Numerical study of localized plastic deformation in polycrystals

A finite element formulation which derives constitutive response form crystal plasticity theory was used to examine localized deformation in fcc polycrystals. The polycrystal model was an idealized planar array of 22 hexagonal grains. The constitutive description used is based on a finite strain kinematical theory that accounts for lattice rotations. Formation of shear bands was successfully modeled in both single crystal and polycrystals. Stress and strain distributions around triple junctions were also analyzed. Results show the distributions of stress and strain are distinctly inhomogeneous. Stress and strain fields across grain boundaries are highly discontinuous. However, this discontinuity will be restrained when shear bands are fully developed.