used. On the basis of examples, it is demonstrated that successful diffraction stress analysis is only possible if an appropriate grain-interaction model is applied.

529 citations


Journal ArticleDOI
01 Oct 2005-Carbon
TL;DR: In this article, the pore texture of both dry and pyrolyzed carbon gels depends on the drying process, and several more or less expensive methods (supercritical drying, freeze-drying, evaporative drying) were tested in order to determine which process is the most suitable for the synthesis of a porous carbon with a definite texture.

420 citations


Journal ArticleDOI
TL;DR: In this article, the development of a twinned microstructure in hexagonal close-packed rolled magnesium compressed in the in-plane direction has been monitored in situ with neutron diffraction.
Abstract: The development of a twinned microstructure in hexagonal close-packed rolled magnesium compressed in the in-plane direction has been monitored in situ with neutron diffraction. The continuous conversion of the parent to daughter microstructure is tracked through the variation of diffraction peak intensities corresponding to each. Approximately 80% of the parent microstructure twins by 8% compression. Elastic lattice strain measurements indicate that the stress in the newly formed twins (daughters) is relaxed relative to the stress field in the surrounding matrix. However, since the daughters are in a plastically “hard” deformation orientation, they quickly accumulate elastic strain as surrounding grains deform plastically. Polycrystal modeling of the deformation process provides insight about the crystallographic deformation mechanism involved.

399 citations


Journal ArticleDOI
TL;DR: Anatase-type TiO2 particles were synthesized by a two-step method consisting of the preparation of a solid precursor through hydrolysis of titanium alkoxide followed by heat treatment at different temperatures under ambient air as discussed by the authors.
Abstract: Anatase TiO2 particles were synthesized by a two-step method consisting of the preparation of a solid precursor through hydrolysis of titanium alkoxide followed by heat treatment at different temperatures under ambient air. This simple method led to a highly porous material with a 200 nm homogenous particle size, while the BET specific surface area and crystallite sizes evolved between 49 m2 g−1 to 223 m2 g−1 and from 17.0 nm to 6.3 nm, respectively. Their electrochemical performances clearly revealed the beneficial influence of the divided texture of anatase-type TiO2 on the reactivity with lithium, namely in terms of reversibility. Furthermore, we showed that the TiO2 texture strongly affects the extent of the solid solution domain. Finally, through a simple chemical titration it was possible to clearly quantify the capacitive/faradaic contributions of the electrochemical reaction.

382 citations


Journal ArticleDOI
TL;DR: In this article, the influence of different starting textures on the deformation characteristics and the development of texture and microstructure of hexagonal metals such as magnesium polycrystals was investigated.
Abstract: Plastic deformation of hexagonal metals such as magnesium is strongly affected by the hexagonal crystal structure, and thus, for an understanding of the deformation behaviour of magnesium polycrystals, texture must be taken into account. Plane-strain compression tests on pure magnesium as well as on magnesium alloy AZ31 were carried out at 100 and 200 °C. A special emphasis was laid upon the influence of different starting textures on the deformation characteristics and the development of texture and microstructure. The measured flow curves and the microstructure investigation reveal that plastic deformation of magnesium at these temperatures is generally inhomogeneous and dominated by the appearance of shear bands. However, if the initial texture is chosen such that the formation of a basal texture is slowed down or even suppressed, substantial ductility can be achieved at temperatures as low as 100 °C. The texture development due to crystallographic slip can be reasonably modelled by a relaxed constraints Taylor simulation and yields information on the activated slip systems.

327 citations


Journal ArticleDOI
TL;DR: In this paper, the distribution and orientation of platelet-shaped particles of α-alumina in a fine-grained alumina matrix is shown to template texture development via anisotropic grain growth.
Abstract: The distribution and orientation of platelet-shaped particles of α-alumina in a fine-grained alumina matrix is shown to template texture development via anisotropic grain growth. The textured microstructure ranges from 4 wt% oriented platelet particles in calcined samples to nearly 100% oriented α-Al2O3 grains after sintering at 1400°C. A CaO + SiO2 liquid phase creates favorable thermodynamic and kinetic conditions for anisotropic grain growth and grain reorientation during sintering. Important criteria for templated grain growth include (1) anisotropic crystal structure and growth, (2) high thermodynamic driving force for template grain growth, and (3) modification of diffusion in the system to continuously provide material to the anisotropically growing template grains.

293 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated Young's modulus and tensile strength in relation to phase transformation and microstructural changes occurring during cold rolling and subsequent heat treatment using β (Ti-35 mass%Nb)-4 mass%Sn and (Ti -35 mass % Nb)-7.9 mass % Sn alloys.
Abstract: Young's modulus and tensile strength were investigated in relation to phase transformation and microstructural changes occurring during cold rolling and subsequent heat treatment using β (Ti-35 mass%Nb)-4 mass%Sn and (Ti-35 mass%Nb)-7.9 mass%Sn alloys. Stress-induced a" martensite is generated on cold rolling of (Ti-35Nb)-4Sn whose martensitic transformation start temperature is around room temperature. Young's modulus in the rolling direction is lowered by the generation of stress induced a" phase with preferred texture, while it is recovered by the reverse martensitic transformation to ft at 523 K. The reverse transformation yields fine β grains which are elongated approximately along the rolling direction and have an average grain size in width of less than 1 μm. This fine microstructure leads to high strength over 800 MPa with keeping low static Young's modulus of 43 GPa. In contrast, mechanical properties of (Ti-35Nb)-7.9Sn in which matensite is not stress-induced are not so significantly improved by cold rolling and heat treatment.

265 citations


Journal ArticleDOI
TL;DR: In this article, the effect of grain size on pseudoelastic behaviors was investigated in shape memory alloy (SMA) wires, and the Taylor and inverse Schmid factors were expressed using the volume fraction of three-dimensional constrained grains.

250 citations


Journal ArticleDOI
TL;DR: In this article, a spray pyrolysis of aqueous copper acetate solutions at temperatures over 200-300 8C range was performed to determine textural and structural properties of the films.

225 citations


Journal ArticleDOI
TL;DR: In this paper, the authors introduced a new processing of textured ceramics with a feeble magnetic susceptibility by slip casting in a high magnetic field and subsequent heating, which can be applied to other non-cubic cerams, such as TiO 2, ZnO, SnO, hydrooxy apatite (HAP), AIN, SiC, Si 3 N 4, etc.
Abstract: The controlled development of texture is one of the ways for effectively improving physical and mechanical properties. In this review paper, we introduce a new processing of textured ceramics with a feeble magnetic susceptibility by slip casting in a high magnetic field and subsequent heating. As an example of feeble magnetic ceramics, we demonstrate the fabrication of textured alumina in details. The susceptibility of diamagnetic α-alumina is very small, but the orientation energy of the alumina particle by a high magnetic field becomes greater than the thermal energy. α-Alumina with a rhombohedral structure shows anisotropic susceptibility, but this anisotropy has up to now been more or less ignored due to its very low value. However, in a high magnetic field, the energy of crystal anisotropy becomes comparable to or greater than the energy of thermal motion. The degree of orientation depends on the processing factors, such as heating temperature, particle size, applied magnetic field, concentration of the suspension, etc. This process technique confers several advantages and it is possible for this type of processing to be applied to other non-cubic ceramics, such as TiO 2 , ZnO, SnO, hydrooxy apatite (HAP), AIN, SiC, Si 3 N 4 , etc.

Journal ArticleDOI
TL;DR: In this paper, the influence of nucleation on the microstructure and properties of CVD Al2O3 was investigated and the experimental layers were characterised using X-ray diffraction, scanning electron microscopy, and transmission electron microscope.
Abstract: The influence of nucleation on the microstructure and properties of CVD Al2O3 was investigated. The experimental α-Al2O3 layers were deposited (a) without nucleation control and (b) with nucleation steps resulting in pronounced 〈101¯2〉, 〈101¯4〉 and 〈101¯0〉 growth textures. The experimental layers were characterised using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Wear properties of the textured coatings were evaluated in turning. The chemistry of the nucleation surface appeared to be an important factor in pre-determining the phase content and growth textures of the Al2O3 layers. Optimised nucleation resulted in substantially improved wear properties and these kinds of α-Al2O3 layers were typically composed of relatively small, defect-free grains exhibiting no porosity. The 〈101¯4〉 textured α-Al2O3 layer showed the best wear resistance.

Journal ArticleDOI
TL;DR: In this article, the relative intensity ratio of ferroelectric poles in poled and unpoled lead zirconate titanate was used to calculate a domain switching fraction (η) or a multiple of a random distribution, which are linearly related.
Abstract: The domain structure of ferroelectric ceramics can be altered by the process of electrical poling. This paper develops quantitative approaches for reflection geometry and spherical harmonic texture analysis, both of which describe these changes at angles parallel to and tilted from the poling axis. The x-ray-diffraction approach uses the relative intensity ratio of ferroelectric poles in poled and unpoled lead zirconate titanate to calculate a domain switching fraction (η) or a multiple of a random distribution, which are shown to be linearly related. An x-ray area detector diffractometer was used for these measurements, although the technique applies to any x-ray reflection geometry. The neutron-diffraction approach employs a Rietveld refinement with a spherical harmonic texture model. Both approaches calculate similar domain textures for two poling fields and the small differences between the approaches can be attributed to surface domain texture. This paper shows that the March–Dollase pole distributio...

Journal ArticleDOI
TL;DR: In this article, the effects of precursor solution type on the microstructure evolution and texture development of oriented PZT films were studied using two solution-based methods, metallo-organic decomposition and solgel processes.
Abstract: Two solution-based methods, metallo-organic decomposition and sol‐gel processes, were used to study the effects of precursor solution type on the microstructure evolution and texture development of oriented PZT films. Microstructure development and perovskite content are strongly dependent on the heating rate. Fast heating rate forms a dense fine-grained microstructure with (111) orientation. Intermediate-temperature pyrolysis followed by a fast heating rate forms clustered or island structures of submicrometer grains with (100) orientation. Intermediatetemperature pyrolysis followed by a very slow heating rate forms larger spherical rosettes with random orientations. Pt5‐7Pb is a (111) textured transient intermetallic phase that nucleates PZT(111) texture. PbO is a (001) textured layer compound that nucleates PZT(100) texture. The texture selection of PZT films is independent of precursor systems but sensitive to the film thickness especially when sol‐gel precursors and oxidizing atmosphere are used. Correlation and comparison of oriented sol‐gel and MOD PZT films with electrical properties are also made.

Journal ArticleDOI
TL;DR: In this article, the substrate bias was used as an important parameter to affect the compressive stress and the texture in TiAlN PVD coatings on WC/Co cutting inserts as analyzed by X-ray diffraction.
Abstract: It is recognized that the quality and performance of PVD coatings on tungsten carbide based cutting tools are strongly affected by the level of residual stress as it may cause the coatings to delaminate from the substrate and affect the tool life. Here we report on the substrate bias as an important parameter to affect the compressive stress and the texture in TiAlN PVD coatings on WC/Co cutting inserts as analyzed by X-ray diffraction. Approximately 3 μm TiAlN coatings were deposited by arc evaporation with constant process parameters except for the negative substrate bias, which was varied between 40, 70, 100, 140 and 200 V. The residual stress was analyzed using X-ray diffraction and the sin 2 ψ method was used to evaluate the data. The compressive stress increased with increasing bias from − 1.7 GPa for the coating deposited at 40 V to about − 5 GPa for the 70–200 V coatings. As seen in SEM-images, the coatings prepared at higher bias (140 and 200 V) showed a glassy-like type of structure, with {111} texture and with a lattice parameter close to TiN. For the 40 V coating, a columnar type of structure with pronounced {200} texture was observed. Nano-indentation measurements show an increase in hardness by 15% in the bias range studied. Cutting tests show a correlation between the increase of the substrate bias and the edge line coating delamination, and also give an indication of a critical residual stress level for these coatings.



Journal ArticleDOI
TL;DR: In this paper, the effect of strain path during severe plastic deformation via equal-channel angular pressing on grain refinement and structural features of a model Cu-Cr alloy is investigated in terms of grain shape, dimensions, preferred crystallographic orientation and distribution of grain boundaries with respect to the angle of misorientation.

Journal ArticleDOI
TL;DR: In this article, a wide range of textures that may be generated by ECAE of magnesium alloys are discussed. And the distribution of strain and texture, as well as its strength, are modeled.
Abstract: Texture strongly impacts the plasticity of metals and the equal channel angular extrusion (ECAE) process has been demonstrated to induce unusual textures and enhance the room temperature ductility of magnesium alloys. This paper documents a wide range of textures that may be generated by ECAE of magnesium alloys. Considered broadly, the ECAE processing of magnesium alloys tends to produce 〈0 0 0 1〉 fiber textures. Unlike conventional rolling, which tends to produce 〈0 0 0 1〉 || normal direction textures, the orientation of the 〈0 0 0 1〉 fiber texture (as well as its strength) is strongly affected by alloying additions and processing history. For example, route B-processing of Mg–Al–Zn (AZ) alloys tends to produce textures with 〈0 0 0 1〉 highly inclined (∼55°) from the extrusion axis. This texture appears to promote excellent ductilities along the axis of the ECAE billets. End effects, which influence the distribution of strain and texture, are modeled.

Journal ArticleDOI
TL;DR: Aligned liquid crystalline nanowires within ordered porous alumina templates show a pronounced texture on a macroscopic scale because of a complex interplay of the pore geometry, interfacial phenomena, and the thermal history.
Abstract: Aligned liquid crystalline nanowires within ordered porous alumina templates show a pronounced texture on a macroscopic scale. We have investigated the influence of the geometric confinement and the nature of the pore walls on the mesophase formation by means of X-ray diffraction. The apparent texture is the result of a complex interplay of the pore geometry, interfacial phenomena, and the thermal history. Pores with a diameter of a few hundred nm guide the mesophase formation more efficiently than those with a diameter below 100 nm.

Journal ArticleDOI
TL;DR: In this article, the evolution of texture during cold rolling of sheets of five commercial aluminium alloys is investigated as a function of initial texture, grain size and yield strength of the respective alloy.

Journal ArticleDOI
TL;DR: In this article, the results obtained during the study of combustion syntheses of intermetallic Al-Ti films, starting from elemental nanoscaled multilayers of Al and Ti, were described.

Journal ArticleDOI
TL;DR: A Rietveld method is described which extracts information on crystal structure, texture and microstructure directly from two-dimensional synchrotron diffraction images, advantageous over conventional texture analysis that relies on individual diffraction peaks, particularly for low-symmetry materials with many overlapping peaks and images with a poor peak-to-background ratio.
Abstract: A Rietveld method is described which extracts information on crystal structure, texture and microstructure directly from two-dimensional synchrotron diffraction images. This is advantageous over conventional texture analysis that relies on individual diffraction peaks, particularly for low-symmetry materials with many overlapping peaks and images with a poor peak-to-background ratio. The method is applied to two mineralized biological samples with hydroxylapatite fabrics: an ossified pachycephalosaurid dinosaur tendon and an Atlantic salmon scale. Both are measured using monochromatic synchrotron X-rays. The dinosaur tendon has very strongly oriented crystals with c-axes parallel to the tendon direction. The salmon scale displays a weak texture.

Journal ArticleDOI
TL;DR: From the temperature-dependent photoluminescence spectra, the activation energies of free and bound excitons are deduced and the Raman spectrum reveals the high quality of the ZnO nanowires.
Abstract: ZnO nanowires have been synthesized on porous silicon substrates with different porosities via the vapour–liquid–solid method. The texture coefficient analysed from the XRD spectra indicates that the nanowires are more highly orientated on the appropriate porosity of porous silicon substrate than on the smooth surface of silicon. The Raman spectrum reveals the high quality of the ZnO nanowires. From the temperature-dependent photoluminescence spectra, we deduced the activation energies of free and bound excitons.

Journal ArticleDOI
TL;DR: In this paper, high-vacuum plasma-assisted chemical vapor deposition (HVP-CVD) was found to be weakly activated with an apparent activation energy of ∼ 0.1 eV, allowing room temperature synthesis.

Journal ArticleDOI
TL;DR: In this article, the isotropic−nematic phase transition has been observed in an aqueous dispersion of multiwall carbon nanotubes (MWNTs) using reflected polarized light microscopy.
Abstract: The unequivocal identification of lyotropic phases in carbon nanotube suspensions has recently been announced (Science 2003, 302, 1363). Here one aspect of that study is explored in further detail. The isotropic−nematic phase transition has been observed in an aqueous dispersion of multiwall carbon nanotubes (MWNTs) using reflected polarized light microscopy. The coexistence of the two phases over a significantly wide range of concentration is attributed to the polydispersity of nanotube dimensions and straightness, the longer and thicker nanotubes packing preferentially in the anisotropic phase. Above a critical concentration, a Schlieren texture characteristic of the nematic phase is apparent in the dispersion. A sufficiently thin film of a nematic dispersion is transparent enough to enable examination in transmitted polarized light. The characteristic features of the optical texture are related to the corresponding direct FEGSEM images of the nanotubes in dried samples.

Journal ArticleDOI
TL;DR: In this paper, surface roughening of polycrystalline Al-Mg alloys during tensile deformation using white light confocal microscopy was investigated and a linear relation was observed between root-mean-square roughness and both strain and grain size.

Journal ArticleDOI
TL;DR: In this paper, the sputtering pressure was varied from 0.35 to 1 Pa at a sputtering power of 300 W. Various sputtering pressures were carried out in order to observe the influence of this parameter on structural and mechanical properties.
Abstract: Titanium carbide thin films show attractive mechanical properties for engineering applications. Thin films of TiC were deposited on a 〈100〉 silicon substrate by RF sputtering from a TiC target. Various sputtering pressures were carried out in order to observe the influence of this parameter on structural and mechanical properties. The sputtering pressure was varied from 0.35 to 1 Pa at a sputtering power of 300 W. Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to characterize TiC thin films. Hardness was obtained by nanoindentation. Residual stress was determined by radius of curvature measurements. Lower pressures induce the formation of a distorted titanium carbide and a dense structure. In correlation to the lower pressure, large residual stress was measured and changed the TiC texture in XRD results. Both the compressive stress and the hardness exhibited a maximum value at a process pressure using pure argon at 0.35 Pa with a pressure of 1 Pa necessary to obtain TiC films with 〈111〉 texture.

Journal ArticleDOI
TL;DR: In this article, the authors examined the drift creep behavior of AZ31 magnesium alloy with different texture and grain sizes at a strain rate of around 10−3 ǫ s−1.

Journal ArticleDOI
TL;DR: In this paper, a numerical study on the influence of crystallographic texture on the earing behavior of a low carbon steel during cup drawing was conducted by using the texture component crystal plasticity finite element method which accounts for the full elastic-plastic anisotropy of the material and for explicit incorporation of texture including texture update.