Diffusion-induced dislocation loops were analyzed by means of large-angle convergent beam electron diffraction and conventional contrast methods of transmission electron microscopy. It was demonstrated that large-angle convergent beam electron diffraction was perfectly suited to analyzing dislocation loops. The method combined analyses of the dislocation-induced splitting of Bragg lines in a large-angle convergent beam electron diffraction pattern, for the determination of the Burgers vector, with analyses of the loop contrast behavior in transmission electron microscopic bright-field images during tilt experiments; from which the habit plane of the dislocation loop was determined. Perfect dislocation loops were found which were formed by the condensation of interstitial atoms or vacancies; depending upon the diffusion conditions. The loops possessed {110}-habit planes, and Burgers vectors parallel to <110>. The large-angle convergent beam electron diffraction findings were compared with the results of contrast analyses based upon the so-called inside–outside contrast of dislocation loops. The advantage of large-angle convergent beam electron diffraction was the possibility of determining the complete Burgers vector of the dislocation loops, and of unambiguous and fast loop-type analysis.

Analysis of Dislocation Loops by Means of Large-Angle Convergent Beam Electron Diffraction. C.Jäger, E.Spiecker, J.P.Morniroli, W.Jäger: Journal of Physics - Condensed Matter, 2002, 14[48], 12777-82