A numerical study of localized plastic deformation in polycrystals

A finite element formulation which derives constitutive response from cryst al plasticity theory was used to examine localized deformation in fee polyc rystals. The polycrystal model was an idealized planar array of 22 hexagona l grains. The constitutive description used is based on a finite strain kin ematical theory that accounts for lattice rotations. Formation of shear ban ds was successfully modeled in both single crystal and polycrystals. Stress and strain distribution around triple junctions was also analyzed. Results show the distributions of stresses and strains are distinctly inhomogeneou s. Stress and strain fields across grain boundaries are highly discontinuou s. However, this discontinuity will be restrained when shear bands are full y developed.