Crystal plasticity finite-element simulation on development of dislocation structures in BCC ferritic single crystals

Abstract

The role of {112} slip activity on the deformation of bcc ferritic single crystals with different crystallographic orientations was studied numerically using a crystal plasticity finite-element method. Peeters model [Peeters et al., Acta Mater., 49 (2001), 1607] was utilized to predict development of dislocation structures as well as work-hardening behavior. To examine the effect of the {112} slip activity in detail, the simulation was carried out using original Peeters model in which development of cell-block boundaries (CBBs) along the {112} planes was not taken into account, Peeters model in which development of CBBs along the {112} planes was taken into account (extended-1 model), and Peeters model in which {112} slip activity was not taken into consideration (extended-2 model). The predicted stress-strain curves were in qualitatively good agreement with the experimental results for all cases when the original and extended-1 models were used, whereas two-stage work hardening observed for the crystal with {100} <011> was not predicted when the extended-2 model was used. Concerning development of CBBs, the extended-1 and extended-2 models gave better prediction as compared to the original model. The abovementioned results suggested that the extended-1 model gave the most appropriate predictions among the models in terms of work-hardening behavior and development of CBBs, showing that it was more reasonable to take into account both {110} and {112} slip systems and development of CBBs along not only the {110} planes but also the {112} planes.