Crystal Plasticity Analysis of Non-uniform Deformation in Symmetric Type Bicrystals under Tensile Load and Formation of Geometrically Necessary Dislocation Bands

Abstract

Slip deformation in symmetric type bicrystal models subjected to tensile load is analyzed by a finite element crystal plasticity analysis code and accumulation of geometrically necessary dislocations (GNDs) is 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 symmetric type bicrystals, but, some results of the analysis show non-uniform deformation and the high density of GNDs accumulated in the form of band. Such kind of non-uniform deformation is observed regardless of the model size and the strain-hardening characteristics. Mechanism of non-uniform deformation and accumulation of GNDs in the form of band in the symmetric type bicrystals is discussed from the viewpoint of the boundary condition and shape change of grains after slip deformation