bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phase separation in Si–(B)–C–N polymer-derived ceramics
Authors: Golczewski Jerzy A. , Aldinger Fritz 
Published: December 2013

Abstract
Details of phase separation in the microstructure of amorphous Si–(B)–C–N ceramics derived from polymers have been resolved using the recent results of structural investigations. The formation of an amorphous phase built of atomic compounds SiC
i/4N(4–i)/3 and consequently located along the composition line between SiC and Si3N4 in the ternary Si–C–N phase diagram demonstrates a generic feature of phase separation in all these materials. The amorphous carbon phase separates as a counterpart in the microstructure of Si–C–N ceramics, and in the case of Si–B–C–N ceramics such counterpart represents B–N–C domains of the composition (BN)
c
C
y
located along the tie line C–BN in the ternary B–C–N phase diagram. The effect of phase separation has been also pondered as a source of exceptional material properties.
Further results on creep behaviour of sand-cast Mg–2.8Nd–0.8Zn–0.5Zr–0.3Gd alloy at 0.56 to 0.61T
m under stresses 40 to 90MPa
Authors: Thomas-Whittington D. , Srivastava V. , Greenwood G. W. , Jones H. 
Published: December 2013

Abstract
An earlier study of the creep behaviour of Elektron 21 alloy has been extended to 290°C (0.61T
m; T
m: melting temperature). The combined results confirm a stress exponent of creep rate close to 6, but with an activation energy for creep of (310 ± 20) kJ/mol for 240 to 290°C and 40 to 90 MPa. Possible mechanisms giving rise to this behaviour are discussed.
Sigma phase formation and its effect on mechanical properties in the corrosion-resistant superalloy K44
Authors: Hou J. S. , Guo J. T. , Zhou L. Z. , Ye H. Q. 
Published: December 2013

Abstract
The sigma phase (σ) formation in long-term aged polycrystalline K44 superalloy has been studied as a function of aging temperature and time. The σ phase in K44 alloy forms mainly in dendrite cores with a few at interdendritic regions. The kinetics of σ formation can be described by the Johnson–Avrami–Mehl equation that yields activation energies of more than 130 kJ/mol in an early stage and less than 100 kJ/mol in steady state. Tensile experiments at room temperature and 1173 K and endurance experiments at 1173 K and 274 MPa were performed to test the effect of σ phases on these properties and no remarkable harmful effect is found. Moreover, the effect of long-term aging on the mechanical properties is realized mostly through the variation of γ′, not σ phase formation.
Structure-induced order–disorder transformation in Cd–Na liquid alloys
Authors: Singh R. N. , Ali I. 
Published: December 2013

Abstract
The origins of the S-shaped entropy of mixing and order–disorder transformation in Cd–Na liquid alloys have been investigated within a first-principle approach of a pseudopotential perturbation scheme with the Gibbs–Bogoliubov variation technique. We find that the deepening of the structure part of the entropy around the stoichiometric composition (c
Na ≍ 0.33) is responsible for the S-shaped entropy and suggests the existence of short-range order in the liquid state. The role of the local-field correction function, G(q), of conduction electrons on the entropy of mixing is examined. The impact of G(q) on partial structure factors is more visible towards low q(q → 0) than at higher q.
Comparison of thermodynamic data of the ternary Cu–Sn–Zn system, measured with the EMF and with the calorimetric method
Authors: Knott Sabine , Mikula Adolf 
Published: December 2013

Abstract
The enthalpy of mixing of the ternary Cu–Sn–Zn system was measured using a Calvet-type calorimeter. The investigations were carried out along the three cross sections Cu:Sn=1:2, 1:1, and 2:1. Zn was added in the concentration range between 0 and 50at.%.
The calorimetric results were compared with EMF data investigated in an earlier work by Peng and Mikula [1]. The results of the calorimetric measurements show very good agreement in the copper-rich region, compared with the EMF measurements, but in the Cu:Sn=1:2 cross section the results do not fit perfectly. The difference between both measuring methods was at the most ΔH = 300J/mol at the cross section Cu:Sn=1:1 and ΔH=150 J/mol at the Cu:Sn=2:1 cross section.
Site preference, thermodynamic, and magnetic properties of the ternary Laves phase Ti(Fe1–xAlx)2 with the crystal structure of the MgZn2-type
Authors: Yan Xinlin , Chen Xing-Qiu , Grytsiv A. , Witusiewicz V. T. , Rogl P. , Podloucky R. , Pomjakushin V. , Giester G. 
Published: December 2013

Abstract
Site preference and thermodynamic properties of the ternary Laves phase Ti(Fe1–xAlx)2 with MgZn2-type have been studied employing Rietveld refinement of X-ray and neutron powder diffraction data, X-ray single crystal data, and isoperibolic drop calorimetry techniques. A detailed relation between lattice parameters of Ti(Fe1–xAlx)2 and the Al content in the Laves phase has been presented. The Rietvelt refinement revealed that Ti atoms occupy the 4f site in the MgZn2-type, whilst Fe and Al atoms randomly share the 2a and 6h site. Heat of formation has been measured for Ti(Fe0.5Al0.5)2. For the ab initio density functional theory applications, a large number of structural models were investigated to calculate the concentration dependent (Al) heats of formation, magnetic structural stabilities, lattice parameters, and site occupancies, which are in good agreement with experiment.
Microemulsion mediated synthesis of nanocrystalline BaTiO3: possibilities, potential and perspectives
Authors: Pithan Christian , Schneller Theodor , Shiratori Yosuke , Majumder Subhasish Basu , Haegel Franz-Hubert , Dornseiffer Jürgen , Waser Rainer 
Published: December 2013

Abstract
The present study gives an overview on the potential, possibilities and perspectives that the synthesis of functional materials, such as BaTiO3, with microemulsions as the reaction medium offers. Well defined nanocrystalline particles in the form of powders for further ceramic processing, as well as stable colloidal dispersions for the preparation of coatings may be obtained. The paper describes the formation, phase behaviour and stabilization of microemulsions and related water/oil/surfactant systems that may be used as a nanoreactor during particle formation. The reaction principles of microemulsion mediated synthesis are outlined and some examples of structural aspects, revealing size effects in these systems are implemented using advanced characterization techniques, such as Raman spectroscopy. Finally, the preparation of mesoscopic layers, covering the thickness gap between thin film and thick film technology, is demonstrated.
The In–Pt–Sb phase diagram
Authors: Patrone Marta , Richter Klaus W. , Borzone Gabriella , Ipser Herbert 
Published: December 2013

Abstract
The ternary phase diagram In–Pt–Sb was studied in two isothermal sections at 400°C and 700°C, respectively, using X-ray powder diffraction (XRD), electron-probe microanalysis (EPMA), and metallographic techniques. The ternary phase reactions were determined by differential thermal analysis (DTA) in the composition range between 0 and 50at.% Pt. The obtained experimental phase diagram data were combined with literature data on the limiting binary systems to construct a ternary reaction scheme (Scheil diagram) in the investigated composition range between 0 and 50at.% Pt. The liquidus surface was derived from the results of DTA measurements.
Evolution of C-rich SiOC ceramics: Part II. Characterization by high lateral resolution techniques: electron energy-loss spectroscopy, high-resolution TEM and energy-filtered TEM
Authors: Gregori Giuliano , Kleebe Hans-Joachim , Blum Yigal D. , Babonneau Florence 
Published: December 2013

AbstractIn this Part II of the paper on the evolution of carbon-rich Si–O–C polymer-derived ceramics (PDCs), emphasis is placed on the strengths and limitations of transmission electron microscopy (TEM) techniques with high lateral resolution, i.e., electron energy-loss spectroscopy (EELS), high-resolution TEM (HRTEM) and energy-filtered TEM (EFTEM). Here, the identical SiOC materials, as described in Part I. EELS studies confirmed the progression of structural rearrangements within the SiOC matrix temperatures exceeding 1200°C. High-resolution TEM imaging showed that the SiOC matrices are indeed predominantly amorphous even upon high thermal treatment. Energy-filtered TEM analysis revealed, in contrast to the results obtained by Raman spectroscopy (Part I), that the excess free carbon phase undergoes a pronounced rearrangement within the amorphous microstructure. HRTEM characterization revealed the distribution of phases within the amorphous SiOC matrix; information that is not accessible by integral spectroscopic techniques. Discrepancies between the interpretation of experimental results obtained by local versus integral characterization tools are discussed in detail.
Nanostructured SiC/BN/C ceramics derived from mixtures of B3N3H6 and [HSi(Me)C≡C]n
Authors: Müller Anita , Gerstel Peter , Bunjes Natascha , Berger Frank , Sigle Wilfried , Müller Klaus , Weinmann Markus 
Published: December 2013

Abstract
Three borazine-modified polycarbosilanes were synthesized by reaction of poly[1,2-ethynediyl-(methylsilylene)], [HSi(Me)C≡C]n, and borazine, B3N3H6 using different stoichiometries. The polymeric precursors were transformed into inorganic Si–B–C–N materials by solid state thermolysis at 1400°C each in 88% yield. High temperature thermogravimetric analysis in an argon atmosphere showed no substantial decomposition reactions below 1800°C. Crystallization behavior up to 2000°C in a nitrogen atmosphere was studied by post-thermolysis heat treatment of as-obtained ceramics at various temperatures and subsequent examination of samples at room temperature using powder X-ray diffraction. Ceramics annealed at 1800°C were additionally characterized by transmission electron microscopy.
Effect of organic self-assembled monolayers on the deposition and adhesion of hydroxyapatite coatings on titanium
Authors: Zou Lijun , De Guire Mark , Wang Russell 
Published: December 2013

Abstract
Organic self-assembled monolayers with nitrogen-containing surface functionalities (amine or alkylammonium) were deposited on acid-etched titanium substrates. These were then coated with apatite deposited from 150% simulated body fluid at 37°C and pH = 7.6 for 2, 4, and 6days (after a 2-day “nucleation” step in contact with bioactive glass in 100% simulated body fluid). Scanning electron microscopy showed that precipitates were numerous on amine- and alkylammonium-modified titanium surfaces after nucleation for 2 days. X-ray diffraction at grazing incidence detected crystalline hydroxyapatite on the modified and unmodified substrates after growth for 2days. Tape peel tests followed by surface chemical analysis showed that the adhesion of the hydroxyapatite coating to the substrates was improved by amine and by alkylammonium modification of the etched titanium surfaces.
Interaction of functionalised surfaces on silica with dissolved metal cations in aqueous solutions
Authors: Majewski Peter 
Published: December 2013

Abstract
The study clearly shows that different metal cations were efficiently removed from water by employing coated silica particles with SO3H-terminated functionalized surfaces. Significant amounts of Fe, Mn, Ca, Mg, Na, and K could be removed from natural water samples with different concentrations varying from 0.075mg/l for Mn up to 12000mg/l for Na by stirring the functionalized silica particles in the water samples for 1h at room temperature. ICP–MS verify the removal of the elements and ToF-SIMS analyses clearly showed the presence of the elements on the particles after the treatment procedure. The removal of the metal cations is believed to be due to electrostatic attraction of the positively charged presumably hydrolysed metal cations to the negatively charged deprotonated SO3H-groups. However, from the current study it can not be excluded that chemisorption of the cations by the SO3H-group may be possible.
XRD and TEM study of NiO–LSGM reactivity
Authors: Rao Manga Venkateswara , Sturm Saso , Phillipp Fritz , Zinkevich Matvei 
Published: December 2013

AbstractNiO–LSGM reactivity during sintering at high temperatures in air leads to the formation of LaNiO3-type phase which is found to be insulating for oxygen ions. XRD analysis of the NiO-LSGM samples after sintering at 1350°C in air showed cubic (Pm-3m) LaNiO3-based phase with a lattice parameter of 3.856Å in addition to the cubic structure of LSGM20-17. STEM/EDX analysis of the NiO–LSGM interface showed the presence of a Ni-containing perovskite phase (La, Sr)(Ga, Ni, Mg)O3−xin the diffusion layer of LSGM. The probable composition of the LaNiO3-type phase that formed during sintering is discussed.
Microstructure and dielectric properties of nanoscale oxide layers on sintered capacitor-grade niobium and V-doped niobium powder compacts
Authors: Störmer H. , Ivers-Tiffée E. , Schnitter C. , Gerthsen D. 
Published: December 2013

Abstract
Electrolytic anodization was used to form amorphous niobium oxide layers on niobium and V-doped niobium powder compacts which act as dielectric layers, e.g. in niobium-based solid electrolyte capacitors. The microstructure development within the layered structure niobium-niobium oxide was studied by scanning- and transmission electron microscopy in order to investigate the influence of processing parameters. It could be shown that the thickness as well as the quality of the oxide layers on niobium vary in a considerable range, depending on processing parameters. Examination of the influence of heat treatments on the structural properties of the oxide layers revealed remarkable changes at the niobium – niobium oxide interface upon heat impact exceeding 300°C. In contrast, the interface remains stable with respect to the as-anodized sample when annealing was performed at lower temperature.
Kinetic study of the + transformation reaction in a CuZnAl alloy
Authors: De Micco Georgina , Bohé Ana Ester , Pasquevich Daniel Miguel 
Published: December 2013

Abstract
In the present work we study the phase transformation reaction of a Cu-20Zn-7Al (wt.%) alloy by isothermal and non-isothermal in situ X-ray diffraction. An effective activation energy for each phase is obtained for the range between 275 and 395°C. The experimental data are also adjusted with the JMA equations. Finally, we present the TTT (time–temperature–transformation) diagram corresponding to the precipitation of alpha and gamma for the lower temperatures. Below 340°C, we found for this alloy that the gamma phase precedes the formation of alpha.
Thermodynamic properties of liquid Cu–In–Zn alloys
Authors: Knott Sabine , Chen C.-J. , Gehringer Friedrich , Mikula Adolf 
Published: December 2013

Abstract
The partial Gibbs energies of zinc in the liquid Cu–In–Zn system as a function of temperature and concentration were measured in the temperature range between the melting points of the alloys and 1073K using an EMF method with a liquid electrolyte. The thermodynamic properties were determined for 30 alloys at three different constant ratios of Cu:In of 1:2, 1:1, and 2:1 with zinc added in the concentration range between 5 and 90at.%. The integral Gibbs free energy and the integral enthalpy of mixing of the ternary system were calculated with the Gibbs Duhem equation.
Failure-mode dependence of the strengthening effect in Ti3AlC2/10 vol.% Al2O3composite
Authors: Chen Jixin , Liu Mingyue , Bao Yiwang , Zhou Yanchun 
Published: December 2013

AbstractThe high-temperature mechanical properties of both Ti3AlC2and Ti3AlC2/10vol.%Al2O3composite, including compressive strength, bending strength, and fracture behavior, were investigated. The strengthening effect caused by Al2O3strongly depended on the mode of failure: significant enhancement in strength was only observed under the brittle mode of failure; whereas under the ductile mode of failure the strengthening effect was impaired due to Ti3AlC2matrix softening and stress relaxation.
Effect of reinforcement size hybridizati on on the wear properties of SiCp/Cu Composites
Authors: Zhan Yongzhong , Xie Haofeng , Shi Xiaobo 
Published: December 2013

Abstract
Reinforcement size is an important factor that influences the mechanical and tribological properties of particulate reinforced metal matrix composites (PRMMCs). However, relatively few works have been carried out to investigate this issue. There are still many problems to be solved, on the optimum design of PRMMCs of tribological applications. In this work, copper-matrix composites reinforced with SiC particles of mono-size and hybrid-size are fabricated through a powder-metallurgy plus hot-extrusion method. The main purpose is to investigate the effect of reinforcement size hybridization on the dry sliding wear behavior of PRMMCs. The results indicate that finer particles result in a better reinforcing effect and significantly reduce the plastic flow and adhesive transfer of surface and subsurface material. The deeply embedded coarse particles bear the external applied load and resist the plowing effect of the counterpart. The different roles of the particulate components with various sizes promote the exertion of the other's strengthening function, therefore resulting in higher wear resistance.
Investigation of SiO2 thin films on Si substrates for use as standards for laser-acoustic measuring devices
Authors: Lucca D. A. , Herrmann K. , Klopfstein M. J. , Menelao F. 
Published: December 2013

Abstract
We report on an investigation of the suitability of SiO2 thin films for use as calibration standards for the measurement of elastic modulus by laser-acoustic measuring devices. Film thicknesses for a range of thin film standards, originally developed for the calibration of ellipsometers, were obtained by X-ray reflectometry, ellipsometry, and metrological scanning force microscopy. Using the calibrated values of film thickness, a laser-acoustic method was used to obtain the elastic moduli of the thin films. Nanoindentation of the films, performed at two different laboratories was used to provide an independent measure of the elastic modulus values. The modulus values determined by nanoindentation and the laser-acoustic method were found to agree within 4.6%, which was within the calculated uncertainty of the measurements performed. As a result of their high homogeneity with respect to film thickness and elastic modulus, their low surface roughness and the good laser-acoustic signal quality, the thin films investigated appear to hold promise as standards for laser-acoustic measuring devices.
Indentation behaviour of (011) thin films of III–V semiconductors: polarity effect differences between GaAs and InP
Authors: Largeau Ludovic , Patriarche Gilles , Bourhis Eric Le , Rivière Jean-Pierre 
Published: December 2013

Abstract
(011) thin films of GaAs and InP (220 and 250 mm thick, respectively) were deformed by a Vickers indenter at elevated temperatures (350–400°C) under loads in the range 0.4–2.9 N. For loads higher than 1.9N, symmetric punching through InP was detected at the opposite face while it was asymmetric through GaAs. In InP, when the punching mechanism took place, pile-up around the indent site progressively disappeared. Moreover, the measured plastic volumes reveal that plastic flow throughout the specimens is volume conservative, implying that pile-up and punching events are related. In GaAs, the anisotropic pile-up plasticity was studied using transmission electron microscopy. Models describing the material flow through the samples and reverse flow of matter are proposed.
Nanoindentation studies of stamp materials for nanoimprint lithography
Authors: Denkiewicz D. , Landis S. , Ratajczyk L. , Rymuza Z. 
Published: December 2013

Abstract
We tested the nanomechanical properties of various materials (Si, SiO2, Si3N4, AlCu, TiN) for the design of stamps used in nanoimprint lithography. Nanoindentation was used on both insulated and non-insulated areas. The test enabled an estimation of the nanohardness and Young's modulus of the tested materials (films). The results are very useful for selecting the material for a protective film on the stamps used in nanoinprinting lithography.
The absolute thermoelectric power of chromium, molybdenum, and tungsten
Authors: Brodowsky Horst , Chen Qiyuan , Xiao Zhongliang , Yin Zhoulan 
Published: December 2013

Abstract
In pure metals or homogeneous alloys, the number of electrons per atom as well as the pressure are constant in a temperature gradient, and the electrochemical potential of the electrons is a unique function of the temperature. That is why it is possible to obtain the thermopower of these materials not only in the conventional evaluation of the Onsager equations, which involves the calculation of two transport coefficients, but also with an alternative approach, which involves the calculation of the temperature dependence of the electrochemical potential. The method is illustrated with the calculation of the thermopower of Cr, Mo, and W from the density of states of these metals.
On the fatigue behavior of ultrafine-grained interstitial-free steel
Authors: Niendorf Thomas , Canadinc Demircan , Maier Hans Jürgen , Karaman Ibrahim , Sutter Steve G. 
Published: December 2013

Abstract
The present paper reports on the cyclic stress–strain response of body-centered cubic ultrafine-grained (UFG) interstitial-free (IF) steel severely plastically deformed at room temperature utilizing equal channel angular extrusion (ECAE). Low-cycle fatigue tests were conducted with various strain amplitudes and strain rates on samples obtained through different ECAE routes and number of ECAE passes in order to determine the optimum processing route(s) for improved fatigue response of this material. UFG IF steel is superior to its coarse grained counterpart under both monotonic and cyclic loading in terms of properties, such as stress ranges tolerated, strength levels attained, and the corresponding fatigue behavior. All UFG steels subjected to more than 4 ECAE passes exhibit stable cyclic stress–strain response. Moreover, it was shown that dynamic grain coarsening, which usually leads to cyclic softening in UFG materials, is not prevalent in the ECAE processed UFG IF steel. For representing the fatigue life of UFG IF steel, the parameter after Smith, Watson and Topper, which is an indication of energy dissipation per cycle, proved adequate while comparing materials obtained through different ECAE routes.
Possibilities and limits in thermohydrogen processing of beta titanium alloy Timetal®10-2-3
Authors: Christ Hans-Jürgen , Lohse Georg 
Published: December 2013

Abstract
The microstructure of the metastable -titanium alloy Timetal®10-2-3 was changed systematically by means of thermohydrogen processing, in order to improve the mechanical properties. The thermodynamic and kinetic data-base was determined experimentally and the change in the beta transus temperature was determined quantitatively. The results were used to design a 4-step heat treatment process involving hydrogen during the first two steps. A comparison of the fatigue properties of the standard heat-treated and the thermohydrogen-processed alloy revealed that, despite the increase of the monotonic strength of the thermohydrogen-treated alloy, the fatigue limit is slightly reduced, while the fatigue crack growth threshold remains almost unaffected. From this correlation a strategy can be deduced for a further improvement of the thermohydrogen-processing procedure, in order to tailor the fatigue properties according to the requirements of the respective application.