bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mg-rich phase equilibria of Mg–Mn–Zn alloys analyzed by computational thermochemistry
Authors: Ohno M. , Schmid-Fetzer R. 
Published: December 2013

Abstract
The phase equilibria of Mg-rich Mg–Mn–Zn alloys are scrutinized on the basis of computational thermochemistry. The experimentally well-established facts are very well reproduced by the present calculation. The important invariant reaction involving Mg-solid solution is calculated to be a transition type reaction L+(Mg)↔αMn+Mg51Mn20 at 340.18°C. Some aspects that were incorrectly interpreted in early experimental works are pointed out and are explained by the present calculations also involving non-equilibrium effects.
Generalized Maugis–Dugdale model of an elastic cylinder in non-slipping adhesive contact with a stretched substrate
Authors: Chen Shaohua , Gao Huajian 
Published: December 2013

Abstract
We have recently developed a generalized JKR model for non-slipping adhesive contact between an elastic cylinder and a stretched substrate where both tangential and normal tractions are transmitted across the contact interface. Here we extend this model to a generalized Maugis–Dugdale model by adopting a Dugdale-type adhesive interaction law to eliminate the stress singularity near the edge of the contact zone. The non-slipping Maugis–Dugdale model is expected to have a broader range of validity in comparison with the non-slipping JKR model. The solution shares a number of common features with experimentally observed behaviors of cell reorientation on a cyclically stretched substrate.
Implications of linear relationships between local and macroscopic flow stresses in the composite model
Authors: Mughrabi Hael 
Published: December 2013

Abstract
Earlier results obtained by X-ray diffraction studies on tensile-deformed [001]-orientated copper single crystals have recently been re-assessed with respect to the evolution of the long-range internal stresses and the local flow stresses of the dislocation cell walls and the cell interiors. It was noted that the magnitudes of the long-range internal stresses and of the local flow stresses increase in good approximation linearly with the applied macroscopic flow stress. In the present work, the results of a similar analysis of earlier published X-ray data, which were obtained on tensile-deformed [001]-orientated Cu–Mn single crystals, are reported. When the friction stress of the alloy is taken into account, similar linear relationships to the case of deformed [001]-orientated copper single crystals were obtained. The implications of these results are analyzed in the framework of the composite model of crystal plasticity. It is shown that linear relationships of the type considered imply, in terms of the composite model, that the ratio between the local dislocation densities in the dislocation cell walls and the cell interiors must remain constant during deformation. This result is discussed with respect to the experimentally obtained data on local dislocation densities.
Thin film formation by oriented attachment of polymer-capped nanocrystalline ZnO
Authors: Lipowsky Peter , Jia Shijun , Hoffmann Rudolf C. , Jin-Phillipp Neng Yun , Bill Joachim , Rühle Manfred 
Published: December 2013

Abstract
Chemical bath deposition has been introduced as a means to produce films of inorganic substances with low engineering expenditure and close to ambient temperature. Organic additives have been used to control the growth of zinc oxide particles in solution and prevent the formation of the typical rod-like morphology. In the present work an attempt is made to combine these two approaches in order to produce thin films of zinc oxide. In the presence of β-cyclodextrin, spherical nano-crystalline deposits were obtained from solution; polyethylene glycol induced the formation of nano-structured thin films. With polyvinylpyrrolidone as an additive, uniform films were deposited. The structure of these films was analyzed by X-ray diffraction and transmission electron microscopy, which revealed the presence of domains of locally oriented nanocrystals. A mechanism of oriented attachment is proposed to explain the formation of domained ZnO films.
High-temperature deformation behavior of nanocrystalline precursor-derived Si–B–C–N ceramics in controlled atmosphere
Authors: Kumar Ravi , Mager R. , Phillipp F. , Zimmermann A. , Rixecker G. 
Published: December 2013

Abstract
In precursor-derived nanocrystalline Si–B–C–N materials, grain or interphase boundaries constitute a major part of the material. They control various properties of nanostructured solids, e.g., by forming fast diffusion pathways. In such highly covalent materials, where the interfaces between the individual crystallites or domains tend to be broadened and structurally disordered, high-temperature plastic deformation (i.e., the creep behavior) can be used as a probe which is particularly sensitive to processes involving internal interfaces and glass-like features of the microstructure. The focus of the present study is an investigation of the deformation behavior of precursor-derived nanocrystalline Si–B–C–N ceramics in the phase-separated amorphous and nanocrystalline states under inert atmospheres. A concise analysis of creep mechanisms free of any oxidation effects was carried out. Isothermal compression creep experiments at 1400°C and at various loads (50MPa–150MPa) have indicated a stress exponent near to unity hinting diffusion creep, and an activation energy of 0.16 ± 0.03 MJ/mol was derived from temperature change experiments under an iso-stress condition. The mechanisms of deformation are elucidated using a free volume model.
Infrared properties of sintered α-MnSe
Authors: Nikolić Maria Vesna , Nikolić Pantelija M. , Blagojević Vladimir , Paraskevopoulos Konstantinos M. , Zorba Triantafyllia T. , Vasiljević-Radović Dana , Risticć Momčvilo M. 
Published: December 2013

Abstract
Far-infrared reflection spectra of sintered α-MnSe were measured at room temperature. The measured spectrum had one pronounced peak in accordance with literature data and group theory estimation and one smaller peak resulting from the applied sintering procedure. The measured reflection spectrum was analyzed using Kramers–Kronig analysis and a three-component effective medium model based on Bruggeman's theory assuming the presence of a small amount of pores, dominant crystalline grains and intergranular material. In the model the crystalline grains were modeled as a single oscillator appropriate to the single crystal and the intergranular material was also defined as a single ionic oscillator.
Evolution of C-rich SiOC ceramics
Authors: Kleebe Hans-Joachim , Gregori Giuliano , Babonneau Florence , Blum Yigal D. , MacQueen D. Brent , Masse Sylvie 
Published: December 2013

AbstractCarbon-rich Si–O–C polymer-derived ceramics (PDCs) were investigated by various spectroscopic techniques, in order to characterize the evolution of their predominantly amorphous microstructure upon thermal treatment up to 1450°C. Particular attention was addressed to modifications of the excess free carbon phase present in these materials. Surprisingly, the carbon clusters exhibited high stability above the pyrolysis temperature. Despite the high volume fraction of carbon, only a very limited carbothermal reduction process was detected. This study is divided into two parts: PartI deals with characterization tools that reveal a rather low lateral resolution and are hence termed here as integral spectroscopic techniques, i.e., solid-state NMR and Raman spectroscopy. In contrast, PartII illustrates the experimental results obtained from the very same materials characterized by spectroscopic and imaging techniques with high lateral resolution, i.e., electron energy-loss spectroscopy (EELS), high-resolution transmission electron microscopy (HRTEM), and energy-filtered TEM. In addition to materials characterization, emphasize of both papers is also to compare the information gained by either integral or local spectroscopy techniques and to highlight the strengths and weaknesses of either approach.
Microstructure, hardness, and fracture toughness evolution of hot-pressed SiC/Si3N4 nano/micro composite after high-temperature treatment
Authors: Šajgalík Pavol , Hnatko Miroslav , Lojanová Štefánia , Lenčéš Zoltán , Pálková Helena , Dusza Ján 
Published: December 2013

Abstract
The grain boundary phases in SiC/Si3N4 nano/micro-composite changes with time of high temperature treatment at 1750°C in nitrogen atmosphere. Stable phases were obtained after 26 hours of annealing. Moreover, the average grain diameter distribution was significantly changed. The hardness and fracture toughness of the SiC/Si3N4 nano/micro-composites decreased with the duration of the high-temperature treatment. Both findings can be explained by the different secondary crystalline phases formed during the high-temperature treatment. Phases Si2N2O, Y2SiO5, and Y2Si2O7, typical for the samples treated up to 4 h, were replaced by the YNSiO2 phase in the samples treated longer than 26 h. Anisotropy of the measured mechanical properties in different sample cross-sections caused by the Si3N4 grain alignment become negligible after long term high-temperature treatment.
Microstructural characterisation of a Co–Cr–Mo laser clad applied on railway wheels
Authors: Farooq Muhammad Umar , Klement Uta , Nolze Gert 
Published: December 2013

Abstract
A Co–Cr–Mo laser cladding applied on railway wheels is characterised by a combination of EBSD and EDX. A complete pass of the cladding is investigated to achieve a better understanding of the microstructure evolution during laser cladding. A microstructure with columnar grains extending over the whole thickness of the cladding is observed. The grains have a <001>-fibre texture with the fibre axis parallel to the normal of the substrate surface, and a substructure consisting of cells/dendrites. During the cladding process, two different kinds of precipitates form in the cell walls, which can be identified as M6C and a non-equilibrium phase. Furthermore, stacking faults are observed to occur in the cladding grains and are discussed with respect to the laser cladding process.
Calorimetric investigation of the binary Cu–In system
Authors: Knott S. , Mikula A. 
Published: December 2013

Abstract
Although some investigations of the integral enthalpy of mixing of the binary Cu–In system have already been done, there is a lack of conformity of these data within the literature. Therefore the integral enthalpy of mixing was determined with a Calvet-type calorimeter. The measurements were performed at four different temperatures to determine the temperature dependence of the integral enthalpy of mixing.
Neutron diffraction analysis of martensite ageing in high-carbon FeCMnSi steel
Authors: Barbé Liesbeth , Samek Ludovic , Verbeken Kim , Conlon Kelly , De Cooman Bruno C. 
Published: December 2013

Abstract
A high-carbon metastable austenite phase was quenched in liquid nitrogen to obtain fresh athermal martensite. Different ageing treatments were performed in order to study the transformation of the martensite phase and the formation of carbides. Neutron diffraction experiments give detailed information on the transformations during the annealing treatment itself. The tetragonal athermal martensite transformed immediately, i.e. during the heating to the ageing temperature, to cubic martensite. Ageing at 400°C resulted in the decomposition of the austenite in ferrite and carbides and the formation of bainite. Those carbides could be determined as -carbides transforming in -carbides after extended annealing times. As was expected, ageing at 170°C resulted in the formation of a small amount of carbides while the austenite phase remained stable.
Novel combinatorial microstructures in Ti-6Al-4V alloy achieved byan electric-current-pulse treatment
Authors: Zhang Wei , Zhao Wei-song , Li Dou-xing , Sui Man-ling 
Published: December 2013

Abstract
An electric-current-pulse (ECP) treatment was employed to rapidly heat a dogbone-shaped Ti-6Al-4V sheet. After the treatment, the alloy was modified from a single micrometer-sized structure to a shape-associated combinatorial counterpart. Coexisting with the original equiaxed coarse-grained -Ti and the intergranular -Ti, two kinds of novel ultrafine structures, nanometer-sized lamellar twins of -Ti martensites and refined bimodal structure have been produced in the different parts of the bulk sample. Formation of the novel microstructures during the ECP treatment was systematically investigated. This work demonstrated that the ECP rapid heating treatment is a promising method to tailor the microstructures of the metallic alloys basically by designing the shape-associated distribution of the current density and offer a new possibility for improving the conventional alloys.
The Effect of Ti–B and Sr on the mechanical behaviour of the Zinc–Aluminum-based ZA-12 alloy produced by gravity casting
Authors: Kurnaz S. Can , Sevik Hüseyin , Türk Ahmet , Ozsarac Uğuur 
Published: December 2013

Abstract
In this study, the effect of Ti–B (0.05–0.7wt.% Ti, 0.01–0.13wt.% B) and Sr additions (0.05–0.7wt.%) on the hardness, ultimate tensile strength (UTS), strain and fatigue properties of the gravity cast Zn–Al-based ZA-12 alloy was investigated. While the Ti–B additions had no significant effect on the hardness of the alloys, the Sr additions lowered the hardness by a small amount. UTS and fatigue resistance of the ZA-12 alloy increased with 0.05wt.% Ti, but the addition of 0.05wt.% Sr to the standard alloy did not change these properties significantly. In excess of 0.05wt.% Ti and Sr, the UTS and fatigue resistance of the alloys decreased and reached a lower value than that of the standard alloy. The failure strain only increased for the ZA-12 alloy containing 0.05wt.% Ti, then decreased with further increase in Ti content. The failure strain values of the alloys decreased with addition of Sr. Metallographic examination indicated that the addition of Ti–B strongly modified the microstructure of the standard ZA-12 alloy, but Sr did not. Ti and Sr have also formed complex-shaped intermetallic compounds, which were identified as Al5Ti2Zn and Zn5Al3Sr by X-ray diffraction and EDS analyses. It can be suggested that these particles cause a decrease in UTS, fatigue resistance, and strain to failure of the ZA-12 alloy.
Determination of retained austenite in multiphase steels by magnetic force microscopy
Authors: Zens Aloisia Saiz , Appel Tamara , Broekaert Jose A. C. , Friedel Frank 
Published: December 2013

Abstract
The use of atomic force microscopy (AFM) in the magnetic force mode (MFM) for the determination of austenite (non-magnetic phase) in duplex and TRIP (transformation-induced plasticity) steels is described. The influence of the sample preparation for the MFM measurements is investigated, showing that a final electropolishing stage is necessary in the case of TRIP-steels.
The results of the determination of austenite in the range of 6–15% with AFM were compared with those obtained with electron backscattered diffraction (EBSD) and light optical microscopy. For TRIP-steels an identification of retained austenite with MFM was found to show a better resolution than classical light optical microscopy.
Determination of the critical tensile stress of sapphire by spherical indentation with additional lateral forces
Authors: Linss V. , Chudoba T. 
Published: December 2013

Abstract
The comprehensive mechanical characterisation of thin films and surfaces is very important for a suitable optimisation of protection layers and layer systems. The Young's modulus and the yield strength are widely accepted material parameters which can be determined by spherical nanoindentation in normal direction. This article reports on the determination of a further parameter, the critical tensile stress, by spherical nanoindentation with additional lateral forces. The critical tensile stress was determined for sapphire. It will be shown that the results obtained with two different nanoindentation devices equipped with spherical diamond indenters of different radii agree with less than 10% deviation.
In situ electrochemical nanoindentation of a nickel (111) single crystal: hydrogen effect on pop-in behaviour
Authors: Barnoush Afrooz , Vehoff Horst 
Published: December 2013

Abstract
The hydrogen effect on dislocation nucleation in Ni single crystals with (111) surface orientation has been examined with the aid of a specifically designed nanoindentation set-up for in situ electrochemical experiments. The effect of the electrochemical potential on the indent load–displacement curve, especially the unstable elastic-plastic transition (pop-in), was studied in detail. The experiments allowed the exclusion of the surface from hydrogen effects. The observations showed a pop-in load drop from an average value of 250 to 100N due to in situ hydrogen charging, which is reproducibly observed within sequential hydrogen charging and discharging. Clear evidence is provided that hydrogen atoms facilitate homogeneous dislocation nucleation.
Residual stresses in random-planar aluminium/Saffil® short-fibre composites deformed in different loading modes
Authors: Garces Gerardo , Bruno Giovanni , Wanner Alexander 
Published: December 2013

Abstract
The evolution of residual stress with plastic pre-strain was studied on a squeeze-cast, 2D-random short-fibre-reinforced metal matrix composite (aluminium/Saffil®). The plastic pre-strain was applied in three different modes: (1) uniaxial compression parallel to the fibre plane, (2) uniaxial tension parallel to the fibre plane, and (3) uniaxial compression normal to the fibre plane. The mean deviatoric residual stresses in the aluminium matrix were analysed using neutron diffraction. A major outcome is that the residual matrix stress is controlled by the load transfer to the fibres during deformation of the composite and reverse matrix plastic flow during unloading. The interplay between matrix and fibres depends strongly on the loading mode, and so does the evolution of the residual stresses as a function of pre-strain. This could be rationalised in a unified way using an Eshelby model.
Microstructure and mechanical properties of the extruded Mg-alloys AZ31, AZ61, AZ80
Authors: Mueller S. , Mueller K. , Tao H. , Reimers W. 
Published: December 2013

Abstract
In order to obtain optimum lightweight constructions in the automobile and aircraft industry, it is important to consider the use of extruded magnesium sections. A lot of the recent research has dealt with the extrusion of AZ31. These extrudates often miss the requirements of the automobile or aircraft industry for mechanical properties. A possible solution might be an increase in the aluminum content. Therefore, this paper deals with the extrusion of AZ31, AZ61 and AZ80 and the effect of the aluminum on the extrusion process as well as on microstructure and the mechanical properties of the extrudates. Whereas the aluminum content does not have a significant influence on the texture of the extrudates, the grain size and structure and, thereby, the mechanical properties can be improved by adding more aluminum to the Mg wrought alloys.
High thermal stability of mechanically-alloyed nanocrystalline Cu–Nb alloys
Authors: Botcharova E. , Freudenberger J. , Schultz L. 
Published: December 2013

Abstract
The high thermal stability of a nanocrystalline mechanically-alloyed Cu–Nb alloy was studied by means of isothermal annealing at high temperatures. The structure of the Cu matrix remains nanocrystalline with a grain size of about 50nm even after annealing at 1000°C for 10h. The copper grain growth is described with the help of kinetic analyses. The activation energy of the copper grain growth in Cu-10at.% Nb is about 0.98eV and the grain growth exponent is 4. The enhanced stability of the nanocrystalline Cu microstructure is attributed to the diffusion of Nb atoms along the Cu grain boundaries, “Zener drag” of NbO, Cu2O or Fe7Nb6 particles, and a non-equilibrium state of Cu grain boundaries.
Residual-stress-induced subsurface crack nucleation in titanium alloys
Authors: Ludian Tomasz , Kocan Marcin , Rack Henry J. , Wagner Lothar 
Published: December 2013

Abstract
This investigation has considered the influence of heat treatment, environment and residual stress level on the response of titanium alloys to mechanical surface treatment. It has been shown that the high cycle fatigue benefits to be gained by mechanical surface treatment will depend upon all of these variables. For example, shot peening of Ti–6Al–7Nb a/b solution treated, water quenched and aged condition results in a substantial increase in the high cycle fatigue performance in laboratory air. In contrast, shot peening of Ti–6Al–7Nb a/b solution treated, air cooled and aged condition has only a relatively small impact on the high cycle fatigue performance. This study also shows that high cycle fatigue crack nucleation of mechanically surface treated titanium alloys within the low stress, high cycle regime is associated with subsurface fatigue crack nucleation. Further, that this phenomenon may be related to the presence of a process-induced residual tensile stress necessarily present below the mechanically treated surface and required to balance the outer process-induced residual compressive stresses.
Thermal relaxation of residual stresses in TiN films deposited by arc ion plating
Authors: Matsue Tatsuya , Hanabusa Takao , Ikeuchi Yasukazu 
Published: December 2013

Abstract
The present study investigates crystal orientations and residual stresses in TiN films deposited by arc ion plating. TiN films approximately 2.0 μm thick were deposited on a steel substrate. With a bias voltage of 0 V, the TiN film exhibited strong {110} texture, whereas the dominant orientation of the film deposited at −100V was {111}. TiN films had very high compressive residual stresses: −8.6 GPa in the {110} textured film and −10.0 GPa in the {111} textured film. These residual stresses decreased with increasing annealing temperature and the reduction rate was greater for the {111} than for the {100} film. The behavior of residual stresses in the {111} and {110} textured layers of {111}/{110} textured double-layer film was identical to that for single-layer films.
Anwendung des lokalen Dauerfestigkeitskonzepts zur Bewertung der Wirksamkeit von Schweißnahtnachbehandlungsmaßnahmen
Authors: Nitschke-Pagel Thomas , Wohlfahrt Helmut 
Published: December 2013

Abstract
Many investigations have revealed the beneficial effect of mechanical surface hardening in combination with induced compressive residual stresses leading to improved fatigue strength. The benefit will be higher, the higher the quality of the weld is. On the other hand, methods like shot peening are useless if the weld toe profile is poor and the connected notch effect strong. Increased fatigue strength is then only possible after a post weld treatment which produces a smoother shape of the weld toe. Experiments reveal that methods which aim to increase the intensity of the penetration depth do not necessarily produce the best fatigue performance. High intensities of the mechanical surface treatments, especially in ductile aluminium alloys, may produce new geometrical defects which may work against the benefit of the deeper penetration depth of cold hardening and compressive residual stresses. A systematic evaluation of the results of improvement methods is possible with the help of the local fatigue strength concept, which compares the local strength properties and the local load stresses.