Abstract
A multiscale model on dislocation patterning of cell structure and subgrain for polycrystal is newly developed on the basis of reaction-diffusion theory. We introduce a threshold value of slip for stage transition corresponding to the initial crystal orientation into a dislocation mean free path model so as to express the dependence of three-stage hardening on the initial crystal orientation of each grain. A FD simulation for dislocation patterning and a FE one for crystal deformation are simultaneously carried out for a FCC polycrystal under severe strain condition. Reflecting stress value on stress-effect coefficients, it is numerically predicted that the evolution of dislocation pattern in a polycrystal is different in response to the stress condition of each grain. Moreover, the formation of GN boundaries with large misorientation angle is observed along subgrain walls due to large deformation.
