bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Sodium Hydroxide Molarity on The Compressive and Splitting Tensile Strength of Ferronickel Slag-Based Alkali-Activated Mortar
Authors: Kuncoro Albert , Djayaprabha Herry Suryadi
Published: March 2022

The use of cement as the main binding agent in construction contributes approximately 7-10% in total of carbon dioxide gas emissions worldwide. In this study, the replacement of Portland cement using ground granulated ferronickel slag (GFNS) activated by the combination of sodium hydroxide (NaOH) dan sodium silicate (Na2SiO3) was utilized for producing alkali-activated mortar (AAM) as construction material. Four different mortar mixtures were prepared in this experimental work. There were three mixtures of ferronickel slag-based alkali activated mortar (FAM) with the variations of NaOH molarity of 6, 8, and 10M and cement-based mortar mixture (PCM) with water-to-cement ratio (w/c) of 0.5 was used as the control specimens. Overall, the flow and workability of the FAM specimen was lower than the PCM specimen due to the presence of silicate caused a sticky characteristic on the paste. On the other hand, the unit weight of FAM mortar was higher than the PCM specimen. Among all FAM mixtures, the most effective compressive strength and splitting tensile strength results were achieved by the FAM8 mixture, with a compressive strength at 28 days of 33.72 MPa and the splitting tensile strength at 28 days of 2.65 MPa, which had both good workability and chemical reaction of the material.
Structure Behavior and Performance from Unconfined Masonry and Confined Masonry Building Design
Authors: Putra Alfien Hernanda , Irlan Ade Okvianti
Published: March 2022

Many buildings in Indonesia were damaged during the earthquake, especially non-engineered brick walls building. One example of non-engineered brick walls building is Bendung Village Head Office in Serang, Banten, which was damaged by the 2019 Pandeglang earthquake. This building was built without reinforced concrete beams and columns known as unconfined masonry buildings. In this study, the building will be redesigned with ETABS software to determine the similarities between the structural weaknesses from ETABS and the actual damage. The results of the structural analysis give a time period of 0.814 seconds, a base shear force of 195.5 kN, and a stress on the wall that is 50% similar to the real damage. Then, the same building was designed following the rules and regulations for earthquake resistant buildings in Indonesia so that it became a confined masonry building. The result is a time period of 1.586 seconds, a base shear force of 114.2 kN, and a brick wall that is not damaged when exposed to earthquake loads. However, the dimensions and reinforcement of beams and columns that comply with the minimum requirements for earthquake resistant buildings in Indonesia need to be enlarged because their strength capacity is exceeded by the working load.
Study on Capacity of Pile Group in Soft Soil Using a Small-Scale Laboratory
Authors: Naibaho Andry Galardo , Waruwu Aazokhi
Published: March 2022

Soft clay is one type of subgrade that is problematic in infrastructure development. Pile reinforcement is an alternative to stabilize and increase the bearing capacity of soft clay soils. This study is expected to determine the capacity of the pile group from observations through a small-scale laboratory model and its comparison with the results of the analysis. Reinforcement of the piles used are concrete piles and wooden piles. The research was conducted through model testing on single piles and group piles in soft clay soil. The piles have a length of 20 cm and a diameter of 2 cm with the number of 1, 2, 4, and 9 piles. The study results show that the overall bearing capacity of the observed results is not much different from the results of the analysis. The average bearing capacity of the wooden and concrete piles is 20% and 18% greater than the analysis. The increase in pile capacity for each additional number of piles from the observations is not as high as the analysis. There is a tendency for the soil in the pile group to move down together, so that the capacity value of the pile group on soft clay is smaller than the single pile capacity value multiplied by the number of piles in the pile group.
Flexural Resistance of LVL Sengon Beams with Lateral Stiffener at Both Ends
Authors: Awaludin Ali , Wusqo Urwatul
Published: March 2022

Slender beams (beams having a large section height to width ratio ( )) are commonly used in a structure that needs a large bending moment capacity. However, the use of slender beams in a structure is susceptible to overturning and torsion occurrence. Therefore, lateral bracing is usually placed in several points of the beam to prevent lateral-torsional buckling. In this study, a three-point bending test was conducted to evaluate the capacity of 250 mm x 50 mm x 2500 mm Laminated Veneer Lumber (LVL) beams made from Sengon. Two lateral supports were placed at both ends to prevent the beam's lateral displacement. The bending test result shows that the ultimate load of the LVL beam reach 27.88 kN before failure. Furthermore, the LVL beams' bending capacity was calculated using the mechanical properties provided by several previous studies. The LVL beam's capacity was predicted using manual calculation (based on SNI 7973: 2013) and numerical analysis. Numerical analysis was performed using ABAQUS software, and the results were evaluated using the Tsai-Hill and maximum strain failure criterion. The results showed that the maximum strain criterion provides a better prediction of the LVL beam's capacity than Tsai-Hill failure criterion.
Flood Evaluation in Bula District Seram Bagian Timur
Authors: Putra Febryhandi Eka Kusuma , Romadhoni Ahmad Zaki , Moe Idham Riyando
Published: March 2022

Bula District is strategic region in Seram Bagian Timur Regency which often experienced flood event especially in downstream areas. Flood Event that occurs causing loss of materials, even human life. This research was conducted to identify inundation that caused by the flood using two-dimensional inundation model. Model’s component consists of three part those are hydrology module, flood routing and inland flooding. Flood simulation result was calibrated with flood observation map in Bula District. Flood simulation resulted with flood discharge 25-year times period shows that inundation area that probably happen in Bula District is 5,4 km2 and flood volume that probably happen is 7,406,708 m3. Bila Besar Watershed contribute >70% to flood event that occurs based on inundation area and flood volume. Based on map overlay between simulation result into Satellite Google Imagery shows that 31.8% of 2,390 unit building in Bula District probably inundated by flood.
Parametric Study of Self Compacting Concrete Beams Using Finite Element Nonlinear Analysis
Authors: Effendi Mahmud Kori , Rahmayanti Novi , Fathurahman Ilman
Published: March 2022

Self-compacting concrete has self-flowing, viscous and compact properties that minimize mechanical compaction. This concrete is suitable for solving the concrete pouring in the narrow and congested reinforcement. Beams made of both self-compacting concrete and normal high-strength concrete are analyzed by MSC Marc / Mentat software. Steel is modeled by being embedded in concrete. The failure criterion of Linear Mohr-Coulomb is used for concrete and Von Mises for reinforcing steel, respectively. Concrete and the plate support are modelled by 3D solid elements. For the steel, the truss element is used. The contact analysis is implemented between beam and both steel plate and steel supports. The load-deflection curve for both concrete are almost the same as the results of the experimental curve. The results of the contact analysis also showed that there were contact and separation in the contact area. The shear retention factor value close to one meaning will restrain greater loads. The results of the study on the reinforcement ratio also showed a reduction of 70% and an increase of 70% when using minimum and maximum reinforcement, respectively. The larger concrete cover also reduces the load that the beams can restrain.
Comparison of Soil Surface Seismic Hazard Maps as Basic Disaster Mitigation Based Spatial Planning in Riau Province
Authors: Saputra Elvis , Nugraheni Fitri , Pawirodikromo Widodo , Makrup Lalu
Published: March 2022

Spatial planning has an important role in disaster mitigation efforts. The availability of earthquake maps is very useful in spatial planning. The need for spatial planning today is micro spatial planning. Therefore, the 2017 national earthquake map needs to be detailed into a micro zonation map at the district or city scale. The ground acceleration presented in the national earthquake map was the acceleration at bedrock, while in spatial planning it is the necessary acceleration at the surface. Therefore, the purpose of this research was to obtain a map of the earthquake at the surface with a micro-scale. Determination of the acceleration value at the surface was carried out by two models. Model-1, the surface acceleration was obtained by multiplying the results of the PSHA analysis at bedrock by the amplification factor based on SNI-1726. While Model-2, the acceleration value at the surface was directly obtained from the results of PSHA analysis using the average surface shear wave velocity (Vs30) based on data from the USGS. The result of this study showed that from the 2 analytical models used, Model-2 has a higher surface acceleration value than Model-1. Riau Province has 12 districts. in general, the 12 districts were included in the low to moderate risk index class, but there was one district that was close to the high index class, namely Rokan Hulu district.
Piping Potential due to springs in dam (Case study : Titab Dam)
Authors: Anggara I Putu Hariawan , Sachro Sri Sangkawati , Putranto Thomas Triadi
Published: March 2022

The dam is one of the water infrastructures that can function as conservation, utilization, and control of thedestructive power of water. Titab Dam is one of the dams in Indonesia that has multifunction as irrigationwater, raw water and hydropower. This dam is a type of rock fill dam with an upright core which has a peaklength of 210 m, a width of 12 m, and a height of 78 m from the deepest foundation. This dam was built withrelatively complex geological conditions and landslides occurred on the spillway walls and springs were foundin the landslides so it was necessary to analyze the potential for piping due to the presence of springs. Thisstudy examines the potential for piping due to the influence of springs near the dam. The study was conductedbased on instrument observations during the inundation period from 2016 to 2019. The analysis was carriedout by calculating the acceptance criteria (KP) for seepage and seepage index (Qi) to determine seepagebehavior in the dam body and a safety factor analysis (FK) for piping hazards was carried out by comparingthe hydraulic gradient based on piezometer instrumentation readings and the hydraulic gradient of the dambody core material. Based on the calculation of the seepage acceptance criteria and the seepage index, theseepage that occurs in the Titab Dam is not safe because it exceeds the requirements, the average seepageoccurs is 6.350 > 0.56 liter/minute/m and Qi > 1. However, the analysis of the safety factor of piping hazardis still safe that is equal to 8,390 > 4.
Entwicklung und Durchsetzung der Monoflexion im 18. Jahrhundert
Authors: Sahel Said
Published: March 2022

In this paper, it is argued that the principle of monoinflection governing the distribution of strong and weak adjective inflection in the New High German noun phrase (NP) definitively became established in the 18th century. Empirical evidence for this assumption is provided by the findings of three corpus studies based on the historical corpus ›Deutsches Textarchiv‹ (German Text Archive). Focusing on three different constructional types within the NP, the evolving distribution of strong and weak adjective inflection is studied for the period from 1600 to 1900. Based on the findings of the three corpus studies, further structural tendencies in the (re)organization of the New High German NP and their interaction with the principle of monoinflection are discussed.
Diffusion of chromium in β-Ti under high pressure
Authors: Araki Hideki , Yamane Toshimi , Nakatuka Tetsuya , Minamino Yoritoshi
Published: March 2022

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

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

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

An 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

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

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

The sigma phase (σ) formation in long-term aged polycrystalline K44 superalloy has been studied as a function of aging temperature and time. The σ phase in K44 alloy forms mainly in dendrite cores with a few at interdendritic regions. The kinetics of σ formation can be described by the Johnson–Avrami –Mehl equation that yields activation energies of more than 130 kJ/mol in an early stage and less than 100 kJ/mol in steady state. Tensile experiments at room temperature and 1173 K and endurance experiments at 1173 K and 274 MPa were performed to test the effect of σ phases on these properties and no remarkable harmful effect is found. Moreover, the effect of long-term aging on the mechanical properties is realized mostly through the variation 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

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

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

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

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

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

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

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

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

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

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

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

Three 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

Organic self-assembled monolayers with nitrogen-containing surface functionalities (amine or alkylammonium) were deposited on acid-etched titanium substrates. These were then coated with apatite deposited from 150% simulated body fluid at 37 °C and pH = 7.6 for 2, 4, and 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

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

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

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.
On the mechanisms governing the texture and microstructure evolution during static recrystallization and grain growth of low alloyed zirconium sheets (Zr702)
Authors: Dewobroto N. , Bozzolo N. , Barberis P. , Wagner F.
Published: March 2022

Low alloyed zirconium sheets (Zr702) have been cold-rolled up to 80% thickness reduction and submitted to various isothermal treatments. The aim was to identify the mechanisms which produce microstructure and texture changes during recrystallization and grain growth. XRD and texture analysis, FEG–SEM with EBSD as well as TEM were used to analyze the various specimens. Three types of substructures were observed in the initial deformed material. Accordingly, the nucleation starts in the most deformed areas and continues in the somewhat less deformed areas, which corresponds to a non oriented nucleation and results in a set of new grains, the size of which is very rapidly stabilized. In the last stage of recrystallization, the grains which have resisted the recrystallization disappear progressively by several mechanisms including in situ recrystallization. Therefore, the texture at the end of the recrystallization resembles the one of the deformed state. Normal grain growth leads to a moderate grain size increase due to the precipitates which slow down the grain boundary motion. This is also the stage where the texture changes due to the size advantage, after recrystallization, of grains in some specific orientations.
The Na–H system: from first-principles calculations to thermodynamic modeling
Authors: Qiu Caian , Opalka Susanne M. , Olson Gregory B. , Anton Donald L.
Published: March 2022

The Na–H system thermodynamic properties were assessed using Gibbs free energy model parameters obtained from best fit optimizations to combined experimental and first-principles predicted data. The first-principles finite temperature thermodynamic property predictions, based upon density functional theory ground state minimizations and direct method lattice dynamics, were used to supplement the Na–H dataset wherever experimental information was unavailable or unattainable. The predictions proved to be important for extending the evaluation of the heat capacity of the stable NaH phase to cover the complete 0 – 2000 K temperature range. The predicted thermodynamic properties of the hypothetical NaH3 end-member representing complete interstitial H substitution in solid body-centered cubic Na, provided a physical basis for modeling H dissolution in the Na lattice. The modeling also showed satisfactory agreement with experimental measurements of NaH enthalpies of formation, NaH decomposition pressures, and H solubility in liquid Na.
Comparing the thermodynamic behaviour of Al(l) + ZrO2(4% Y2O3) and Al(l) + Al2O3
Authors: Copland Evan
Published: March 2022

In an effort to better determine the thermodynamic properties of Al(g) and Al2O(g) the vapour in equilibrium with Al(l) + 4 at.% yttria-stabilized zirconia (YSZ) was compared to the vapour in equilibrium with Al(l) + Al2O3(s) over the temperature range 1197 – 1509 K. This comparison was made directly by Knudsen effusion-cell mass spectrometry with an instrument configured for a multiple effusion-cell vapour source (multi-cell KEMS). Second-law enthalpies of vaporization of Al(g) and Al2O(g) together with activity measurements show that Al(l) + YSZ is thermodynamically equivalent to Al(l) + Al2O3(s), indicating that Al(l) remained pure and Al2O3(s) was present in the YSZ-cell. Subsequent observation of the Al(l)/YSZ and vapour/YSZ interfaces revealed a thin Al2O3-layer had formed, separating the YSZ-cell from Al(l) and Al(g) + Al2O(g), effectively transforming it into an Al2O3 effusion-cell. This behaviour agreed with observations made for β-NiAl(Pt) alloys measured in YSZ effusion-cell.
Failure-mode dependence of the strengthening effect in Ti3AlC2/10 vol.% Al2O3 composite
Authors: Chen Jixin , Liu Mingyue , Bao Yiwang , Zhou Yanchun
Published: March 2022

The high-temperature mechanical properties of both Ti3AlC2 and Ti3AlC2/10 vol.%Al2O3 composite, including compressive strength, bending strength, and fracture behavior, were investigated. The strengthening effect caused by Al2O3 strongly depended on the mode of failure: significant enhancement in strength was only observed under the brittle mode of failure; whereas under the ductile mode of failure the strengthening effect was impaired due to Ti3AlC2 matrix softening and stress relaxation.
Novel combinatorial microstructures in Ti-6Al-4V alloy achieved by an electric-current-pulse treatment
Authors: Zhang Wei , Zhao Wei-song , Li Dou-xing , Sui Man-ling
Published: March 2022

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 coarsegrained α-Ti and the intergranular β-Ti, two kinds of novel ultrafine structures, nanometer-sized lamellar twins of β-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.
Determination of the critical tensile stress of sapphire by spherical indentation with additional lateral forces
Authors: Linss V. , Chudoba T.
Published: March 2022

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.
Experimental and thermodynamic evaluation of the Co–Cr–C system
Authors: Markström Andreas , Norgren Susanne , Frisk Karin , Jansson Bo , Sterneland Thérèse
Published: March 2022

New experimental results on the liquid + graphite + M7C3 equilibrium are presented. The solubility of Co in the M7C3 carbide has been measured at 1523 and 1723 K. These measurements together with recently published measurements on the fcc + graphite + M7C3 equilibrium show that the solubility of Co in the M7C3 is much higher than predicted from thermodynamic calculations. A new thermodynamic description of the Co–Cr –C system is presented which accurately describes the solubility of Co in the M7C3 carbide in the temperature range 1373 – 1723 K.
Sintering of Si3N4 with Li-exchanged zeolite additive
Authors: Matovic B. , Rixecker G. , Boskovic S. , Aldinger F.
Published: March 2022

This paper deals with the densification and phase transformation of Si3N4 with additives of Li-exchanged zeolite during pressureless sintering at significantly reduced temperatures. Dilatometric shrinkage data show that the first liquid forms as low as 1080 °C. Upon sintering at 1500 °C the bulk density increases to more than 95% of the theoretical density without phase transformation from α-S3N4 to β-Si3N4, i. e. the phase transformation lags behind the densification process. Above 1500 °C the secondary phase is completely converted into a glass and the α-to-β transformation takes place. Under these conditions the grain growth is anisotropic, leading to a microstructure which has potential for enhanced fracture toughness. The results show that a very effective low-temperature sintering additive for silicon nitride can be obtained from Li-exchanged zeolite.
The absolute thermoelectric power of chromium, molybdenum, and tungsten
Authors: Brodowskya Horst , Chen Qiyuan , Xiao Zhongliang , Yin Zhoulan
Published: March 2022

In pure metals or homogeneous alloys, the number of electrons per atom as well as the pressure are constant in a temperature gradient, and the electrochemical potential of the electrons is a unique function of the temperature. That is why it is possible to obtain the thermopower of these materials not only in the conventional evaluation of the Onsager equations, which involves the calculation of two transport coefficients, but also with an alternative approach, which involves the calculation of the temperature dependence of the electrochemical potential. The method is illustrated with the calculation of the thermopower of Cr, Mo, and W from the density of states of these metals.
Re-evaluation of phase equilibria in the Al–Mo system
Authors: Eumann Markus , Sauthoff Gerhard , Palm Martin
Published: March 2022

Phase equilibria and homogeneity ranges of the intermetallic phases in the Al –Mo system have been determined. The microstructures of samples of fixed composition and of diffusion couples were investigated by light-optical and scanning electron microscopy, the crystallographic structures and lattice constants were established by X-ray diffraction and the compositions of the phases were determined by electron probe microanalysis. In addition, transition temperatures were determined by differential thermal analysis. The homogeneity ranges of the Al-rich intermetallic phases are narrow, with about 0.1 to 0.4 at.% widths. The phases and phase equilibria as established in previous studies have been confirmed with the exception of the phase Al3+xMo1– x
, which has not been detected. The congruent melting point of Al8Mo3 was found at 1546 ± 3 °C and the Al-rich phase boundary for AlMo3 has been determined between 800 and 1200 °C.
Microstructure of the “white layer” formed on nitrided Fe-7 wt.% Cr alloys
Authors: Hosmani Santosh S. , Schacherl Ralf E. , Mittemeijer Eric J.
Published: March 2022

The formation of a compound, “white” layer on the surface of Fe-7 wt.% Cr alloy, by exposure to a gas mixture of ammonia and hydrogen at 580 °C, was investigated. The microstructure of the surface layer was analysed employing light and scanning electron microscopy, X-ray diffraction and electron probe microanalysis. For the first time a quantitative (phase) analysis of such a white layer was carried out, demonstrating the presence of a dispersed CrN phase within a γ| iron-nitride matrix.
The effect of ageing on tensile behaviour, mode I and mixed mode I/III fracture toughness of 7010 aluminium alloy
Authors: Eswar Raju K. S. S. , Mukhopadhyay Ashim K. , Kamat Samir V.
Published: March 2022

The effect of ageing on the tensile behaviour, mode I fracture toughness and mixed mode I/III fracture toughness of 7010 aluminium alloy plate was investigated. It was found that the 0.2% proof stress in this alloy increased from the under-aged temper to the peak-aged (T6) temper and then subsequently decreased in the over-aged (T73) temper. On the other hand, the ductility exhibited a monotonic decrease from the under-aged temper to the over-aged temper. The Ludwigson equation was found to best describe the flow behaviour in all the three ageing tempers. Under mode I as well as mixed mode I/III loading, the highest fracture toughness was seen in the under-aged temper, whereas the fracture toughness values in the peak-aged and over-aged tempers were comparable.
Influence of process parameters on particle characteristics using a combined pressure-swirl-gas atomizer
Authors: Achelis Lydia , Uhlenwinkel Volker , Bauckhage Klaus
Published: March 2022

This paper summarizes the latest results in the development of a combined pressure-swirl-gas atomizer. The main goals of this investigation are to characterize the generated metal powders in terms of spray pattern and particle size distribution. With the combined pressure-swirl-gas atomizer it is possible to create 150 kg h – 1 of tin powder with mass medians between 30 and 110 μm (tin alloys) and geometric standard deviations below 1.9 with a nitrogen consumption of 100 kg h – 1. Gas flow and melt mass flow can be varied independently of each other, while their characteristic ratio of mass flows can be held below 0.7, which opens new potential for low gas consumption in gas atomization. The experiments were conducted with water and tin melts as model fluids. The comparison of the dimensionless numbers shows that the model experiments are comparable and basically extendable to other melts as long as the material characteristics allow this.