bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Mechanical Behaviour and Durability of Ultra-High Performance Cementitious Composite
Authors: Sun Wei , Lai Jian Zhong
Published: March 2009

Ultra-high performance cementitious composite (UHPCC) with 200MPa compressive strength was prepared by substitution of ultra-fine industrial waste powder for 60% cement by weight. Compressive impact behaviour of UHPCC with different fiber volume fraction was researched by split Hopkinson pressure bar in four kinds of impact modes. Standard strength of UHPCC under impact was defined. The effects of strain rate, impact times, impact modes and fiber volume fraction on the properties of UHPCC under impact were researched. Results showed that impact resistance of UHPCC was improved with the increase of fiber volume fraction. With the increase of strain rate the dynamic strength of UHPCC was improved. With the increase of impact times the damage of material increased while the standard strength decreased. With the change of impact modes the damage of material on the first impact and the rate of the reduction of peak stress on the second and third impact increased. After a long time freezing-thaw cycle, corrosion and carbonation, results indicated that UHPCC had excellent durability.
Experimental Evaluation of Steel Beam Bolted to Reinforced Concrete Column Connections
Authors: Li Xian , Xiao Yan
Published: March 2009

In order to improve the constructability and meanwhile ensure excellent seismic behavior, an innovative bolted endplate connection to steel beam and reinforced concrete column (RCS) was developed, and three full scale model joints with or without floor slab were tested under simulated seismic loading. The proposed composite joint is characterized by an extended endplate which is welded to steel beam with reduced sections in factory and then bolted to reinforced concrete column using high-strength steel rods in field. The effect of material strength and concrete floor slab on the seismic behavior of joints was studied. Experimental results indicated that both specimens without floor slab exhibited good ductility and energy-dissipating ability with full plastic hinging formed at the reduced sections of steel beam. However, owing to the effect of floor slab, the beam sections became unsymmetrical and positive moment strength of the joint was increased significantly. The specimen with floor slab fractured at the weld between the bottom flange of the beam and the endplate, and the failure mode resembled what occurred during the Northridge earthquake.
Analysis on Punching Shear Behavior of the Raft Slab Reinforced with Steel Fibers
Authors: Wang Xiao Wei , Tian Wen Ling , Huang Zhi Yuan , Zhou Ming Jie , Zhao Xiao Yan
Published: March 2009

The thickness of the raft slab is determined by punching shear. The raft slab is commonly thick, which causes concrete volume is large. Mass concrete can bring disadvantage to the foundation. In order to increase the bearing capacity and reduce the thickness, it is suggested that the raft slab to be reinforced by steel fibers. There are five groups of specimens in this paper. S1 is the common reinforced concrete slab. S2 and S3 are concrete slabs reinforced by steel fibers broadcasted layer by layer when casting specimen. S4 and S5 are concrete slabs reinforced by steel fibers mixed homogeneously when making concrete. The punching shear tests of these slabs were done. The test results indicate that the punching shear capacity of the slab reinforced with steel fibers is higher than that of concrete slab, the stiffness and crack resistance of the steel fibers reinforced concrete slab are better than those of the common concrete slab and the punching shear of the slabs with different construction methods of steel fibers is similar. It analyses the punching shear behavior of the slab reinforced with steel fibers and suggests the ultimate bearing formula. The calculative values are coincided with the measured values well.
Analysis on Load-Deformation Curves of the Concentrically Compressed Concrete Filled Circular CFRP-Steel Tubular Stub Columns
Authors: Wang Qing Li , Gao Guo Rui , Ren Qing Xin
Published: March 2009

Based on experimental study and stress-strain curve of the concrete confined by circular CFRP-steel tube subjected to axial load, the fiber element approach was used to analyse load-deformation curves of the concentrically compressed concrete filled circular CFRP-steel tubular stub columns, and it shows that the results predicted check well with those of the tests and are on the safe side. Influences of confinement factor of the steel tube and the that of the CFRP tube on curves were analysed. The typical load-deformation curves were proposed and it could be defined as following four stages, e.g., elasticity stage, nonlinear stage, strengthening stage and softening stage. The method presented here is suitable for load-deformation curves analysis of the concentrically compressed concrete filled steel tubular (CFST) stub columns with circular cross-section also.
An Experimental Study on Effectiveness of Reinforcing Methods on L-Shaped Prestressed Concrete Beam-Column Joints
Authors: Yue Wei , Nishiyama Minehiro
Published: March 2009

This paper presents experimental results of cyclic loading tests carried out on three L-shaped prestressed concrete beam-column corner joints. Three types of reinforcing methods to enhance the anchorage performance of beam and column longitudinal reinforcing bars were studied based on the experimental results such as the load-displacement relation curves, deformation capacity, prestressing force variation, and strain measurements of the beam and column reinforcing bars. The test specimens were KPCL1 with the column longitudinal reinforcement with 180-degree hooks at their ends, KPCL2 with the column longitudinal reinforcement bent in a U-shape, and KPCL3 with U-shaped column longitudinal reinforcement and additional transverse reinforcement on the beam longitudinal reinforcement. It can be concluded that the anchorage performance was somehow enhanced by the three reinforcing methods in the positive direction of loading (closing direction), while in the negative direction of loading (opening direction) there was no remarkable improvement.
New Ceramic Phases in the Ternary Si-C-N System
Authors: Riedel Ralf , Horvath-Bordon Elisabeta , Kleebe Hans Joachim , Kroll Peter , Miehe G. , van Aken P.A. , Lauterbach Stefan
Published: March 2009

The ultra-high pressure and temperature synthesis of spinel silicon nitride and germanium nitride on the one hand as well as the successful synthesis of tin nitride at ambient pressure on the other hand have caused an enormous impact on both basic science and technological development of advanced nitrides. Aim and scope of the research in this field is to synthesize novel nitrides for structural and functional applications. High presssure nitrides may combine ultra-high hardness with high thermal stability in terms of decomposition in different environments and are expected to show interesting optoelectronic properties. Here, the state of the art and the progress in the field of novel advanced nitrides and related materials synthesized reproducibly under high pressure are reviewed.
Application of Nitride and Oxynitride Compounds to Various Phosphors for White LED
Authors: Uheda Kyota
Published: March 2009

Multiternary nitride and oxynitride compounds doped with rare earth ions, such as Eu2+ and Ce3+ have been enthusiastically applied as various phosphors to white LED. New red and green phosphors, CaAlSiN3:Eu and Ba3Si6O12N2:Eu, have been successfully synthesized, recently. The red phosphor has intense emission around 650 nm under two different irradiations at 405 and 455 nm from blue- and near UV-LED chips, respectively; while strong emission is observed around 520 nm from the green phosphor. Both phosphors also show small thermal quenching over the temperatures up to 150 °C. In addition, both LaSi3N5:Ce and La3Si8O4N11:Ce in lanthanum silicon nitride and oxynitride were examined as candidates for a blue phosphor in white LED with near UV-LED chip.
Preparation of Precursors for Aluminum Nitride-Based Ceramic Composites from Cage-Type and Cyclic Building Blocks
Authors: Sugahara Yoshiyuki , Nakashima Hiroaki , Koyama Seiichi , Mori Yusuke
Published: March 2009

Precursors for nitride-based ceramic composites have been prepared from two types of building blocks, cage-type poly(iminoalane) with Al-N backbones and cyclic poly(silazane) with Si-N backbones. Two combinations of poly(iminoalane) and cyclic poly(silazane) were utilized to prepare precursors. For the combination of poly(isopropyliminoalane) and [MeSi(H)NH]n, two building blocks were connected via dehydrocoupling, while Pt-catalyzed hydrosilylation was utilized for the combination of poly(allyliminoalane-co-ethyliminoalane) and [Me(H)SiNH]n. The ceramic yields of poly(iminoalane)s increased upon reactions with [MeSi(H)NH]n.
Exergy Analysis on the Life Cycle of Ceramic Parts
Authors: Kita Hideki , Hyuga Hideki , Kondo Naoki , Ohji Tatsuki
Published: March 2009

Exergy is a measure which can commonly deal with the quantification of the variety of resources, products and energy coming in and going out the manufacturing systems. In this study, exergy analysis was conducted on ceramics and steel heater protection tube used in aluminum casting, and the amount of exergies consumed through their life cycle were calculated. In the production stage, ceramic heater tube consumes much higher exergy than the steel one does, however, analysis throughout the life cycle including production, operation and waste in seven years shows that exergy consumption for the ceramic tube is less than that of the steel tube.
SiAlON Microstructures
Authors: Falk L.K.L.
Published: March 2009

This paper is focussed on the development of microstructure during liquid phase sintering and post-densification crystallisation heat treatment of ceramic materials based on the α- and β-Si3N4 structures. Grain shape and size distributions, assessed by quantitative microscopy in combination with stereological methods, and fine scale microstructures, investigated by electron diffraction and high resolution imaging and microanalysis in the transmission electron microscope, are discussed in relation to the fabrication process and the overall composition of the ceramic material.
Preparation and Characterization of MM’Si4N6C Ceramics
Authors: Thompson Derek P. , Zhang Yue
Published: March 2009

The preparation of high temperature ceramics simultaneously containing silicon, nitrogen and carbon has only relatively recently become an area of interest for inorganic crystal chemists, and the recent discovery of a new series of carbonitrides with the general formula MM’Si4N6C is of interest because of the good high temperature properties they appear to display. On the one hand, M and M’ can be the same trivalent metal - either rare earth or yttrium; in this case, the resulting compounds display orthorhombic (pseudo-hexagonal) structures. Alternatively the metals may be a mix of di- (Ca,Sr, Ba) and tri-valent (Y,Ln) cations, in which case the carbon is replaced by nitrogen, and the overall symmetry is hexagonal. Other quaternary nitrides of a similar type can be produced if the two metal cations remain trivalent and one of the silicon atoms is replaced by aluminium. The present study describes the preparation of powder samples of Y2Si4N6C and LaYSi4N6C starting from YH2, La, Si3N4 and carbon precursors, and summarises attempts to achieve a dense product by hot-pressing at 1700-1800oC. Some preliminary mechanical property measurements are included.
Oxidation of Rare Earth Silicon Oxynitride J-Phases
Authors: Takahashi Junichi , Suehiro Takayuki
Published: March 2009

Oxidation behavior of R4Si2O7N2 (J-phase; R = Y and rare-earth element) has been investigated by thermometric measurements in air. All R4Si2O7N2, of which the powder samples are prepared by gas-pressured sintering method under 1 MPa of N2 gas, are oxidized to R2SiO5 with an exothermic reaction in air under an ambient pressure. The oxidation temperature to produce the final oxide increases from c.a. 930 to 1060 °C with decreasing the ionic radii of the rare earth elements.
Viscosity Measurement of Molten RE-Mg-Si-O-N (RE=Y, Gd, Nd and La) Glasses
Authors: Saito Noritaka , Nakata Daiji , Sukenaga Sohei , Nakashima Kunihiko
Published: March 2009

Viscosities of molten RE-Mg-Si-O-N (RE=Y, Gd, Nd and La) glasses have been measured using rotating bob viscometer with a gas tight furnace at elevated temperature (~1873 K). Moreover, structural characterizations of these quenched vitreous samples have been investigated using solid state 29Si MAS-NMR, which would resolve the relationship between the viscosity of high temperature melts and network structure of RE-Mg-Si-O-N systems. The viscosities of molten RE-Mg-Si-O-N glasses exponentially increased with nitrogen content. 29Si MAS-NMR spectra of RE-Mg-Si-O-N (RE=Y and La) glasses revealed that content of silicon-oxynitride species, like SiO3N, increased with nitrogen content, which indicates that nitrogen clearly modifies the glass network structure. Depending on cationic radius of rare-earth elements, Y was found to be more effective in silicon-oxynitride species formation than La, which are consistent with the results of viscosity measurement of molten RE-Mg-Si-O-N glasses at elevated temperature (~1873 K).
Advances in Computation of Temperature-Pressure Phase Diagrams of High-Pressure Nitrides
Authors: Kroll Peter
Published: March 2009

A combination of first-principle and thermochemical calculations is applied to compute the phase diagrams of rhenium-nitrogen and of ruthenium-nitrogen at elevated temperature and high pressure. We augment total energy calculations with our approach to treat the nitrogen fugacity at high pressures. We predict a sequential nitridation of Re at high-pressure/high-temperature conditions. At 3000 K, ReN will form from Re and nitrogen at about 32 GPa. A ReN2 with CoSb2-type structure may be achieved at pressures exceeding 50 GPa at this temperature. Marcasite-type RuN2 will be attainable at 3000 K at pressures above 30 GPa by reacting Ru with nitrogen.
Corrective Abrasive Polishing Processes for Freeform Surface
Authors: Chen Xun
Published: March 2009

Traditionally, abrasive finishing process only focused on producing excellent surface finish on regular form shapes. Ever increasing demands in freeform features in aerospace, energy and medicine applications require abrasive finishing technology not only provides excellent surface finish but also is capable to correct the errors on freeform surfaces. The paper presents current development of corrective polishing technology for freeform surfaces.
High Speed Grinding of Advanced Ceramics: A Review
Authors: Huang Han
Published: March 2009

In this paper, the characteristics of high speed grinding of advanced ceramics, including alumina, alumina-titania, zirconia, silicon nitride and silicon carbide, were reviewed. The associated material removal mechanisms were discussed. Pragmatic technologies for the high speed grinding of advanced ceramics were also presented.
Experimental Study on Flexural Performance of Corroded RC Beams Strengthened with AFRP Sheets
Authors: Deng Zong Cai , Li Jian Hui , Lin He Fei
Published: March 2009

In order to investigate the strengthening effects of aramid fiber reinforced polymer (AFRP) sheets on the flexural performance of the corroded beams, the flexural behaviors of corroded RC beams strengthened with AFRP sheets under different degrees of corrosion (minor: reinforcement mass loss is 2.0％, medium: reinforcement mass loss is 6.0％) are researched experimentally in this paper, and compared with that of the control beams (un-corroded) and un-strengthened corroded beams. The results show that，compared with un-strengthened corroded beams under same degrees of corrosion, the cracking load, yield load and ultimate load of minor corroded RC beam strengthened with AFRP sheets is respectively increased by 20%, 27% and 60%, and increased by 15%, 36% and 83% for medium corroded RC beam strengthened with AFRP sheets respectively; The ultimate deflection of the medium corroded beam strengthened with AFRP sheets is 166% larger than that of corroded un-strengthened beam. AFRP sheets can improve significantly the bearing capacity and deformation for corroded RC beams.
Effect of Hydration of Unreacted Cement in Hardened Mortar with Low W/C on the Long-Term Strength
Authors: Feng Xiao Xin , Sun Xiao Hua , Wang Xiao Yan , Wei Qing Min
Published: March 2009

Through accelerating the hydration by heighening the curing temperature, the effect of the hydration of the unreacted cement in the hardened mortar with low W/C on the long-term strength was investigated. The results show that in the hardened mortar with low W/C, there exists a lot of unreacted cement at the age of 28 days, and when these cement particles hydrate again at the long age, it is disadvantageous to the long-term strength of the mortar. Moreover, the lower the W/C, the lower the hydration degree at the earlier age, and the more disadvantageous to the development of strength at the long age.
Experimental Study of Lubrication Influence in the Production of Hydroformed T-Joint Tubes
Authors: Fiorentino Antonio , Ceretti Elisabetta , Aldo Attanasio , Braga Dario , Giardini Claudio
Published: March 2009

THF process is a forming technique that consists of tube deformation by means of hydraulic pressure and punches which guarantee the tube ends feeding and sealing. In the last years, this technique found a large and rapid diffusion thanks to its many advantages with respect to conventional processes: parts weight reduction, tighter dimensional tolerances, lower costs or fewer secondary assembly operations. Besides, many lacks in the process knowledge still represent an obstacle and they are usually bypassed by trial and error methods. Therefore, lot of studies were conducted to better understand the influence of the process parameters, such as pressure path, punch stroke or material behaviour. In this paper, an experimental study of tubular T-joints made of copper manufactured by means of THF process is described. The aim of this work is to analyze the tube-die interface friction condition effects on the final part. In fact, material flow during the process is greatly influenced by the friction conditions between tube and die especially due to the high pressure acting inside the tube. Different lubrication types were considered: dry, oil, Teflon, Teflon with oil, Teflon spray and Graphitic oil. Two different experimental campaigns were performed in this investigation. The first one was carried out in order to estimate the lubricant friction coefficients using a Pin on Disk tribometer. The second one was performed to study the effects of the lubrication on the process and the tests were conducted hydroforming T-joints under the different lubrication conditions considered. The collected data allowed to identify how the different lubrication conditions affect the final workpiece geometry. Moreover, a critical aspect of the process related to the tube wrinkling was identified and a solution was proposed.
Stamping of Titanium Sheets
Authors: Adamus Janina
Published: March 2009

In this paper, some technological problems (e.g. low drawability, high susceptibility to galling, spring-back) occurring in the sheet-titanium forming process are discussed. A numerical simulation of the stamping process was carried out with the Adina System v.8.3 based on the finite element method. The effects of friction, the holding-down force and tool geometry on the course of the stamping process were analysed. The mechanical and technological material data needed for the calculations were determined experimentally. The friction coefficients for the frictional pair: ”titanium – tool steel” for different lubricants and antiadhesive layers determined in the “strip drawing” test were found. The role played by lubrication and antiadhesive layers in preventing titanium “build-ups” on the tools is presented. The calculated results were then confirmed experimentally.
Assessment of the Modified Maximum Force Criterion for Aluminum Metallic Sheets
Authors: Banabic Dorel , Soare Stefan
Published: March 2009

The paper presents an analysis of a recently proposed failure criterion for thin sheets. According to Aretz [1], this criterion becomes numerically unstable for yield surfaces with locally constant exterior normal fields. Here we make more precise statements about the nature of this instability, asses the predictive capabilities of the criterion, and introduce a fitting parameter for its plane strain calibration.
UHS Steel Formability in Flexible Roll Forming
Authors: Mäntyjärvi Kari , Merklein Marion , Karjalainen Jussi A.
Published: March 2009

Ultra-high-strength (UHS) steels are very interesting materials for many applications where high strength can be utilized to create lighter and more effective constructions. The poor formability of UHS steels, however, may limit the usefulness of these materials in many applications. In this work, some experiments using a flexible roll forming machine developed at the Chair of Manufacturing Technology (LFT), University of Erlangen-Nuremberg were carried out using 4mm-thick bainitic martensitic UHS steels (YS/TS 960/1000 and 1100/1250) and the outcomes have been analysed. Results of these experimental tests show that using roll forming it is possible to bend test materials to an angle of 90º without damages with an evidently smaller radius than in air bending. The radius obtained using roll forming can be as small as 40% of the value used in air bending. Tests also show that with the method used in these tests it is possible to make roll forming for the whole length of the plate. The tests proved that the NC-controlled single-step roll forming method has potential for manufacturing small batches of bend profiles; however, more development has to be carried out if the process is to be made suitable for industry.
Approximate Estimation of Contributions to Pure X-Ray Diffraction Line Profiles from Crystallite Shapes, Sizes and Strains by Analysing Peak Widths
Authors: Kojdecki Marek Andrzej
Published: March 2009

A polycrystalline material may be considered as a set of crystallites. Since the crystallites have rather regular shapes, the assumption about the same shape is not far from physical reality for most polycrystals, especially powders. Such a system may be characterised in a statistical manner by two functions, the crystallite size distribution and the crystalline lattice strain distribution (for some materials other lattice distortions inside the crystallites, like stacking faults or dislocations, are to be considered additionally). The crystalline microstructure can be determined by investigating an X-ray diffraction pattern, what should be based on comparing an experimental pattern with a simulated one, derived from an appropriate physical model. Pure X-ray diffraction line profiles, containing information about crystalline microstructure, can be extracted from
experimental data. An important step in analysing them is the separation of contributions from crystallite shapes and sizes and from strains, enabling the proper determination of both distributions together with the estimation of prevalent crystallite shape. A model of polycrystalline material combined with a description of X-ray diffraction on it, making such an analysis possible, is
presented in this article. An approximate formula for separating both effects is based on results of computer simulation of pure X-ray diffraction line profiles from different crystalline powders, done under simplifying assumptions that the crystallites are prismatic or spherical, the size distribution is logarithmic-normal and the second-order strain distribution is normal.
Fundamental Developments in Direct-Space Techniques for Structure Solution from Powder Diffraction Data
Authors: Habershon Scott , Albesa-Jové David , Cheung Eugene Y. , Turner Giles W. , Johnston Roy L. , Harris Kenneth D.M.
Published: March 2009

Solids that can be prepared only as microcrystalline powders are not suitable for structural investigation using single crystal diffraction techniques, and it is necessary instead to carry out structure determination using powder diffraction data. In this paper, we focus on a direct-space strategy for solving crystal structures directly from powder diffraction data in which a hypersurface based on the powder profile R-factor Rwp is searched using a Genetic Algorithm, and we highlight some recent fundamental developments relating to this methodology.
Study of Submicrocrystalline Materials by Conventional Powder Diffraction and Diffuse Scattering in Transmitted Wave
Authors: Kužel Radomír , Šimek D. , Kub J. , Islamgaliev Rinat K.
Published: March 2009

Two methods were used for the analysis of submicro-crystalline copper prepared by high-pressure (6 GPa) severe plastic deformation. Conventional powder XRD study was carried in terms of the modified Williamson-Hall (WH) plots and shown large line-broadening anisotropy. A new high-resolution small-angle transmission diffuse scattering method was applied for determination of
crystallite size. Two methods were used for the evaluation of the diffuse scattering - calculation of the autocorrelation function of the crystalline shape by the transformation of the measured signal and by the direct fitting. Bimodal block size distribution has to be assumed for annealed samples. This was also confirmed by classical back-reflection film method as well as by the long tails of
conventional diffraction profiles.
Line Profile Analysis (LPA) Methods: Systematic Ranking of the Quality of their Basic Assumptions
Authors: Vermeulen Arnold C. , Delhez Rob
Published: March 2009

All methods of analyzing the broadening of XRD line profiles have to take into account two basic effects: broadening by the instrument - including the X-ray spectrum - and the characteristics of broadening by size effects and by lattice defects - including their interaction. These effects are handled in practice by a wide range of auxiliary assumptions. In this paper these assumptions and their quality with respect to "appropriateness of purpose" are listed and compared.
By systematic ranking of these assumptions in accordance with their quality, a 2-dimensional map can be constructed that visualizes the differences in the quality of the assumptions. This 2-dimensional map brings a new viewpoint to the various methods for line profile analysis, because it enables a qualitative comparison of the assumptions of existing methods and new developments.
Single Reflection Method for Pole-Density Measurements Accounting for Secondary Extinction in Textured Films
Authors: Tomov I.
Published: March 2009

A method of pole density measurements is described, which uses the differences in X-ray beam polarisation of two monochromators. The method requires a single reflection at an intermediate diffraction angle. Experimental verification is provided by pole density measurements of Ag films and comparison the results obtained with the proposed method with results from the reflection-pair method [8-10].
Investigating X-Ray Bragg-Line Displacement as a Technique for Determination of the Thermal Expansion Coefficient of Solid Samples
Authors: Battaglia S. , Mango F.
Published: March 2009

Thermal expansion coefficients (TEC) of some metallic samples and rocks, along with one sample of amorphous silica, were determined by means of a standard X-ray diffractometer without any modification to the equipment. Only the sample holder was modified in order to fix the sample within the standard goniometer and avoid heat dispersion into the chamber during heating of the sample. The latter was achieved by the Joule effect through a thermo-coaxial wire coil wrapped directly around the bulk sample. A thin metal foil, aluminium in our case, was placed on the flat surface of the cylinder sample. The variations in Al peak position recorded at various sample temperatures were related directly to the dilatation of the material supporting the thin foil.
Effect of Annealing on Structural Properties of Co Thin Films and Co/Cu Multilayers
Authors: Hecker M. , Mattern N. , Brückner W. , Schneider C.M.
Published: March 2009

The subject of the present investigation is the influence of annealing on the
microstructure of Co thin films. In particular, the evolution of the texture during annealing is studied and compared with that of Co/Cu multilayers of different individual layer thicknesses. 400nm thick Co films show a h.c.p. structure with a weak preference of the <001> texture component and a broad distribution of grain orientations. Annealing at about 350°C results in a strong increase of the h.c.p. <001> component, nearly complete disappearance of the statistical distribution and grain growth of a minor f.c.c. fraction in the films. In-situ XRD measurements on
single Co films during annealing confirm that the texture change is irreversible. Multilayer stacks of Co/Cu layers show various texture changes depending on the individual layer thickness (ranging between 100nm and 1nm). Generally, with decreasing individual layer thickness and increasing annealing temperature the f.c.c. content in the multilayers increases at the expense of the h.c.p. fraction.
X-Ray Diffraction Investigation of Electrochemically Deposited Copper
Authors: Pantleon Karen , Jensen Jens Dahl , Somers Marcel A.J.
Published: March 2009

Copper layers were deposited from acidic electrolytes containing different amounts of
organic additives, designed for the formation of Cu-interconnect structures. Amorphous Ni-P substrates allow to study the unbiased growth of the electrodeposits. The crystallographic texture was investigated by the determination of X-ray diffraction (XRD) pole figures and the calculation of the orientation distribution functions. XRD results are discussed in relation to the morphologies of the electrodeposits as investigated with light optical microscopy and correlated with the process parameters during electrodeposition.
Structure of Zr52Ti5Cu18Ni15Al10 Bulk Metallic Glass at Elevated Temperatures
Authors: Mattern N. , Kühn U. , Sakowski J. , Neuefeind J. , Eckert Jürgen
Published: March 2009

The glass transition and the phase formation during crystallization of the
Zr52Ti5Cu18Ni15Al10 bulk metallic glass were followed in situ by high-temperature X-ray diffraction using synchrotron radiation at the high energy beam-line BW5 ( λ = 0.01040 nm) at the storage ring DORIS (HASYLAB, Hamburg). The experimental set-up enables to record intensities in transmission up to scattering vectors q of 200 nm -1 with a measuring time of 20 s per diagram. The crystallization starts with the formation of an extremely fine nanostructure followed by the transformation into tetragonal NiZr2-type crystals plus an unknown phase. Both phases are metastable and transform at about 1123 K into the stable equilibrium phases. The temperature dependence of the structure factor S(q) of the glass can be well described within the framework of the Debye theory. At the glass transition the first derivative dS(q)/dT changes. A Debye temperature Θ = 412 K was estimated for the glassy, and Θ = 162 K for the liquid state of the
Zr52Ti5Cu18Ni15Al10 alloy. The short-range order of the glass, of the supercooled liquid state, and
of the equilibrium melt at T = 1193 K is found to be quite similar.
Texture Analysis of Nanostructured Metals Produced by Severe Plastic Deformation
Authors: Kilmametov A.R. , Alexandrov Igor V. , Dubravina Anna
Published: March 2009

In the present work the processes of crystallographic texture formation during severe plastic deformation (SPD), which has been carried out in the conditions of high imposed pressures (up to 6 GPa) and extremely large cumulative deformation degree (e up to 1÷100 and more) in pure metals, are investigated. It is shown that the processes of nanostructure formation as a result of SPD are accompanied not only by known processes such as a fragmentation, extension of misorientation angles, character modification of dislocation density, but also by the formation of deformation textures. The deformation textures, having been formed as a result of SPD are analyzed for the examples of FCC Cu, BCC W and HPC Ti, depending on a cumulative deformation degree and SPD scheme. The obtained crystallographic texture data are used for the analysis of the nanostructured state formation regularities.
Small-Angle Neutron Scattering in F.C.C. Fe-Ni and Fe-Ni-C Alloys
Authors: Nadutov V.M. , Garamus V.M. , Willumeit R. , Svystunov Ye.O.
Published: March 2009

Small-angle neutron scattering was studied in Invar Fe-Ni-C alloys in comparison with the Fe-Ni alloy. Mössbauer measurement was carried out to indicate magnetic structure. The non-linear SANS curves were analysed using a power law function and the Porod approximation and interpreted in terms of aggregates characterized by smooth surfaces or fractal properties. The size and shape of the inhomogeneities were estimated by using the Indirect Fourier Transformation analysis.
Distributions of Domain Size, Lattice Distortion and Dislocation Density in Tubes of Zr-Based Alloys Studied by a Method Combining X-Ray Line Profile Analysis with Texture Measurements
Authors: Perlovich Yuriy , Isaenkova Margarita
Published: March 2009

The distributions of substructure parameters for tubes of Zr-based alloys were
constructed by use of the X-ray method of Generalized Pole Figures, combining X-ray line analysis and texture measurement. Obtained distributions cover α-Zr crystallites of all orientations and give the fullest description of substructure features of the studied tubes. The interconnection of different substructure parameters are analyzed.
Structure Relations and XRD Patterns of the Disorder-Order Transition of Metastable RE2TM17 Alloys
Authors: Teresiak A.
Published: March 2009

By using non-equilibrium methods and subsequent annealing, rare-earth transitionŒ
metal-alloys with the nominal chemical composition 2:17 show a hexagonal metastable TbCu7 like structure. This disordered hexagonal (P6/mmm) metastable compound can be represented by a rhombohedral cell by using a cell transition of the hexagonal space group P6/mmm into the translationsgleiche subgroup P -31m (162) and subsequently into the klassengleiche subgroup II b R -3m. The atomic positions of the obtained rhombohedral cell correspond to appropriate coordinates in the hexagonal cell. In that way, a partial order of the 2:17 structure can be described. For the binary system Sm-Fe, a compound with similar structure and the formula SmFe8.5 exists. Examples are given for the obtained phases after ball milling the elemental powders Fe and Sm and subsequent annealing, and also after HDDR of Sm2Fe17.
Synthesis and Characterization of Al, Y, Co and Cr Substituted Ultrafine Powder of NiFe2O4
Authors: Blanuša Jovan , Antić B. , Nikolić A.S. , Rakić S. , Jovic N. , Srećković Milesa
Published: March 2009

The ultrafine spinel NiFe1.9M0.1O4 powders (M=Al, Y, Cr, Fe) were synthesized by thermal decomposition of appropriate mixtures of complex compounds with acetylacetone - (2,4 pentadione) ligands ([M(AA)x]) at 500 °C.
Samples were annealed in the temperature range 600-1000 °C and the crystallization process was followed by XRD. The largest crystallite size and the highest crystallization rate are observed for NiFe1.9Al0.1O4, while the opposite was found for NiFe1.9Y0.1O4. Strain value in NiFe1.9Y0.1O4 changes sign at temperatures between 700-800 °C, while for NiFe1.9M0.1O4 (M=Al, Cr) it has a
positive sign and reaches the maximum value at 700 °C.
The crystal structure of the samples annealed at 1000 °C was refined using the Rietveld profile method. Cation substitution in Ni-ferrite changes its structural and microstructural parameters, and can also significantly influence other physical properties.
Sorbate Rearrangement and Cation Migration in HFC-134 Loaded NaY Zeolite: a Temperature Dependent Synchrotron Powder Diffraction Study
Authors: Gualtieri A.F. , Norby P. , Grey C. P. , Hanson J.C.
Published: March 2009

The HFC-134/NaY binding has been monitored by temperature dependent X-ray powder diffraction. Diffraction patterns were obtained as a function of different loading levels to investigate the rearrangement of the cations and of the HFC-134 molecules, in the temperature range 100-230 K. In situ real-time data were collected using a Translating Imaging Plate System (TIPS) at the NSLS (USA). Rietveld structure refinements were performed for the HFC-134 (32 molecules per unit cell [m/uc = molecules per unit cell] or 4 molecules per supercage [m/sc = molecules per
supercage]) using data collected from 100 to 230 K. A phase transition is observed at about 180 K (A to B phase transition) where a disordering of the HFC-134 molecule takes place and modification of its surrounding due to Na+ migrations is observed. These results are preliminary and the experiment with the 32 m/uc should be repeated in order to assess whether the observed effect is reproducible.
Synthesis, Properties and Characterisation of Manganeous Layered Double Hydroxides Using In Situ X-Ray Techniques
Authors: König Uwe , Pöllmann Herbert
Published: March 2009

Synthetic manganeous Layered Double Hydroxides of the Hydrotalcite- and Shigaite-
type were prepared by the coprecipitation method. The thermal behaviour of two compounds, [Mn6Al3(OH)18] [(SO4)2Na·12H2O] and [Mn6Al3(OH)18] [Cl·4H2O] was investigated by several experimental techniques. Thermal analysis and in-situ X-ray diffractometry show several dehydration stages of the synthesis products in the temperature range of 25 < T < 170°C followed by decomposition at temperatures above 200°C.
Calcination of ZSM-5. An In Situ Synchrotron Powder Diffraction Study
Authors: Ståhl Kenny , Gustavsson Ester , Jacobsen Claus J.H. , Schmidt Iver
Published: March 2009

The calcination of the zeolite ZSM-5 was studied by in situ X-ray synchrotron powder diffraction. Two samples were studied: One conventionally synthesized (CONV) and one synthesized in a charcoal matrix according to the confined space synthesis method (CSS). The powder diffraction data were collected between 375 K and 975 K in steps of approximately 8 K/5 min. and evaluated by Rietveld refinements. Both sets of powder diffraction patterns displayed the
characteristic intensity changes for calcination, but neither of them showed the expected orthorhombic to monoclinic phase transition. Refinements of the extra-framework occupancy showed that the calcination starts at about 475 K and is essentially completed at 675 K for CSS, while the CONV calcination starts at 525 K and ends at 650 K. The refinement results agree very well with the TGA results. The carbon matrix of the CSS sample is combusted between 700 and 850 K. The unit cell dimensions continuously decrease from 475 to 975 K. An initial slow 1.2 % reduction between 375 and 875 K is followed by a fast 1.2 % reduction between 875 and 950 K for the CSS sample. This second unit cell reduction step is unrelated to the calcination process and does not involve any weight loss. It is suggested that this step is a recrystallisation/annealing process reducing the amount of defects and strain.
Structural Study of a High Ionic Conductor Rb4Cu16I7.2Cl12.8
Authors: Oikawa Katsunari , Kamiyama Takashi , Kanno R. , Izumi Fujio , Ikeda T. , Chakoumakos B.C.
Published: March 2009

The structure of a high ionic conductor Rb4Cu16I7.2Cl12.8 at low temperature has been reinvestigated by use of angle-dispersive neutron powder diffraction. All the diffraction data have been analyzed with integrated software REMEDY consisting of RIETAN-2000 for whole-pattern fitting and MEED for calculating densities of electrons or atomic nuclei by the maximum-entropy method. The resulting nuclear-density maps have reconfirmed that Cu1-Cu2 chains are the main conduction pathways in this material, as previously suggested from the Rietveld analysis of neutron powder diffraction data.
Influence of the Cation Distribution on the Physical Properties of the Diluted Magnetics Li1.33Ti1.67O4/Co2TiO4
Authors: Antić B. , Blanuša Jovan , Jovic N. , Kusigerski V. , Kremenović A.
Published: March 2009

Spinel samples of Li1.33xCo2-2xTi1+0.67xO4 crystallize in two space groups: Fd- 3 m for 0≤x≤0.40 and x=1, and P4332 for 0.50≤x≤0.875. In S.G. P4332 magnetic Co2+ ions occupy 8c sites (for x=0.75 and 0.875), or 8c, 4b and 12d sites (for x=0.50). In x=0.25 and 0.40 samples Co2+ occupy both 8a and 16d cation sites of the S.G. Fd- 3 m [1]. Observed differences in magnetic behaviour of the samples are induced by crystallographic distribution of Co2+. Possible paths for exchange interactions in S.G. P4332 were analysed. It was found that the superexchange is the dominant exchange mechanism where Co2+
(8c)-O(24e)-Co2+(12d) path was the most important
one. On the basis of the results on crystallographic distribution we suggest x=0.50 sample as potential electrode material in Li ion rechargeable batteries.
Low Temperature Magnetic Structure of CrNiAs
Authors: Bacmann M. , Fruchart Daniel , Koumina A. , Wolfers P.
Published: March 2009

The magnetic structure of CrNiAs was determined from magnetisation and powder
neutron diffraction experiments. In the 110-182 K temperature range, the compound is ferromagnetic, resulting mainly from the Cr moment of 1.25(5) μB. Below 110 K, neutron diffraction data reveals typical satellite reflections which propagation vector is 0.228 c*. A model of oscillating magnetic moments was refined from the integrated intensity of the few additional lines.
X-Ray Powder Diffraction Study of Atomic Structure of Nanocrystalline SiC and Diamond Materials
Authors: Grzanka Ewa , Palosz Bogdan F. , Gierlotka Stanislaw , Stelmakh Svetlana , Pielaszek Roman , Bismayer Ulrich , Neuefeind J. , Jóvári P. , Palosz W.
Published: March 2009

A considerable fraction of atoms in nanosize particles is at the grain surface (due to the small size of the crystals). We assume that the surface atoms form a separate structural phase relative to the bulk of the grain (the core). Therefore, one set of the lattice parameters characterizing a nanocrystal may be inadequate for a unique description of its structure. An alternative evaluation of diffraction data of nanocparticles, based on the 'apparent lattice parameter' is proposed. Based on this new methodology it is shown that real nano-crystals constitiute a complex, more than a one-uniform-phase structure.
Quantitative Phase Analysis Using the Rietveld Method - Estimates of Possible Problems Based on Two Interlaboratory Comparisons
Authors: Peplinski B. , Kleeberg R. , Bergmann J. , Wenzel J.
Published: March 2009

On the basis of data gathered in connection with a certification project, problems were investigated that impair the accuracy of quantitative phase analyses (QPA) using the Rietveld method. Some mechanisms were elucidated by which insufficient counting statistics of the diffraction data or inappropriate data handling and refinement strategy influence the QPA results.
New Method for Estimation of the Magnesium Fraction in Magnesian Calcite
Authors: Gržeta B. , Medaković D. , Popović S.
Published: March 2009

A new method for estimation of the magnesium fraction in magnesian calcite is described. It involves measuring the XRD pattern of magnesian calcite in a narrow 20 range and individual profile fitting of diffraction lines 113 and 202. The intensity ratio I113/I202 is linearly correlated with the Mg fraction. The method resulted from an XRD study of adult sea urchins Sterechinus neumayeri.
The Microstructure of Nanocrystalline Powders from Line Profile Analysis
Authors: Audebrand Nathalie , Louër Daniel
Published: March 2009

The theoretical background currently used in line profile analysis is reviewed. It covers the size and structure imperfection effects at the origin of diffraction line broadening. The propagation of errors, i.e. old errors and new errors related to profile fitting techniques, is commented. The experimental conditions for minimising errors are described. Representative examples of microstructure characterisation of nanopowders are presented.
Elastic Behaviour of Thin Stabilized-Zirconia Coatings
Authors: Scardi Paolo , Leoni Matteo , Loch M. , Barbezat G.
Published: March 2009

The residual stress in thin coatings of yttria stabilised-zirconia produced by Low Pressure Plasma Spraying were measured by X-ray Diffraction, using laboratory as well as synchrotron radiation sources. The specific microstructure, with absence of texture and fine distribution of nearly equiaxed grains, point out that despite the markedly anisotropic nature of cubic zirconia,
coatings can be considered as macroscopically isotropic. This picture is also confirmed by the results of a parallel study, where the X-ray elastic constants were measured in-situ along two crystallographic directions ([440] and [620]): measured values agree fairly well with those calculated from single-crystal data under the Neerfeld-Hill assumptions.
SR XRD provided a detailed information on the stress field across the thickness of the zirconia coatings. In particular the presence of a stress gradient was observed and modelled. The average stress is compressive, and increases with the coating thickness. Compression tend to increase from the surface toward the inside of the coating reaching a maximum of ~-1.0 GPa in a 24 µm coating.
Characterization of Crystalline Silicon via XRPD
Authors: Berti Giovanni , Bartoli U. , Basile G. , Becker P. , Fitch Andy
Published: March 2009

Three blocks of silicon have been crashed in this experiment in order to verify
the crashing effects on specimens having distinct original micro-structural arrangements. One of them comes from a rod bar of mono-crystal silicon, two others were from polycrystalline silicon manufactured by two distinct manufacturers with distinct growing process. Several specimens of powders, differing in type and grain size, were obtained by treating these source samples. This paper reports on data collected from synchrotron and conventional radiation and the results show that powders obtained from mono-crystalline silicon provide diffraction profiles, where the structural contribution is smaller than for
polycrystalline silicon specimens. The peaks from the 'mono-crystal powder' resulted even narrower than peaks from SRM Silicon 640b by NIST.
Reconstruction of Stress and Composition Profiles from X-Ray Diffraction Experiments — How to Avoid Ghost Stresses?
Authors: Christiansen Thomas L. , Somers Marcel A.J.
Published: March 2009

On evaluating lattice strain-depth or stress-depth profiles with X-ray diffraction, the variation of the information depth while combining various tilt angles, in combination with lattice spacing gradients leads to artefacts, so-called ghost or fictitious stresses.
X-ray diffraction lattice-strain analysis was simulated for a model stress-depth profile combined with a composition-depth profile. Two principally different methods were investigated for the reconstruction of the actual stress and composition profiles from the simulated data:
- considering the stress/strain determined at a specific depth as a weighted average over the actual stress/strain depth profile
- considering the lattice spacing determined at a specific depth, for a specific value for as a weighted average over the actual lattice spacing profile for this direction.
On the basis of the results it is possible to propose a preferred method for the evaluation of stress/strain and composition profiles, while minimising the risk for ghost stresses.
Computer Simulation for X-Ray Analysis of Nanostructured Cu Processed by Severe Plastic Deformation
Authors: Enikeev Nariman A. , Alexandrov Igor V. , Valiev Ruslan
Published: March 2009

A computer simulation-based approach has been developed in order to reveal grain boundary defect structure of nanomaterials, which is described in terms of extrinsic grain boundary dislocations. On the basis of comparative analysis of numerically obtained results to experimental data, the defect structure parameters of nanostructured materials produced by severe plastic
deformation have been evaluated.