A novel method of geometrical analysis, based upon transmission electron microscopic measurements, was developed for determining the 3-dimensional orientations of extended planar dislocation boundaries in polycrystals. The analysis was applied to data for tensile-deformed Al, and revealed that the boundaries had a strong preference for certain crystallographic planes; depending upon the crystallographic orientation of the grain. The crystallographic boundary planes were distributed around, but did not coincide with, the most stressed macroscopic planes - which were inclined at 45º to the tensile axis. A strong correlation between the crystallographic boundary planes and the grain orientation showed that the boundary orientation was closely linked to the active slip systems. The observed correlation could be explained by means of a Schmid factor analysis which assumed that activity occurred on the 5 most stressed slip systems.

Crystallographic and Macroscopic Orientation of Planar Dislocation Boundaries - Correlation with Grain Orientation. G.Winther, X.Huang, N.Hansen: Acta Materialia, 2000, 48[9], 2187-98