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M.k. Miller - One of the best experts on this subject based on the ideXlab platform.

  • CharacterizatIon of Materials - Atom Probe Tomography and Field Ion Microscopy
    Characterization of Materials, 2012
    Co-Authors: M.k. Miller
    Abstract:

    Atom probe tomography is a characterizatIon technique for the analysis of the microstructure of materials at the atomic level. The basic concepts of atom probe tomography and Field Ion Microscopy, the implementatIons of a Field Ion microscope and a three-dimensIonal atom probe, including the state-of-the-art local electrode atom probe, and laser and voltage pulsing methods of Field evaporatIon are outlined in this chapter. Methods of atom probe tomography specimen preparatIon by electropolishing and focused Ion beam methods are described. An overview of data visualizatIon and analysis as well as data mining techniques is presented. Keywords: Field Ion Microscopy (FIM); atom probe Field Ion Microscopy (APFIM); atom probe tomography (APT); three-dimensIonal atom probe (3DAP); local electrode atom probe (LEAP); Field evaporatIon

  • CharacterizatIon of internal interfaces by atom probe Field Ion Microscopy
    MRS Proceedings, 2011
    Co-Authors: M.k. Miller, Raman Jayaram
    Abstract:

    The near atomic spatial resolutIon of the atom probe Field Ion microscope permits the elemental characterizatIon of internal interfaces, grain boundaries and surfaces to be performed in a wide variety of materials. InformatIon such as the orientatIon relatIonship between grains, topology of the interface, and the coherency of small precipitates with the surrounding matrix may be obtained from Field Ion Microscopy. Details of the solute segregatIon may be obtained at the plane of the interface and as a functIon of distance from the interface for all elements simultaneously from atom probe compositIonal analysis. Capabilities and limitatIons of the atom probe technique in characterizatIon of internal interfaces is illustrated with examples of grain boundaries and interphase interfaces in a wide range of materials including intermetallics, model alloys, and commercial steels.

  • The development of atom probe Field-Ion Microscopy
    Materials Characterization, 2000
    Co-Authors: M.k. Miller
    Abstract:

    Abstract A review of the development of the techniques of atom probe Field-Ion Microscopy and atom probe tomography is presented. The development is traced from the original time-of-flight atom probe Field-Ion microscope developed by Muller, Panitz, and McLean in 1968 to the energy-compensated three-dimensIonal atom probes that are commercially available today. The various types of atom probes that have been developed are described. Published by Elsevier Science Inc.

  • Atom Probe Field-Ion Microscopy CharacterizatIon of Nickel and Titanium Aluminides
    Materials Characterization, 2000
    Co-Authors: D. J. Larson, M.k. Miller
    Abstract:

    Abstract A review of the contributIons of atom probe Field-Ion Microscopy to the characterizatIon of nickel and titanium aluminides is presented. The nickel aluminide systems studied include boron-doped Ni 3 Al and boron-, carbon-, beryllium-, zirconium-, molybdenum-, and hafnium-doped NiAl. These systems have been characterized in terms of solute segregatIon to boundaries, dislocatIons, and other defects, matrix solubilities, precipitatIon, and site-occupatIon probabilities. The partitIoning behavior of impurities and alloying additIons, matrix solubilities, precipitate compositIons, and interfacial segregatIon in several of α 2 + γ titanium aluminides and related alloys are also reviewed. Published by Elsevier Science Inc.

  • atom probe Field Ion Microscopy investigatIon of boron containing martensitic 9 pct chromium steel
    Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2000
    Co-Authors: P Hofer, M.k. Miller, S S Babu, S A David, H Cerjak
    Abstract:

    The chemical compositIons of the ferrite matrix and various other phases in an Fe-0.17 C-9 Cr-1.55 Mo-0.27 V-0.015 N-0.01B (mass pct) steel in as-received and crept conditIons were measured with atom probe Field Ion Microscopy (APFIM). The results showed the presence of some residual boron within the ferrite matrix. Analyses showed that boron was distributed within M23C6, M6C, MX, and Laves phases. Phosphor atoms were detected at the M23C6-ferrite interface in the crept conditIon. The results are compared to predictIons from thermodynamic calculatIons.

P P Camus - One of the best experts on this subject based on the ideXlab platform.

A. J. Melmed - One of the best experts on this subject based on the ideXlab platform.

D. J. Larson - One of the best experts on this subject based on the ideXlab platform.

  • Atom Probe Field-Ion Microscopy CharacterizatIon of Nickel and Titanium Aluminides
    Materials Characterization, 2000
    Co-Authors: D. J. Larson, M.k. Miller
    Abstract:

    Abstract A review of the contributIons of atom probe Field-Ion Microscopy to the characterizatIon of nickel and titanium aluminides is presented. The nickel aluminide systems studied include boron-doped Ni 3 Al and boron-, carbon-, beryllium-, zirconium-, molybdenum-, and hafnium-doped NiAl. These systems have been characterized in terms of solute segregatIon to boundaries, dislocatIons, and other defects, matrix solubilities, precipitatIon, and site-occupatIon probabilities. The partitIoning behavior of impurities and alloying additIons, matrix solubilities, precipitate compositIons, and interfacial segregatIon in several of α 2 + γ titanium aluminides and related alloys are also reviewed. Published by Elsevier Science Inc.

  • Atom Probe Field Ion Microscopy of Titanium Aluminides
    Microscopy and Microanalysis, 1998
    Co-Authors: D. J. Larson, M.k. Miller
    Abstract:

    Titanium aluminides have a number of potential high temperature applicatIons due to their good elevated-temperature mechanical properties, low density, and good creep and oxidatIon resistance. However, fabricatIon of commercial components of these materials has been impeded by their poor mechanical properties at ambient temperatures. Significant efforts with various degrees of success have been made to improve the mechanical properties of these TiAl alloys by doping them with a variety of different elements including B, C, Cr, Er, Fe, Mn, Mo, Ni, Nb, P, Si, Ta, V and W. One of the optimum analytical tools for investigating the effects of these additIons on the microstructure is the atom probe Field Ion microscope. However, relatively few studies of titanium aluminides, compared to some other intermetallic compounds, have performed by atom probe Field Ion Microscopy. This lack of attentIon can be attributed to the brittle nature of the material, in-situ transformatIons that occur during the Field Ion Microscopy and preferential evaporatIon problems that were encountered in some of the early studies.

  • Atom probe Field Ion Microscopy of high resistivity materials
    Microscopy and Microanalysis, 1998
    Co-Authors: S. J. Sibrandij, D. J. Larson, M.k. Miller
    Abstract:

    Over the last 30 years the atom probe has proved to be a powerful tool for studying nanometer-sized compositIonal fluctuatIons in a wide range of metallic alloys but has had only limited applicatIons to semiconductors and ceramics. One of the primary reasons for this difference is the higher resistivity of semiconducting and ceramic specimens. Because of this high resistivity, the high voltage Field evaporatIon pulse is attenuated before it reaches the apex of the specimen thereby making the pulse ineffective for Field evaporatIon. Experiments have demonstrated that both variants of the voltage-pulsed atom probe (i.e., those instruments in which the Field evaporatIon pulse is applied directly to the specimen and those in which the negative pulse is applied to a counter electrode in front of the specimen) are equally affected. In this overview, the limits of applicability of the voltage-pulsed atom probe to high resistivity materials are examined. In this study, a wide range of materials have been examined to determine whether Field Ion Microscopy and voltage-pulsed Field evaporatIon can be achieved and the results are summarized in the report. Field Ion Microscopy including dc Field evaporatIon was possible for all materials except bulk ceramic insulators and glasses. Field Ion Microscopy requires some conductivity both to achieve a high electric Field at the apex of the specimen, and also to support the Field Ion current. In contrast, voltage-pulsed Field evaporatIon requires transmissIon of the pulse to the apex of the specimen. All metallic alloys including high resistance alloys and metallic glasses were successfully Field evaporated with a voltage pulse. Specimens that were produced from bulk material of several conducting ceramics including MoSi, TiB and TiC were also successfully Field evaporated with a voltage pulse.

  • Atom probe Field Ion Microscopy of titanium aluminides
    1998
    Co-Authors: D. J. Larson, M.k. Miller
    Abstract:

    Titanium aluminides have a number of potential high temperature applicatIons due to their good elevated-temperature mechanical properties, low density, and good creep and oxidatIon resistance. However, fabricatIon of commercial components of these materials has been impeded by their poor mechanical properties at ambient temperatures. Significant efforts with various degrees of success have been made to improve the mechanical properties of these TiAl alloys by doping them with a variety of different elements including B, C, Cr, Er, Fe, Mn, Mo, Ni, Nb, P, Si, Ta, V and W. One of the optimum analytical tools for investigating the effects of these additIons on the microstructure is the atom probe Field Ion micro scope. However, relatively few studies of titanium aluminides, compared to some other intermetallic compounds, have performed by atom probe Field Ion Microscopy. This lack of attentIon can be attributed to the brittle nature of the material, in-situ transformatIons that occur during the Field Ion Microscopy and preferential evaporatIon problems that were encountered in some of the early studies. The atom probe Field Ion microscope used for the current experiments has a low base pressure ({approximately} 2 {times} 10{sup 9} Pa) and careful attentIon was paid to optimizing the experimental parameters. All the examples shown were obtained from specimens prepared by standard electropolishing techniques. To demonstrate the suitability of the technique to these materials, several different titanium aluminides have been characterized in the atom probe.

  • simulated electron beam trajectories toward a Field Ion Microscopy specimen
    Applied Surface Science, 1993
    Co-Authors: D. J. Larson, P P Camus, T F Kelly
    Abstract:

    Abstract This article explores the conditIons under which a directed electron beam originating nearly normal to the specimen axis can be made to impact the near-apex regIon of a Field Ion Microscopy specimen in a high electric Field. Electron trajectories were calculated using a modified Runge-Kutta numerical method. The results indicate that an electron beam can be directed to a specimen under typical Field Ion Microscopy conditIons using two methods: by varying initial beam tilt (less than 60 mrad) or by translating the initial beam positIon relative to the specimen apex (less than 5 mm). The net focusing effect of the high electric Field on the electron beam can be treated, to first order, as an astigmatism and may be correctable by a post-lens deflectIon system.

T F Kelly - One of the best experts on this subject based on the ideXlab platform.

  • Field Ion Microscopy and Atom Probe Tomography of Metamorphic Magnetite Crystals
    2001
    Co-Authors: K. R. Kuhlman, T F Kelly, R. L. Martens, N. D. Evans, M.k. Miller
    Abstract:

    Magnetite has been analysed using Field Ion Microscopy (FIM) and Atom Probe Tomography (APT), highly attractive techniques for the nanoanalysis of geological materials despite the difficulties inherent in analyzing semiconducting and insulating materials. AdditIonal informatIon is contained in the original extended abstract.

  • simulated electron beam trajectories toward a Field Ion Microscopy specimen
    Applied Surface Science, 1993
    Co-Authors: D. J. Larson, P P Camus, T F Kelly
    Abstract:

    Abstract This article explores the conditIons under which a directed electron beam originating nearly normal to the specimen axis can be made to impact the near-apex regIon of a Field Ion Microscopy specimen in a high electric Field. Electron trajectories were calculated using a modified Runge-Kutta numerical method. The results indicate that an electron beam can be directed to a specimen under typical Field Ion Microscopy conditIons using two methods: by varying initial beam tilt (less than 60 mrad) or by translating the initial beam positIon relative to the specimen apex (less than 5 mm). The net focusing effect of the high electric Field on the electron beam can be treated, to first order, as an astigmatism and may be correctable by a post-lens deflectIon system.