On the reversibility of dislocation slip during small scale low cycle fatigue

C. Kirchlechner (1, 2) , P. J. Imrich (3) , W. Liegl (3) , J. Poernbacher (2) , Jean-Sébastien Micha (4) , Olivier Ulrich (5) , C. Motz (6)

1 Max-Planck-Institut für Eisenforschung GmbH
2 MUL - Montanuniversität Leoben
3 OeAW - Austrian Academy of Sciences
4 PCI - Polymères Conducteurs Ioniques
5 NRS - Nanostructures et Rayonnement Synchrotron
6 Saarland University [Saarbrücken]

The evolution of low cycle fatigue damage in copper is studied by in situ micro Laue diffraction. Free standing single crystalline micro-cantilevers with a cross-section of 10 x 10 mu m(2) were loaded in displacement controlled mode with a surface strain amplitude up to 5%. The point to point misorientation and the diffraction peak width as a measure of geometrically necessary dislocation density was analyzed locally during deformation and globally after 0, 1/4, 1/2, 3/4, 1 and multiples up to a maximum of 22 full cycles. Two different behaviors were observed (i) samples geometrically suppressing cross-slip show a steady state deformation pattern with dislocations in a pile-up. (ii) The sample with cross-slip does not reach a steady state with dislocations accumulating at the neutral plane. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Mots clés: Size effect; Synchrotron diffraction; Micromechanics; Fatigue; Thin Cu Films; Laue Diffraction; Length-Scale; Plasticity; Microdiffraction; Compression; Tensile

Domaines: Physique [physics]

C. Kirchlechner, P. J. Imrich, W. Liegl, J. Poernbacher, Jean-Sébastien Micha, et al.. On the reversibility of dislocation slip during small scale low cycle fatigue. Acta Materialia, 2015, 94, pp.69-77. ⟨10.1016/j.actamat.2015.04.029⟩. ⟨hal-01615210⟩