Abstract
The interfacial structure of Ni3Al-Ni3Cb directionally solidified eutectic composites has been investigated by transmission electron microscopy. These interfaces contain at least three distinguishable arrays of features. Two of the arrays, misfit dislocations, have been discussed previously by Nakagawa and Weatherly. The third set, ledges which can fulfill both structural and kinetic growth functions, may interact with the dislocation arrays through strain-energy mechanisms. The interaction is manifested both as a local alteration of the line vector of the dislocation in certain circumstances, and as a change in the response of the dislocation image to ±g electron-microscope image-contrast experiments. A simple model of the strain field of a ledge based on that of an edge dislocation is formulated to rationalize the behavior of a misfit dislocation lying in close proximity to a ledge. The interaction of ledges and dislocation segments is expected to have significance in physical processes of practical interest such as production of matrix slip dislocations, misfit dislocation rearrangement, boundary sliding, and coarsening, and these processes are discussed in some detail.
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Garmong, G., Rhodes, C.G. Interfacial ledge structures in Ni3 Al-Ni3Cb eutectic composites. Metall Trans A 6, 2209 (1975). https://doi.org/10.1007/BF02818645
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DOI: https://doi.org/10.1007/BF02818645