Moving boundaries in polycrystals-lattice curvature effects

We model polycrystals as Cosserat continua and focus on the three independent mechanisms working at the boundary of grains: glide, growth (progression of the discontiniuty front), and relative rotation of lattices. We propose a criterion and a flow rule for the three mentioned phenomena, then we introduce some costitutive assumptions and derive some new results on the relative spin of contiguous lattices.