In situ micro-Laue diffraction was used to study the plasticity in three 7μm, initially identical, single-crystalline Cu pillars during compression. Movements of the Laue spot as well as Laue spot streaking were analyzed to obtain real-time insights into the storage of excess dislocations and the possible formation of dislocation cell structures. The results revealed that instrumental constraints lead to dislocation storage at the sample base and top, but will not affect the storage of excess dislocations in the sample center in case of an ideal alignment. In contrast, misaligned samples showed early yielding due to the activation of an unpredicted slip system, storage of excess dislocations also in the sample center and, at a later stage, the formation of a complex dislocation substructure.

Impact of Instrumental Constraints and Imperfections on the Dislocation Structure in Micron-Sized Cu Compression Pillars. C.Kirchlechner, J.Keckes, C.Motz, W.Grosinger, M.W.Kapp, J.S.Micha, O.Ulrich, G.Dehm: Acta Materialia, 2011, 59[14], 5618-26