The dislocation configurations in compression-tested single crystals were studied by means of transmission electron microscopy. The dislocations were found to be of edge or near-edge character, and to form dipoles. This agreed with observations of other face-centered cubic Cu-based solid solutions that had been deformed into stage I. It was noted that the small L12 long-range ordered antiphase domains in this alloy could not couple 2 dislocations with identical a/2<110> Burgers vectors so as to form a pair. In fully L12 ordered materials, with large antiphase domains, such pairs of identical dislocations were normal. The separation of the two a/2<110> edge dislocations which formed a pair in fully L12 ordered Cu3Au was about 18nm. As this separation was expected to be proportional to the reciprocal of the square of the L12 long-range order parameter, it was estimated that the separation of the 2 identical a/2<110> edge dislocations of a pair in Cu-10at%Au whose L12 order parameter equalled 0.238 (and which contained no antiphase boundaries) would be about 320nm. This was some 60 times as large as the actual size of the antiphase domains in the present single crystals, and explained why there were no pairs of identical a/2<110> dislocations.

Dislocation Configurations in Ordered Copper-10at%Gold Solid Solutions H.Rösner, O.Kuhlmann, E.Nembach: Materials Science and Engineering A, 1998, 242, 296-8