Modeling of Microstructure Evolution in Process with Severe Plastic Deformation by Cellular Automata

摘要

Prediction of microstructure evolution and properties of ultrafine-grained materials is one of the most significant, current problems in materials science. Recently, an interest to apply the cellular automata (CA) to the simulation of different phenomena in materials has been rising constantly. The main asset of the CA is the ability for accurate modeling of the microstructure. Deformation in micro-scale shows anisotropy, which is related with the different crystallographic orientation of the grains in the polycrystalline material. To improve the accuracy of modeling, CA and FEM must be combined with crystal plasticity theory. In present model, deformation in macroscale is transferred to meso-scale, where a representative element contains several, score or hundreds grains, and then is applied in micro-scale to each grain. Strain and strain rate are decomposed into the crystallographic directions. For each crystallographic direction, development of dislocation and subgrain boundaries are considered. In each grain development of dislocation structure is distinctive because their orientation is unique. Creation of low-angle boundaries and their development into high-angle boundaries are simulated by the cellular automata on the base of calculations using finite element method and crystal plasticity theory. Some algorithms implemented into CA are described in the paper, as well as simulation results.