Atom Probe Tomography is aimed at beginners and researchers interested in expanding their expertise in this area. It provides the theoretical background and practical information necessary to investigate how materials work using atom probe microscopy techniques, and includes detailed explanations of the fundamentals, the instrumentation, contemporary specimen preparation techniques, and experimental details, as well as an overview of the results that can be obtained. The book emphasizes processes for assessing data quality and the proper implementation of advanced data mining algorithms. For those more experienced in the technique, this book will serve as a single comprehensive source of indispensable reference information, tables, and techniques. Both beginner and expert will value the way the book is set out in the context of materials science and engineering. In addition, its references to key research outcomes based upon the training program held at the University of Rouen-one of the leading scientific research centers exploring the various aspects of the instrument-will further enhance understanding and the learning process. Provides an introduction to the capabilities and limitations of atom probe tomography when analyzing materials Written for both experienced researchers and new users Includes exercises, along with corrections, for users to practice the techniques discussed Contains coverage of more advanced and less widespread techniques, such as correlative APT and STEM microscopy
Nanocharacterization by Atom Probe Tomography is a practical guide for researchers interested atomic level characterization of materials with atom probe tomography. Readers will find descriptions of the atom probe instrument and atom probe tomography technique, field ionization, field evaporation and field ion microscopy. The fundamental underlying physics principles are examined, in addition to data reconstruction and visualization, statistical data analysis methods and specimen preparation by electropolishing and FIB-based techniques. A full description of the local electrode atom probe – a new state-of-the-art instrument – is also provided, along with detailed descriptions and limitations of laser pulsing as a method to field evaporate atoms. Valuable coverage of the new ionization theory is also included, which underpins the overall technique.
The microanalytical technique of atom probe tomography (APT) permits the spatial coordinates and elemental identities of the individual atoms within a small volume to be determined with near atomic resolution. Therefore, atom probe tomography provides a technique for acquiring atomic resolution three dimensional images of the solute distribution within the microstructures of materials. This monograph is designed to provide researchers and students the necessary information to plan and experimentally conduct an atom probe tomography experiment. The techniques required to visualize and to analyze the resulting three-dimensional data are also described. The monograph is organized into chapters each covering a specific aspect of the technique. The development of this powerful microanalytical technique from the origins offield ion microscopy in 1951, through the first three-dimensional atom probe prototype built in 1986 to today's commercial state-of-the-art three dimensional atom probe is documented in chapter 1. A general introduction to atom probe tomography is also presented in chapter 1. The various methods to fabricate suitable needle-shaped specimens are presented in chapter 2. The procedure to form field ion images of the needle-shaped specimen is described in chapter 3. In addition, the appearance of microstructural features and the information that may be estimated from field ion microscopy are summarized. A brief account of the theoretical basis for processes of field ionization and field evaporation is also included.
Atom probe microscopy enables the characterization of materials structure and chemistry in three dimensions with near-atomic resolution. This uniquely powerful technique has been subject to major instrumental advances over the last decade with the development of wide-field-of-view detectors and pulsed-laser-assisted evaporation that have significantly enhanced the instrument’s capabilities. The field is flourishing, and atom probe microscopy is being embraced as a mainstream characterization technique. This book covers all facets of atom probe microscopy—including field ion microscopy, field desorption microscopy and a strong emphasis on atom probe tomography. Atom Probe Microscopy is aimed at researchers of all experience levels. It will provide the beginner with the theoretical background and practical information necessary to investigate how materials work using atom probe microscopy techniques. This includes detailed explanations of the fundamentals and the instrumentation, contemporary specimen preparation techniques, experimental details, and an overview of the results that can be obtained. The book emphasizes processes for assessing data quality, and the proper implementation of advanced data mining algorithms. Those more experienced in the technique will benefit from the book as a single comprehensive source of indispensable reference information, tables and techniques. Both beginner and expert will value the way that Atom Probe Microscopy is set out in the context of materials science and engineering, and includes references to key recent research outcomes.
Chapter 6 presents a study using a modified version of the atom probe simulation code, TAPSim, which allows for the performance of molecular dynamics on simulated emitters in between evaporation steps. TAPSim-MD simulations of an Al0.98Cu0.02 emitter reveal the origin of the clustering artifact seen in experimental observations of AlCu alloys. The drag effect, an athermal surface migration process that occurs partly due to a non-ideal evaporation sequence of the alloy emitter, a new mechanism for these types of atom probe artifacts is described. Finally, DFT calculations of the surface binding energy of the dilute limit for alloyed adatoms are presented in chapter 7. Fitting a simple exponential function to the per-bond energy of the studied evaporations yields better results than fitting to the ZBEF computed by the Image Hump model, since the desorption energy should be neighbor dependent but the work function is surface dependent. The results of these DFT calculations suggest that for some alloyed elements, namely Mg when alloyed in Al, reduction of the ZBEF of the solute may occur. The weaker binding energy also leads to longer surface bonds, meaning Mg will be naturally more exposed, leading to a higher probability of undergoing evaporation before reaching a terrace edge. Predicting this type of situation is important so that it is not convoluted with other artifacts, such as the drag effect. While large advancements have been made in the hardware necessary to run the atom probe, advances in the development of reconstruction algorithms have not been so quick. Much of this stems from a lack of information about how exactly samples behave while in the instrument and how field evaporation proceeds for a given sample composition. Development of forward simulations with more complete physical models has shown promise for identifying the mechanisms for atom probe artifacts, and will be crucial as part of a testing framework for new reconstruction protocols. As the atom probe becomes more popular, the need for verifying and improving the quality of the data reconstructions becomes more important.
This book is the first, single-source guide to successful experiments using the local electrode atom probe (LEAP®) microscope. Coverage is both comprehensive and user friendly, including the fundamentals of preparing specimens for the microscope from a variety of materials, the details of the instrumentation used in data collection, the parameters under which optimal data are collected, the current methods of data reconstruction, and selected methods of data analysis. Tricks of the trade are described that are often learned only through trial and error, allowing users to succeed much more quickly in the challenging areas of specimen preparation and data collection. A closing chapter on applications presents selected, state-of-the-art results using the LEAP microscope.
|Author||: David L. J. Engberg|
|Publisher||: Linköping University Electronic Press|
|Release Date||: 2019-08-02|
|ISBN 10||: 9176850439|
|Pages||: 79 pages|
Hard ceramic thin films, including TiSiN, ZrAlN, ZrB2, and ZrTaB2, with applications for wear-resistant coatings, have been studied using atom probe tomography and correlated with several other analytical techniques, including X-ray diffraction, electron microscopy, and elastic recoil detection analysis. Outstanding obstacles for quantitative atom probe tomography of ceramic thin films have been surmounted. Mass spectral overlaps in TiSiN, which make 28Si indistinguishable from 14N, was resolved by isotopic substitution with 15N, and the nanostructural distribution of elements was thus revealed in 3-D, which enabled the identification of additional structural elements within the nanostructured Ti0.81Si0.1915N film. Improvements to the growth model of TiSiN by cathodic arc deposition was suggested. A self-organized nanolabyrinthine structure of ZrAlN, consisting of standing lamellae of fcc-ZrN and hexagonal AlN, was investigated with focus on the onset and limits of the self-organization. The local crystallographic orientational relationships were (001)ZrN || (0001)AlN and <110>ZrN || <2-1-10>AlN. Close to the MgO substrates, a smooth transition region was formed, going from segregated and disordered to the self-organized nanolabyrinthine structure. With increased growth temperature, coarse (111)-oriented ZrN grains occasionally precipitated and locally replaced the nanolabyrinthine structure. Significant local magnification effects rendered the Zr and N signals unusable, thereby inhibiting quantitative compositional analysis of the constituent phases, but the nanostructure was resolved using the Al signal. Ceramic materials are often affected by correlated evaporation, which can result in losses due to the detector dead-time/space. A compositional correction procedure was suggested, tested against an established procedure, and applied to ZrB2. The correction was found to be less dependent on the isotope abundances and background correction compared to the established procedure. While losses due to dead-time/space occur in atom probe tomography of all materials, the correlative field evaporation behavior of ceramics significantly increases the compositional error. The evaporation behavior of ZrB2 was therefore thoroughly investigated and evidence of preferential retention, correlated evaporation, and inhomogeneous field distributions at a low-index pole was presented. The high mass resolution, relatively low multiple events percentage, and quality of the co-evaporation correlation data was partly attributed to the crystal structure and film orientation, which promoted a layer-by-layer field evaporation. The evaporation behavior of the related ZrTaB2 films was found to be similar to that of ZrB2. The distribution of Ta in relation to Zr was investigated, showing that the column boundaries were both metal- and Ta-rich, and that there was a significant amount of Ta in solid solution within the columns. In addition, an instrumental artefact previously not described in atom probe tomography was found in several of the materials investigated in this thesis. The artefact consists of high-density lines along the analysis direction, which cannot be related to pole artefacts. The detection system of the atom probe was identified as the cause, because the artefact patterns on detector histograms coincided with the structure of the microchannel plate. Inconsistencies in the internal boundaries of the microchannel plate multifibers from the manufacturing process can influence the signal to the detector and locally increase the detection efficiency in a pattern characteristic to the microchannel plate in question. Altogether, this thesis shows that atom probe tomography of nitride and boride thin films is burdened by several artefacts and distortions, but that relevant material outcomes can nevertheless be achieved by informed choices of film isotopic constituents and analytical parameters, exclusion of heavily distorted regions (such as pole artefacts), and the use of compositional correction procedures when applicable.
|Release Date||: 2001|
|Pages||: 38 pages|
A combined atom probe tomography and atom probe field ion microscopy study has been performed on a submerged arc weld irradiated to high fluence in the Heavy-Section Steel irradiation (HSSI) fifth irradiation series (Weld 73W). The composition of this weld is Fe - 0.27 at. % Cu, 1.58% Mn, 0.57% Ni, 0.34% MO, 0.27% Cr, 0.58% Si, 0.003% V, 0.45% C, 0.009% P, and 0.009% S. The material was examined after five conditions: after a typical stress relief treatment of 40 h at 607 C, after neutron irradiation to a fluence of 2 x 1023 n m−2 (E> 1 MeV), and after irradiation and isothermal anneals of 0.5, 1, and 168 h at 454 C. This report describes the matrix composition and the size, composition, and number density of the ultrafine copper-enriched precipitates that formed under neutron irradiation and the change in these parameters with post-irradiation annealing treatments.
Microstructural Geochronology Geochronology techniques enable the study of geological evolution and environmental change over time. This volume integrates two aspects of geochronology: one based on classical methods of orientation and spatial patterns, and the other on ratios of radioactive isotopes and their decay products. The chapters illustrate how material science techniques are taking this field to the atomic scale, enabling us to image the chemical and structural record of mineral lattice growth and deformation, and sometimes the patterns of radioactive parent and daughter atoms themselves, to generate a microstructural geochronology from some of the most resilient materials in the solar system. First compilation of research focusing on the crystal structure, material properties, and chemical zoning of the geochronology mineral archive down to nanoscale Novel comparisons of mineral time archives from different rocky planets and asteroids and their shock metamorphic histories Fundamentals on how to reconstruct and date radiogenic isotope distributions using atom probe tomography Microstructural Geochronology will be a valuable resource for graduate students, academics, and researchers in the fields of petrology, geochronology, mineralogy, geochemistry, planetary geology, astrobiology, chemistry, and material science. It will also appeal to philosophers and historians of science from other disciplines.
|Author||: James Douglas|
|Release Date||: 2018|
|Pages||: 329 pages|
|Author||: Andrew P. Proudian|
|Release Date||: 2019|
|Pages||: 113 pages|