Modelling the Bauschinger effect in copper during preliminary load cycles

Abstract

This research utilizes established cyclic deformation models to simulate the Bauschinger effect observed in copper monocrystal cantilever experiments during the initial bending and straightening phases. Crystal plasticity finite element simulations employing Armstrong-Frederick, Orowan-Sleeswyk, and various other backstress models have drawbacks to reproduce the experimental force–displacement curves accurately since they are not able to reproduce the isotropic hardening measured during cantilever straightening. However, the Armstrong-Frederick model combined with Voce-type hardening and a newly proposed modified Orowan-Sleeswyk model has proven to be effective. In this work, we propose a modified Orowan-Sleeswyk model, based on recent studies, where not all the geometrically necessary dislocations (GND) recombine during the straightening phase, but instead reorient to achieve a net zero-strain gradient with ongoing hardening during load reversal.