Discrete slip plane analysis of ferrite microtensile tests: Influence of dislocation source distribution and non-Schmid effects on slip system activity

Abstract

The slip system activity in microtensile tests of ferrite single crystals is compared with predictions made by the discrete slip plane model proposed by Wijnen et al. (2021) [24]. This is an extension of conventional crystal plasticity in which the stochastics and physics of dislocation sources are taken into account in a discrete slip band. It results in discrete slip traces and non-deterministic mechanical behavior, similar to what is observed in experiments. A detailed analysis of which slip systems are presumed to be active in experiments is performed. Non-Schmid effects are incorporated by extending a non-Schmid framework commonly used to model {110} slip to {112} planes. The slip activity in the simulations is compared to that in the tests. Conventional crystal plasticity fails to predict the diversity in active slip systems that is observed experimentally. The slip activity obtained with the discrete slip plane model is in much better agreement with the experiments. Including non-Schmid effects only entails minor differences. This suggests that stochastic effects dominate the behavior of ferrite crystals with dimensions in the order of a few micrometers and that non-Schmid effects may not play a large role.