Model for partitioning slip patterns at triple junctions of grains

Abstract

A rate insensitive model based on interfacial compatibility of plastic strains is formulated to predict partitioning slip patterns in interaction of polyhedral grains at triple junctions. The model imposes macroscopic deformation on a skeleton of grain boundaries that, in turn, prescribes a particular common projection of plastic strains on both sides of any boundary facet. To accommodate three independent components of this projection, each of two adjacent domains deform with three slip systems. Unlike Taylor's model, such slip patterns at different facets of the same grain prove to be dissimilar and hence trigger the crystal orientation splitting near triple lines. For a case study of this phenomenon, the model applies to a grain junction of low deformed IF steel regardless of slip patterns in grain cores. Allowance for the latter is finally discussed that will be indispensable for the model extension to entire grains and, eventually, the entire polycrystal.