bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of tension–compression loading history on plastic deformation of Mg wrought alloy AZ31
Authors: Götting Martin , Scholtes Berthold 
Published: December 2013

AbstractThe plastic deformation behavior of the Mg wrought alloy AZ31 is investigated in tension–compression tests at room temperature. It strongly depends on the loading direction and is characterized by dislocation slip as well as by the formation of deformation twins. The latter is reversible in the case of a change of the deformation direction. Because of the pronounced crystallographic texture of the material investigated, a macroscopic deformation anisotropy exists with lower flow stresses in compression than in tension. Hysteresis loops with characteristic shapes are observed when the material is cyclically plastically deformed, depending on the tension–compression loading history.
Analysis of defect configurations with positron lifetime measurements by pulsed low energy beams
Authors: Egger W. , Kögel G. , Sperr P. , Gudladt H.-J. 
Published: December 2013

Abstract
To understand the damage behavior of mechanically deformed metallic materials in more detail, the kind of defect and its concentration have to be known. In addition, the kinetics of decomposition and of precipitation hardening are influenced by the presence of defects and the corresponding concentration. Consequently, an analysis of dominating defects would be helpful. Compared with well known techniques, positron annihilation spectroscopy offers the opportunity for lifetime measurements that are characteristic for special kinds of defects, e.g. dislocations, small vacancy clusters and micro-voids. To detect the spatial distribution and to determine the concentration of defects, the low energy pulsed positron beam technique can be used. This technique, in combination with the scanning positron microscope, opens a broad field of applications for defect analysis in metallic and ceramic materials.
The nature of the TRIP-effect in metastable austenitic steels
Authors: Oettel Heinrich , Martin Ulrich 
Published: December 2013

AbstractThe TRIP-effect in metastable austenitic steels is caused by a moderate local martensitic transformation, influencing both the strain hardening and the damage behaviour. The main conditions of a marked TRIP-effect are a low flow stress in the undeformed state, a high strain hardening exponent, a continuous martensitic transformation up to about 20% and a high resistance to damage (e.g. crack formation and propagation). The martensite transformation starts in glide or shear bands and their intersections even at temperatures clearly above the conventionalMd-temperatures, reducing the local stress concentrations and so preventing the onset of damage. Furthermore, high martensite content can be detected along the fracture path impeding the crack propagation by the transformation. To demonstrate the influence of damage on the TRIP-effect the deviations from the so-called Considere-criterion for maximum uniform elongation can be used.
Diffusion of 65Zn in the Mg17Al12 intermetallic compound and in the Mg-33.4wt.% Al eutectic
Authors: Čermák Jiří , Stloukal Ivo 
Published: December 2013

Abstract
The coefficient of 65Zn heterodiffusion in the Mg17Al12 intermetallic compound (-phase) and the eutectic alloy Mg-33.4wt.% Al was measured in the temperature region 598–698K using serial sectioning and residual activity methods. The diffusion coefficient of65Zn in the intermetallic can be written as DI=1.5×10−2m2s−1× exp(–154.3kJmol−1/RT). At temperatures T648K, where the mean diffusion path is greater than the mean interlamellar distance in the eutectic, the effective diffusion coefficient Deff=2.710−2m2s−1exp(–155.1kJmol−1/RT) was evaluated. At two lower temperatures, the diffusion coefficients 65Zn in interphase boundaries were estimated: Db (623K)=1.610−12m2s−1 and Db (598K)=4.4 10−13m2s−1. The specific (Mg)/ interfacial energy =140mJm−2 was assessed from measurement of the time dependence of interlamellar distance during isothermal anneal.
Thermodynamic modeling of the sodium alanates and the Na–Al–H system
Authors: Qiu Caian , Opalka Susanne M. , Olson Gregory B. , Anton Donald L. 
Published: December 2013

Abstract
The thermodynamic properties of the Al–Na and Na–Al–H systems have been assessed by combining the “calculation of phase diagram” approach with first-principles predictions. The Gibbs energies of the individual phases were thermodynamically modeled, where the model parameters were obtained from best fit optimizations to combined experimental and first-principles predicted finite temperature data. The first-principles thermodynamic predictions were based upon density functional theory ground state minimizations and direct method lattice dynamics. The predictions proved to be important adjuncts to the assessments whenever experimental measurements were lacking or not feasible. It was shown that the phase stability conditions of sodium alanates, NaAlH4 and Na3AlH6, were well described with the present models.
Density and excess volumes of liquid copper, cobalt, iron and their binary and ternary alloys
Authors: Brillo Jürgen , Egry Ivan , Matsushita Taishi 
Published: December 2013

Abstract
The densities of liquid copper, cobalt, and iron, their binary and ternary alloys have been measured over a temperature range including the undercooled regime. A non-contact technique was used, consisting of electromagnetic levitation combined with optical dilatometry.
For all samples, the density was a linear function of temperature. The concentration dependence was studied by means of the excess volume which was negligible for Co–Fe and positive for Cu–Fe, Cu–Co, and Cu–Co–Fe.
The density of the ternary alloy could be predicted from the excess volumes of the binary phases without the need to introduce any ternary interactions.
Fracture behaviour of ultrafine-grained materials under static and cyclic loading
Authors: Hübner Peter , Kiessling Rene , Biermann Horst , Vinogradov Alexei 
Published: December 2013

Abstract
Fracture-mechanics experiments were carried out on ultrafine-grained (UFG) samples of copper, titanium and an Al alloy to obtain the fracture behaviour under static and cyclic loading. The UFG-materials investigated show crack resistance behaviour under static loading, which was confirmed by ductile fracture surfaces. Under cyclic load the crack growth rate was described well by the ESACRACK model.
Neutron diffraction residual stress analysis of steel engineering components: a study of the elastic and plastic anisotropy
Authors: Bruno Giovanni 
Published: December 2013

Abstract
The effect of the elastic and plastic anisotropy has been investigated in a welded pipe for nuclear applications (AISI 347) and in a welded plate for conventional power plants (Uni-Fe510D). The analysis has been performed exploiting neutron conventional and reverse time-of-flight spectra and comparing the single peak fit of some set of lattice planes with the Rietveld average. The results show that only some crystallographic directions (namely the 〈311〉 and the 〈111〉 for γ-Fe and 〈211〉 and the 〈110〉 for α-Fe) are in agreement with the average inherent in the Rietveld refinement. Those peaks are therefore recommended for residual stress analysis at steady state sources. The other peaks yield more scattered data (with higher statistical error), but allow spotting the influence of plastic anisotropy. The latter has a greater influence on all single peak data if the macroscopic stress exceeds the bulk yield strength.
Fluidity of Mg–Al–Ca alloys in the high-pressure die casting process
Authors: Zhao Peng , Wang Qudong , Liu Liufa , Wei Zhongshan , Zhai Chunquan 
Published: December 2013

Abstract
The fluidity of Mg – Al – Ca alloys under high-pressure die casting conditions was studied using fluidity tests with spiral specimens. The flow behavior analyses suggest that flow with zero superheat plays a more important role under high-pressure die casting conditions than gravity casting. This can be attributed to the difference between the two kinds of casting process. Fluidity results with a degree of superheat were interpreted on the basis of the effects of calcium on (1) latent heat, (2) viscosity and (3) solidification characteristics. The latent heat and phase accumulation formed by high pressure are the important factors influencing the fluidity of magnesium alloys in the high-pressure die casting process.
Influence of interfaces on the mechanical properties of ultrahigh carbon steel multilayer laminates
Authors: Pozuelo Marta , Carreño Fernando , Carsí Manuel , Ruano Oscar A. 
Published: December 2013

Abstract
To improve impact and flexure properties of ultrahigh carbon steel (UHCS-1.3 wt.% C), a multilayer laminate consisting of 20 layers of the same UHCS has been processed by hot rolling. Two different rolling conditions gave rise to “soft” and “severe” laminates. The toughness of the “soft” laminate, measured by impact test absorbed energy, was more than forty times higher than that of the monolithic UHCS and three times higher than that of mild steels. In contrast, the “severe” laminate showed no increase in toughness with respect to the monolithic UHCS. This large difference in behaviour was studied by means of shear and bend tests, which gave valuable information on bond quality and delamination.
Standard Gibbs energy of formation of Zn17Y2 and Zn12Y determined by solution calorimetry and measurement of heat capacity from near zero Kelvin
Authors: Morishita Masao , Yamamoto Hiroaki , Tsuboki Kohei , Horike Tomohiro 
Published: December 2013

Abstract
The thermodynamic properties of Zn17Y2 and Zn12Y were investigated by calorimetry. The standard entropies of formation at 298 K, were determined from measuring the heat capacities, Cp, from near absolute zero (2 K) to 300 K by the relaxation method. The standard enthalpies of formation at 298 K, were determined by solution calorimetry in hydrochloric acid solution. The standard Gibbs energies of formation at 298 K, were determined from these data. The results obtained are: (Zn17Y2) = – 23.53 ± 1.4 kJ · (mol of atoms)−1; (Zn17Y2) = – 3.05 ± 0.39 J · K−1 · (mol of atoms)−1; (Zn17Y2) = – 22.62 ± 1.4 kJ · (mol of atoms)−1; (Zn12Y) = – 23.89 ± 1.8 kJ · (mol of atoms)−1; (Zn12Y) = – 0.78 ± 0.41 J · K−1 · (mol of atoms)−1; (Zn12Y) = – 23.66 ± 1.8 kJ · (mol of atoms)−1. The electronic contribution to the heat capacity of Zn17Y2 and Zn12Y is found to be similar to pure zinc, indicating that the valence electrons of yttrium in the compound are trapped by the density of states for zinc.
Phase equilibria in the Zn–Fe–S system at 450°C
Authors: Tan Zheng , Su Xuping , Li Zhi , Liu Ya , Wang Jianhua 
Published: December 2013

Abstract
The 450 °C isothermal section of the Zn – Fe – S phase diagram has been constructed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and X-ray diffraction. In addition to the ternary extensions of the binary Zn – Fe intermediate compounds of ς, δ, Γ1, and Γ, the extensions of the ZnS, FeS and FeS2 compounds were also determined. The solubility of Fe in ZnS is about 20.2 at.%. The solubility of sulfur in all Fe – Zn intermetallic compounds is negligible. The zinc contents of Fe sulfides were not detectable.
Effect of tempering on the microstructure and hardness of ledeburitic chromium steel X155CrVMo12.1
Authors: Markoli Boštjan , Spaić Savo 
Published: December 2013

Abstract
Ledeburitic chromium steel X155CrVMo12.1 for cold-work tools was investigated in the quenched and tempered condition. Using appropriate investigative methods the evolution of the microstructure in all conditions was characterized. The change in state of a multicomponent matrix during tempering is crucial for attaining the required properties of this steel. In the material investigated, shape, size, fraction and distribution of eutectic (primary) carbides played a secondary role. The evolution of tempered martensite and precipitation of secondary hardening carbides of M23C6-type and MC-type from the supersaturated matrix during tempering led to secondary hardening and a secondary hardness peak at about 530 °C. The results show that steel X155CrVMo12.1 also exhibits performance ability at moderately elevated temperatures.
Design of carbide-free low-temperature ultra high strength bainitic steels
Authors: Garcia-Mateo Carlos , Caballero Francisca Garcia 
Published: December 2013

AbstractThere are severe limitations to attaining submicrostructured steels by means of continuous cooling, the achievement of fine grain sizes is limited by the need to dissipate enthalpy during rapid transformation, so that the actual grain size obtained is more than an order of magnitude greater than can be obtained theoretically. Bainitic microstructures obtained by isothermal heat treatment at low temperatures, can overcome the recalescence limitations and at the same time provide a very fine microstructure (nanostructure) that leads to extraordinary mechanical properties. Steel grades for this purpose have been designed by means of phase transformation theory alone and their mechanical properties tested. The results obtained reveal that the microstructure is indeed extremely fine and exhibits high levels of strength accompanied by reasonable ductility and toughness, mainly due to the fine scale of the bainitic ferrite plates achieved. The influence that retained austenite has on the mechanical properties through the TRIP effect is also discussed.
Texture and microstructure evolution of ECAP processed AlMg1Mn0.14 alloy
Authors: Molodova X. , Berghammer R. , Gottstein G. , Hellmig R. J. 
Published: December 2013

Abstract
Microstructure and texture evolution of an AlMg1Mn0.14 alloy after Equal-Channel Angular Pressing (ECAP) and subsequent heat treatment were investigated. Initially the material was subjected to up to 8 passes with a 90° die angle using routes A and Bc. The deformed and annealed states were characterised by crystallographic texture analysis, Electron Back Scatter Diffraction, Transmission Electron Microscopy, optical microscopy and microhardness tests. The recorded texture and microstructure changes were compared to the behaviour of specimens produced by conventional cold rolling. It was shown that the observed discontinuous change in texture, microstructure and microhardness has to be attributed to discontinuous recrystallisation, which proceeded faster for route Bc samples. Furthermore, it was found that ECAP deformed material is more stable against recrystallisation than cold rolled material.
Modelling grain refinement in fcc metals during equal-channel angular pressing by route “C”
Authors: Enikeev Nariman A. , Abdullin Marat F. , Nazarov Ayrat A. , Beyerlein Irene J. 
Published: December 2013

Abstract
Grain refinement and texture evolution during equal channel angular pressing (ECAP) by route “C” are modelled by the visco-plastic self-consistent (VPSC) model incorporating a disclination-based grain subdivision criterion. Simple shear and analytical fan models are used to describe the deformation history during ECAP. Textures calculated after the first four passes of ECAP by both the standard VPSC and the VPSC/disclination models are compared to available experimental data that show a better predictive capacity of the model incorporating the disclination subdivision criterion.
Compressive behaviour of ultrafine-grained AA6063T6 over a wide range of strains and strain rates
Authors: Meyer Lothar W. , Hockauf Matthias , Krüger Lutz , Schneider Ines 
Published: December 2013

Abstract
The flow stress behaviour of commercially available AA6063-AlMg0.5Si0.4 with ultrafine-grain size is investigated over a wide range of strain and strain rates under uniaxial compression. The ultrafine-grained microstructure is achieved by equal channel angular extrusion and characterised by grain sizes well below 1 μm. Results of quasi-static loading show that the ultrafine-grained states behave in an elastic – nearly perfect plastic manner with significantly reduced strain hardening capacity. When compared to the coarse grained counterpart, no change in strain rate sensitivity was measured for the material after two extrusions. In contrast to that, after eight extrusions the material shows significantly increased strain rate sensitivity especially in the range of highest rates above 102 s−1.
Effect of Nb–V addition on the mechanical behaviour and structural stability of ultrafine grained steels
Authors: Vedani M. , Arnaboldi S. , Vimercati G. , Bassani P. , Tuissi A. 
Published: December 2013

Abstract
A study is presented on the microstructural evolution and mechanical behaviour of three ultrafine grained steels produced by severe plastic deformation. Two Nb – V microalloyed steel grades differing only in their Nb content and a C – Mn steel were extensively refined at 773 K by caliber rolling to a reduction of section of the order of 98 %. Grain stability and evolution of mechanical properties during annealing at 873 K were then investigated.
It was demonstrated that tailored annealing treatments lead to a modification of the tensile behaviour of the ultrafine steels, with a more satisfactory combination of strength and uniform elongation. Nb – V microalloying contributed to increasing the stability of the grain structure and allowed achieving slightly improved properties with respect to the C – Mn grade.
Shear deformation of submicron-structured materials
Authors: Hafok Martin , Pippan Reinhard 
Published: December 2013

Abstract
Shear samples with special geometry were produced from high purity nickel and copper in order to study the deformation mechanism in the saturation region of severely plastically deformed metals. The shear samples, pre-deformed by high pressure torsion, were tested in situ at room temperature. Electron back scatter diffraction and back scatter images were used to characterise the change in micro-texture and microstructure after the shear deformation. The experiment revealed that almost all grains were sheared simultaneously, while at higher shear strains the formation of micro shear bands were observed.
Mechanical behavior of nanostructured metals and alloys in the 300–4.2 K temperature interval
Authors: Tabachnikova Elena , Bengus Vladimir 
Published: December 2013

Abstract
Original data of the authors and literature data are presented describing the mechanical behavior of nanostructured metals and alloys at cryogenic temperatures. Bulk ultrafine grained metals and alloys processed by severe plastic deformation through equal channel angular pressing are considered. The mechanical behavior of a number of nanostructured metals and alloys (Cu, Ni, Ti, VT6 and others) were investigated under uniaxial compression and tension at cryogenic temperatures in a wide range of strain-rates. The most important low temperature peculiarities of the nanostructured materials mechanical behavior have been indicated.
Nanoindentation behavior and mechanical properties measurement of polymeric materials
Authors: Cook Robert F. , Oyen Michelle L. 
Published: December 2013

Abstract
During sharp contacts, polymeric materials can exhibit elastic (reversible), plastic (instantaneous irreversible), and viscous (time-dependent irreversible) deformation. Due to viscous effects commonly observed in experiments conducted on polymeric materials, the analytical methods developed for instrumented indentation testing (“nanoindentation”) of elastic-plastic materials cannot be used to determine polymer mechanical properties. Here, a viscous-elastic-plastic sharp indentation model is reframed into normalized coordinates. The updated scheme allows the mechanical properties of polymeric materials to be determined simply from single- or multiple-cycle nanoindentation tests; output parameters are the relative resistance to plastic vs elastic deformation during indentation and the relative time scales for viscous flow during the contact event. The scheme allows the indentation behavior of all materials to be placed on a single map.
Testing the viscoelastic properties of SU8 photo resist thin films at different stages of processing by nanoindentation creep and stress relaxation
Authors: Schiffmann Kirsten Ingolf , Brill Carsten 
Published: December 2013

Abstract
The viscoelastic properties of SU8-25 photo resist coatings have been investigated by means of nanoindentation creep and stress relaxation tests. Different stages of processing of SU8 have been tested: (a) Spin coating and pre-bake only, (b) exposure to ultraviolet light for different durations, (c) different cross-linking times of the resist and finally (d) the completely processed sample (post-bake, develop and hard-bake). At each stage creep and stress relaxation tests have been performed with loads of 2 mN or indentation depth of 500 nm covering creep/relaxation times from 0.1 s to 1000 s. From the raw data the following viscoelastic functions have been computed: the creep compliance J(t) and relaxation modulus G(t), the relaxation and retardation time spectra H() and L(), and the dynamic viscosity (t). It has been found that different pre-bake times influence the viscosity of the film. The cross-linking of the SU8 starts immediately after exposure even without applying a post-bake. A strong increase in viscosity can be observed within the first 4 h after exposure due to the progress of cross-linking at room temperature. After the finish of cross-linking the dynamic viscosity has increased by 50 times. Observation of impression recovery after unloading over 3 days indicated up to 75 % immediate and retarded elastic recovery for the fully processed film, while the simply pre-baked sample only exhibied 25 % recovery and 75 % irreversible viscous flow.
Viscosity measurement of liquid ternary Cu–Ni–Fe alloys by an oscillating cup viscometer and comparison with models
Authors: Brillo Jürgen , Brooks Rob , Egry Ivan , Quested Peter 
Published: December 2013

Abstract
Viscosity data on Cu – Ni – Fe have been obtained using an oscillating cup viscometer. In this method, a liquid sample is suspended in a crucible which performs damped angular oscillations. Viscosities are calculated from the time period and the decay of the amplitude.
The temperature dependence of the measured viscosities can be described by an exponential Arrhenius law, taking into account an activation energy for the viscous flow. The activation energies for the ternary alloys were found to be linear combinations of the corresponding activation energies of the pure elements Cu, Ni, and Fe. At constant temperature, a non ideal mixing behaviour was observed and the data were compared with several quantitative models. Close agreement of the experimental results was found with the predictions of two models by Kaptay and Hirai.
A kinetic study of nickel coating on boron nitride micro-particles
Authors: Li Fan , Zhang Dengjun , Sichen Du 
Published: December 2013

Abstract
In the present work, the mechanism of nickel coating on BN particles by hydrazine reduction was studied. A nickel sulfate – ammonium sulfate – ammonia – hydrazine hydrate plating system was employed. It was found that Pd on the surface of BN particles acted as an active center for nickel deposition at the initial stage of the process. Thereafter, Ni itself would act as an active center to catch Ni from the solution through the reaction: Ni2+ + 2H*ad ß Ni + 2H+. The rate of the process was found to be controlled by the reaction at the interface under the present experimental conditions. A kinetic model was proposed on the basis of the experimental results. The model predictions were found to be in agreement with the experimental data.