Lattice Imaging of Grain Boundary Precipitation Reactions

Materials and Molecular Research Division, Lawrence Berkeley Laboratory and Department of Materials Science and Mineral Engineering, University of California, Berkeley, California 94720.Grain boundaries are known to catalyze a wide variety of solid state phase transformations which drastically affect metallurgical properties. The study of these reactions has traditionally required transmission electron microscopy, particularly when the transformation products are only partially developed. In the present paper, an application of lattice fringe imaging to the study of grain boundary reactions in Al-Zn alloys is described. The technique has proven to be far superior to conventional TEM methods in providing information on not only the detailed structural configuration of lattice planes at boundaries, but also the compositional changes, to within ∽10Å of the boundary plane, accompanying the transformations.

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Transmission Electron Microscopy Study on the Grain Boundary Precipitation of an Fe-Ni-Mn Maraging Steel

Metallurgical and Materials Transactions A ◽

10.1007/s11661-007-9407-z ◽

2007 ◽

Vol 39 (1) ◽

pp. 19-27 ◽

Cited By ~ 23

Author(s):

S. Hossein Nedjad ◽

M. Nili Ahmadabadi ◽

T. Furuhara

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Grain Boundary ◽

Maraging Steel ◽

Microscopy Study ◽

Electron Microscopy Study ◽

Transmission Electron Microscopy Study ◽

Transmission Electron ◽

Boundary Precipitation ◽

Grain Boundary Precipitation

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Transmission Electron Microscopy Studies of Grain Boundary Precipitation in Spinodally Decomposed Cu-Ni-Fe Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005250x ◽

1974 ◽

Vol 32 ◽

pp. 498-499

Author(s):

R. Gronsky

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Grain Boundary ◽

Grain Boundaries ◽

Miscibility Gap ◽

Phase Identification ◽

Transmission Electron ◽

Boundary Precipitation ◽

Binary Section ◽

Grain Boundary Precipitation

In many alloy systems the grain boundaries play an important role in controlling properties but little is known about the mechanism of grain boundary precipitation reactions. Transmission electron microscopy and diffraction are necessary to distinguish reactions such as discontinuous precipitation and preferential coarsening. The present paper describes current progress on the Cu-Ni-Fe system which is known to be embrittled at the grain boundaries. Two alloys are considered, having their compositions on a binary section through the Cu-Ni-Fe ternary with terminal values at the Cu corner and the point Ni0.7Fe0.3. Alloy A(51.5 at % Cu-33.5 at % Ni-15 at % Fe) lies very near to the center of the miscibility gap. Phase identification in the electron micrographs is facilitated by comparison with alloy B (69.3 at % Cu-19.4 at X Ni-11.1 at % Fe) of asymmetrical composition. The microstructure shown in Fig. 1 results from aging alloy B within the spinodal (650°C) for 10 hrs.

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Application of Lattice Imaging Techniques to Amorphous Films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113664 ◽

1975 ◽

Vol 33 ◽

pp. 8-9

Author(s):

S. R. Herd ◽

P. Chaudhari

Keyword(s):

Nearest Neighbor ◽

Random Network ◽

Imaging Techniques ◽

Network Models ◽

Accurate Method ◽

Direct Transmission ◽

Lattice Imaging ◽

Transmission Electron ◽

Lattice Planes ◽

Nearest Neighbor Distances

Electron diffraction and direct transmission have been used extensively to study the local atomic arrangement in amorphous solids and in particular Ge. Nearest neighbor distances had been calculated from E.D. profiles and the results have been interpreted in terms of the microcrystalline or the random network models. Direct transmission electron microscopy appears the most direct and accurate method to resolve this issue since the spacial resolution of the better instruments are of the order of 3Å. In particular the tilted beam interference method is used regularly to show fringes corresponding to 1.5 to 3Å lattice planes in crystals as resolution tests.

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