bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diffusion of chromium in β-Ti under high pressure
Authors: Araki Hideki , Yamane Toshimi , Nakatuka Tetsuya , Minamino Yoritoshi 
Published: March 2022

Abstract
It is shown that Arrhenius plots of diffusion coefficients of Cr in β-Ti can be represented under each pressure by two straight lines which are fitted in the temperature regions above and below about 1390 K. The activation enthalpies for high temperature are 167 kJ/mol under 0.1 MPa and 191 kJ/mol under 2.1 GPa, and those for low temperature are 147 kJ/mol under 0.1 MPa and 153 kJ/mol under 2.1 GPa. The ratios of activation volumes for impurity diffusion to the molar matrix volume are in the range of 0.38 to 0.45. When the phonon-softening model is applied, the activation enthalpy for the impurity diffusion in the absence of any phonon-induced lattice instabilities is 226 kJ/mol under 0.1 MPa and increases with pressure. Its pressure dependence indicates that the activation volume for the diffusion with no assistance from phonons is 66% of the molar matrix volume, and this result agrees with the activation volume for the diffusion in “normal” bcc metals.
Density and surface tension of liquid ternary Ni–Cu–Fe alloys
Authors: Brillo Jürgen , Egry Ivan , Matsushita Taishi 
Published: March 2022

Abstract
Density and surface tension of liquid Ni –Cu –Fe alloys have been measured over a wide temperature range, including the undercooled regime. A non-contact technique was used, consisting of an electromagnetic levitator, an optical densitometer, and an oscillating drop tensiometer.
At temperatures above and below the liquidus point, density and surface tension are linear functions of temperature. The concentration dependence of the density is significantly influenced by a third-order (ternary) parameter in the volume, while the surface tensions can be derived from the thermodynamic potentials E
G of the binary phases alone.
The effect of exposure to elevated temperatures on the microstructure and hardness of Mg–Ca–Zn alloy
Authors: Finkel Amir , Shepeleva Ludmila , Bamberger Menachem , Rabkin Eugen 
Published: March 2022

Abstract
The die cast Mg-5 wt.% Ca-6 wt.% Zn ternary alloy was exposed to 160 °C for different times of up to 40 days. Microstructural analysis and microhardness and hardness measurements of the samples after different exposure times enabled the thermal stability of the cast alloy to be monitored. The as-cast structure is composed mainly of α-Mg solid solution, elliptical grain boundary particles of CaMg2, and an intergranular eutectics of Mg and Ca2Mg6Zn3. The grain size of α-Mg and the structure of the alloy did not change during the treatment, but the amount of the intergranular phases increased slightly. Exposure to 160 °C resulted in a decrease in micro-hardness of the α-Mg grains, but no change in the overall hardness of the samples was observed. Microstructural analyses indicated diffusion of the solute elements from the α-Mg grains to the grain boundaries, resulting in a decrease in hardness of the α-Mg which is, however, compensated by an increase in hardness related to intergranular precipitates. Using a simple diffusion model, the diffusion coefficient of Ca atoms in Mg at 160 °C was estimated to be 2.1 · 10 –17 m2 s– 1, which is greater than that of Zn by two orders of magnitude.
Solidification curves for commercial Mg alloys obtained from heat-transfer modeled DTA experiments
Authors: Mirković Djordje , Schmid-Fetzer Rainer 
Published: March 2022

AbstractAn improved method is presented for determination of solidification curves, i. e., solid fraction versus temperature, for commercial Mg alloys using heat-transfer modeled differential thermal analysis (DTA) curves. A better simulation of the measured DTA signal is attained through an independent measurement of the time constant as function of temperature for the applied equipment. This enables a better desmearing of the DTA signal. Challenging Mg alloys could be appropriately handled by redesigning the tantalum encapsulation. Due to high oxygen affinity and vapor pressure of the investigated magnesium alloys, this special adaptation of the DTA setup using sealed Ta capsules was indispensable for generation of reproducible and reliable data.
Fabrication and electrical sliding wear of graphitic Cu–Cr–Zr matrix composites
Authors: Zhan Yongzhong , Zeng Jianmin 
Published: March 2022

Abstract
The present work was undertaken to prepare graphitic Cu–Cr –Zr matrix composites in order to develop new materials for application under sliding contact in an electrical field. The electrical sliding wear behavior of the graphite (Gr)/CuCrZr composite was investigated from a microstructural viewpoint, compared with the matrix alloy. The results indicate that by using the water atomized Cu–Cr–Zr powder and copper-coated graphite particles as starting materials, compact and homogeneous microstructure can be obtained in the composites. Fine and coherent particulate precipitations are formed in the Cu–Cr–Zr matrix during the aging treatment process, which help to improve the mechanical properties. Under the electrical sliding wear condition, incorporation of graphite in the Cu–Cr–Zr matrix not only decrease the wear loss of the sliding pair but also maintain steady-state friction coefficient. The main reason is that the graphite film that smears on the contacting surfaces can alleviate materials loss induced by electric arc discharge and adhesion wear. Proper aging treatment helps to make full use of the solid lubricant effect of the graphite particles.
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 90 MPa
Authors: Thomas-Whittington D. , Srivastava V. , Greenwood G. W. , Jones H. 
Published: March 2022

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: March 2022

AbstractThe 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 ofγ′, not σ phase formation.
Formation of the ABC6-type ordered structure in fcc alloys
Authors: Ohshima Ken-ichi , Takahashi Miwako , Iwasaki Hiroshi 
Published: March 2022

Abstract
A new class of ordered structures designated as of the ABC6-type has been found in the ternary CuMnPt6 alloy. It has a cubic symmetry with the unit cell consisting of 2 ⨯ 2 ⨯ 2 fcc unit cells, whose space group is Fm3m. A closely related structure with Cu replaced by Pt has also been found in the binary MnPt7 alloy. Both alloys undergo a double-step order – disorder phase transition, ABC6-type – Cu3Au-type – fcc disorder. A partial phase diagram was constructed on the Pt-rich side of Pt –Mn. MnPt7 is isostructural to CuPt7 previously found by Schneider and Esch, though the latter does not show the double-step transition. Within the Bragg–Williams approximation, the order – disorder phenomena in the three alloy systems can be successfully reproduced. It has been found that an ordering energy of negative sign, a preference of unlike pairs, between second-nearest neighbours plays a decisive role in the formation of the ABC6-type structure. An increase in the relative magnitude of the ordering energy suppresses the double-step transition and the ABC6-type phase forms directly from the disordered phase.
Short-range order in Fe-21.9 at.% Al
Authors: Schönfeld Bernd , Bucher Rémy , Portmann Michael J. , Zolliker Markus 
Published: March 2022

Abstract
Elastic diffuse neutron scattering of an Fe-21.9 at.% Al single crystal was measured at 878, 966 and 1073 K. The separated short-range order scattering revealed the building elements of the B2 structure as the characteristic local atomic arrangement for all states investigated. Effective pair interaction parameters, obtained by the inverse Monte-Carlo method, were found to depend on temperature, thus prohibiting a determination of possible ground state structures from the high-temperature measurements. An additional X-ray study of single-crystalline Fe-18.2 at.% Al aged at 598 K, gave no indication for B32 as ground state structure.
Late-stage coarsening of oil droplets of excess oil in microemulsions following a temperature quench
Authors: Roshan Deen G. , Skov Pedersen Jan 
Published: March 2022

Abstract
An oil-in-water microemulsion of the system C12E5/water/ n-decane with a fixed surfactant-to-oil volume fraction ratio φs/φo of 0.85 is studied. This clear microemulsion is temperature-quenched from a clear one-phase region (26 °C) with spherical microemulsion droplets to an unstable region (13 °C) where the excess oil phase is in equilibrium with the microemulsion droplets. Using a high-resolution version of a laboratory small-angle X-ray scattering (SAXS) instrument, the evolution of the excess oil and its growth as a function of time is studied. Unlike coarsening in alloys and polymer blends, a maximum in the intensity at a finite scattering vector is not observed. This clearly indicates that the droplet of the excess oil is formed homogeneously and that there is no depletion zone around the formed droplets. The scattering curves are quantitatively analysed as a function of time. The microemulsion droplets are modeled as polydisperse core-shell ellipsoidal particles, using molecular constraints and the oil droplets are modeled as polydisperse spheres. The average radius of the oil droplets increases with a scaling exponent in agreement with that of coarsening of precipitates in alloys and phase separations in polymer blends, suggesting some degree of universality of coarsening processes.
Modulated structures in amorphous films of Cr-silicide prepared by electron-beam-deposition
Authors: Kitano Yasuyuki , Yamamoto Koichi , Wada Masashi , Yin Jingtian , Toda Yumio , Tanaka Koji , Tanabe Eishi , Komatsu Masao , Sakai Tetsuo 
Published: March 2022

Abstract
Amorphous Cr-silicide films are prepared by electron-beam-deposition on a Cu-substrate at room temperature. The microstructures of as-grown films are investigated using transmission and analytical electron microscopy. The morphology of the amorphous films is dendritic. In addition, one-dimensional concentration modulations are observed. The modulated structure is revealed not only by TEM imaging but also by a series of satellite spots at the centre of the diffraction pattern. This concentration modulation is confirmed by analytical electron microscopy.
Early stages of nucleation and growth of Guinier –Preston zones in Al–Zn–Mg and Al–Zn–Mg–Cu alloys
Authors: Kenesei Péter , Horváth Győző , Bernstorff Sigrid , Ungár Tamás , Lendvai János 
Published: March 2022

Abstract
The early stages of nucleation and growth of Guinier–Preston zones in Al –Zn –Mg and Al –Zn –Mg–Cu alloys are investigated by in situ synchrotron X-ray small-angle scattering. The in situ synchrotron measurements enable to follow the decomposition kinetics from about 2 minutes after quenching. Based on the measurement of the radii of gyration and integrated intensities, three distinct kinetic regimes are observed and discussed.
Damage behaviour of an Al2O3 particle-reinforced 6061 alloy induced by monotonic and cyclic deformation
Authors: Bär J. , Berger W. , Gudladt H.-J. 
Published: March 2022

Abstract
The influence of damage and its correlation with the failure behaviour is discussed in the light of microstuctural aspects. The failure induced by microstructural mechanisms of the Al2O3-particle reinforced aluminium alloy 6061 under uniaxial tensile as well as under cyclic loading was investigated. The damage behaviour as a function of the strain ε can be correlated with stiffness E(ε). Under cyclic loading conditions the damage increases with the number of cycles and can be correlated with the strain amplitude εa. Furthermore, the damage is associated with crack formation and propagation and the damage evolution depends sensitively on the kind of deformation. The crack formation was detected by metallographic investigations and calculated by numerical methods (FEM), taking the size and shape of particles into account. Generally, damage under mechanical loading is initiated by broken particles and agglomerations of particles. In case of the particulate-reinforced specimens the evolution of damage is quite different for monotonic and cyclic loading conditions but, nevertheless, in both cases the damage parameter is given by inhomogeneities characteristic for the MMC which act as seeds for crack initiation.
Deformation behaviour of ultrafine-grained magnesium with 3 vol.% graphite
Authors: Lukáč Pavel , Trojanová Zuzanka , Száraz Zoltán , Svoboda Milan , Ferkel Hans 
Published: March 2022

Abstract
Magnesium micropowder was mixed and ball-milled with 3 vol.% graphite powder. The Mg + Graphite composite was deformed in compression at temperatures between room temperature and 300 °C at a constant crosshead speed, giving an initial strain rate between 1.4 · 10 –5 and 1.4 · 10– 3 s –1. The yield stress of the composite is higher than that of unreinforced magnesium prepared with the same technology. The yield stress and the maximum stress decrease rapidly with increasing temperature. At temperatures higher than room temperature, the true stress– true strain curves exhibit a work-hardening rate close to zero, which indicates a dynamic equilibrium between hardening and softening. Double cross-slip of screw components of c + a dislocations is considered as the main recovery mechanism.
Liquid–liquid transition in elemental liquids investigated by sound velocity measurements: trends in the periodic table
Authors: Tsuchiya Y. 
Published: March 2022

Abstract
The velocity of sound has been measured as a function of temperature to investigate structural changes in the molten As–Sb alloy. The overall profile of temperature dependence of the sound velocity changes smoothly from Sb to As. The results indicate that a tendency to change structures in the supercooled state develops with increasing As fraction, and confirm the previous conclusion that molten As changes rapidly its structure in the undercooled state and is already in the high-temperature side of an assumed liquid – liquid transition at the melting point.
By confirming the structural transition in molten As, it is possible to mark the elements in the periodic table that undergo a crossover liquid –liquid transition around the melting point under the saturating vapor pressure. Observed trends for liquid – liquid transitions are discussed on the basis of the Peierls distortion mechanism.
The magnesium-ytterbium system: A contribution to the thermodynamics of solid alloys
Authors: Borzone Gabriella , Parodi Nadia , Ferro Riccardo 
Published: March 2022

Abstract
Magnesium-ytterbium alloys were investigated in order to determine the enthalpy of formation of YbMg2 and to check the phase diagram of the system. The system was investigated by using differential scanning calorimetry, electron microscopy, electron microprobe analysis, and X-ray diffraction analysis. The enthalpy of formation was measured by high temperature drop calorimetry. A value of – 13.5 ± 0.5 kJ/mol of atoms was obtained for the standard formation enthalpy of YbMg2.
Activity measurements on the Al-rich region of the Ni–Al system – A high temperature mass spectrometric study
Authors: Narasimhan Tiruppatur Subramaniam Lakshmi , Kath Dieter , Markus Torsten , Hilpert Klaus 
Published: March 2022

Abstract
Systematic vaporisation studies on the Ni –Al system with 0.32 ≤ x(Ni) ≤ 0.50 were carried out in the temperature range 1077 – 1592 K by Knudsen effusion mass spectrometry. While Al(g) was the vapour species observed over all the samples, Ni(g) was also detected over samples with the compositions x(Ni) = 0.50 and 0.49. From the p(Al) –T relations, activities of Al, and subsequently activities of Ni (by Gibbs–Duhem integration) were obtained. Moreover, partial and integral molar enthalpies and Gibbs energies of formation were evaluated. The variation of activities and other thermodynamic properties with composition are discussed. The enthalpy and Gibbs energy of formation of Ni0.5Al0.5(s) at 298.15 K were obtained as

Δ
f

H
m
o

=

${{\Delta }_{\text{f}}}H_{\text{m}}^{\text{o}}=$

– 62.1 ± 4.2 kJ mol –1 and

Δ
f

G
m
o

=
−
57.7
±
1.2

kJ

${{\Delta }_{\text{f}}}G_{\text{m}}^{\text{o}}=-57.7\pm 1.2~\,\text{kJ}$

mol– 1, respectively. This is the first time that a systematic mass spectrometric investigation has been carried out on the aluminium rich region of Ni –Al system where the vacancy concentration in the NiAl phase can be as high as 10 %.
Low temperature deposition with inductively coupled plasma
Authors: Lee Seung-Hoon , Jung Dong-Ha , Jung Seung-Jae , Hong Seung-Chan , Lee Jung-Joong 
Published: March 2022

Abstract
The processing temperature of chemical and physical vapor deposition could be successfully lowered by applying inductively coupled plasma without deteriorating the film quality. Despite the low process temperature, the deposition rate was higher than that observed in conventional deposition processes, and the impurity content could be kept low. Some examples of inductively coupled plasma applicationse. g. TiB2, TiN, TiO2, and SnO2 films are shown.
Nanostructured SiC/BN/C ceramics derived from mixtures of B3N3H6and [HSi(Me)C≡C]n
Authors: Müller Anita , Gerstel Peter , Bunjes Natascha , Berger Frank , Sigle Wilfried , Müller Klaus , Weinmann Markus 
Published: March 2022

AbstractThree borazine-modified polycarbosilanes were synthesized by reaction of poly[1,2-ethynediyl-(methylsilylene)], [HSi(Me)C≡C]n, and borazine, B3N3H6using 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 , Guire Mark De , Wang Russell 
Published: March 2022

AbstractOrganic 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 6 days (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 2 days. 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.
Reconstruction and structural transition at metal/diamond interfaces
Authors: Zhang Wenqing 
Published: March 2022

Abstract
Based on density-functional calculations, interfacial reconstruction and structural transition at diamond(111)/M/copper (M = Ag, Cu, Ni, Co) interfaces are studied by analyzing the atomistic structures of the interfaces. Tuning the strength of chemical bonds across the interfacial plane (out-of-plane), we show that interfacial reconstruction happens as a result of competition between the out-of-plane chemical bonds and the in-plane bonds within the diamond substrate. A relatively weak out-of-plane bond may easily lead to reconstruction of interfacial structures. A structural transition from one-dangling-bond- to three-dangling-bond-terminated interface is also observed as the out-of-plane bond is sufficiently strong, which leads to a dramatic enhancement of the adhesion of the interface.
XRD and TEM study of NiO–LSGM reactivity
Authors: Rao Manga Venkateswara , Sturm Saso , Phillipp Fritz , Zinkevich Matvei 
Published: March 2022

Abstract
NiO–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 3.856 Å 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 –x
in 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: March 2022

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.