Showing papers on "Texture (crystalline) published in 2006"
TL;DR: In this article, the relationship between texture distribution and tensile behavior of a FSP AZ31B Mg alloy is discussed, where the texture distribution is associated with the tensile properties of the alloy.
245 citations
TL;DR: In this article, a surface texture pattern was designed to maximize the texture effect on the load carrying capacity of silicon carbide surfaces sliding in water, and the friction coefficient of such textured surface was evaluated and compared with that of untextured and those only with large or small dimples only.
224 citations
TL;DR: In this paper, a transmission electron microscopy investigation was performed on oxides formed on three zirconium alloys (Zircaloy-4, ZIRLO and Zr-2.5Nb) in pure water and lithiated water environments.
223 citations
TL;DR: In this paper, the authors synthesize ultra-high-strength, ductile pure metals via control of twin spacing and twin orientation in vapor-deposited materials, achieving tensile strength of 1.2 GPa.
Abstract: Bulk Cu foils have been synthesized via magnetron sputtering with an average twin spacing of 5 nm. Twin interfaces are of {111} type and normal to the growth direction. Growth twins with such high twin density and preferred orientation have never been observed in elemental metals. These Cu foils exhibited tensile strengths of 1.2 GPa, a factor of 3 higher than that reported earlier for nanocrystalline Cu, average uniform elongation of 1%-2%, and ductile dimple fracture surfaces. This work provides a route for the synthesis of ultrahigh-strength, ductile pure metals via control of twin spacing and twin orientation in vapor-deposited materials. (c) 2006 American Institute of Physics.
206 citations
TL;DR: In this paper, deformation-induced phase transformation in a type 304 austenitic stainless steel has been studied in tension at room temperature and −50 °C. The evolution of transformation products was monitored using X-ray diffraction (XRD) line profile analysis of diffraction peaks from a single XRD scan employing the direct comparison method.
Abstract: Deformation-induced phase transformation in a type 304 austenitic stainless steel has been studied in tension at room temperature and −50 °C. The evolution of transformation products was monitored using X-ray diffraction (XRD) line profile analysis of diffraction peaks from a single XRD scan employing the direct comparison method. Crystallographic texture transitions due to deformation strain have been evaluated using (111)
γ
pole figures. The tensile stress-strain data have been analyzed to explain the influence of underlying deformation-induced microstructural changes and associated texture changes in the steel. It is found that the initial stage of rapidly decreasing strain hardening rate in type 304 steel is primarily influenced by hcp ɛ-martensite formation, and the second stage of increasing strain hardening rate is associated with an increase in the α′-martensite formation. The formation of ɛ-martensite is associated with a gradual strengthening of the copper-type texture components up to 15 pct strain and decreasing with further strain at −50 °C. Texture changes during low-temperature deformation not only change the mechanism of ɛ-martensite formation but also influence the strain rate sensitivity of the present steel.
195 citations
TL;DR: The Mg-Zn-Al alloy processed by hot extrusion typically exhibits strong grain size dependence of yield stress as discussed by the authors, however, the same friction-stir processed Mg−Zn−Al alloy samples exhibited much weaker grain size dependent.
176 citations
TL;DR: In this paper, the piezoelectric coefficient d 33eff of aluminium nitride thin films was measured using both, piezoresponse force microscopy and an interferometric technique.
Abstract: The piezoelectric coefficient d 33eff of aluminium nitride thin films was measured using both, the piezoresponse force microscopy and an interferometric technique. Wurtzite AlN thin films were prepared on Si (1 1 1) substrates by reactive dc-sputtering and by metal organic chemical vapor deposition (MOCVD). Direct measurements of the inverse piezoelectric effect in the picometer range showed that the acceptable tolerance in the crystal orientation is much larger for MEMS applications than expected previously. The value of the effective piezoelectric coefficient d 33 for the prepared AlN thin films remained as high as 5.1 pm/V even for lower degrees of texture.
176 citations
TL;DR: In this article, a comparison of the absorber properties of thin-film Cu(In,Ga)Se 2 materials is presented, showing that -oriented thin films are more homogeneous than -oriented films in terms of their optoelectronic properties.
175 citations
TL;DR: In this article, the microstructure around a hard Laves particle in a warm-rolled intermetallic Fe3Al-based alloy was studied using a system for three-dimensional orientation microscopy (3D electron backscattering diffraction, EBSD).
172 citations
TL;DR: In this article, Ni-doped ZnO thin films of single phase with preferred c-axis growth orientation were formed on Si (100) substrates by pulsed-laser deposition at room temperature.
Abstract: High-quality Ni-doped ZnO thin films of single phase with preferred c-axis growth orientation were formed on Si (100) substrates by pulsed-laser deposition at room temperature. The films exhibited room-temperature ferromagnetic behaviors with saturation magnetic moment per Ni atom of 0.37μB,0.26μB,0.25μB and 0.21μB for the Ni concentration of 1, 3, 5, and 7 at. %, respectively. The decrease of ferromagnetism with doping concentration demonstrates that ferromagnetism observed at room temperature is an intrinsic property of Ni–ZnO thin films, not from any secondary phase.
TL;DR: In this paper, the deformation behavior and texture evolution of two-phase Ti-6Al-4V subjected to severe plastic deformation using equal channel angular extrusion (ECAE) at a high temperature (∼0.55Tm).
TL;DR: In this article, different modeling strategies are tested for the prediction of texture development and microscopic strain heterogeneity in cold-rolled ULC steel and in multiphase steel under uniaxial tension.
TL;DR: An exact solution for the nematic ground state is derived in the one Frank constant approximation and the stability of the corresponding texture against thermal fluctuations is studied.
Abstract: The equilibrium texture of nematic shells is studied as a function of their thickness. For ultrathin shells the ground state has four short 1/2 disclination lines but, as the thickness of the film increases, a three-dimensional escaped configuration composed of two pairs of half-hedgehogs becomes energetically favorable. We derive an exact solution for the nematic ground state in the one Frank constant approximation and study the stability of the corresponding texture against thermal fluctuations.
TL;DR: In this paper, the effects of Zn acetate or/and Zn chloride as ZnO precursors have been studied on the c-preferred orientations of pure ZnOs and ZnsO films doped with aluminium obtained by spray pyrolysis.
TL;DR: In this article, the authors conducted a comprehensive survey to organize the information of previous works and to summarize the current status of research on preferred orientation of polycrystalline ZnO films.
TL;DR: In this paper, the effect of preparation parameters on the properties of activated carbons was investigated, and their EDLC properties were measured in an organic electrolytic solution, and as-prepared activated carbon carbons (NCD-ACs) exhibit large surface areas (400−2900 m2/g), high EDLC capacitances (14−44 F/g) and low system resistances (8.3−18.7 Ω) on the basis of the anisotropic texture of their precursor.
Abstract: Petroleum-based needle coke was activated by KOH to develop high-performance activated carbons as carbon electrodes for an electric double-layer capacitor (EDLC). The effect of preparation parameters on the properties of activated carbons was investigated, and their EDLC properties were measured in an organic electrolytic solution. As-prepared activated carbons (NCD-ACs) exhibit large surface areas (400−2900 m2/g), high EDLC capacitances (14−44 F/g), and low system resistances (8.3−18.7 Ω) on the basis of the anisotropic texture of their precursor.
TL;DR: The electrical properties of Pb-modified BaSnO 3 having general formula Ba 1− x Pb x O 3 ( x ǫ= 0, 005, 010, 015) were investigated by ac impedance spectroscopy over a wide range of temperature up to 500°C starting from room temperature in the frequency range 100 Hz to 1 MHz X-ray diffraction (XRD) studies have confirmed the formation of a single phase compound Scanning electron micrographs show polycrystalline texture of the material as discussed by the authors.
TL;DR: In this paper, a high-pressure pretreatment (200 to 500 MPa) at 60°C for 15 min resulted in a more pronounced texture improvement compared with the same pretreatment at 20°C and 40°C, respectively.
Abstract: Carrots (Daucus carota) pretreated under different high-pressure conditions were thermally processed at temperatures in the range of 90°C to 110°C. Texture degradation (hardness) was monitored objectively using a texture analyzer. For a given thermal treatment, the rate constant (k-value) decreased with increasing pretreatment pressure. A high-pressure pretreatment (200 to 500 MPa) at 60°C for 15 min resulted in a more pronounced texture improvement compared with the same pretreatment at 20°C and 40°C, respectively. Calcium impregnation conferred more beneficial effects when applied immediately after the high-pressure pretreat-ment. The observed changes in texture characteristics were associated with the degree of methylation of carrot pectins, which is dependent on pectinmethylesterase (PME) activity.
TL;DR: Grain boundary engineering (GBE) was applied to INCOLOY alloy 800H by means of thermomechanical processing as mentioned in this paper, which improved the protective oxidation behavior by enhancing spallation resistance and reducing oxidation rate.
TL;DR: In this article, the plane-strain bulge test was used to investigate the mechanical behavior of freestanding electroplated Cu thin films as a function of film thickness and microstructure.
Abstract: The plane-strain bulge test is used to investigate the mechanical behavior of freestanding electroplated Cu thin films as a function of film thickness and microstructure. The stiffness of the films increases slightly with decreasing film thickness because of changes in the crystallographic texture and the elastic anisotropy of Cu. Experimental stiffness values agree well with values derived from single-crystal elastic constants and the appropriate orientation distribution functions. No modulus deficit is observed. The yield stress of the films varies with film thickness and heat treatment as a result of changes in the grain size of the films. The yield stress follows typical Hall-Petch behavior if twins are counted as distinct grains, indicating that twin boundaries are effective barriers to dislocation motion. The Hall-Petch coefficient is in good agreement with values reported for bulk Cu. Film thickness and crystallographic texture have a negligible effect on the yield stress of the films.
TL;DR: In this paper, an electron beam directed vapor deposition method was used to grow 7-wt.% Y 2 O 3 -ZrO 2 (7YSZ) coatings and the effects of substrate rotation upon the coating porosity, morphology, texture, and thermal conductivity were explored.
TL;DR: In this paper, Ga and N were used to realize p-type conduction in ZnO films using rf magnetron sputtering and obtained resistivity and hole concentrations of 38Ωcm and 3.9×1017cm−3, respectively.
Abstract: Codoping of Ga and N was utilized to realize p-type conduction in ZnO films using rf magnetron sputtering. The films obtained at 550°C on sapphire showed resistivity and hole concentrations of 38Ωcm and 3.9×1017cm−3, respectively. ZnO films also showed a p-type behavior on p-Si with better electrical properties. ZnO homojunctions synthesized by in situ deposition of Ga–N codoped p-ZnO layer on Ga doped n-ZnO layer showed clear p-n diode characteristics. Low temperature photoluminescence spectra of codoped films also revealed a dominant peak at 3.12eV. The codoped films showed a dense columnar structure with a c-axis preferred orientation.
TL;DR: In this paper, the defect microstructures as a function of initial texture, deformation temperature and plastic strain were characterized using orientation imaging microscopy in a scanning electron microscope and defect analysis via transmission electron microscopy.
Abstract: Clock-rolled, high-purity, textured polycrystalline zirconium exhibits significant plastic anisotropy for compression along the through-thickness and in-plane directions and strong temperature dependence of flow stress for both orientations. Orientation imaging microscopy in a scanning electron microscope and defect analysis via transmission electron microscopy are used to characterize the defect microstructures as a function of initial texture, deformation temperature and plastic strain. The observed deformation mechanisms are correlated with the measured mechanical response.
TL;DR: Nano-crystalline diamond (NCD)-coated surfaces were efficiently functionalized with bone morphogenetic protein-2 (BMP-2) by means of physisorption to allow generating highly versatile surfaces with complex biomimetic coatings, essentials for novel medical devices and implants as well as for innovative scaffolds in tissue engineering.
TL;DR: In this paper, the deformation behavior of a coarse grained AZ31 alloy during hot rolling was investigated and it was shown that the basal texture originates from the {10−12} twins at the initial stage of rolling and during subsequent deformation, the grains with the c-axis parallel to compression stress are insensitive to dynamic recrystallization.
TL;DR: In this paper, a Co-based full-Heusler alloy thin film of Co2Cr0.6Fe0.4Al (CCFA) and Co2MnGe (CMG) was epitaxially grown on MgO-buffered mgO (001) substrates using magnetron sputtering.
Abstract: Cobalt-based full-Heusler alloy thin films have recently attracted much interest as highly desirable ferromagnetic electrodes for spintronic devices because of the half-metallic ferromagnetic nature theoretically predicted for some of these alloys and because of their high Curie temperatures, which are well above room temperature (RT). In this study, Co-based full-Heusler alloy thin films of Co2Cr0.6Fe0.4Al (CCFA) and Co2MnGe (CMG) were epitaxially grown on MgO-buffered MgO (001) substrates using magnetron sputtering. The films were deposited at RT and subsequently annealed in situ at temperatures ranging from 400 to 600??C. X-ray pole figure measurements of the CCFA films indicated that these films were epitaxial and crystallized in the B2 structure. X-ray pole figure measurements of the annealed CMG films showed (111) peaks with four-fold symmetry, which provides direct evidence that these films were epitaxial and crystallized in the L21 structure. Furthermore, cross-sectional transmission electron microscope images of a fabricated CMG film indicated that it was single-crystalline. The annealed films of CCFA and CMG had sufficiently flat surface morphologies with roughness of about 0.23?nm rms for 100?nm thick CCFA films and 0.26?nm rms for 45?nm thick CMG films. Using these epitaxially grown thin films, we fabricated fully epitaxial magnetic tunnel junctions (MTJs) consisting of a Co-based full-Heusler thin film of either CCFA or CMG as a lower electrode, a MgO tunnel barrier and a Co50Fe50 (CoFe) upper electrode. All layers were successively deposited in an ultrahigh vacuum chamber through the combined use of magnetron sputtering and electron beam evaporation. Reflection high-energy electron diffraction patterns observed in situ for each layer during preparation clearly indicated that all layers grew epitaxially in both the CCFA/MgO/CoFe and CMG/MgO/CoFe MTJ layer structures. The microfabricated epitaxial CCFA/MgO/CoFe MTJs demonstrated relatively high tunnel magnetoresistance (TMR) ratios, for MTJs using a full-Heusler alloy, of 42% at RT and 74% at 55?K. On the other hand, the microfabricated epitaxial CMG/MgO/CoFe MTJs showed strongly temperature-dependent TMR characteristics with typical TMR ratios of 14% at RT and 70% at 7?K. These results confirm the promise of epitaxial MTJs as a key device structure for clarifying and utilizing the potentially high spin-polarization of Co-based full-Heusler alloy thin films.
TL;DR: In this paper, texture engineering using reactive-templated grain growth (RTGG) is reviewed as a key processing technique for lead free piezoelectric ceramics.
Abstract: Texture engineering using reactive-templated grain growth (RTGG) is reviewed as a key processing technique for lead free piezoelectric ceramics. Bismuth layer structured ferroelectric ABi4Ti4O15 (A=Na0·5Bi0·5, Ca, Sr) ceramics with a highly preferred {001} orientation were fabricated with enhanced piezoelectric properties using Bi4Ti3O12 platelets. Textured simple perovskite type ceramics were also prepared in Bi0·5Na0·5TiO3 (BNT), BaTiO3 and K0·5Na0·5NbO3 (KNN) based compositions with Lotgering's factor higher than 0·8. The textured BNT and KNN based ceramics exhibited enhanced electromechanical coupling coefficients and piezoelectric constants when compared with their randomly oriented counterparts. The development of microstructure and texture in the RTGG processed ceramics is dependent on the target system, starting materials and processing parameters, and optimum preparation conditions must be found by analytical investigation.
15 Mar 2006-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the plastic behavior at room temperature of magnesium and magnesium metal matrix composites reinforced with yttria particles of two sizes is studied and a tension/compression asymmetry is observed.
Abstract: The plastic behaviour at room temperature of magnesium and magnesium metal matrix composites reinforced with yttria particles of two sizes is studied. All the materials are produced by powder metallurgy. During extrusion both the unreinforced magnesium and the composites develop a fibre texture with the { 1 0 1 ¯ 0 } planes perpendicular to the extrusion direction. The fibre intensity decreases as the volume fraction of yttria particles increases. A tension/compression asymmetry is observed. The extrusion texture prevents deformation by the basal slip system in both tension and compression. Deformation in the { 1 0 1 ¯ 2 } 〈 1 0 1 ¯ 1 〉 twinning system is only possible in compression. As the volume fraction of yttria particles increases, the texture becomes more random and the tension/compression asymmetry tends to decrease and is eventually reversed. The composites reinforced with the smallest ceramic particles present the highest yield stress.