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Misfit Dislocations at Metal/Ceramics Interfaces

Published online by Cambridge University Press:  21 February 2011

G. Gutekunst
Affiliation:
Max-Planck-Institut für Metallforschung, Institut für Werkstoffwissenschaft, Seestr. 92 D-70174 Stuttgart, Germany
J. Mayer
Affiliation:
Max-Planck-Institut für Metallforschung, Institut für Werkstoffwissenschaft, Seestr. 92 D-70174 Stuttgart, Germany
M. RÜHle
Affiliation:
Max-Planck-Institut für Metallforschung, Institut für Werkstoffwissenschaft, Seestr. 92 D-70174 Stuttgart, Germany
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Abstract

The atomistic structure of the coherent regions of Nb/A12O3-interfaces of various substrate orientations have been determined by high-resolution electron microscopy (HREM). The substrate surfaces were parallel to (0001)A12O3, (0110)A12O3, (2110)A12O3 and (0112)A12O3. In all cases, the Al sublattice of the A12O3 substrate is continued in the first Nb layer at the interface. This principle results in the unique orientation relationship.

The Burgers vectors of the misfit dislocations and the geometry of the dislocation network of all Nb/A12O3-interfaces have been determined by HREM. All Burgers vectors are lattice vectors. Thus no coherent regions with different atomistic structures are found. The Burgers vectors are of the type 1/2<111>. These Burgers vectors correspond to the Burgers vector of bulk dislocations. All Burgers vector components which do not accommodate the lattice mismatch are compensated in the networks. The network geometry is rectangular for the following interface planes: (0110)A12O3||(112)Nb (orientation 2) and (0112)A12O3||(001)Nb. If the interface is parallel to (0001)A12O3 and (111)Nb the geometry is rhombic.

The core structure of misfit dislocations of orientation 2 with line direction ξ1=[110] are calculated with an atomistic model and a continuum approach. The calculated core structures are in good agreement with the experimental HREM-micrographs of misfit dislocations of orientation 2.

Type
Research Article
Copyright
Copyright © Materials Research Society 1994

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References

1) Rühle, M., Heuer, A. H., Evans, A. S. and Ashby, M. F., Proc. Int. Symp. Metal/Ceramic interfaces, Supplement Acta Met. Mater. 40, S1–S368 (1992)Google Scholar
2) Durbin, S. M., Cunningham, J. E., Mochel, M. E., Flynn, C. P., J. Phys. F. 11, L223 (1981)CrossRefGoogle Scholar
3) Mayer, J., Flynn, C. P., Rüihle, M., Ultramicroscopy 33, 51 (1990)Google Scholar
4) Mayer, J., Gutekunst, G., Möbus, G., Dura, J., Flynn, C. P.. Riihle, M., Acta Met. Mater. 40, S217 (1992)Google Scholar
5) Strecker, A., Salzberger, U., Rtihle, M., Prakt. Metallogr. 3(10), 481 (1993)Google Scholar
6) Gutekunst, G., Ph.D. Thesis, University Stuttgart 1993 Google Scholar
7) Bourret, A., J. de Physique, 46 C427 (1985)Google Scholar
8) Vitek, V., to be publishedGoogle Scholar
9) Gutekunst, G., Mayer, J., Vitek, V. and Riihle, M., to be publishedGoogle Scholar
10) Kamet, S.V., Hirth, J. P., Carnahan, B., Mater. Res. Soc. Symp. Proc. 102, 55 (1988)Google Scholar
11) Mader, W., Z. Metallkunde 80, 139 (1989)Google Scholar
12) Raj, R., Ernst, F., Gutekunst, G., Mader, W., Mayer, J., Trampert, A. and Riihle, M., to be publishedGoogle Scholar
13) Thinioshenko, S. P., Goodier, J. N., Theory of Elasticity, McGraw Hill (1970)Google Scholar
14) krüse, C., Finnis, M. W., Milmar, V. Y., Payne, M. C., Vita, A. De, Gillan, M. J., J. Amer. Cer. Soc. 77(1994), in pressGoogle Scholar