bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of the thermoelastic response of long-fibre reinforced thermoplasticsby comparison with different non-contactstrain measurement techniques
Authors: Stelzer G. , Klavzar A. , Bos M. , Renz R. 
Published: December 2013

Abstract
Processing of long-fibre reinforced thermoplastics with a discontinuous reinforcement of long glass fibres, especially by direct-processing, leads to inhomogeneous and anisotropic properties. Because of this, locally resolved characterisation of the material properties is necessary. Non-contact testing methods are required to derive these material properties. Locally resolving hysteresis measurement, full-field strain measurement techniques and thermoelastic stress analysis (TSA) are applied to an incremental step test and to a fatigue test. It is shown that there is good correspondence between the local TSA-signals and the locally measured values of the major strain. This correlation is valid not only for lower linear elastic load levels, but also up to nonlinear-viscoelastic levels. A model is presented to describe the correlation between the TSA-signal and the measured major strain.
Experimental observations on thecorrelation between microstructure andfracture of multiphase steels
Authors: Papaefthymiou Spyros , Prahl Ulrich , Bleck Wolfgang , van der Zwaag Sybrand , Sietsma Jilt 
Published: December 2013

Abstract
The aim of this study is to clarify the role of the microstructure in damage evolution. The influence of the transformation induced plasticity effect on the crack initiation and the impact of the different phases in development of cracks are important factors that control the fracture mechanisms. The fracture mechanisms of multiphase steels have been investigated on the basis of extensive light optical microscopy and scanning electron microscopy investigations. On the micro-scale, two failure modes appear: cleavage and ductile fracture, depending on the stress–strain conditions, the internal cleanness, the volume fraction of the retained austenite and the position of the austenite and the martensite grains. If a martensite or an austenite grain fails inside a bainitic island, the crack develops rapidly leading to cleavage fracture. If the failure starts inside the ferritic matrix due to void initiation at hard phases, the emerged void causes ductile damage to the surrounding ferrite.
Thermodynamic assessment of the systems La2O3–Al2O3 and La2O3–Y2O3
Authors: Fabrichnaya O. , Zinkevich M. , Aldinger F. 
Published: December 2013

Abstract
The thermodynamic parameters of the systems La2O3–Al2O3 and La2O3–Y2O3 are assessed using the Calphad technique. The available phase equilibrium data and calorimetric measurements for the LaAlO3, perovskite phase have been used. The calculated phase diagrams are in reasonable agreement with experimental results. However, experimental data for the La2O3–Y2O3 system demonstrated large uncertainty and new experimental study of solid state reactions would be useful to verify the calculated diagram. Experimental investigations of thermodynamic properties are necessary for both systems to verify the calculated phase diagrams and thermodynamic properties.
Thermodynamic investigation of Co–Cr alloys, III: Thermo-analytical measurements using DSC and DTA techniques
Authors: Sterneland Thérèse 
Published: December 2013

Abstract
Several Co–Cr alloys have been investigated by Differential Scanning Calorimetry (DSC) as well as by Differential Thermal Analysis (DTA) in the temperature range 298–1823K. The compositional range investigated was from 0 to 87wt.% Cr with special attention given to alloys with low Cr contents, i.e. 0 to 10wt.% Cr. From the DSC measurements molar heat capacity values, phase transformation temperatures, enthalpies of transformation and Curie transition temperatures were derived. From the DTA measurements, the melting temperatures and melting enthalpies were evaluated. The trends obtained were compared with the results for pure Co as well as the proposed phase diagram reported in literature.
Processing and mechanical behaviour of a dual scale particle strengthened copper composite
Authors: Tiziani C. , Götting M. , Rösler J. 
Published: December 2013

Abstract
Oxide dispersion strengthened (ODS) and dual scale particle strengthened (DSPS) copper composites were successfully manufactured by a powder metallurgical processing route, containing Al2O3 particles with a mean diameter of 17nm as dispersoids and, in the case of the DSPS material, 15% tungsten fibres about 3mm long. Their mechanical behaviour was investigated at ambient and elevated temperatures. The ODS material displayed mechanical properties comparable to those of commercial GlidCop® alloys. Addition of tungsten fibres in case of the DSPS material increased the elevated temperature flow strength relative to the ODS counterpart by about 12%. This result is rationalised by finite element calculations, taking fibre orientation, plastic deformation of the fibres as well as the role of the fibre coating into account.
Electrochemical characterisation of magnesium and wrought magnesium alloys
Authors: Nascimento Maria Lúcia , Fleck Claudia , Müller Wolf-Dieter , Löhe Detlef 
Published: December 2013

Abstract
The electrochemical behaviour of magnesium and different wrought alloys, AZ31, AE42, LAE442, and ZEK100, with and without heat treatment, was examined with the Mini-cell System by linear sweep voltammetry in 0.5wt.% and 3.5wt.% NaCl solution. The corrosion damage was characterised by scanning electron microscopy. Magnesium and the different alloys exhibited strong differences in their electrochemical behaviour. Alloying with aluminium increases the corrosion resistance. However, the magnitude of this improvement depends on uniform sizes and distributions of the Al-rich phases. Similarly, the influence of the heat treatment on the corrosion resistance depends on the produced distribution of precipitates. Magnesium and its alloys corrode quite rapidly in comparison with other metals, and there is pronounced hydrogen development. The latter increased with increasing NaCl concentration, although no great differences in the corrosion in both concentrations were observed, except on pure magnesium and ZEK100.
Low-cycle fatigue and damage of an uncoated and coated single crystal nickel-base superalloy SCB
Authors: Stekovic Svjetlana , Ericsson Torsten 
Published: December 2013

Abstract
This paper presents low-cycle fatigue (LCF) behaviour and damage mechanisms of uncoated and coated specimens of a single crystal nickel-base superalloy SCB tested at 500 °C and 900 °C. Four coatings were deposited on the base material, an overlay coating AMDRY997, a platinum-modified aluminide diffusion coating RT22 and two innovative coatings called IC1 and IC3 with a NiW diffusion barrier in the interface. AMDRY997 and RT22 were used as reference coatings. The LCF tests were performed at three strain amplitudes, 1.0, 1.2 and 1.4 %, with, in laboratory air and without any dwell time. The LCF life of the specimens is determined by crack initiation and propagation. Crack data are presented for different classes of crack size in the form of crack density, that is, the number of cracks normalised to the investigated interface length. Micrographs of damage of the coatings are also shown.
The effect of the coatings on the LCF life of the superalloy was dependent on the test temperature and deposited coating. At 500 °C all coatings had a detrimental effect on the LCF life of the superalloy. At 900 °C both AMDRY997 and IC1 prolonged the fatigue life of the superalloy by factors ranging between 1.5 and 4 while RT22 and IC3 shortened the life of the coating – substrate system. Specimens coated with RT22 exhibited generally more damage than other tested coatings at 900 °C. Most of the cracks observed initiated at the coating surface and a majority were arrested in the interdiffusion zone between the base material and the coating. No topologically close-packed phases were found. Delamination was only found in AMDRY997 at higher strains. Surface roughness or rumpling was found in the overlay coating AMDRY997 with some cracks initiating from the rumples. The failure morphology at 900 °C reflected the role of oxidation in the fatigue life, the crack initiation and propagation of the coated specimens. The wake of the cracks grown into the substrate was severely oxidised leading to the loss of Al and Ti to the oxide and resulting in the formation of a γ′ depleted zone. The cracks grew more or less perpendicular to the load axis in a Stage II manner.
Liquid–solid phase equilibria in metal-rich Hf–Ti–Si alloys
Authors: Bewlay Bernard P. , Jackson Melvin R. , Yang Ying , Chang Y. Austin 
Published: December 2013

Abstract
A range of metal-rich Hf – Ti – Si alloys with Si concentrations up to 35.0 at.% was directionally solidified. Liquid – solid phase equilibria in these alloys have been investigated using scanning electron microscopy, X-ray diffraction, and electron beam microprobe analysis. Four phases were identified: (Hf, Ti)5Si3, Hf(Ti)2Si, β(Hf, Ti, Si), and α(Hf, Ti, Si). Microstructural and microchemical evidence provided a clear definition of the Hf – Ti – Si liquidus surface at the metal-rich end and indicated the existence of the invariant reaction:
Liquid + Hf(Ti)2Si → (Hf, Ti)5Si3 + β(Hf, Ti, Si)
This invariant reaction occurs at a composition of approximately Ti-50Hf-9.5Si, and at a temperature of ∼1420 °C.
A comparison of different distributions of azimuth angles in the sin2 ψ-method
Authors: Ortner Balder 
Published: December 2013

Abstract
X-ray stress measurement in a specimen with a biaxial stress state is usually done with the -method, where measurements are carried out at different and. For the values the most usual choice is 0°, 45°, 90°. A better choice would be. The reason why is explained in detail by comparing the error calculus for these two cases.
Deformation twins in ultrafine grained commercial aluminum
Authors: Liu Manping , Roven Hans J. , Yu Yingda 
Published: December 2013

Abstract
Deformation twins in an ultrafine grained commercial Al – Mg – Si alloy with nonequilibrium grain boundaries processed by equal channel angular pressing at room temperature have been observed by means of a transmission electron microscope and a high-resolution transmission electron microscope. It was found that deformation twins formed frequently at the intersections of several grain bands where the critical stress level is reached locally and a change in the dominant slip system may occur due to the significant plastic deformation. Deformation twinning was also observed to occur via partial dislocations emission from grain boundaries and grain boundary junctions in the ultrafine grained alloy. Twins and stacking faults formed by Shockley partial dislocations dissociated from 0° screw dislocations were characterized and analyzed. Three twinning mechanisms suggested by molecular dynamic simulations were identified and their relevance was discussed.
Time-dependent directional solidification of binary Al–Cu alloys in the initial transient
Authors: Zimmermann Gerhard , Drevermann Anne , Sturz Laszlo , Warnken Nils 
Published: December 2013

Abstract
At the start of directional solidification a complex interaction between the movement of the solidification front, the concentration pile-up ahead of the front and the temperature gradient at the solid – liquid interface takes place. Experiments with binary Al-Cu1.3 wt.% were performed in this regime in a Bridgman – Stockbarger type gradient furnace allowing solidification with a planar solid – liquid interface. The time-dependent velocity and temperature profiles were measured during the experiments, whereas the concentration profiles were analysed from the processed samples. The experimental results were compared to predictions from numerical simulations based on the model of Coriell et al. Good agreement is obtained in the description of time-dependent diffusive, planar growth in the initial transient.
Preparation of NiO–LiFeO2 solid solutions: the role of mechanical and thermal treatments
Authors: Berbenni Vittorio , Milanese Chiara , Bruni Gianna , Cofrancesco Pacifico , Marini Amedeo , Chiodelli Gaetano 
Published: December 2013

Abstract
Ternary mixtures of Ni – Li2CO3 – Fe2O3 have been used as starting materials in order to prepare binary NiO – LiFeO2 solid solutions to be used as cathodic materal for molten carbonate fuel cells. By a combination of thermoanalytical techniques (Thermogravimetry and differential scanning calorimetry) and diffractometric techniques (X-ray powder diffraction) the present work deals with the study of the role played by thermal and mechanical treatment of the starting mixtures on the preparation of the final solid solutions.
Retained coarse grains in bulk nanocrystalline Ni3Al
Authors: Rentenberger Christian , Karnthaler Hans-Peter 
Published: December 2013

Abstract
Transmission electron microscopy methods were used to study the nanocrystalline structure achieved by severe plastic deformation of L12 long-range ordered Ni3Al. The deformation by high-pressure torsion (up to 40 000 %) leads to a duplex structure consisting of a disordered nanocrystalline and an ordered coarse-grained structure carrying different shear strains. The volume fraction of the nanocrystalline structure increases with strain but varies locally. During the deformation micrometer sized coarse-grained volumes embedded in the nanocrystalline structure are retained; they show a predominance of orientations of high symmetry. This leads to the conclusion that the stability of the coarse grains results from their homogeneous slip caused by a homogeneous activation of the slip systems.
The influence of post-ECAP annealing on the properties of ultrafine-grained 5005 aluminum alloy sheet
Authors: Lapovok R. , McKenzie P. W. J. , Thomson P. F. , Semiatin S. L. 
Published: December 2013

Abstract
Equal Channel Angular Pressing is a well-known method of severe plastic deformation used to obtain ultrafine grained materials with significantly improved mechanical properties. To the present, Equal Channel Angular Pressing has essentially been restricted to the treatment of bulk billets of square or circular cross-section of limited size. A machine developed at Monash University allows the Equal Channel Angular Pressing of sheet material. In the present work, improvement in biaxial formability, associated textures and mechanical properties after one Equal Channel Angular Pressing pass followed by annealing for aluminium alloy 5005 were investigated. An optimal annealing treatment to obtain a good balance of properties was defined.
New trends in superplasticity in SPD-processed nanostructured materials
Authors: Valiev Ruslan , Islamgaliev Rinat , Semenova Irina , Yunusova Nina 
Published: December 2013

Abstract
Recent studies have revealed that bulk nanostructured metals and alloys produced by severe plastic deformation can demonstrate extraordinary superplasticity at low temperatures and/or high strain rates. This work presents new results on superplasticity in several nanostructured Al and Ti alloys focusing on microstructural evolution and strain hardening, as well as the challenges of their application. Grain refinement in these alloys was accomplished using severe plastic deformation techniques. Subsequent superplastic deformation allowed not only to attain their efficient forming, but also to improve the ultrafine-grained structure and to obtain enhanced mechanical properties in the articles produced. The results demonstrate the possibilities of new applications of superplastic forming using bulk nanostructured materials.
Non-microscopical methods for characterization of microstructures and properties of UFG metals
Authors: Zehetbauer Michael J. , Schafler Erhard , Ungár Tamas 
Published: December 2013

Abstract
The paper reports on non-microscopical methods which allow for close investigation of ultrafine-grained metals especially of those processed by different techniques of Severe Plastic Deformation. These are as follows: (i) X-ray Bragg profile analysis, (ii) electrical residual resistivity, (iii) annealing calorimetry, and (iv) positron annihilation spectroscopy. The advantage of these methods lies in their integration/averaging over a certain sample volume so that they are often much closer to macroscopic physical properties than methods of microscopy; furthermore, the values of quantities obtained are more reliable because of strictly objective rules of determination. Typical quantities being relevant for ultra-fine grained materials are (a) grain size and grain size distribution, (b) long range internal stresses, (c) dislocation densities, and (d) concentration of vacancies and/or vacancy agglomerates. While quantities (a) and (b) are important for all classes of ultra-fine grained materials, those of (c) and (d) particularly occur with nanomaterials processed by severe plastic deformation also being responsible for their specific features such as ductility and the presence of non-equilibrium phases.
Indentation-induced densification of soda-lime silicate glass
Authors: Yoshida Satoshi , Sanglebœuf Jean-Christophe , Rouxel Tanguy 
Published: December 2013

Abstract
Glass is densified under a sharp diamond indenter. The densification is not a volume conservative process, and does not contribute to the volume strain around the indentation. This means that densification affects residual stresses around the indentation impression. In order to estimate the densification volume, three-dimensional images of Vickers indentations on soda-lime silicate glasses were obtained before and after annealing. Only the densified volume can be recovered by annealing. After annealing at around glass transition temperature, large volume recovery (55 – 80 %) of Vickers indentation was observed for soda-lime silicate glass. The volume recovery is much larger than the recoveries of indentation diagonal and depth. It is found that the densification of glass under the sharp indenter cannot be ignored for evaluating crack initiation and brittleness of glass. In addition, the residual stresses around the indentation impression were also estimated from the plastically deformed volume and the size of plastic zone around the indentation.
Nanomechanical studies of MEMS structures
Authors: Pustan Marius , Ekwinski Grzegorz , Rymuza Zygmunt 
Published: December 2013

Abstract
The stiffness is a fundamental qualifier of elastically deformable mechanical microcomponents and micromechanisms whose static, modal or dynamic responses need to be evaluated. This paper presents the results of theoretical studies of microcantilevers and microbridges and also a method for experimental stiffness testing using atomic force microscopy. Castigliano's displacement theorem is used herein to derive the stiffness equations. The results of the theoretical and experimental studies are compared and discussed.
Mechanical properties of nanostructured polymer particles for anisotropic conductive adhesives
Authors: He J. Y. , Zhang Z. L. , Kristiansen H. 
Published: December 2013

Abstract
Metal-coated polymer particles are used as a critical component in anisotropic conductive adhesives. The mechanical properties of polymer particles are of crucial importance to both application and design. In this study, a nanoindentation-based flat punch test approach has been developed to determine the mechanical properties of two polymer particles. Particle A failed at an average deformation of 67.2 %, while no failure was observed for particle C when a maximum 10 mN normal load was applied. The contact stress – strain behavior and contact modulus were obtained from the flat punch test.
Visco-elastic properties of thin nylon films using multi-cycling nanoindentation
Authors: Richter Asta , Gojżewski Hubert , Belbruno Joseph J. 
Published: December 2013

Abstract
Time dependent behavior of thin nylon films is investigated by depth sensing nanoindentation. Different loading rates and holding times are applied in single indentation procedures to study the relaxation behavior of nylon resulting in a characteristic nonlinear displacement – time dependence. Several load – time functions of multi-cycling indentation are developed, such as constant load repetition and incremental load increase mode sometimes containing holding segments. Hysteresis loops in multi-cycling nanoindentation quantify the visco-elastic energy of nylon films. The loading rate does not change the loop size if the maximum and minimum load of the cycle are the same. The unloading process has to be sufficiently large to allow the performance of the visco-elastic relaxation of the material.
The microstructure of ball milled nanocrystalline vanadium; variation of the crystal imperfection and the lattice parameter
Authors: Lamparter Peter , Mittemeijer Eric J. 
Published: December 2013

Abstract
Nanocrystalline vanadium powders have been produced by ball milling in a planetary mill. The morphology of the powder particles has been investigated by scanning electron microscopy. Crystallite size (size of coherently diffracting domains) and lattice-strain variation (microstrain) have been determined from the analysis of the X-ray diffraction-line broadening using the established integral breadth Williamson – Hall and Fourier Warren – Averbach methods. Results obtained from transmission electron microscopy analysis have been compared with the X-ray diffraction results. Ball milling causes an increase in the particle size and a decrease in the grain (crystallite) size with increasing milling time, a lattice-strain variation, due to deformation-induced dislocations, that increases with milling time and deformation-induced stacking faults of density increasing with milling time. The lattice parameter of the vanadium powders, as deduced from the diffraction-peak positions, decreases upon milling linearly with the inverse of the grain size, which has been attributed to grain (crystallite)-boundary stress.
Improved mechanical properties of the high pressure die casting alloy AlSi9Cu3(Fe)(Zn) as a result of the combination of natural and artificial ageing
Authors: Pabel Thomas , Geier Georg F. , Rockenschaub Horst , Hopfinger Michael 
Published: December 2013

Abstract
The present study was performed on the alloy AlSi9Cu3(Fe)(Zn) (EN 1706: 1998) to investigate the effect of different heat treatment conditions. High pressure die cast samples were quenched directly after casting and subsequently stored at room temperature or elevated temperatures. Combinations of natural and artificial ageing were also tested. The static mechanical properties of the alloy were measured at all stages. The results show that it is possible to attain improved mechanical properties by an optimised combination of both treatments.
Rapidly solidified Fe-base alloys as electrode materials for water electrolysis
Authors: Schmidt Andreas , Schubert Thomas , Röntzsch Lars , Weißgärber Thomas , Kieback Bernd 
Published: December 2013

Abstract
Amorphous ribbons of the systems Fe60Co20Si10B10 and Fe50Co20V10Si10B10 have been prepared via melt spinning to be used as electrode materials in alkaline water electrolysis. It turned out that the gas atmosphere during melt-spinning has a significant impact on the surface morphology and microstructure of the ribbons. Furthermore, a comprehensive characterization of the microstructure depending on the peripheral speeds of the cooling wheel was conducted. Moreover, the transition from the amorphous to the crystalline state was investigated via differential scanning calorimetry measurements. Preliminary electrochemical investigations suggest a noticeable improvement of the electrocatalytic activity of the melt-spun amorphous ribbons after an anodic–cathodic pretreatment.