MONTE-CARLO SIMULATION OF RECRYSTALLIZATION

초록

Two-dimensional Monte-Carlo simulation code for recrystallization phenomenon in hcp polycrystals was developed on the basis of Q-state Potts model. In order to verify the validity of the simulation the grain boundary character distribution characteristics of pure Ti during recrystallization were studied. Commercial pure Ti (CP-Ti) was deformed by cold rolling at room temperature up to 90% in thickness reduction. Recrystallization heat treatment was conducted at 600℃ for various time periods. The initial stage of recrystallization was monitored by OM, EBSD and XRD. For simulation, the initial computer microstructure was composed of the orientation imaging microscopy (OIMTM) obtained by EBSD from which the image quality (IQ) values for local deformed areas could be quantified. Strain induced boundary migration model was used for the computer simulation, where the orientation of the recrystallized grain adopts that of the neighboring grain of less stored plastic strain. Topographical morphology of nucleated grains, distribution of grain boundary misorientation angles, as well as the texture of the specimen were predicted by the simulation and compared with the experimental results. Despite some uncertainties associated with the crystal orientation in the regions of highly localized strains a reasonable agreement in the qualitative evolution characteristics of the recrystallized microstructure could be obtained between the experiment and the computer simulation.