Grain Boundary Accumulation of Geometrically Necessary Dislocations and Asymmetric Deformations in Compatible Bicrystals with Tilted Angle Grain Boundary under Tensile Loading

Slip deformation in compatible bicrystal models with a tilted angle grain boundary subjected to tensile load is investigated using a finite element crystal plasticity analysis code. The accumulation of geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) is studied in detail. Uniform deformation was expected to occur because the mutual constraint of crystal grains through the grain boundary plane does not occur in compatible bicrystals, but some results of the analysis show asymmetric deformation with the accumulation of GNDs near the grain boundary caused by the difference in 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 bands. The mechanism of dislocation pattern formation in the bicrystals with a tilted angle grain boundary is discussed from the viewpoint of an imaginary disclination deformation field with pair body interaction.