bluuebunny/crossref_metadata_2025_split huggingface dataset:
In-Situ Observation of Deformation Processes by OIM
Authors: Weiland Hasso 
Published: July 2020

Abstract
The thermo-mechanical response of single crystals has been studied in detail since the discovery of X-ray and electron diffraction. While an extensive knowledge exists on the effect of crystallographic orientation on deformation and recrystallization behavior of single crystals, the thermo-mechanical response of grains of different orientations embedded in a polycrystalline matrix are not well understood. With the emergence of microstructure based models predicting the structure evolution during deformation or recrystallization, data validating the predicted structure changes are essential. This requires to study the evolution of microstructural attributes such as morphology or orientation of an individual grain within a specific grain neighborhood during mechanical or thermal exposure. Interrupted coupon scale testing, with a separation of testing and microstructural observation is not sufficient due to the small size of the objects to be observed. Thus, the structure evolution of selected grains has to be followed in-situ.
Strain Estimation by Electron Back Scattered Diffraction
Authors: Baudin T , Chastel Y , Pennelle R 
Published: July 2020

Abstract
The quality of the Kikuchi patterns obtained for example by electron backscattered diffraction decreases when the dislocation density increases in strained materials, and consequently, it can theoretically be correlated to the strain through the average dislocation density measurement particularly for monotonic deformation paths. For that purpose, in a first step it is necessary to define a quality factor defined in the Hough space or with the Burns method currently used when the Kikuchi patterns are automatically analyzed. Then, and it is the most important point, the quality factor must be linked to the strain through a calibration curve independent of crystallographic orientation.
The main objective of this study is to test the reliability of this method in the simple case of the hardness test. This test is simulated using the finite element method and the obtained results are compared to those measured by electron backscattered diffraction. Several calibration methods are defined.
Application of Microdiffraction in Sem for Assessing Intrinsic Materials Susceptibility to Intergranular Corrosion and Stress Corrosion Cracking
Authors: Palumbo G , Lehockey EM , Lin P 
Published: July 2020

Abstract
Intergranular degradation processes (e.g., corrosion, stress corrosion cracking) are a frequent cause of premature and unpredictable service failure of engineering components. Since these processes cause component failure via propagation through the intercrystalline network, they are strongly dependent upon the distribution of specific grain boundary structures in the material. Previous studies have shown that grain boundaries crystallographically described by low Σ (Σ≤29) Coincidence Site Lattice (CSL) relationships can often selectively display a high resistance (and often immunity) to corrosion and fracture. Recent advances in automated microdiffraction techniques (e.g., EBSP) in SEM have now made it possible to readily evaluate grain boundary character distributions in conventional polycrystalline materials. by utilizing this technique, and by formulating and applying simple stochastic models for the propagation of intergranular cracking and corrosion processes, the opportunity now exists for (1) improved component lifetime prediction, and (2) the optimization of materials synthesis techniques to yield intergranular-degradation resistant microstructures.
Ultrahigh-Vacuum Field-Emission Electron Microscope as Applied to Observation and Analysis of Crystal Surface
Authors: Takeguchi M , Honda T , Ishida Y , Kersker M , Tanaka M , Furuya K 
Published: July 2020

Abstract
UHV(ultrahigh-vacuum) TEM has long been used as a powerful tool for studying crystal surfaces, particularly for both the direct imaging of the surface structure and for in-situ observation of surface reaction processes with atomic resolution.
This paper reports a newly developed 200kV UHV TEM equipped with a field emission gun(FEG). The instrument is designed to obtain information about elemental or bonding states of surfaces in addition to observation of surface atomic structure with high contrast. Basic performances of the UHV FE-TEM includes a specimen vacuum of 2.0X10-8Pa, probe size less than 1.0nm Ø with 0.5nA probe current, point-to-point resolution of 0.21 nm, and a lattice resolution of 0.10nm.
A UHV Energy Dispersive X-ray Spectrometer (EDS) originally developed by JEOL Ltd. and a Parallel Electron Energy Loss Spectrometer (PEELS) are attached to the UHV FE-TEM, which combined with a fine focused probe of 1.Onm Ø allows atomic scale spectroscopy of surfaces.
In-SituEELS Analysis of Cobalt Valence in La1-xSrxCoO3-y
Authors: Yin JS , Wang ZL 
Published: July 2020

Abstract
Transition and rare earth metal elements have played a vital role in synthesis of functional and smart materials because of their unique electronic structures and mixed valences. Experimental measurement of the valence states is thus important for understanding the mechanism which drives the functional properties. Lai1.xSrxCoO3-y(LSCO), for example, is an ionic conductor with potential applications in fuel cells and many other fields. In this type of materials, the anion deficiency is directly associated with the ratio of Co2+/Co3+ (or Co3+/Co4+) present in the specimen. It is known that the anion deficiency of the material depends on the operation temperature, but a direct measurement of anion deficiency is a challenge to existing microscopy techniques. In this paper, we present the in-situ analysis of Co valence in LSCO using electron energy-loss spectroscopy (EELS) in a transmission electron microscope.
LSCO thin films (with x = 0.5) were grown on polished MgO(00l) substrate by liquid source metal-organic chemical vapor deposition (MOCVD) method [1].
ESEM Hot Stage Evaluation of Sol-Gel Insulation Coatings for High Field HTS Magnets.
Authors: Mutlu I H , Goddard R E , Hascicek Y S 
Published: July 2020

Abstract
High temperature, thin ceramic insulation coatings are necessary for the application of High Temperature Superconductors (HTS) in high field magnet technology. Especially in the so called “wind and react” technology, insulation coatings have to withstand the final heat treatment at about 900°C, otherwise turn to turn insulation will be broken. We have developed a sol-gel coating method for HTS tape conductors at NHMFL. Excellent adhesion at the interface due to the significant interfacial reactions, indicates that this sol-gel route is a feasible method for applying zirconia coatings. Sol-gel technology is a low temperature chemical route of preparing inorganic material. The stability and the coating characteristics of a organozirconium compound have been investigated to coat ZrO2 films on silver sheathed HTS tape conductors. This method was used to coat stainless steel with ZrO2.
The ZrO2 coatings were obtained by dipping the silver sheathed HTS tape in a solution of zirconiumtetrabutoxide, isopropanol and acetylacetone.
In Situ Nitride Growth Studies by Low Energy Electron Microscopy (LEEM) and Low Energy Electron Diffraction (LEED)
Authors: Bauer E , Pavlovska A , Tsong IST 
Published: July 2020

Abstract
Nitride films play an increasing role in modern electronics, for example silicon nitride as insulating layer in Si-based devices or GaN in blue light emitting diodes and lasers. For this reason they have been the subject of many ex situ electron microscopic studies. A much deeper understanding of the growth of these important materials can be obtained by in situ studies. Although these could be done by SEM, LEEM combined with LEED is much better suited because of its excellent surface sensitivity and diffraction contrast. We have in the past studied the high temperture nitridation of Si(l11) by ammonia (NH3)and the growth of GaN and A1N films on Si(l11) and 6H-SiC(0001) by depositing Ga and Al in the presence of NH3 and will report some of the results of this work for comparison with more recent work using atomic nitrogen instead of NH3.
A High Voltage Scanning Electron Microscope for the In-SituObservation and Recording of Electromigration Voids in Metal Lines on Integrated Circuits.
Authors: Flinn P A , Lee S , Doan J C , Bravman J C , Marieb T , Madden C 
Published: July 2020

Abstract
The passing of current through thin metal lines results in the formation of voids which will eventually cause the line to fail electrically. Gathering of experimental data on electromigration has been limited by two facts: The dimensions of the metal lines on modern integrated circuits are on the order of the resolution limit of light microscopy; and voids in these lines behave quite differently when they are surrounded by a protective film of SiO2 or other dielectric. This dielectric protects the metal surface and constrains the line, pushing back on the metal displaced by void formation. Several additional factors further complicate experimental analysis: the sample test current must be precisely controlled during observation; the sample must be accurately heated to several hundred degrees; the metal lines must be long and narrow (typically 0.2-3.0 (am wide by 300 μm long); testing is often lengthy, sometimes extending over several days even under conditions selected to minimize the time to failure; and electromigration failures are characterized by long incubation periods during which no changes are observed followed by rapid and complex behavior.
Unveiling Novel Reaction Processes in Catalysis by Environmentalhrem (EHREM)
Authors: Gai Pratibha L 
Published: July 2020

Abstract
Dynamic interactions between gas molecule and solid surfaces are central to heterogeneous catalytic processes. Recently, we have developed a novel in-situ environmental high resolution electron microscopy (EHREM) method, capable of probing live gas-catalyst reactions at elevated temperatures directly (in-situ) on the atomic scale1. A Philips CM30 (S)TEM has been modified with an integrated environmental cell maintaining atomic resolution in controlled gas environments, upto ∼ 1000 °C. Using this method, we have studied important real-life catalysts, vanadyl pyrophosphates ((VO)2P2O7, hereafter referred to as VPO), used in n-butane oxidation to maleic anhydride (MA with end uses in furans.
The catalyst samples were prepared using V2O5, anhydrous phosphoric acid in isobutyl alcohol and benzyl alcohol followed by calcination and activation. VPO is orthorhombic with a ∼ 16.59Å, b ∼ 7.76Å and c ∼ 9.58 Å. An EHREM lattice image of the fresh catalyst with electron diffraction (ED) and ‘rose’ morphology, is shown in Fig 1(a).
In SituHigh-Resolution Electron Spectroscopic Imaging and Real-Time Image Simulation of Precipitate Growth Mechanisms
Authors: Howe J M , Tsai M M , Csontos A A 
Published: July 2020

Abstract
Precipitate interfaces are ideal for studying the relationship between atomic bonding, structure and composition at internal interfaces and the mechanisms and kinetics of their motion as a function of temperature or driving force for reaction. The crystallography between coherent and semicoherent precipitates and the matrix is well-defined and the precipitate interfaces are often planar and grow by a terrace-ledge-kink mechanism, making them well-suited for study by conventional and high-resolution transmission electron microscopy (HRTEM).
Motion of precipitate interfaces, or more generally, interphase boundaries, involves a change in lattice, composition or both. In order to understand the mechansims of interfacial motion, it is necessary to determine the structural and compositional changes that occur at the highest possible resolution, i.e., as close to the atomic level as possible, and also, to determine the corresponding kinetics of interface motion. HRTEM is an excellent technique for determining the atomic structure of transformation interfaces and in situhot-stage HRTEM is deal for determining interface dynamics at the atomic level, provided the transformation mechanisms are not altered by the thinness of the TEM foil.
Atomic Structure Determination of Nio-Y2O3 Interfaces by HRTEM
Authors: Bailey GW , Dimlich RVW , Alexander KB , McCarthy JJ , Pretlow TP , Dickey EC , Dravid VP 
Published: July 2020

Abstract
The investigation of interfaces between NiO and Y2O3 is part of a research initiative to understand low-energy heterophase interface structures between different oxide materials. In-situ oxide composites formed by the directional solidification of pseudo-binary eutectics are used as model materials in this study because they are amenable to chemical and structural characterization at the atomic length-scale. Previously, interfaces in NiO-ZrO2(cubic) directionally solidified eutectics (DSEs) were examined by various electron imaging and spectroscopy techniques to reveal the three-dimensional interface structure.[l] The second DSE system studied, NiO-Y2O3,[2] was chosen because it is very similar in crystallography to NiO-ZrO2(cubic). The goal of this second, analogous study is not only to understand the NiO-Y2O3 interface structure but, by comparing the results to NiO-ZrO2, is to draw more general conclusions about low energy oxide-oxide interfaces. Table one compares the crystallography of the NiO-ZrO2 and the NiO-Y2O3 DSEs.
Electron Spectroscopy and Holography of Electrically Active Electroceramic Interfaces
Authors: Bailey GW , Dimlich RVW , Alexander KB , McCarthy JJ , Pretlow TP , Johnson Kevin , Ravikumar V , Rodrigues R , Dravid Vinayak P 
Published: July 2020

Abstract
Many electroceramics derive their technologically useful and scientifically appealing properties through electrically active grain boundaries (GBs). Examples of such properties include traditional nonlinear current-voltage relationship (i.e. varistor behavior) and positive temperature of coefficient of resistance (PTCR effect), to recently “rediscovered” phenomena of space-charge formation across functional interfaces, including ferroeletric thin films.
In many such cases, the transport of charge across these interfaces is mediated through potential barriers which form at the core of these interfaces. For example, varistor behavior is attributed to formation of Schottky barriers at GBs which modify the transport of electrons, leading to the nonlinearity in I-V characteristics. The formation of Schottky barrier at the GB core, in turn, is attributed to the formation of space-charge across GBs. The formation of space-charge, further, is clearly attributable to decoration of GB core with charged defects with compensating opposite charge across the GB. The presence, sign, magnitude and spatial distribution of space-charge form the key to understand the Schottky barriers, thus the transport properties of interfacial systems.
Determining Atomic Structure-Property Relationships at Grain Boundaries in High-Tc Superconductors
Authors: Browning N D , Buban J P , Prouteau C , Duscher G , Chisholm M F , Pennycook S J 
Published: July 2020

Abstract
The short coherence length in high-Tc superconductors (5-15Å) makes an atomic scale understanding of the electronic properties at defects and interfaces essential for device applications. This understanding is particularly relevant for grain boundaries in YBa2CU3O7-δ (YBCO), where although extensive studies have shown a clear exponential decrease in critical current with misorientation angle, the absolute value can vary by several orders of magnitude at any given misorientation angle.
Figure 1 shows Z-contrast images of an [001] low-angle tilt boundary and a 30° [001] asymmetric tilt grain boundary. An interesting feature of both of these boundaries is that there appear to be sites where two atom columns are too close together. However, the problem of like-ion repulsion can be avoided if the columns are taken to be partially occupied. Insight into the effect of this partial occupancy can be obtained through the use of bond-valence sum analysis. Here, the formal valence of an atom is made up of contributions from all of its nearest neighbors, the magnitude of which are determined by the bond length.
Iterative Structure Retrieval Techniques for Aperiodic Defects (e.g. Dislocations) using QHREM
Authors: Bailey GW , Dimlich RVW , Alexander KB , McCarthy JJ , Pretlow TP , Möbus G , Schweinfest R , Bernath S , Wagner T 
Published: July 2020

Abstract
The determination of unknown crystal defect structures by iterative digital image matching (“quantitative HREM”) has previously been successfully applied to grain boundaries (e.g. in niobium [1]) or phase boundaries with small misfit (e.g. Nb-sapphire [2]), which offer several advantages: (i) the supercell is small leading to fast cycle times in iterative structure refinement and thus to a secure global optimum, (ii) noise-filtering is possible by translation symmetry, (iii) the interface structure is mostly planar (i.e. perfectly columnar). For dislocations and other aperiodic defects all these three issues are missing and curved atomic columns from surface strains especially cause problems [3]. Any progress in this area must therefore address (i) - (iii) separately and estimate the change of the confidence level of the retrieved structure when switching from interface-refinement to dislocation-refinement. First results of this project address questions of convergency and speed.
Since each HREM-Lab is only concerned with a limited number of materials (and elements) as well as with a few microscope-voltages only, it is advisable to calculate transmission functions for single atoms for each element and voltage a single time, and store these data files in a library.
Characterization of Precipitate Distributions in Modified S5 Tool Steels
Authors: Hsieh KC , Kenik EA 
Published: July 2020

Abstract
There has been increasing interest from industry to characterize the different precipitate distributions in ferrous materials to account for different mechanical properties that are observed. For this study, two different heat treatments were chosen for the experimental S5 tool steel, modified to have 0.24 wt% C. Alloy S5-1 received 1 hour of austenitizing at 970°C, was quenched at rate of 140°C/s and tempered for 1 hour at 200°C. Alloy S5-2 received 40 minutes of austenitizing at 940°C, was quenched at rate of 16°C/s and tempered for 1 hour at 200 °C. In this relatively low hardenability steel, both S5-1 and S5-2 show mixed microstructures of tempered martensite and bainite (Fig. 1, 2). Not surprisingly, the slower cooling rate for S5-2 created an alloy with inferior microstructure and mechanical properties. Even though these differences in precipitate distributions, could not directly account for differences in mechanical properties, it is of interest to study how the different heat treatments affected the precipitate distributions in S5-1 and S5-2.
Microstructural Characterization of Crystalline and Quasicrystalline Phases in AlCuFe Alloys.
Authors: Rosas G , Reyes-Gasga J , Pérez R 
Published: July 2020

Abstract
Recent interest in the literature on ternary compounds of the AlCuFe type has been prompted by the discovery of stable quasicrystalline phases in these type of alloys (1). Therefore, different investigationes have been carried out in the past, related with the structural characteristics and also the mechanical properties of these compounds (2). It is interesting to point out that very few studies have been carried out on the structural characteristics of the phases which commonly coexist with the icosahedral phase in this ternary alloy (3). In this investigation an assessment of the chemical and structural properties of the phases obtained in alloys of AlCuFe is carried out.
Ternary alloys with approximately 20 different compositions have been prepared. The compositional ranges were: Al(60-65%at), Cu(20-25%at) and Fe(10-15%at). The preparation of the alloys used two different casting process; a gravity chill casting technique and also the spin wheel casting method. These casting techniques were able to provide different cooling velocities in the final ingots or metallic strips.
Crystallography and Phase Transitions in the Ta-Ru and Nb-Ru Shape Memory Alloys
Authors: Fonda R W , Vandermeer R A 
Published: July 2020

Abstract
A new class of shape memory alloys, based on near-equiatomic compositions of Ta-Ru and Nb-Ru, was recently discovered at the Naval Research Laboratory. These alloys exhibit transformation temperatures ranging up to 1400 °C for Ta-Ru and 1100 °C for Nb-Ru, making them the highest transition temperature shape memory alloys yet discovered. Other shape memory alloys typically have transition temperatures within a couple hundred degrees of room temperature. These two alloy systems are quite similar in their transformation behavior. Near the equiatomic composition, the high temperature β phase of both systems has a B2-ordered cubic crystal structure. During cooling, the cubic lattice of β undergoes a slight tetragonal distortion to form the β' phase. Continued cooling of the tetragonal β'(within specific composition ranges) causes a transformation to β'', which is reported to have an orthorhombic crystal structure. The effect of alloy composition on the temperatures, hysteresis, and strains of these transformations was determined by dilatometry.
Microstructural Investigation of Strength Degradation in A Developmental Cvd Sic Fiber At 2000° C
Authors: Garg A , Hull D R , Bhatt R T 
Published: July 2020

Abstract
SiC fibers fabricated by chemical vapor deposition (CVD) methods are being used as reinforcement for metal and ceramic matrix materials because of their high modulus, high strength and good corrosion resistance. These fibers have a complex composite microstructure consisting of a pyrolytic-carbon coated graphite core and a SiC sheath which is often protected by a single or a double layer of carbon-rich coating. Commercially available SCS-6 SiC fibers with a diameter of ˜ 140 μm have been most widely in use for composite fabrication. However, with an ever increasing demand for thinner and stronger fibers, an experimental SiC fiber with a diameter of ˜ 50 μm and having a C-rich SiC sheath was developed by Textron Specialty Materials. The as-fabricated tensile strength of this fiber was found to be ˜ 6 GPa, which is ˜ 50 % higher than that of the SCS-6 fiber.While the room temperature tensile strengths of these fibers heat treated for 1 h in Ar to temperatures ≤ 1600° C were better than those of the SCS-6 fiber, strength of the 2000° C heated fibers decreased to &lt; 1 GPa.
Corrosion of a Plutonium-Bearing Titanate Ceramic
Authors: Buck E C , DiSanto T , Bakel A J , Bates J K 
Published: July 2020

Abstract
A titanate-based ceramic waste form, rich in phases structurally related to zirconolite (CaZrTi2O7), is being developed as a possible candidate for immobilizing excess plutonium from dismantled nuclear weapons. The waste form is made by cold pressing and sintering of CaO, TiO2, ZrO2, A12O3, BaO, and Gd and Pu oxides. A prototype Pu-loaded ceramic that is being tested contains Pu,Gd-zirconolite-(3T), Pu-bearing brannerite, Gd-zirconolite-(4M), zirconolite-(2M) (see Figure 1), rutile (TiO2), Gd-bearing perovskites, various aluminotitanate phases, and undissolved plutonium oxide. Evidence from laboratory testing and natural analogues of titanates suggests that these phases are extremely corrosion resistant. Zirconolite-rich ceramics have also been considered for the disposal of actinide-bearing waste streams, because zirconolite and related polytypes are able to incorporate at least 20 wt% of actinides. However, since each phase in the multiphase ceramic corrodes at a different rate, the release of any one component or the corrosion of the bulk waste form is difficult to predict