Crystallographic and macroscopic orientation of planar dislocation boundaries - Correlation with grain orientation

A novel geometric analysis method for determination of the three-dimensiona l orientation of extended planar dislocation boundaries in polycrystals bas ed on TEM measurements is presented. The analysis is applied to data for te nsile deformed aluminium, revealing that the boundaries have a strong prefe rence for certain crystallographic planes, depending on the crystallographi c orientation of the grain. The crystallographic boundary planes are distri buted around, but do not coincide with, the most stressed macroscopic plane s inclined 45 degrees to the tensile axis. The strong correlation between t he crystallographic boundary planes and the grain orientation shows that th e boundary orientation is closely linked to the active slip systems. The ob served correlation can be explained by a Schmid factor analysis assuming ac tivity on the five most stressed slip systems. (C) 2000 Acta Metallurgica I nc. Published by Elsevier Science Ltd. All rights reserved.