Journal article
Dislocation boundary formation in a cold-rolled cube-oriented Al single crystal
Crystallite orientations in a high-purity cube-oriented Al single crystal deformed 30% by cold rolling have been measured using EBSP and TEM diffraction methods. The deformed crystal is subdivided into macroscopic bands parallel to the rolling plane, and dislocation cells and cell blocks at the microscopic scale.
At both scales, crystallite rotations are predominantly about the traverse direction (TD). A Schmid factor analysis of plane strain compression revealed that four slip systems are active during deformation. The critical slip systems form two codirectional pairs, i.e. the Burgers vector is the same for the two systems that comprise a pair.
The analysis further reveals that, in a cube-oriented crystal subject to plane strain compression, TD rotations can be produced by a shear amplitude imbalance between the pairs of codirectional critical slip systems; this shear amplitude imbalance does not introduce strain incompatibility. The shear amplitude inbalance needed to produce the observed crystallite rotations at the dislocation cell scale is about 20% of the average shear amplitude on a single slip system.
A model for constructing boundaries between crystallite pairs from the dislocations that participate in the deformation process yields boundaries that exactly accommodate the crystal rotations associated with the shear amplitude imbalance between the crystallites. In a cube-oriented crystal, this boundary construction process does not limit the orientation of allowable boundary planes.
Language: | English |
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Year: | 1997 |
Pages: | 2565-2576 |
ISSN: | 18732453 and 13596454 |
Types: | Journal article |
DOI: | 10.1016/S1359-6454(96)00348-5 |