Grain Boundary Accumulation of Geometrically Necessary Dislocation and Asymmetric Deformation in Compatible-type Bicrystals with Tilt Angle Grain Boundary under Tensile Loading

Slip deformation in compatible type bi-crystal models with tilt angle grain boundary subjected to tensile load is investigated by a finite element crystal plasticity analysis code. Accumulation of geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) are studied in detail. Uniform deformation was expected to take place because mutual constraint of crystal grains through the grain boundary plane does not occur in compatible-type bicrystals, but some results of the analysis show asymmetric deformation with accumulation of GNDs near the grain boundary caused by difference of strain hardening of slip systems, kink bands perpendicular to the primary slip direction and secondary slip bands parallel to the primary slip plane with accumulation of GNDs on the primary slip system in the form of band. Mechanism of dislocation pattern formation in the bicrystals with tilt angle grain boundary is discussed from the viewpoint of imaginary disclination type deformation field with pair body interaction