No abstract available

[en] This volume of the Treatise on Materials Science and Technology shows how neutron scattering methods can be used to obtain important information on materials, by guiding the reader through the principles and describing recent applications. Materials scientists, but also solid state physicists, physical chemists, and metallurgists interested in this field, will find a completely referenced survey of the ''classical topics'' of neutron scattering and a more detailed presentation of methods and techniques that are more specifically related to materials science. After a brief review of the general principles in the first chapter, subsequent chapters concentrate on particular methods and problems. The techniques used in neutron crystallography are presented, and selected applications of nuclear and magnetic scattering are discussed. The measurement of phonons, their role in phase transformations, and their behavior in the presence of crystal defects are considered, and quasi-elastic scattering is given detailed treatment. The methods of small-angle scattering and diffuse scattering have been developed to a considerable perfection in recent years and are presented in detail. The structure and dynamics of hydrogen dissolved in metals and the conformation and dynamics of polymers are two outstanding subjects to which neutron scattering has contributed so much in recent years that separate chapters are devoted to covering these fields. Finally, the choice of the appropriate materials is also becoming increasingly crucial in the design and construction of neutron spectrometers. Therefore, the last chapter deals with special materials problems in neutron devices

No abstract available

[en] Guinier-Preston (GP) zones in Al-3 at.% Ag were studied by high-resolution Z-contrast scanning transmission electron microscopy. The favorable atomic number (Z)-contrast of Ag atoms dissolved in Al and the limited delocalization of the object information by the imaging process allow nanometer-sized Ag-rich pre-precipitates to be analyzed, even on an atomic level. GP zones with a diameter of about 3 nm in Al-3 at.% Ag aged for 15 h at 105 deg. C, for 4 h at 140 deg. C and for 3 min at 180 deg. C reveal a common structural feature. The zones consist of a Ag-rich shell and a Ag-depleted core. This result confirms previous conclusions based on small-angle X-ray scattering and neutron scattering

No abstract available

[en] The microstructure of Ni-11.3 at.% Ti single crystals was investigated after quenching from the solid solution at 1440 K and after ageing at 873 K for various periods of time by using transmission electron microscopy and X-ray scattering near fundamental reflections and superstructure reflections of the ordered precipitates. The two-stage decomposition sequence with the initial formation of metastable γ'' precipitates followed by metastable γ' precipitates as found by small-angle neutron scattering is confirmed. The long-range order parameter of these precipitates is always close to the maximum value achievable at a given composition. The presence of the first metastable state (γ'') is related to a rearrangement of the precipitates on a macro-lattice in order to minimize the elastic energy due to coherency strains

[en] The incoherent imaging model is applied to interpret high-resolution Z-contrast micrographs. A simple method for a column-by-column resolved characterisation of Ag-rich precipitates in Al-Ag is developed. No information on the detailed imaging process is required. Evaluating the high-angle scattering intensities of Al and Ag by image analysis, the number of Ag atoms contained in individual atomic columns can be determined accurately and moreover, the thickness of the thin foil can be calculated. Multislice simulations confirm the broad validity of the incoherent imaging model for Z-contrast STEM and are used to check the method presented. Finally, the image analysis is applied to experimental Z-contrast images of Guinier-Preston zones in Al-3 at% Ag. The Ag content of the individual atomic columns can be determined with an accuracy better than ±10%

[en] Recent applications of small angle neutron scattering techniques in the study of small-scale (1 nm - 1 μm) inhomogeneities and microstructural changes in metals and alloys are reviewed. Results on the kinetics of phase separation and defect agglomeration and on the size, shape and arrangement of precipitates, dispersed phases and deformation- or radiation-induced voids and cavities are summarized. (author) 90 refs., 11 figs

No abstract available

[en] Scattering experiments are helpful to locate phase transformations. There are classical methods (e.g. powder diffraction) and very sophisticated recent techniques (e.g. quasi-elastic neutron scattering) to study transformations and phase separation in metallic systems. Some examples are discussed. Much space, however, is devoted to studies of inhomogeneities, i.e. deviations from the average structure (point defects, clusters, short-range order, precipitates, etc.). Some remarks on scattering from crystalline materials containing defects are followed by a discussion of X-rays and neutrons as the two types of radiation now commonly used for scattering studies of essentially bulk materials. (Auth.)