Academic literature on the topic 'Atom probe crystallography'

Electron scattering, significantly stronger than that for X-rays, is sensitive to surfaces and small volumes of materials. Low-energy electron diffraction (LEED) provides information on surface reconstruction and the arrangement of adsorbed atoms. Reflection high energy electron diffraction (RHEED) probes surface crystallography, and monitors, in situ, mechanisms of thin film growth. Transmission electron diffraction reveals a planar cross-section of the reciprocal lattice, where intensities are products of the structure and lattice amplitude factors determined by the overall shape of the specimen. The amplitude of any diffracted beam at the exit surface oscillates with thickness (fringes) and the excitation error (bend contours). Selected area diffraction produce spot or ring patterns, where low-index zone-axis orientations reflect the symmetry of the crystal, and double-diffraction shows positive intensities even for reflections forbidden by extinction rules. Kikuchi lines appear as pairs of dark and bright lines, and help in tilting the specimen. A focused probe produces convergent beam electron diffraction (CBED), useful for symmetry analysis at nanoscale resolution. Neutrons interact with the nucleus and the magnetic moment of the atom via the spin of the neutron; the latter finds particular use in studies of magnetic order. The atomic scattering factor for neutrons shows negligible angular dependence.

This article provides a guideline for selection of analytical methodologies for aluminum precipitates. These methodologies include: crystallographic structure, precipitate size, volume fraction, atom probe tomography, compositional chemistry, precipitation sequence, second phase particle characterization, and geometrical information analysis.

The technique of helium atom scattering is intrinsically very sensitive to all types of surface defects. With dynamic sensitivites of order 105, or more, one is able to observe and characterise very low densities of either point[1] or linear type defects[2]. The diffuse elastic scattering from isolated step edge defects, for example, is able to give detailed information about the characteristic shape of a step edge, as observed by the thermal energy He probe[3]. The linear nature of a step edge ensures that the intensity is scattered predominately along certain crystallographic azimuths. The l

The effect of oxygen partial pressure on fatigue and SCC growth rates in alloy 617 has been studied using both static and fatigue loading @ 650°C over the oxygen partial pressure range 10−19–10−2 atm. Tests were conducted at either constant stress intensity factor, K, for static conditions or constant ΔK in fatigue. Oxygen concentration was measured on both the inlet and outlet as well as in-situ with a probe located directly at the specimen surface. For fatigue loading the crack path was observed to be transgranular but crystallographic with a decreasing growth rate as the oxygen concentratio

Tribological performance of sub-nano to nanometer-thick Ag layers deposited on Si(111) have been examined to understand the role of surface thin layers to the wear and friction characteristics. The slider was made of diamond sphere of 3 mm in radius. Sliding tests were carried out in an ultra-high vacuum environment (lower than 4 × 10−8 Pa) and analyzed in-situ by Auger electron spectroscopy (AES) for the quantitative thickness-measurements, by reflection high-energy electron diffraction (RHEED) to clarify the substrate cleanliness and crystallography of the Ag films, and by scanning probe mic