Beschreibung
The combined influence of grain orientation, cycle number and local strain amplitude on the dislocation structures during low cycle fatigue of austenitic stainless steel (AISI 316L) and aluminum single- and bi-crystals is studied. To this aim a novel approach which combines electron backscatter diffraction, digital image correlation and electron channeling contrast imaging is applied. This approach enables to systematically probe a large matrix of different parameters. Polycrystalline steel samples with three different double-slip orientations ( // LD, // LD, // LD) and three different multiple-slip orientations ( // LD, // LD, // LD) are cyclically deformed for 5, 30, 50 and 100 cycles. The dislocation structures are investigated for three local strain amplitudes of 0.35%, 0.65% and 0.95%. Three double-slip oriented aluminum single crystals ( // LD, // LD, // LD) are cycled for 50 and 100 cycles with a constant strain amplitude of 0.3-0.4%. The dislocation structures formed after 50 cycles in two aluminum bi-crystals are studied. It is observed that the local strain amplitude differs significantly from the average global strain amplitude in polycrystalline stainless steel samples, having a high influence on the formation of dislocation structures. A significant orientation-dependence of the dislocation structure evolution in cyclically deformed polycrystalline stainless steel samples is observed. Aluminum single- and bi-crystals form dislocation cell structures during LCF. Analysis of dislocation structures formed in cyclically deformed Al bi-crystals reveals that the respective grain orientations are of higher importance for dislocation structure formation than the grain boundary character.
Herstellerkennzeichnung:
Shaker Verlag GmbH
Am Langen Graben 15a
52353 Düren
DE
E-Mail: info@shaker.de
